Issue #1258 - Part 1: Import mailnews, ldap, and mork from comm-esr52.9.1

26 files changed, 12592 insertions, 0 deletions

diff --git a/mailnews/db/msgdb/moz.build b/mailnews/db/msgdb/moz.build
new file mode 100644
index 000000000..27dcb8746
--- /dev/null
+++ b/mailnews/db/msgdb/moz.build
@@ -0,0 +1,9 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DIRS += [
+    'public',
+    'src',
+]
diff --git a/mailnews/db/msgdb/public/moz.build b/mailnews/db/msgdb/public/moz.build
new file mode 100644
index 000000000..9bf74e1d6
--- /dev/null
+++ b/mailnews/db/msgdb/public/moz.build
@@ -0,0 +1,27 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPIDL_SOURCES += [
+    'nsIDBChangeAnnouncer.idl',
+    'nsIDBChangeListener.idl',
+    'nsIDBFolderInfo.idl',
+    'nsIMsgDatabase.idl',
+    'nsIMsgOfflineImapOperation.idl',
+    'nsINewsDatabase.idl',
+]
+
+XPIDL_MODULE = 'msgdb'
+
+EXPORTS += [
+    'nsDBFolderInfo.h',
+    'nsImapMailDatabase.h',
+    'nsMailDatabase.h',
+    'nsMsgDatabase.h',
+    'nsMsgDBCID.h',
+    'nsMsgHdr.h',
+    'nsMsgThread.h',
+    'nsNewsDatabase.h',
+]
+
diff --git a/mailnews/db/msgdb/public/nsDBFolderInfo.h b/mailnews/db/msgdb/public/nsDBFolderInfo.h
new file mode 100644
index 000000000..9b3a51348
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsDBFolderInfo.h
@@ -0,0 +1,135 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* This class encapsulates the global information about a folder stored in the
+	summary file.
+*/
+#ifndef _nsDBFolderInfo_H
+#define _nsDBFolderInfo_H
+
+#include "mozilla/MemoryReporting.h"
+#include "nsStringGlue.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+#include "nsTArray.h"
+#include "nsIDBFolderInfo.h"
+#include <time.h>
+
+class nsMsgDatabase;
+
+// again, this could inherit from nsISupports, but I don't see the need as of yet.
+// I'm not sure it needs to be ref-counted (but I think it does).
+
+// I think these getters and setters really need to go through mdb and not rely on the object
+// caching the values. If this somehow turns out to be prohibitively expensive, we can invent
+// some sort of dirty mechanism, but I think it turns out that these values will be cached by 
+// the MSG_FolderInfo's anyway.
+class nsDBFolderInfo : public nsIDBFolderInfo
+{
+public:
+  friend class nsMsgDatabase;
+  
+  nsDBFolderInfo(nsMsgDatabase *mdb);
+  
+  NS_DECL_ISUPPORTS
+    // interface methods.
+    NS_DECL_NSIDBFOLDERINFO
+    // create the appropriate table and row in a new db.
+    nsresult			AddToNewMDB();
+  // accessor methods.
+  
+  bool      TestFlag(int32_t flags);
+  int16_t   GetIMAPHierarchySeparator() ;
+  void      SetIMAPHierarchySeparator(int16_t hierarchyDelimiter) ;
+  void      ChangeImapTotalPendingMessages(int32_t delta);
+  void      ChangeImapUnreadPendingMessages(int32_t delta) ;
+  
+  nsresult      InitFromExistingDB();
+  // get and set arbitrary property, aka row cell value.
+  nsresult SetPropertyWithToken(mdb_token aProperty, const nsAString &propertyStr);
+  nsresult SetUint32PropertyWithToken(mdb_token aProperty, uint32_t propertyValue);
+  nsresult SetInt64PropertyWithToken(mdb_token aProperty, int64_t propertyValue);
+  nsresult SetInt32PropertyWithToken(mdb_token aProperty, int32_t propertyValue);
+  nsresult GetPropertyWithToken(mdb_token aProperty, nsAString &propertyValue);
+  nsresult GetUint32PropertyWithToken(mdb_token aProperty, uint32_t &propertyValue, uint32_t defaultValue = 0);
+  nsresult GetInt32PropertyWithToken(mdb_token aProperty, int32_t &propertyValue, int32_t defaultValue = 0);
+  nsresult GetInt64PropertyWithToken(mdb_token aProperty,
+                                     int64_t &propertyValue, int64_t defaultValue = 0);
+
+  nsTArray<nsMsgKey> m_lateredKeys; // list of latered messages
+
+  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return m_lateredKeys.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  }
+  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+protected:
+  virtual ~nsDBFolderInfo();
+
+  // initialize from appropriate table and row in existing db.
+  nsresult InitMDBInfo();
+  nsresult LoadMemberVariables();
+
+  nsresult AdjustHighWater(nsMsgKey highWater, bool force);
+
+  void ReleaseExternalReferences(); // let go of any references to other objects.
+
+  int64_t   m_folderSize;
+  int64_t   m_expungedBytes; // sum of size of deleted messages in folder
+  uint32_t  m_folderDate;
+  nsMsgKey  m_highWaterMessageKey; // largest news article number or imap uid whose header we've seen
+
+  //  m_numUnreadMessages and m_numMessages can never be negative. 0 means 'no msgs'.
+  int32_t   m_numUnreadMessages;
+  int32_t   m_numMessages;    // includes expunged and ignored messages
+
+  int32_t   m_flags;  // folder specific flags. This holds things like re-use thread pane,
+  // configured for off-line use, use default retrieval, purge article/header options
+
+  uint16_t    m_version;                // for upgrading...
+  int16_t     m_IMAPHierarchySeparator;	// imap path separator
+  
+  // mail only (for now)
+  
+  // IMAP only
+  int32_t     m_ImapUidValidity;
+  int32_t     m_totalPendingMessages;
+  int32_t     m_unreadPendingMessages;
+  
+  // news only (for now)
+  nsMsgKey    m_expiredMark;		// Highest invalid article number in group - for expiring
+  // the db folder info will have to know what db and row it belongs to, since it is really
+  // just a wrapper around the singleton folder info row in the mdb. 
+  nsMsgDatabase *m_mdb;
+  nsIMdbTable   *m_mdbTable;	// singleton table in db
+  nsIMdbRow     *m_mdbRow;	// singleton row in table;
+
+  nsCString     m_charSet;
+  bool          m_charSetOverride;
+  bool          m_mdbTokensInitialized;
+  
+  mdb_token     m_rowScopeToken;
+  mdb_token     m_tableKindToken;
+  // tokens for the pre-set columns - we cache these for speed, which may be silly
+  mdb_token     m_mailboxNameColumnToken;
+  mdb_token     m_numMessagesColumnToken;
+  mdb_token     m_numUnreadMessagesColumnToken;
+  mdb_token     m_flagsColumnToken;
+  mdb_token     m_folderSizeColumnToken;
+  mdb_token     m_expungedBytesColumnToken;
+  mdb_token     m_folderDateColumnToken;
+  mdb_token     m_highWaterMessageKeyColumnToken;
+  
+  mdb_token     m_imapUidValidityColumnToken;
+  mdb_token     m_totalPendingMessagesColumnToken;
+  mdb_token     m_unreadPendingMessagesColumnToken;
+  mdb_token     m_expiredMarkColumnToken;
+  mdb_token     m_versionColumnToken;
+};
+
+#endif
diff --git a/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl b/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl
new file mode 100644
index 000000000..28551ea60
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsIDBChangeAnnouncer.idl
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "MailNewsTypes2.idl"
+
+interface nsIDBChangeListener;
+interface nsIMsgDBHdr;
+
+[scriptable, uuid(22baf00b-939d-42c3-ac51-21d99dfa1f05)]
+
+interface nsIDBChangeAnnouncer  : nsISupports {
+ /* these 2 calls return NS_OK on success, NS_COMFALSE on failure */
+  void AddListener(in nsIDBChangeListener listener);
+  void RemoveListener(in nsIDBChangeListener listener);
+
+  void NotifyHdrChangeAll(in nsIMsgDBHdr aHdrChanged, in unsigned long aOldFlags, in unsigned long aNewFlags, 
+                                in nsIDBChangeListener instigator);
+  void NotifyHdrAddedAll(in nsIMsgDBHdr aHdrAdded, in nsMsgKey parentKey, in long flags, 
+                               in nsIDBChangeListener instigator);
+  void NotifyHdrDeletedAll(in nsIMsgDBHdr aHdrDeleted, in nsMsgKey parentKey, in long flags, 
+                                 in nsIDBChangeListener instigator);
+  void NotifyParentChangedAll(in nsMsgKey keyReparented, in nsMsgKey oldParent, in nsMsgKey newParent, in nsIDBChangeListener instigator); 
+
+  void NotifyReadChanged(in nsIDBChangeListener instigator);
+
+  void NotifyJunkScoreChanged(in nsIDBChangeListener aInstigator);
+
+  void NotifyAnnouncerGoingAway();
+};
+
diff --git a/mailnews/db/msgdb/public/nsIDBChangeListener.idl b/mailnews/db/msgdb/public/nsIDBChangeListener.idl
new file mode 100644
index 000000000..3acda8ad8
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsIDBChangeListener.idl
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "MailNewsTypes2.idl"
+
+interface nsIDBChangeAnnouncer;
+interface nsIMsgDBHdr;
+interface nsIMsgDatabase;
+
+/**
+ * These callbacks are provided to allow listeners to the message database
+ * to update their status when changes occur.
+ */
+[scriptable, uuid(21c56d34-71b9-42bb-9606-331a6a5f8210)]
+
+interface  nsIDBChangeListener : nsISupports {
+  /**
+   * Callback when message flags are changed.
+   *
+   * @param aHdrChanged The changed header.
+   * @param aOldFlags   Message flags prior to change.
+   * @param aNewFlags   Message flags after change.
+   * @param aInstigator Object that initiated the change.
+   */
+  void onHdrFlagsChanged(in nsIMsgDBHdr aHdrChanged, in unsigned long aOldFlags,
+                   in unsigned long aNewFlags, in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message is marked as deleted.
+   *
+   * @param aHdrChanged The message header that is going to be deleted.
+   * @param aParentKey  Key of parent.
+   * @param aFlags      Flags that message has before delete.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onHdrDeleted(in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags,
+                    in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message is added.
+   *
+   * @param aHdrChanged The message header that is added.
+   * @param aParentKey  Parent key of message.
+   * @param aFlags      Flags that new message will have.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onHdrAdded(in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags,
+                  in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when message parrent is changed. Parent is changed when message is deleted or moved.
+   *
+   * @param aKeyChanged The message key that parent key was changed.
+   * @param oldParent   Old parent key.
+   * @param newParent   New parent key.
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onParentChanged(in nsMsgKey aKeyChanged, in nsMsgKey oldParent, in nsMsgKey newParent,
+                       in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback when announcer is going away. This is good place to release strong pointers to announcer.
+   *
+   * @param instigator Object that initiated the change. Can be null.
+   */
+  void onAnnouncerGoingAway(in nsIDBChangeAnnouncer instigator);
+
+  /**
+   * Callback when read flag is changed.
+   *
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onReadChanged(in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback used in case when "junkscore" property is changed.
+   *
+   * @param aInstigator Object that initiated the change. Can be null.
+   */
+  void onJunkScoreChanged(in nsIDBChangeListener aInstigator);
+
+  /**
+   * Callback used in the general case where any field may have changed.
+   * OnHdrPropertyChanged is called twice per change. On the first call, aPreChange
+   * is true, and aStatus is undefined. OnHdrPropertyChanged saves any required status in aStatus
+   * (such as a filter match). The calling function stores the value of aStatus, changes the
+   * header aHdrToChange, then calls OnHdrPropertyChanged again with aPreChange false. On this
+   * second call, the stored value of aStatus is provided, so that any changes may be noted.
+   *
+   * @param aHdrToChange the message header that is changing.
+   * @param aPreChange   true on first call before change, false on second call after change
+   * @param aStatus      storage location provided by calling routine for status
+   * @param aInstigator  object that initiated the change
+   */   
+  void onHdrPropertyChanged(in nsIMsgDBHdr aHdrToChange, in boolean aPreChange, inout uint32_t aStatus,
+                       in nsIDBChangeListener aInstigator);
+
+  /**
+   * Generic notification for extensibility. Common events should be documented
+   * here so we have a hope of keeping the documentation up to date.
+   * Current events are:
+   * "DBOpened" - When a pending listener becomes real. This can happen when
+   *              the existing db is force closed and a new one opened. Only
+   *              registered pending listeners are notified.
+   *
+   * @param aDB      the db for this event.
+   * @param aEvent   type of event. 
+   *
+   */
+  void onEvent(in nsIMsgDatabase aDB, in string aEvent);
+};
+
diff --git a/mailnews/db/msgdb/public/nsIDBFolderInfo.idl b/mailnews/db/msgdb/public/nsIDBFolderInfo.idl
new file mode 100644
index 000000000..59b294d3b
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsIDBFolderInfo.idl
@@ -0,0 +1,108 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "MailNewsTypes2.idl"
+
+[scriptable, uuid(a72dab4b-b3bd-471e-9a38-1b242b385459)]
+interface  nsIDBFolderInfo : nsISupports {
+  attribute long flags;
+
+  /**
+   * Or's aFlags into flags.
+   *
+   * @param - the flags(s) to set
+   *
+   * @return - the resulting flags.
+   */
+  long  orFlags(in long aFlags);
+  /**
+   * And's aFlags with flags, set flags to the result
+   *
+   * @param             the flags(s) to AND
+   *
+   * @return            the resulting flags.
+   */
+  long  andFlags(in long aFlags);
+
+  /**
+   * Allows us to keep track of the highwater mark
+   *
+   * @param aNewKey     If larger than the current highwater
+   *                    mark, sets the highwater mark to aNewKey.
+   */
+  void  onKeyAdded(in nsMsgKey aNewKey);
+
+  attribute nsMsgKey highWater;
+  attribute nsMsgKey expiredMark;
+  attribute long long folderSize;
+  attribute unsigned long folderDate;
+  void changeNumUnreadMessages(in long aDelta);
+  void changeNumMessages(in long aDelta);
+
+  // numUnreadMessages and numMessages will never return negative numbers. 0 means 'no msgs'.
+  attribute long numUnreadMessages;
+  attribute long numMessages;
+
+  attribute long long expungedBytes;
+  attribute long imapUidValidity;
+  attribute unsigned long version;
+  attribute long imapTotalPendingMessages;
+  attribute long imapUnreadPendingMessages;
+
+  attribute nsMsgViewTypeValue viewType;
+  attribute nsMsgViewFlagsTypeValue viewFlags;
+  attribute nsMsgViewSortTypeValue sortType;
+  attribute nsMsgViewSortOrderValue sortOrder;
+
+  void changeExpungedBytes(in long aDelta);
+
+  /**
+   * Gets a string property from the folder.
+   *
+   * @param propertyName The name of the property for the value to retrieve.
+   */
+  ACString getCharProperty(in string propertyName);
+
+  /**
+   * Sets a string property from the folder.
+   *
+   * @param propertyName   The name of the property for which to set a value
+   * @param propertyValue  The new value of the property.
+   */
+  void setCharProperty(in string aPropertyName, in ACString aPropertyValue);
+  void setUint32Property(in string propertyName, in unsigned long propertyValue);
+  void setInt64Property(in string propertyName, in long long propertyValue);
+  unsigned long getUint32Property(in string propertyName, in unsigned long defaultValue);
+  long long     getInt64Property(in string propertyName, in long long defaultValue);
+  boolean getBooleanProperty(in string propertyName, in boolean defaultValue);
+  void setBooleanProperty(in string propertyName, in boolean aPropertyValue);
+  nsIDBFolderInfo	GetTransferInfo();
+  void	initFromTransferInfo(in nsIDBFolderInfo transferInfo);
+
+  /**
+   * Gets/Sets the current character set for the folder. If there is no
+   * specific character set for the folder, it will return an empty string.
+   */
+  attribute ACString characterSet;
+
+  /**
+   * Returns the effective character set on the folder. If there is no specific
+   * set defined for the folder, it will return the default character set.
+   */
+  readonly attribute ACString effectiveCharacterSet;
+
+  attribute boolean characterSetOverride;
+
+  attribute AString locale;
+  attribute AString mailboxName;
+
+
+  AString getProperty(in string propertyName);
+  void setProperty(in string propertyName, in AString propertyStr);
+
+  attribute string knownArtsSet;
+  attribute ACString folderName;
+};
diff --git a/mailnews/db/msgdb/public/nsIMsgDatabase.idl b/mailnews/db/msgdb/public/nsIMsgDatabase.idl
new file mode 100644
index 000000000..6b79fc940
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsIMsgDatabase.idl
@@ -0,0 +1,570 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * @defgroup msgdb Mailnews message database
+ * This module is the access point to locally-stored databases.
+ *
+ * These databases are stored in .msf files. Each file contains useful cached
+ * information, like the message id or references, as well as the cc header or
+ * tag information. This cached information is encapsulated in nsIMsgDBHdr.
+ *
+ * Also included is threading information, mostly encapsulated in nsIMsgThread.
+ * The final component is the database folder info, which contains information
+ * on the view and basic information also stored in the folder cache such as the
+ * name or most recent update.
+ *
+ * What this module does not do is access individual messages. Access is
+ * strictly controlled by the nsIMsgFolder objects and their backends.
+ * @{
+ */
+#include "nsISupports.idl"
+#include "nsIDBChangeAnnouncer.idl"
+
+%{C++
+#include "nsTArray.h"
+%}
+
+interface nsIMutableArray;
+interface nsIMsgDatabase;
+interface nsIMsgDBView;
+interface nsIDBChangeListener;
+interface nsIMsgDBHdr;
+interface nsISimpleEnumerator;
+interface nsIMsgThread;
+interface nsIDBFolderInfo;
+interface nsIMsgOfflineImapOperation;
+interface nsIMsgFolder;
+interface nsIMsgKeyArray;
+interface nsIFile;
+interface nsIArray;
+
+typedef unsigned long nsMsgRetainByPreference;
+
+
+[scriptable, uuid(fe8b7cec-eec8-4bcd-82ff-d8bb23cef3da)]
+
+interface nsIMsgRetentionSettings : nsISupports
+{
+  const unsigned long nsMsgRetainAll = 1;
+  const unsigned long nsMsgRetainByAge = 2;
+  const unsigned long nsMsgRetainByNumHeaders = 3;
+
+  attribute boolean useServerDefaults;
+  attribute nsMsgRetainByPreference retainByPreference;
+  attribute unsigned long daysToKeepHdrs;
+  attribute unsigned long numHeadersToKeep;
+
+  // this is for keeping offline bodies.
+  attribute boolean cleanupBodiesByDays;
+  attribute unsigned long daysToKeepBodies;
+
+  /**
+   * Should retention settings be applied to flagged/starred messages?
+   * If false, flagged messages are never automatically deleted.
+   */
+  attribute boolean applyToFlaggedMessages;
+};
+
+[scriptable, uuid(86a9da90-14f1-11d5-a5c0-0060b0fc04b7)]
+interface nsIMsgDownloadSettings : nsISupports
+{
+  attribute boolean useServerDefaults;
+  attribute boolean downloadByDate;
+  attribute boolean downloadUnreadOnly;
+  attribute unsigned long ageLimitOfMsgsToDownload;
+};
+
+typedef long nsMsgDBCommit;
+
+[scriptable, uuid(15431853-e448-45dc-8978-9958bf74d9b7)]
+
+interface nsMsgDBCommitType 
+{
+  const long kLargeCommit = 1;
+  const long kSessionCommit = 2;
+  const long kCompressCommit = 3;
+};
+
+[ref] native nsMsgKeyArrayRef(nsTArray<nsMsgKey>);
+[ptr] native nsMsgKeyArrayPtr(nsTArray<nsMsgKey>);
+
+/**
+ * A service to open mail databases and manipulate listeners automatically.
+ *
+ * The contract ID for this component is
+ * <tt>\@mozilla.org/msgDatabase/msgDBService;1</tt>.
+ */
+[scriptable, uuid(4cbbf024-3760-402d-89f3-6ababafeb07d)]
+interface nsIMsgDBService : nsISupports
+{
+  /**
+   * Opens a database for a given folder.
+   *
+   * This method is preferred over nsIMsgDBService::openMailDBFromFile if the
+   * caller has an actual nsIMsgFolder around. If the database detects that it
+   * is unreadable or out of date (using nsIMsgDatabase::outOfDate) it will
+   * destroy itself and prepare to be rebuilt, unless aLeaveInvalidDB is true.
+   *
+   * If one gets a NS_MSG_ERROR_FOLDER_SUMMARY_MISSING message, then one
+   * should call nsIMsgDBService::createNewDB to create the new database.
+   *
+   * @param aFolder         The folder whose database should be returned.
+   * @param aLeaveInvalidDB Whether or not the database should be deleted if it
+   *                        is invalid.
+   * @return                A new nsIMsgDatabase object representing the folder
+   *                        database that was opened.
+   * @exception NS_ERROR_FILE_TARGET_DOES_NOT_EXIST
+   *                        The file could not be created.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE
+   *                        The database is present (and was opened), but the
+   *                        summary file is out of date.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_MISSING
+   *                        The database is present, but the summary file is
+   *                        missing.
+   * @see nsIMsgDatabase::Open
+   * @see nsIMsgDBService::createNewDB
+   */
+  nsIMsgDatabase openFolderDB(in nsIMsgFolder aFolder,
+                              in boolean aLeaveInvalidDB);
+
+  /**
+   * This is the same as a synchronous open in terms of params and errors.
+   * But to finish opening the db, the caller must call
+   * nsIMsgDBService::OpenMore repeatedly until the open is finished.
+   * @see nsIMsgDBService::openFolderDB
+   * @see nsIMsgDBService::openMore
+   */
+  nsIMsgDatabase asyncOpenFolderDB(in nsIMsgFolder aFolder,
+                                   in boolean aLeaveInvalidDB);
+
+  /**
+   * Continues the open process for a db opened with
+   * nsIMsgDBService::asyncOpenFolderDB. Returns true if the db is ready
+   * to use, false if openMore needs to be called again.
+   * This will throw the same kinds of exceptions as openFolderDB.
+   * @param aTimeHint approximate number of milliseconds to spend
+   *                  before returning. This is more of a floor than
+                      a ceiling, since we can't guarantee that there
+                      won't be one big chunk that we can't interrupt.
+   * @return true if db is ready to use, false if openMore needs to
+   *         be called again.
+   * @see nsIMsgDBService::openFolderDB
+   */
+  boolean openMore(in nsIMsgDatabase aDB, in unsigned long aTimeHint);
+
+  /**
+   * Creates a new database for the given folder.
+   *
+   * If the database already exists, it will return the database, emit a
+   * warning, but not fully initialize it. For this reason, it should only be
+   * used when it is known that the database does not exist, such as when
+   * nsIMsgDBService::openFolderDB throws an error.
+   *
+   * @see nsIMsgDBService::openFolderDB
+   */
+  nsIMsgDatabase createNewDB(in nsIMsgFolder aFolder);
+
+  /**
+   * Opens or creates a database for a given file.
+   *
+   * This method should only be used if the caller does not have a folder
+   * instance, because the resulting db and message headers retrieved from the
+   * database would not know their owning folder, which limits their usefulness.
+   * For this reason, one should use nsIMsgDBService::openFolderDB instead
+   * except under special circumstances.
+   *
+   * Unlike nsIMsgDBService::openFolderDB, there is no corresponding method to
+   * create a new database if opening the database failed. However, this method
+   * will never throw NS_MSG_ERROR_FOLDER_SUMMARY_MISSING, so no corresponding
+   * method is needed.
+   *
+   * @param aFile           The file for which the database should be returned.
+   * @param aFolder         Folder the db corresponds to (may be null)
+   * @param aCreate         Whether or not the file should be created.
+   * @param aLeaveInvalidDB Whether or not the database should be deleted if it
+   *                        is invalid.
+   * @return                A new nsIMsgDatabase object encapsulating the file
+   *                        passed in.
+   * @exception NS_ERROR_FILE_TARGET_DOES_NOT_EXIST
+   *                        The file could not be created.
+   * @see nsIMsgDBService::openFolderDB
+   * @see nsIMsgDatabase::Open
+   */
+  nsIMsgDatabase openMailDBFromFile(in nsIFile aFile,
+                                    in nsIMsgFolder aFolder,
+                                    in boolean aCreate,
+                                    in boolean aLeaveInvalidDB);
+  /**
+   * Adds the given listener to the listener set for the folder.
+   *
+   * Since the message database will likely be opened and closed many times, by
+   * registering using this method, one will be guaranteed to see all subsequent
+   * modifications. This will also add the listener to the database if it is
+   * already opened.
+   *
+   * @param aFolder         The folder to add a listener to.
+   * @param aListener       The listener to add the folder to.
+   */
+  void registerPendingListener(in nsIMsgFolder aFolder,
+                               in nsIDBChangeListener aListener);
+  /**
+   * Removes the listener from all folder listener sets.
+   *
+   * @param aListener       The listener to remove.
+   * @exception NS_ERROR_FAILURE
+   *                        The listener is not registered.
+   */
+  void unregisterPendingListener(in nsIDBChangeListener aListener);
+
+  /**
+   * Get the db for a folder, if already open.
+   *
+   * @param aFolder   The folder to get the cached (open) db for.
+   *
+   * @returns         null if the db isn't open, otherwise the db.
+   */
+  nsIMsgDatabase cachedDBForFolder(in nsIMsgFolder aFolder);
+
+  /**
+   * Close the db for a folder, if already open.
+   *
+   * @param aFolder   The folder to close the cached (open) db for.
+   */
+  void forceFolderDBClosed(in nsIMsgFolder aFolder);
+
+  /// an enumerator to iterate over the open dbs.
+  readonly attribute nsIArray openDBs;
+};
+
+[scriptable, uuid(b64e66f8-4717-423a-be42-482658fb2199)]
+interface nsIMsgDatabase : nsIDBChangeAnnouncer {
+  void Close(in boolean aForceCommit);
+
+  void Commit(in nsMsgDBCommit commitType);
+  // Force closed is evil, and we should see if we can do without it.
+  // In 4.x, it was mainly used to remove corrupted databases.
+  void ForceClosed();
+  void clearCachedHdrs();
+  void resetHdrCacheSize(in unsigned long size);
+
+  readonly attribute nsIDBFolderInfo  dBFolderInfo;
+
+  /// Size of the database file in bytes.
+  readonly attribute long long databaseSize;
+
+  /// Folder this db was opened on.
+  readonly attribute nsIMsgFolder folder;
+
+  /**
+   * This is used when deciding which db's to close to free up memory
+   * and other resources in an LRU manner. It doesn't track every operation
+   * on every object from the db, but high level things like open, commit,
+   * and perhaps some of the list methods. Commit should be a proxy for all
+   * the mutation methods.
+   *
+   * I'm allowing clients to set the last use time as well, so that
+   * nsIMsgFolder.msgDatabase can set the last use time.
+   */
+  attribute PRTime lastUseTime;
+
+  // get a message header for the given key. Caller must release()!
+
+  nsIMsgDBHdr GetMsgHdrForKey(in nsMsgKey key);
+  nsIMsgDBHdr getMsgHdrForMessageID(in string messageID);
+
+  /**
+   * get a message header for a Gmail message with the given X-GM-MSGID.
+   */
+  nsIMsgDBHdr GetMsgHdrForGMMsgID(in string aGmailMessageID);
+  //Returns whether or not this database contains the given key
+  boolean ContainsKey(in nsMsgKey key);
+
+/**
+ * Must call AddNewHdrToDB after creating. The idea is that you create
+ * a new header, fill in its properties, and then call AddNewHdrToDB.
+ * AddNewHdrToDB will send notifications to any listeners.
+ *
+ * @param aKey msgKey for the new header. If aKey is nsMsgKey_None,
+ *             we will auto-assign a new key.
+ */
+  nsIMsgDBHdr CreateNewHdr(in nsMsgKey aKey);
+
+  void AddNewHdrToDB(in nsIMsgDBHdr newHdr, in boolean notify);
+
+  nsIMsgDBHdr CopyHdrFromExistingHdr(in nsMsgKey key, in nsIMsgDBHdr existingHdr, in boolean addHdrToDB);
+
+  /**
+   * Returns all message keys stored in the database.
+   * Keys are returned in the order as stored in the database.
+   * The caller should sort them if it needs to.
+   */
+  void ListAllKeys(in nsIMsgKeyArray array);
+
+  nsISimpleEnumerator EnumerateMessages();
+  nsISimpleEnumerator ReverseEnumerateMessages();
+  nsISimpleEnumerator EnumerateThreads();
+
+  /**
+   * Get an enumerator for use with nextMatchingHdrs. The enumerator
+   * will only return messages that match the passed-in search terms.
+   *
+   * @param     searchTerms       array of search terms to evaluate.
+   * @param     reverse           start at the end, defaults to false.
+   *
+   * @returns   an enumerator for passing into nextMatchingHdrs
+   */
+  nsISimpleEnumerator getFilterEnumerator(in nsIArray searchTerms,
+                                          [optional] in boolean reverse);
+
+  /**
+   * Get the next N matching headers using a filter enumerator
+   * obtained by calling getFilterEnumerator.
+   *
+   * @param     enumerator -      This *must* be a filter enumerator
+   * @param     numHdrsToLookAt   if non 0, the number of hdrs to advance the
+   *                              enumerator before returning.
+   * @param     maxResults        if non 0, the max results to return.
+   * @param     matchingHdrs      if non null, array of matching hdrs.
+   * @param     numMatches        if non null, the number of matching hdrs.
+   *
+   * @returns   false, if done, true if more hdrs to look at.
+   */
+  boolean nextMatchingHdrs(in nsISimpleEnumerator enumerator,
+                           in long numHdrsToLookAt,
+                           in long maxResults,
+                           in nsIMutableArray matchingHdrs,
+                           out long numMatches);
+
+
+  // count the total and unread msgs, and adjust global count if needed
+  void syncCounts();
+
+  nsIMsgThread GetThreadContainingMsgHdr(in nsIMsgDBHdr msgHdr) ;
+
+  // helpers for user command functions like delete, mark read, etc.
+
+  void MarkHdrRead(in nsIMsgDBHdr msgHdr, in boolean bRead,
+                         in nsIDBChangeListener instigator);
+
+  void MarkHdrReplied(in nsIMsgDBHdr msgHdr, in boolean bReplied,
+                         in nsIDBChangeListener instigator);
+
+  void MarkHdrMarked(in nsIMsgDBHdr msgHdr, in boolean mark,
+                         in nsIDBChangeListener instigator);
+  /**
+   * Remove the new status from a message.
+   *
+   * @param aMsgHdr        The database reference header for the message
+   * @param aInstigator    Reference to original calling object
+   */
+  void MarkHdrNotNew(in nsIMsgDBHdr aMsgHdr,
+                     in nsIDBChangeListener aInstigator);
+
+  // MDN support
+  void MarkMDNNeeded(in nsMsgKey key, in boolean bNeeded,
+                           in nsIDBChangeListener instigator);
+
+  // MarkMDNneeded only used when mail server is a POP3 server
+  // or when the IMAP server does not support user defined
+  // PERMANENTFLAGS
+  boolean IsMDNNeeded(in nsMsgKey key);
+
+  void MarkMDNSent(in nsMsgKey key, in boolean bNeeded,
+                         in nsIDBChangeListener instigator);
+  boolean IsMDNSent(in nsMsgKey key);
+
+// methods to get and set docsets for ids.
+  void MarkRead(in nsMsgKey key, in boolean bRead, 
+                      in nsIDBChangeListener instigator);
+
+  void MarkReplied(in nsMsgKey key, in boolean bReplied, 
+                         in nsIDBChangeListener instigator);
+
+  void MarkForwarded(in nsMsgKey key, in boolean bForwarded, 
+                           in nsIDBChangeListener instigator);
+
+  void MarkHasAttachments(in nsMsgKey key, in boolean bHasAttachments, 
+                                in nsIDBChangeListener instigator);
+
+  void MarkThreadRead(in nsIMsgThread thread, in nsIDBChangeListener instigator,
+                      out unsigned long aCount,
+                      [array, size_is(aCount)] out nsMsgKey aKeys);
+
+  /// Mark the specified thread ignored.
+  void MarkThreadIgnored(in nsIMsgThread thread, in nsMsgKey threadKey,
+                         in boolean bIgnored,
+                         in nsIDBChangeListener instigator);
+
+  /// Mark the specified thread watched.
+  void MarkThreadWatched(in nsIMsgThread thread, in nsMsgKey threadKey,
+                         in boolean bWatched,
+                         in nsIDBChangeListener instigator);
+
+  /// Mark the specified subthread ignored.
+  void MarkHeaderKilled(in nsIMsgDBHdr msg, in boolean bIgnored,
+                        in nsIDBChangeListener instigator);
+
+  /// Is the message read.
+  boolean IsRead(in nsMsgKey key);
+  /// Is the message part of an ignored thread.
+  boolean IsIgnored(in nsMsgKey key);
+  /// Is the message part of a watched thread.
+  boolean IsWatched(in nsMsgKey key);
+  /// Is the message flagged/starred.
+  boolean IsMarked(in nsMsgKey key);
+  /// Does the message have attachments.
+  boolean HasAttachments(in nsMsgKey key);
+
+  void MarkAllRead(out unsigned long aCount,
+                   [array, size_is(aCount)] out nsMsgKey aKeys);
+
+  void deleteMessages(in unsigned long aNumKeys,
+                      [array, size_is(aNumKeys)] in nsMsgKey nsMsgKeys,
+                      in nsIDBChangeListener instigator);
+  void DeleteMessage(in nsMsgKey key, 
+                           in nsIDBChangeListener instigator,
+                           in boolean commit);
+  void DeleteHeader(in nsIMsgDBHdr msgHdr, in nsIDBChangeListener instigator,
+                          in boolean commit, in boolean notify);
+
+  // lower level routine that doesn't remove hdr from thread or adjust counts
+  void RemoveHeaderMdbRow(in nsIMsgDBHdr msgHdr);
+
+  void UndoDelete(in nsIMsgDBHdr msgHdr);
+
+  void MarkMarked(in nsMsgKey key, in boolean mark,
+                        in nsIDBChangeListener instigator);
+  void MarkOffline(in nsMsgKey key, in boolean offline,
+                         in nsIDBChangeListener instigator);
+  void SetLabel(in nsMsgKey key, in nsMsgLabelValue label);
+  void setStringProperty(in nsMsgKey aKey, in string aProperty, in string aValue);
+  /**
+   * Set the value of a string property in a message header
+   *
+   * @param msgHdr    Header of the message whose property will be changed
+   * @param aProperty the property to change
+   * @param aValue    new value for the property
+   */
+  void setStringPropertyByHdr(in nsIMsgDBHdr msgHdr, in string aProperty, in string aValue);
+
+  /**
+   * Set the value of a uint32 property in a message header.
+   *
+   * @param aMsgHdr   header of the message whose property will be changed
+   * @param aProperty the property to change
+   * @param aValue    new value for the property
+   */
+  void setUint32PropertyByHdr(in nsIMsgDBHdr aMsgHdr,
+                              in string aProperty, in unsigned long aValue);
+
+  void MarkImapDeleted(in nsMsgKey key, in boolean deleted,
+                             in nsIDBChangeListener instigator);
+
+  readonly attribute nsMsgKey FirstNew;
+
+  attribute nsIMsgRetentionSettings msgRetentionSettings;
+  // purge unwanted message headers and/or bodies. If deleteViaFolder is
+  // true, we'll call nsIMsgFolder::DeleteMessages to delete the messages.
+  // Otherwise, we'll just delete them from the db.
+  void applyRetentionSettings(in nsIMsgRetentionSettings aMsgRetentionSettings, 
+                              in boolean aDeleteViaFolder);
+
+  attribute nsIMsgDownloadSettings msgDownloadSettings;
+
+  boolean HasNew();
+  void ClearNewList(in boolean notify);
+  void AddToNewList(in nsMsgKey key);
+
+  // used mainly to force the timestamp of a local mail folder db to
+  // match the time stamp of the corresponding berkeley mail folder,
+  // but also useful to tell the summary to mark itself invalid
+  // Also, if a local folder is being reparsed, summary will be invalid
+  // until the reparsing is done.
+  attribute boolean summaryValid;
+
+  // batching - can be used to cache file stream for local mail,
+  // and perhaps to use the mdb batching mechanism as well.
+  void StartBatch();
+  void EndBatch();
+  // offline operations - we could move these into an offline operation interface
+  // but it would have to be in nsMailDatabase, since local folders can be move destinations
+  nsIMsgOfflineImapOperation GetOfflineOpForKey(in nsMsgKey messageKey, in boolean create);
+  void  RemoveOfflineOp(in nsIMsgOfflineImapOperation op);
+  nsISimpleEnumerator EnumerateOfflineOps();
+  [noscript] void ListAllOfflineOpIds(in nsMsgKeyArrayPtr offlineOpIds);
+  [noscript] void ListAllOfflineDeletes(in nsMsgKeyArrayPtr offlineDeletes);
+  void ListAllOfflineMsgs(in nsIMsgKeyArray aKeys);
+
+  void setAttributeOnPendingHdr(in nsIMsgDBHdr pendingHdr, in string property,
+                                  in string propertyVal);
+
+  void setUint32AttributeOnPendingHdr(in nsIMsgDBHdr pendingHdr, in string property,
+                                  in unsigned long propertyVal);
+
+  /**
+   * Sets a pending 64 bit attribute, which tells the DB that when a message
+   * which looks like the pendingHdr (e.g., same message-id) is added to the
+   * db, set the passed in property and value on the new header. This is
+   * usually because we've copied an imap message to a different folder, and
+   * want to carry forward attributes from the original message to the copy,
+   * but don't have the message hdr for the copy yet so we can't set
+   * attributes directly.
+   *
+   * @param aPendingHdr usually the source of the copy.
+   * @param aProperty name of property to set.
+   * @param aPropertyVal 64 bit value of property to set.
+   */
+  void setUint64AttributeOnPendingHdr(in nsIMsgDBHdr aPendingHdr,
+                                      in string aProperty,
+                                      in unsigned long long aPropertyVal);
+
+  /**
+   * Given a message header with its message-id set, update any pending
+   *  attributes on the header.
+   *
+   * @param aNewHdr a new header that may have pending attributes.
+   */
+  void updatePendingAttributes(in nsIMsgDBHdr aNewHdr);
+
+  readonly attribute nsMsgKey lowWaterArticleNum;
+  readonly attribute nsMsgKey highWaterArticleNum;
+  attribute nsMsgKey nextPseudoMsgKey;   //for undo-redo of move pop->imap
+  readonly attribute nsMsgKey nextFakeOfflineMsgKey; // for saving "fake" offline msg hdrs
+  // for sorting
+  void createCollationKey(in AString sourceString, out unsigned long aCount,
+                          [array, size_is(aCount)] out octet aKey);
+  long compareCollationKeys(in unsigned long aLen1,
+                            [array, size_is(aLen1)] in octet key1,
+                            in unsigned long aLen2,
+                            [array, size_is(aLen2)] in octet key2);
+
+  // when creating a view, the default sort order and view flags 
+  // use these for the default.  (this allows news to override, so that
+  // news can be threaded by default)
+  readonly attribute nsMsgViewFlagsTypeValue defaultViewFlags;
+  readonly attribute nsMsgViewSortTypeValue  defaultSortType;
+  readonly attribute nsMsgViewSortOrderValue defaultSortOrder;
+
+  // for msg hdr hash table allocation. controllable by caller to improve folder loading preformance.
+  attribute unsigned long msgHdrCacheSize;
+
+  /**
+   * The list of messages currently in the NEW state.
+   * 
+   * If there are no such messages, a null pointer may be returned.
+   * the caller should free when done using free.
+   */
+  void getNewList(out unsigned long count, [array, size_is(count)] out nsMsgKey newKeys);
+  
+  // These are used for caching search hits in a db, to speed up saved search folders.
+  nsISimpleEnumerator getCachedHits(in string aSearchFolderUri);
+  void refreshCache(in string aSearchFolderUri, in unsigned long aNumKeys, [array, size_is (aNumKeys)] in nsMsgKey aNewHits,
+     out unsigned long aNumBadHits, [array, size_is(aNumBadHits)] out nsMsgKey aStaleHits);
+  void updateHdrInCache(in string aSearchFolderUri, in nsIMsgDBHdr aHdr, in boolean aAdd);
+  boolean hdrIsInCache(in string aSearchFolderUri, in nsIMsgDBHdr aHdr);
+
+};
+/** @} */
diff --git a/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl b/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl
new file mode 100644
index 000000000..b07beef63
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsIMsgOfflineImapOperation.idl
@@ -0,0 +1,53 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "MailNewsTypes2.idl"
+// #include "nsIImapUrl.idl" // for imapMessageFlagsType
+
+typedef unsigned short imapMessageFlagsType;
+
+typedef long nsOfflineImapOperationType;
+
+[scriptable, uuid(b5229a55-22bb-444b-be92-13d719353828)]
+
+interface nsIMsgOfflineImapOperation : nsISupports
+{
+// type of stored imap operations
+  const long kFlagsChanged      = 0x1;
+  const long kMsgMoved          = 0x2;
+  const long kMsgCopy           = 0x4;
+  const long kMoveResult        = 0x8;
+  const long kAppendDraft       = 0x10;
+  const long kAddedHeader       = 0x20;
+  const long kDeletedMsg        = 0x40;
+  const long kMsgMarkedDeleted	= 0x80;
+  const long kAppendTemplate    = 0x100;
+  const long kDeleteAllMsgs     = 0x200;
+  const long kAddKeywords       = 0x400;
+  const long kRemoveKeywords    = 0x800;
+
+  attribute nsOfflineImapOperationType operation;
+  void clearOperation(in nsOfflineImapOperationType operation);
+  attribute nsMsgKey messageKey;
+
+  // for move/copy operations, the msg key of the source msg.
+  attribute nsMsgKey srcMessageKey;
+
+  attribute imapMessageFlagsType flagOperation;
+  attribute imapMessageFlagsType newFlags; // for kFlagsChanged
+  attribute string destinationFolderURI; // for move or copy
+  attribute string sourceFolderURI;
+  void addKeywordToAdd(in string aKeyword);
+  void addKeywordToRemove(in string aKeyword);
+  readonly attribute string keywordsToAdd; 
+  readonly attribute string keywordsToRemove;
+  readonly attribute long numberOfCopies;
+  void addMessageCopyOperation(in string destinationBox);
+  string getCopyDestination(in long copyIndex);
+  attribute unsigned long msgSize;
+  attribute boolean playingBack;
+};
+
diff --git a/mailnews/db/msgdb/public/nsINewsDatabase.idl b/mailnews/db/msgdb/public/nsINewsDatabase.idl
new file mode 100644
index 000000000..151a42f01
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsINewsDatabase.idl
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{C++
+#include "nsMsgKeySet.h"
+%}
+
+[ptr] native nsMsgKeySetPtr(nsMsgKeySet);
+
+[scriptable, uuid(f700208a-1dd1-11b2-b947-e4e1e4fdf278)]
+
+interface nsINewsDatabase : nsISupports {
+  [noscript] attribute nsMsgKeySetPtr readSet;
+};
diff --git a/mailnews/db/msgdb/public/nsImapMailDatabase.h b/mailnews/db/msgdb/public/nsImapMailDatabase.h
new file mode 100644
index 000000000..b6092c284
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsImapMailDatabase.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _nsImapMailDatabase_H_
+#define _nsImapMailDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMailDatabase.h"
+
+class nsImapMailDatabase : public nsMailDatabase
+{
+public:
+  // OK, it's dumb that this should require a fileSpec, since there is no file
+  // for the folder. This is mainly because we're deriving from nsMailDatabase;
+  // Perhaps we shouldn't...
+  nsImapMailDatabase();
+  virtual ~nsImapMailDatabase();
+  
+  NS_IMETHOD    StartBatch() override;
+  NS_IMETHOD    EndBatch() override;
+  NS_IMETHOD    GetSummaryValid(bool *aResult) override;
+  NS_IMETHOD    SetSummaryValid(bool valid = true) override;
+  virtual nsresult AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr) override;
+
+  NS_IMETHOD    ForceClosed() override;
+  NS_IMETHOD    AddNewHdrToDB(nsIMsgDBHdr *newHdr, bool notify) override;
+  NS_IMETHOD    SetAttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr, const char *property,
+                                         const char *propertyVal) override;
+  NS_IMETHOD    SetUint32AttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr, const char *property,
+                                               uint32_t propertyVal) override;
+  NS_IMETHOD    SetUint64AttributeOnPendingHdr(nsIMsgDBHdr *aPendingHdr,
+                                               const char *aProperty,
+                                               uint64_t aPropertyVal) override;
+  NS_IMETHOD    DeleteMessages(uint32_t aNumKeys, nsMsgKey* nsMsgKeys,
+                               nsIDBChangeListener *instigator) override;
+  NS_IMETHOD    UpdatePendingAttributes(nsIMsgDBHdr* aNewHdr) override;
+
+protected:
+  // IMAP does not set local file flags, override does nothing
+  virtual void UpdateFolderFlag(nsIMsgDBHdr *msgHdr, bool bSet,
+                                nsMsgMessageFlagType flag, nsIOutputStream **ppFileStream);
+
+  nsresult      GetRowForPendingHdr(nsIMsgDBHdr *pendingHdr, nsIMdbRow **row);
+  nsresult     GetAllPendingHdrsTable();
+  mdb_token    m_pendingHdrsRowScopeToken;
+  mdb_token    m_pendingHdrsTableKindToken;
+  nsCOMPtr<nsIMdbTable> m_mdbAllPendingHdrsTable;
+};
+
+
+#endif
diff --git a/mailnews/db/msgdb/public/nsMailDatabase.h b/mailnews/db/msgdb/public/nsMailDatabase.h
new file mode 100644
index 000000000..6a5c6b5c4
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsMailDatabase.h
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsMailDatabase_H_
+#define _nsMailDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMsgDatabase.h"
+#include "nsMsgMessageFlags.h"
+#include "nsIFile.h"
+#include "nsTArray.h"
+
+// This is the subclass of nsMsgDatabase that handles local mail messages.
+class nsIOFileStream;
+class nsIFile;
+class nsOfflineImapOperation;
+
+class nsMailDatabase : public nsMsgDatabase
+{
+public:
+  nsMailDatabase();
+  virtual ~nsMailDatabase();
+  NS_IMETHOD  ForceClosed() override;
+  NS_IMETHOD DeleteMessages(uint32_t aNumKeys, nsMsgKey* nsMsgKeys,
+                            nsIDBChangeListener *instigator) override;
+
+  NS_IMETHOD StartBatch() override;
+  NS_IMETHOD EndBatch() override;
+
+  nsresult  Open(nsMsgDBService* aDBService, nsIFile *aSummaryFile, bool create, bool upgrading) override;
+  virtual nsMailDatabase  *GetMailDB() {return this;}
+
+  virtual uint32_t  GetCurVersion() override {return kMsgDBVersion;}
+  
+  NS_IMETHOD  GetOfflineOpForKey(nsMsgKey opKey, bool create,
+                                 nsIMsgOfflineImapOperation **op) override;
+  NS_IMETHOD  RemoveOfflineOp(nsIMsgOfflineImapOperation *op) override;
+
+  NS_IMETHOD  SetSummaryValid(bool valid) override;
+  NS_IMETHOD  GetSummaryValid(bool *valid) override;
+	
+  NS_IMETHOD    EnumerateOfflineOps(nsISimpleEnumerator **enumerator) override;
+  NS_IMETHOD    ListAllOfflineOpIds(nsTArray<nsMsgKey> *offlineOpIds) override;
+  NS_IMETHOD    ListAllOfflineDeletes(nsTArray<nsMsgKey> *offlineDeletes) override;
+
+  friend class nsMsgOfflineOpEnumerator;
+protected:
+
+  nsresult        GetAllOfflineOpsTable(); // get this on demand
+
+  // get the time and date of the mailbox file
+  void            GetMailboxModProperties(int64_t *aSize, uint32_t *aDate); 
+
+  nsCOMPtr <nsIMdbTable>  m_mdbAllOfflineOpsTable;
+  mdb_token       m_offlineOpsRowScopeToken;
+  mdb_token       m_offlineOpsTableKindToken;
+
+  virtual void    SetReparse(bool reparse);
+  
+protected:
+  
+  bool            m_reparse;
+};
+
+#endif
diff --git a/mailnews/db/msgdb/public/nsMsgDBCID.h b/mailnews/db/msgdb/public/nsMsgDBCID.h
new file mode 100644
index 000000000..557cc24c0
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsMsgDBCID.h
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMsgDBCID_h__
+#define nsMsgDBCID_h__
+
+#include "nsISupports.h"
+#include "nsIFactory.h"
+#include "nsIComponentManager.h"
+
+// 03223c50-1e88-45e8-ba1a-7ce792dc3fc3
+#define NS_MSGDB_SERVICE_CID \
+{  0x03223c50, 0x1e88, 0x45e8, \
+    { 0xba, 0x1a, 0x7c, 0xe7, 0x92, 0xdc, 0x3f, 0xc3 } }
+
+#define NS_MSGDB_SERVICE_CONTRACTID \
+  "@mozilla.org/msgDatabase/msgDBService;1"
+
+#define NS_MSGDB_CONTRACTID \
+  "@mozilla.org/nsMsgDatabase/msgDB-"
+
+#define NS_MAILBOXDB_CONTRACTID \
+  NS_MSGDB_CONTRACTID"mailbox"
+
+//	a86c86ae-e97f-11d2-a506-0060b0fc04b7
+#define NS_MAILDB_CID                      \
+{ 0xa86c86ae, 0xe97f, 0x11d2,                   \
+    { 0xa5, 0x06, 0x00, 0x60, 0xb0, 0xfc, 0x04, 0xb7 } }
+
+#define NS_NEWSDB_CONTRACTID \
+  NS_MSGDB_CONTRACTID"news"
+
+// 36414aa0-e980-11d2-a506-0060b0fc04b7
+#define NS_NEWSDB_CID                      \
+{ 0x36414aa0, 0xe980, 0x11d2,                  \
+    { 0xa5, 0x06, 0x00, 0x60, 0xb0, 0xfc, 0x04, 0xb7 } }
+
+#define NS_IMAPDB_CONTRACTID \
+  NS_MSGDB_CONTRACTID"imap"
+
+// 9e4b07ee-e980-11d2-a506-0060b0fc04b7
+#define NS_IMAPDB_CID                      \
+{ 0x9e4b07ee, 0xe980, 0x11d2,                  \
+    { 0xa5, 0x06, 0x00, 0x60, 0xb0, 0xfc, 0x04, 0xb7 } }
+
+#define NS_MSG_RETENTIONSETTINGS_CID \
+{ 0x1bd976d6, 0xdf44, 0x11d4,       \
+  {0xa5, 0xb6, 0x00, 0x60, 0xb0, 0xfc, 0x04, 0xb7} }
+
+#define NS_MSG_RETENTIONSETTINGS_CONTRACTID \
+  "@mozilla.org/msgDatabase/retentionSettings;1"
+
+// 4e3dae5a-157a-11d5-a5c0-0060b0fc04b7
+#define NS_MSG_DOWNLOADSETTINGS_CID \
+{ 0x4e3dae5a, 0x157a, 0x11d5,       \
+  {0xa5, 0xc0, 0x00, 0x60, 0xb0, 0xfc, 0x04, 0xb7} }
+
+#define NS_MSG_DOWNLOADSETTINGS_CONTRACTID \
+  "@mozilla.org/msgDatabase/downloadSettings;1"
+
+#endif
diff --git a/mailnews/db/msgdb/public/nsMsgDatabase.h b/mailnews/db/msgdb/public/nsMsgDatabase.h
new file mode 100644
index 000000000..bb011e85c
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsMsgDatabase.h
@@ -0,0 +1,462 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsMsgDatabase_H_
+#define _nsMsgDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MemoryReporting.h"
+#include "nsIMsgDatabase.h"
+#include "nsMsgHdr.h"
+#include "nsStringGlue.h"
+#include "nsAutoPtr.h"
+#include "nsIDBChangeListener.h"
+#include "nsIDBChangeAnnouncer.h"
+#include "nsMsgMessageFlags.h"
+#include "nsIMsgFolder.h"
+#include "nsIMutableArray.h"
+#include "nsDBFolderInfo.h"
+#include "nsICollation.h"
+#include "nsIMsgSearchSession.h"
+#include "nsIMimeConverter.h"
+#include "nsCOMPtr.h"
+#include "nsCOMArray.h"
+#include "PLDHashTable.h"
+#include "nsTArray.h"
+#include "nsTObserverArray.h"
+class ListContext;
+class nsMsgKeySet;
+class nsMsgThread;
+class nsMsgDatabase;
+class nsIMsgThread;
+class nsIDBFolderInfo;
+
+const int32_t kMsgDBVersion = 1;
+
+// Hopefully we're not opening up lots of databases at the same time, however
+// this will give us a buffer before we need to start reallocating the cache
+// array.
+const uint32_t kInitialMsgDBCacheSize = 20;
+
+class nsMsgDBService final : public nsIMsgDBService
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGDBSERVICE
+
+  nsMsgDBService();
+
+  void AddToCache(nsMsgDatabase* pMessageDB);
+  void DumpCache();
+  void EnsureCached(nsMsgDatabase* pMessageDB)
+  {
+    if (!m_dbCache.Contains(pMessageDB))
+      m_dbCache.AppendElement(pMessageDB);
+  }
+  void RemoveFromCache(nsMsgDatabase* pMessageDB)
+  {
+    m_dbCache.RemoveElement(pMessageDB);
+  }
+
+protected:
+  ~nsMsgDBService();
+  void HookupPendingListeners(nsIMsgDatabase *db, nsIMsgFolder *folder);
+  void FinishDBOpen(nsIMsgFolder *aFolder, nsMsgDatabase *aMsgDB);
+  nsMsgDatabase* FindInCache(nsIFile *dbName);
+
+  nsCOMArray <nsIMsgFolder> m_foldersPendingListeners;
+  nsCOMArray <nsIDBChangeListener> m_pendingListeners;
+  AutoTArray<nsMsgDatabase*, kInitialMsgDBCacheSize> m_dbCache;
+};
+
+class nsMsgDBEnumerator : public nsISimpleEnumerator {
+public:
+    NS_DECL_ISUPPORTS
+
+    // nsISimpleEnumerator methods:
+    NS_DECL_NSISIMPLEENUMERATOR
+
+    // nsMsgDBEnumerator methods:
+    typedef nsresult (*nsMsgDBEnumeratorFilter)(nsIMsgDBHdr* hdr, void* closure);
+
+    nsMsgDBEnumerator(nsMsgDatabase* db, nsIMdbTable *table,
+                      nsMsgDBEnumeratorFilter filter, void* closure,
+                      bool iterateForwards = true);
+    void Clear();
+
+    nsresult                        GetRowCursor();
+    virtual nsresult                PrefetchNext();
+    RefPtr<nsMsgDatabase>         mDB;
+    nsCOMPtr<nsIMdbTableRowCursor>  mRowCursor;
+    mdb_pos                         mRowPos;
+    nsCOMPtr<nsIMsgDBHdr>           mResultHdr;
+    bool                            mDone;
+    bool                            mNextPrefetched;
+    bool                            mIterateForwards;
+    nsMsgDBEnumeratorFilter         mFilter;
+    nsCOMPtr <nsIMdbTable>          mTable;
+    void*                           mClosure;
+    // This is used when the caller wants to limit how many headers the
+    // enumerator looks at in any given time slice.
+    mdb_pos                         mStopPos;
+
+protected:
+    virtual ~nsMsgDBEnumerator();
+};
+
+class nsMsgFilteredDBEnumerator : public nsMsgDBEnumerator
+{
+public:
+  nsMsgFilteredDBEnumerator(nsMsgDatabase* db, nsIMdbTable *table,
+                            bool reverse, nsIArray *searchTerms);
+  virtual ~nsMsgFilteredDBEnumerator();
+  nsresult InitSearchSession(nsIArray *searchTerms, nsIMsgFolder *folder);
+
+protected:
+  virtual nsresult               PrefetchNext() override;
+
+  nsCOMPtr <nsIMsgSearchSession> m_searchSession;
+
+};
+
+namespace mozilla {
+namespace mailnews {
+class MsgDBReporter;
+}
+}
+
+class nsMsgDatabase : public nsIMsgDatabase
+{
+public:
+  friend class nsMsgDBService;
+  friend class nsMsgPropertyEnumerator; // accesses m_mdbEnv and m_mdbStore
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDBCHANGEANNOUNCER
+  NS_DECL_NSIMSGDATABASE
+
+  /**
+   * Opens a database folder.
+   *
+   * @param aFolderName     The name of the folder to create.
+   * @param aCreate         Whether or not the file should be created.
+   * @param aLeaveInvalidDB Set to true if you do not want the database to be
+   *                        deleted if it is invalid.
+   * @exception NS_ERROR_FILE_TARGET_DOES_NOT_EXIST
+   *                        The file could not be created.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE
+   *                        The database is present (and was opened), but the
+   *                        summary file is out of date.
+   * @exception NS_MSG_ERROR_FOLDER_SUMMARY_MISSING
+   *                        The database is present (and was opened), but the
+   *                        summary file is missing.
+   */
+  virtual nsresult Open(nsMsgDBService *aDBService, nsIFile *aFolderName,
+                        bool aCreate, bool aLeaveInvalidDB);
+  virtual nsresult IsHeaderRead(nsIMsgDBHdr *hdr, bool *pRead);
+  virtual nsresult MarkHdrReadInDB(nsIMsgDBHdr *msgHdr, bool bRead,
+                               nsIDBChangeListener *instigator);
+  nsresult OpenInternal(nsMsgDBService *aDBService, nsIFile *aFolderName,
+                        bool aCreate, bool aLeaveInvalidDB, bool sync);
+  nsresult CheckForErrors(nsresult err, bool sync, nsMsgDBService *aDBService, nsIFile *summaryFile);
+  virtual nsresult OpenMDB(const char *dbName, bool create, bool sync);
+  virtual nsresult CloseMDB(bool commit);
+  virtual nsresult CreateMsgHdr(nsIMdbRow* hdrRow, nsMsgKey key, nsIMsgDBHdr **result);
+  virtual nsresult GetThreadForMsgKey(nsMsgKey msgKey, nsIMsgThread **result);
+  virtual nsresult EnumerateMessagesWithFlag(nsISimpleEnumerator* *result, uint32_t *pFlag);
+  nsresult         GetSearchResultsTable(const char *searchFolderUri, bool createIfMissing, nsIMdbTable **table);
+
+  // this might just be for debugging - we'll see.
+  nsresult ListAllThreads(nsTArray<nsMsgKey> *threadIds);
+  //////////////////////////////////////////////////////////////////////////////
+  // nsMsgDatabase methods:
+  nsMsgDatabase();
+
+  void GetMDBFactory(nsIMdbFactory ** aMdbFactory);
+  nsIMdbEnv             *GetEnv() {return m_mdbEnv;}
+  nsIMdbStore           *GetStore() {return m_mdbStore;}
+  virtual uint32_t      GetCurVersion();
+  nsresult              GetCollationKeyGenerator();
+  nsIMimeConverter *    GetMimeConverter();
+
+  nsresult GetTableCreateIfMissing(const char *scope, const char *kind, nsIMdbTable **table,
+                                   mdb_token &scopeToken, mdb_token &kindToken);
+
+  //helper function to fill in nsStrings from hdr row cell contents.
+  nsresult RowCellColumnTonsString(nsIMdbRow *row, mdb_token columnToken, nsAString &resultStr);
+  nsresult RowCellColumnToUInt32(nsIMdbRow *row, mdb_token columnToken, uint32_t *uint32Result, uint32_t defaultValue = 0);
+  nsresult RowCellColumnToUInt32(nsIMdbRow *row, mdb_token columnToken, uint32_t &uint32Result, uint32_t defaultValue = 0);
+  nsresult RowCellColumnToUInt64(nsIMdbRow *row, mdb_token columnToken, uint64_t *uint64Result, uint64_t defaultValue = 0);
+  nsresult RowCellColumnToMime2DecodedString(nsIMdbRow *row, mdb_token columnToken, nsAString &resultStr);
+  nsresult RowCellColumnToCollationKey(nsIMdbRow *row, mdb_token columnToken, uint8_t **result, uint32_t *len);
+  nsresult RowCellColumnToConstCharPtr(nsIMdbRow *row, mdb_token columnToken, const char **ptr);
+  nsresult RowCellColumnToAddressCollationKey(nsIMdbRow *row, mdb_token colToken, uint8_t **result, uint32_t *len);
+
+  nsresult GetEffectiveCharset(nsIMdbRow *row, nsACString &resultCharset);
+
+  // these methods take the property name as a string, not a token.
+  // they should be used when the properties aren't accessed a lot
+  nsresult        GetProperty(nsIMdbRow *row, const char *propertyName, char **result);
+  nsresult        SetProperty(nsIMdbRow *row, const char *propertyName, const char *propertyVal);
+  nsresult        GetPropertyAsNSString(nsIMdbRow *row, const char *propertyName, nsAString &result);
+  nsresult        SetPropertyFromNSString(nsIMdbRow *row, const char *propertyName, const nsAString &propertyVal);
+  nsresult        GetUint32Property(nsIMdbRow *row, const char *propertyName, uint32_t *result, uint32_t defaultValue = 0);
+  nsresult        GetUint64Property(nsIMdbRow *row, const char *propertyName, uint64_t *result, uint64_t defaultValue = 0);
+  nsresult        SetUint32Property(nsIMdbRow *row, const char *propertyName, uint32_t propertyVal);
+  nsresult        SetUint64Property(nsIMdbRow *row, const char *propertyName, uint64_t propertyVal);
+  nsresult        GetBooleanProperty(nsIMdbRow *row, const char *propertyName,
+                                     bool *result, bool defaultValue = false);
+  nsresult        SetBooleanProperty(nsIMdbRow *row, const char *propertyName,
+                                    bool propertyVal);
+  // helper function for once we have the token.
+  nsresult        SetNSStringPropertyWithToken(nsIMdbRow *row, mdb_token aProperty, const nsAString &propertyStr);
+
+  // helper functions to put values in cells for the passed-in row
+  nsresult        UInt32ToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, uint32_t value);
+  nsresult        CharPtrToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, const char *charPtr);
+  nsresult        RowCellColumnToCharPtr(nsIMdbRow *row, mdb_token columnToken, char **result);
+  nsresult        UInt64ToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, uint64_t value);
+
+  // helper functions to copy an nsString to a yarn, int32 to yarn, and vice versa.
+  static struct mdbYarn *nsStringToYarn(struct mdbYarn *yarn, const nsAString &str);
+  static struct mdbYarn *UInt32ToYarn(struct mdbYarn *yarn, uint32_t i);
+  static struct mdbYarn *UInt64ToYarn(struct mdbYarn *yarn, uint64_t i);
+  static void YarnTonsString(struct mdbYarn *yarn, nsAString &str);
+  static void YarnTonsCString(struct mdbYarn *yarn, nsACString &str);
+  static void YarnToUInt32(struct mdbYarn *yarn, uint32_t *i);
+  static void YarnToUInt64(struct mdbYarn *yarn, uint64_t *i);
+
+#ifdef DEBUG
+  virtual nsresult DumpContents();
+  nsresult DumpThread(nsMsgKey threadId);
+  nsresult DumpMsgChildren(nsIMsgDBHdr *msgHdr);
+#endif
+
+  friend class nsMsgHdr;  // use this to get access to cached tokens for hdr fields
+  friend class nsMsgThread;  // use this to get access to cached tokens for hdr fields
+  friend class nsMsgDBEnumerator;
+  friend class nsMsgDBThreadEnumerator;
+protected:
+  virtual ~nsMsgDatabase();
+
+  // prefs stuff - in future, we might want to cache the prefs interface
+  nsresult        GetBoolPref(const char *prefName, bool *result);
+  nsresult        GetIntPref(const char *prefName, int32_t *result);
+  virtual void    GetGlobalPrefs();
+    // retrieval methods
+  nsIMsgThread *  GetThreadForReference(nsCString &msgID, nsIMsgDBHdr **pMsgHdr);
+  nsIMsgThread *  GetThreadForSubject(nsCString &subject);
+  nsIMsgThread *  GetThreadForMessageId(nsCString &msgId);
+  nsIMsgThread *  GetThreadForThreadId(nsMsgKey threadId);
+  nsMsgHdr     *  GetMsgHdrForReference(nsCString &reference);
+  nsIMsgDBHdr  *  GetMsgHdrForSubject(nsCString &subject);
+  // threading interfaces
+  virtual nsresult CreateNewThread(nsMsgKey key, const char *subject, nsMsgThread **newThread);
+  virtual bool    ThreadBySubjectWithoutRe();
+  virtual bool    UseStrictThreading();
+  virtual bool    UseCorrectThreading();
+  virtual nsresult ThreadNewHdr(nsMsgHdr* hdr, bool &newThread);
+  virtual nsresult AddNewThread(nsMsgHdr *msgHdr);
+  virtual nsresult AddToThread(nsMsgHdr *newHdr, nsIMsgThread *thread, nsIMsgDBHdr *pMsgHdr, bool threadInThread);
+
+  static PRTime gLastUseTime; // global last use time
+  PRTime m_lastUseTime;       // last use time for this db
+  // inline to make instrumentation as cheap as possible
+  inline void RememberLastUseTime() {gLastUseTime = m_lastUseTime = PR_Now();}
+
+  bool    MatchDbName(nsIFile *dbName);  // returns TRUE if they match
+
+  // Flag handling routines
+  virtual nsresult SetKeyFlag(nsMsgKey key, bool set, uint32_t flag,
+                              nsIDBChangeListener *instigator = NULL);
+  virtual nsresult SetMsgHdrFlag(nsIMsgDBHdr *msgHdr, bool set, uint32_t flag,
+                                 nsIDBChangeListener *instigator);
+
+  virtual bool    SetHdrFlag(nsIMsgDBHdr *, bool bSet, nsMsgMessageFlagType flag);
+  virtual bool    SetHdrReadFlag(nsIMsgDBHdr *, bool pRead);
+  virtual uint32_t GetStatusFlags(nsIMsgDBHdr *msgHdr, uint32_t origFlags);
+  // helper function which doesn't involve thread object
+
+  virtual nsresult RemoveHeaderFromDB(nsMsgHdr *msgHdr);
+  virtual nsresult RemoveHeaderFromThread(nsMsgHdr *msgHdr);
+  virtual nsresult AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr);
+
+  nsCOMPtr <nsICollation> m_collationKeyGenerator;
+  nsCOMPtr <nsIMimeConverter> m_mimeConverter;
+  nsCOMPtr <nsIMsgRetentionSettings> m_retentionSettings;
+  nsCOMPtr <nsIMsgDownloadSettings> m_downloadSettings;
+
+  nsresult PurgeMessagesOlderThan(uint32_t daysToKeepHdrs,
+                                  bool applyToFlaggedMessages,
+                                  nsIMutableArray *hdrsToDelete);
+  nsresult PurgeExcessMessages(uint32_t numHeadersToKeep,
+                               bool applyToFlaggedMessages,
+                               nsIMutableArray *hdrsToDelete);
+
+  // mdb bookkeeping stuff
+  virtual nsresult      InitExistingDB();
+  virtual nsresult      InitNewDB();
+  virtual nsresult      InitMDBInfo();
+
+  nsCOMPtr <nsIMsgFolder> m_folder;
+  nsDBFolderInfo      *m_dbFolderInfo;
+  nsMsgKey      m_nextPseudoMsgKey;
+  nsIMdbEnv     *m_mdbEnv;  // to be used in all the db calls.
+  nsIMdbStore   *m_mdbStore;
+  nsIMdbTable   *m_mdbAllMsgHeadersTable;
+  nsIMdbTable   *m_mdbAllThreadsTable;
+
+  // Used for asynchronous db opens. If non-null, we're still opening
+  // the underlying mork database. If null, the db has been completely opened.
+  nsCOMPtr<nsIMdbThumb> m_thumb;
+  // used to remember the args to Open for async open.
+  bool m_create;
+  bool m_leaveInvalidDB;
+
+  nsCString     m_dbName;
+  nsTArray<nsMsgKey> m_newSet;  // new messages since last open.
+  bool          m_mdbTokensInitialized;
+  nsTObserverArray<nsCOMPtr<nsIDBChangeListener> > m_ChangeListeners;
+  mdb_token     m_hdrRowScopeToken;
+  mdb_token     m_threadRowScopeToken;
+  mdb_token     m_hdrTableKindToken;
+  mdb_token     m_threadTableKindToken;
+  mdb_token     m_allThreadsTableKindToken;
+  mdb_token     m_subjectColumnToken;
+  mdb_token     m_senderColumnToken;
+  mdb_token     m_messageIdColumnToken;
+  mdb_token     m_referencesColumnToken;
+  mdb_token     m_recipientsColumnToken;
+  mdb_token     m_dateColumnToken;
+  mdb_token     m_messageSizeColumnToken;
+  mdb_token     m_flagsColumnToken;
+  mdb_token     m_priorityColumnToken;
+  mdb_token     m_labelColumnToken;
+  mdb_token     m_statusOffsetColumnToken;
+  mdb_token     m_numLinesColumnToken;
+  mdb_token     m_ccListColumnToken;
+  mdb_token     m_bccListColumnToken;
+  mdb_token     m_threadFlagsColumnToken;
+  mdb_token     m_threadIdColumnToken;
+  mdb_token     m_threadChildrenColumnToken;
+  mdb_token     m_threadUnreadChildrenColumnToken;
+  mdb_token     m_messageThreadIdColumnToken;
+  mdb_token     m_threadSubjectColumnToken;
+  mdb_token     m_messageCharSetColumnToken;
+  mdb_token     m_threadParentColumnToken;
+  mdb_token     m_threadRootKeyColumnToken;
+  mdb_token     m_threadNewestMsgDateColumnToken;
+  mdb_token     m_offlineMsgOffsetColumnToken;
+  mdb_token     m_offlineMessageSizeColumnToken;
+
+  // header caching stuff - MRU headers, keeps them around in memory
+  nsresult      AddHdrToCache(nsIMsgDBHdr *hdr, nsMsgKey key);
+  nsresult      ClearHdrCache(bool reInit);
+  nsresult      RemoveHdrFromCache(nsIMsgDBHdr *hdr, nsMsgKey key);
+  // all headers currently instantiated, doesn't hold refs
+  // these get added when msg hdrs get constructed, and removed when they get destroyed.
+  nsresult      GetHdrFromUseCache(nsMsgKey key, nsIMsgDBHdr* *result);
+  nsresult      AddHdrToUseCache(nsIMsgDBHdr *hdr, nsMsgKey key);
+  nsresult      ClearUseHdrCache();
+  nsresult      RemoveHdrFromUseCache(nsIMsgDBHdr *hdr, nsMsgKey key);
+
+  // not-reference holding array of threads we've handed out.
+  // If a db goes away, it will clean up the outstanding threads.
+  // We use an nsTArray because we don't expect to ever have very many
+  // of these, rarely more than 5.
+  nsTArray<nsMsgThread *> m_threads;
+  // Clear outstanding thread objects
+  void ClearThreads();
+  nsMsgThread *FindExistingThread(nsMsgKey threadId);
+
+  mdb_pos       FindInsertIndexInSortedTable(nsIMdbTable *table, mdb_id idToInsert);
+
+  void          ClearCachedObjects(bool dbGoingAway);
+  void          ClearEnumerators();
+  // all instantiated headers, but doesn't hold refs.
+  PLDHashTable  *m_headersInUse;
+  static PLDHashNumber HashKey(const void* aKey);
+  static bool MatchEntry(const PLDHashEntryHdr* aEntry, const void* aKey);
+  static void MoveEntry(PLDHashTable* aTable, const PLDHashEntryHdr* aFrom, PLDHashEntryHdr* aTo);
+  static void ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry);
+  static PLDHashTableOps gMsgDBHashTableOps;
+  struct MsgHdrHashElement : public PLDHashEntryHdr {
+    nsMsgKey       mKey;
+    nsIMsgDBHdr     *mHdr;
+  };
+  PLDHashTable  *m_cachedHeaders;
+  bool          m_bCacheHeaders;
+  nsMsgKey  m_cachedThreadId;
+  nsCOMPtr <nsIMsgThread> m_cachedThread;
+  nsCOMPtr<nsIMdbFactory> mMdbFactory;
+
+  // Message reference hash table
+  static PLDHashTableOps gRefHashTableOps;
+  struct RefHashElement : public PLDHashEntryHdr {
+    const char     *mRef;       // Hash entry key, must come first
+    nsMsgKey        mThreadId;
+    uint32_t        mCount;
+  };
+  PLDHashTable *m_msgReferences;
+  nsresult GetRefFromHash(nsCString &reference, nsMsgKey *threadId);
+  nsresult AddRefToHash(nsCString &reference, nsMsgKey threadId);
+  nsresult AddMsgRefsToHash(nsIMsgDBHdr *msgHdr);
+  nsresult RemoveRefFromHash(nsCString &reference);
+  nsresult RemoveMsgRefsFromHash(nsIMsgDBHdr *msgHdr);
+  nsresult InitRefHash();
+
+  // not-reference holding array of enumerators we've handed out.
+  // If a db goes away, it will clean up the outstanding enumerators.
+  nsTArray<nsMsgDBEnumerator *> m_enumerators;
+
+  // Memory reporter details
+public:
+  static size_t HeaderHashSizeOf(PLDHashEntryHdr *hdr,
+                                 mozilla::MallocSizeOf aMallocSizeOf,
+                                 void *arg);
+  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+private:
+  uint32_t m_cacheSize;
+  RefPtr<mozilla::mailnews::MsgDBReporter> mMemReporter;
+};
+
+class nsMsgRetentionSettings : public nsIMsgRetentionSettings
+{
+public:
+  nsMsgRetentionSettings();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGRETENTIONSETTINGS
+protected:
+  virtual ~nsMsgRetentionSettings();
+  nsMsgRetainByPreference m_retainByPreference;
+  uint32_t                m_daysToKeepHdrs;
+  uint32_t                m_numHeadersToKeep;
+  bool                    m_useServerDefaults;
+  bool                    m_cleanupBodiesByDays;
+  uint32_t                m_daysToKeepBodies;
+  bool                    m_applyToFlaggedMessages;
+};
+
+class nsMsgDownloadSettings : public nsIMsgDownloadSettings
+{
+public:
+  nsMsgDownloadSettings();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGDOWNLOADSETTINGS
+protected:
+  virtual ~nsMsgDownloadSettings();
+  bool m_useServerDefaults;
+  bool m_downloadUnreadOnly;
+  bool m_downloadByDate;
+  int32_t m_ageLimitOfMsgsToDownload;
+};
+
+#endif
diff --git a/mailnews/db/msgdb/public/nsMsgHdr.h b/mailnews/db/msgdb/public/nsMsgHdr.h
new file mode 100644
index 000000000..6d23e7b49
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsMsgHdr.h
@@ -0,0 +1,86 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsMsgHdr_H
+#define _nsMsgHdr_H
+
+#include "mozilla/MemoryReporting.h"
+#include "nsIMsgHdr.h"
+#include "nsStringGlue.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+#include "nsTArray.h"
+
+class nsMsgDatabase;
+class nsCString;
+class nsIMsgThread;
+
+class nsMsgHdr : public nsIMsgDBHdr {
+public:
+    NS_DECL_NSIMSGDBHDR
+	friend class nsMsgDatabase;
+    friend class nsMsgPropertyEnumerator; // accesses m_mdb
+    ////////////////////////////////////////////////////////////////////////////
+    ////////////////////////////////////////////////////////////////////////////
+    // nsMsgHdr methods:
+    nsMsgHdr(nsMsgDatabase *db, nsIMdbRow *dbRow);
+
+    virtual nsresult    GetRawFlags(uint32_t *result);
+    void                Init();
+    virtual nsresult    InitCachedValues();
+    virtual nsresult    InitFlags();
+    void                ClearCachedValues() {m_initedValues = 0;}
+
+    NS_DECL_ISUPPORTS
+
+    nsIMdbRow   *GetMDBRow() {return m_mdbRow;}
+    bool        IsParentOf(nsIMsgDBHdr *possibleChild);
+    bool        IsAncestorOf(nsIMsgDBHdr *possibleChild);
+    bool        IsAncestorKilled(uint32_t ancestorsToCheck);
+    void        ReparentInThread(nsIMsgThread *thread);
+
+    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOfFun) const
+    {
+      return m_references.ShallowSizeOfExcludingThis(aMallocSizeOfFun);
+    }
+    size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOfFun) const
+    {
+      return aMallocSizeOfFun(this) + SizeOfExcludingThis(aMallocSizeOfFun);
+    }
+
+protected:
+  virtual ~nsMsgHdr();
+    nsresult SetStringColumn(const char *str, mdb_token token);
+    nsresult SetUInt32Column(uint32_t value, mdb_token token);
+    nsresult GetUInt32Column(mdb_token token, uint32_t *pvalue, uint32_t defaultValue = 0);
+    nsresult SetUInt64Column(uint64_t value, mdb_token token);
+    nsresult GetUInt64Column(mdb_token token, uint64_t *pvalue, uint64_t defaultValue = 0);
+
+    // reference and threading stuff.
+    nsresult	ParseReferences(const char *references);
+    const char* GetNextReference(const char *startNextRef, nsCString &reference,
+                                 bool acceptNonDelimitedReferences);
+
+    nsMsgKey	m_threadId; 
+    nsMsgKey	m_messageKey; 	//news: article number, mail mbox offset, imap uid...
+    nsMsgKey	m_threadParent;	// message this is a reply to, in thread.
+    PRTime      m_date;                         
+    uint32_t    m_messageSize;	// lines for news articles, bytes for mail messages
+    uint32_t    m_statusOffset;	// offset in a local mail message of the mozilla status hdr
+    uint32_t    m_flags;
+    // avoid parsing references every time we want one
+    nsTArray<nsCString> m_references;
+    nsMsgPriorityValue  m_priority;
+
+    // nsMsgHdrs will have to know what db and row they belong to, since they are really
+    // just a wrapper around the msg row in the mdb. This could cause problems,
+    // though I hope not.
+    nsMsgDatabase *m_mdb;
+    nsIMdbRow     *m_mdbRow;
+    uint32_t      m_initedValues;
+};
+
+#endif
+
diff --git a/mailnews/db/msgdb/public/nsMsgThread.h b/mailnews/db/msgdb/public/nsMsgThread.h
new file mode 100644
index 000000000..62d303bc8
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsMsgThread.h
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _nsMsgThread_H
+#define _nsMsgThread_H
+
+#include "nsAutoPtr.h"
+#include "nsIMsgThread.h"
+#include "nsStringGlue.h"
+#include "MailNewsTypes.h"
+#include "mdb.h"
+
+class nsIMdbTable;
+class nsIMsgDBHdr;
+class nsMsgDatabase;
+
+class nsMsgThread : public nsIMsgThread {
+public:
+  nsMsgThread();
+  nsMsgThread(nsMsgDatabase *db, nsIMdbTable *table);
+
+  friend class nsMsgThreadEnumerator;
+  friend class nsMsgDatabase;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGTHREAD
+
+  RefPtr<nsMsgDatabase> m_mdbDB;
+
+protected:
+  virtual ~nsMsgThread();
+
+  void                  Init();
+  void                  Clear();
+  virtual nsresult      InitCachedValues();
+  nsresult              ChangeChildCount(int32_t delta);
+  nsresult              ChangeUnreadChildCount(int32_t delta);
+  nsresult              RemoveChild(nsMsgKey msgKey);
+  nsresult              SetThreadRootKey(nsMsgKey threadRootKey);
+  nsresult              GetChildHdrForKey(nsMsgKey desiredKey, 
+                                          nsIMsgDBHdr **result, int32_t *resultIndex); 
+  nsresult              RerootThread(nsIMsgDBHdr *newParentOfOldRoot, nsIMsgDBHdr *oldRoot, nsIDBChangeAnnouncer *announcer);
+  nsresult              ReparentChildrenOf(nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeAnnouncer *announcer);
+  
+  nsresult              ReparentNonReferenceChildrenOf(nsIMsgDBHdr *topLevelHdr, nsMsgKey newParentKey,
+                                                       nsIDBChangeAnnouncer *announcer);
+  nsresult              ReparentMsgsWithInvalidParent(uint32_t numChildren, nsMsgKey threadParentKey);
+
+  nsMsgKey              m_threadKey; 
+  uint32_t              m_numChildren;
+  uint32_t              m_numUnreadChildren;
+  uint32_t              m_flags;
+  nsCOMPtr<nsIMdbTable> m_mdbTable;
+  nsCOMPtr<nsIMdbRow>   m_metaRow;
+  bool                  m_cachedValuesInitialized;
+  nsMsgKey              m_threadRootKey;
+  uint32_t              m_newestMsgDate;
+};
+
+#endif
+
diff --git a/mailnews/db/msgdb/public/nsNewsDatabase.h b/mailnews/db/msgdb/public/nsNewsDatabase.h
new file mode 100644
index 000000000..33e225913
--- /dev/null
+++ b/mailnews/db/msgdb/public/nsNewsDatabase.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _nsNewsDatabase_H_
+#define _nsNewsDatabase_H_
+
+#include "mozilla/Attributes.h"
+#include "nsMsgDatabase.h"
+#include "nsINewsDatabase.h"
+#include "nsTArray.h"
+
+class nsIDBChangeListener;
+class MSG_RetrieveArtInfo;
+class MSG_PurgeInfo;
+// news group database
+
+class nsNewsDatabase : public nsMsgDatabase , public nsINewsDatabase
+{
+public:
+  nsNewsDatabase();
+
+  NS_DECL_ISUPPORTS_INHERITED 
+  NS_DECL_NSINEWSDATABASE
+
+  NS_IMETHOD Close(bool forceCommit) override;
+  NS_IMETHOD ForceClosed() override;
+  NS_IMETHOD Commit(nsMsgDBCommit commitType) override;
+  virtual uint32_t GetCurVersion() override;
+
+  // methods to get and set docsets for ids.
+  NS_IMETHOD  IsRead(nsMsgKey key, bool *pRead) override;
+  virtual nsresult  IsHeaderRead(nsIMsgDBHdr *msgHdr, bool *pRead) override;
+
+  NS_IMETHOD         GetHighWaterArticleNum(nsMsgKey *key) override;
+  NS_IMETHOD         GetLowWaterArticleNum(nsMsgKey *key) override;
+  NS_IMETHOD         MarkAllRead(uint32_t *aNumMarked, nsMsgKey **thoseMarked) override;
+
+  virtual nsresult    ExpireUpTo(nsMsgKey expireKey);
+  virtual nsresult    ExpireRange(nsMsgKey startRange, nsMsgKey endRange);
+ 
+  virtual bool        SetHdrReadFlag(nsIMsgDBHdr *msgHdr, bool bRead) override;
+ 
+  virtual nsresult  AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr) override;
+  nsresult          SyncWithReadSet();
+  
+  NS_IMETHOD GetDefaultViewFlags(nsMsgViewFlagsTypeValue *aDefaultViewFlags) override;
+  NS_IMETHOD GetDefaultSortType(nsMsgViewSortTypeValue *aDefaultSortType) override;
+  NS_IMETHOD GetDefaultSortOrder(nsMsgViewSortOrderValue *aDefaultSortOrder) override;
+
+protected:
+  virtual ~nsNewsDatabase();
+  // this is owned by the nsNewsFolder, which lives longer than the db.
+  nsMsgKeySet           *m_readSet;
+};
+
+#endif
diff --git a/mailnews/db/msgdb/src/moz.build b/mailnews/db/msgdb/src/moz.build
new file mode 100644
index 000000000..07f537462
--- /dev/null
+++ b/mailnews/db/msgdb/src/moz.build
@@ -0,0 +1,18 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SOURCES += [
+    'nsDBFolderInfo.cpp',
+    'nsImapMailDatabase.cpp',
+    'nsMailDatabase.cpp',
+    'nsMsgDatabase.cpp',
+    'nsMsgHdr.cpp',
+    'nsMsgOfflineImapOperation.cpp',
+    'nsMsgThread.cpp',
+    'nsNewsDatabase.cpp',
+]
+
+FINAL_LIBRARY = 'mail'
+
diff --git a/mailnews/db/msgdb/src/nsDBFolderInfo.cpp b/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
new file mode 100644
index 000000000..0260738d0
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
@@ -0,0 +1,977 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgDatabase.h"
+#include "nsMsgFolderFlags.h"
+#include "nsIPrefService.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefLocalizedString.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsIMsgDBView.h"
+#include "nsServiceManagerUtils.h"
+#include "nsImapCore.h"
+#include "mozilla/Services.h"
+
+static const char *kDBFolderInfoScope = "ns:msg:db:row:scope:dbfolderinfo:all";
+static const char *kDBFolderInfoTableKind = "ns:msg:db:table:kind:dbfolderinfo";
+
+struct mdbOid gDBFolderInfoOID;
+
+static const char * kNumMessagesColumnName ="numMsgs";
+// have to leave this as numNewMsgs even though it's numUnread Msgs
+static const char * kNumUnreadMessagesColumnName = "numNewMsgs";
+static const char * kFlagsColumnName = "flags";
+static const char * kFolderSizeColumnName = "folderSize";
+static const char * kExpungedBytesColumnName = "expungedBytes";
+static const char * kFolderDateColumnName = "folderDate";
+static const char * kHighWaterMessageKeyColumnName = "highWaterKey";
+
+static const char * kImapUidValidityColumnName = "UIDValidity";
+static const char * kTotalPendingMessagesColumnName = "totPendingMsgs";
+static const char * kUnreadPendingMessagesColumnName = "unreadPendingMsgs";
+static const char * kMailboxNameColumnName = "mailboxName";
+static const char * kKnownArtsSetColumnName = "knownArts";
+static const char * kExpiredMarkColumnName = "expiredMark";
+static const char * kVersionColumnName = "version";
+static const char * kCharacterSetColumnName = "charSet";
+static const char * kCharacterSetOverrideColumnName = "charSetOverride";
+static const char * kLocaleColumnName = "locale";
+
+
+#define kMAILNEWS_VIEW_DEFAULT_CHARSET        "mailnews.view_default_charset"
+#define kMAILNEWS_DEFAULT_CHARSET_OVERRIDE    "mailnews.force_charset_override"
+static nsCString* gDefaultCharacterSet = nullptr;
+static bool       gDefaultCharacterOverride;
+static nsIObserver *gFolderCharsetObserver = nullptr;
+
+// observer for charset related preference notification
+class nsFolderCharsetObserver : public nsIObserver {
+
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  nsFolderCharsetObserver() { }
+private:
+  virtual ~nsFolderCharsetObserver() {}
+};
+
+NS_IMPL_ISUPPORTS(nsFolderCharsetObserver, nsIObserver)
+
+NS_IMETHODIMP nsFolderCharsetObserver::Observe(nsISupports *aSubject, const char *aTopic, const char16_t *someData)
+{
+  nsresult rv;
+
+  nsCOMPtr<nsIPrefService> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID, &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIPrefBranch> prefBranch;
+  rv = prefs->GetBranch(nullptr, getter_AddRefs(prefBranch));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!strcmp(aTopic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID))
+  {
+    nsDependentString prefName(someData);
+
+    if (prefName.EqualsLiteral(kMAILNEWS_VIEW_DEFAULT_CHARSET))
+    {
+      nsCOMPtr<nsIPrefLocalizedString> pls;
+      rv = prefBranch->GetComplexValue(kMAILNEWS_VIEW_DEFAULT_CHARSET,
+                      NS_GET_IID(nsIPrefLocalizedString), getter_AddRefs(pls));
+      if (NS_SUCCEEDED(rv))
+      {
+        nsString ucsval;
+        pls->ToString(getter_Copies(ucsval));
+        if (!ucsval.IsEmpty())
+        {
+          if (gDefaultCharacterSet)
+            CopyUTF16toUTF8(ucsval, *gDefaultCharacterSet);
+        }
+      }
+    }
+    else if (prefName.EqualsLiteral(kMAILNEWS_DEFAULT_CHARSET_OVERRIDE))
+    {
+      rv = prefBranch->GetBoolPref(kMAILNEWS_DEFAULT_CHARSET_OVERRIDE, &gDefaultCharacterOverride);
+    }
+  }
+  else if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID))
+  {
+    rv = prefBranch->RemoveObserver(kMAILNEWS_VIEW_DEFAULT_CHARSET, this);
+    rv = prefBranch->RemoveObserver(kMAILNEWS_DEFAULT_CHARSET_OVERRIDE, this);
+    NS_IF_RELEASE(gFolderCharsetObserver);
+    delete gDefaultCharacterSet;
+    gDefaultCharacterSet = nullptr;
+  }
+  return rv;
+}
+
+
+NS_IMPL_ADDREF(nsDBFolderInfo)
+NS_IMPL_RELEASE(nsDBFolderInfo)
+
+NS_IMETHODIMP
+nsDBFolderInfo::QueryInterface(REFNSIID iid, void** result)
+{
+  if (! result)
+    return NS_ERROR_NULL_POINTER;
+
+  *result = nullptr;
+  if(iid.Equals(NS_GET_IID(nsIDBFolderInfo)) ||
+    iid.Equals(NS_GET_IID(nsISupports)))
+  {
+    *result = static_cast<nsIDBFolderInfo*>(this);
+    AddRef();
+    return NS_OK;
+  }
+  return NS_NOINTERFACE;
+}
+
+
+nsDBFolderInfo::nsDBFolderInfo(nsMsgDatabase *mdb)
+                  : m_flags(0),
+                    m_expiredMark(0),
+                    m_expiredMarkColumnToken(0)
+{
+  m_mdbTable = NULL;
+  m_mdbRow = NULL;
+  m_version = 1; // for upgrading...
+  m_IMAPHierarchySeparator = 0; // imap path separator
+  // mail only (for now)
+  m_folderSize = 0;
+  m_folderDate = 0;
+  m_expungedBytes = 0; // sum of size of deleted messages in folder
+  m_highWaterMessageKey = 0;
+
+  m_numUnreadMessages = 0;
+  m_numMessages = 0;
+  // IMAP only
+  m_ImapUidValidity = kUidUnknown;
+  m_totalPendingMessages =0;
+  m_unreadPendingMessages = 0;
+
+  m_mdbTokensInitialized = false;
+  m_charSetOverride = false;
+
+  if (!gFolderCharsetObserver)
+  {
+    nsresult rv;
+    nsCOMPtr<nsIPrefService> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID, &rv);
+    nsCOMPtr<nsIPrefBranch> prefBranch;
+    if (NS_SUCCEEDED(rv))
+    {
+      rv = prefs->GetBranch(nullptr, getter_AddRefs(prefBranch));
+    }
+    if (NS_SUCCEEDED(rv))
+    {
+      nsCOMPtr<nsIPrefLocalizedString> pls;
+      rv = prefBranch->GetComplexValue(kMAILNEWS_VIEW_DEFAULT_CHARSET,
+        NS_GET_IID(nsIPrefLocalizedString), getter_AddRefs(pls));
+      if (NS_SUCCEEDED(rv))
+      {
+        nsString ucsval;
+        pls->ToString(getter_Copies(ucsval));
+        if (!ucsval.IsEmpty())
+        {
+          if (!gDefaultCharacterSet)
+            gDefaultCharacterSet = new nsCString;
+
+          if (gDefaultCharacterSet)
+            CopyUTF16toUTF8(ucsval, *gDefaultCharacterSet);
+        }
+      }
+      rv = prefBranch->GetBoolPref(kMAILNEWS_DEFAULT_CHARSET_OVERRIDE, &gDefaultCharacterOverride);
+
+      gFolderCharsetObserver = new nsFolderCharsetObserver();
+      NS_ASSERTION(gFolderCharsetObserver, "failed to create observer");
+
+      // register prefs callbacks
+      if (gFolderCharsetObserver)
+      {
+        NS_ADDREF(gFolderCharsetObserver);
+        rv = prefBranch->AddObserver(kMAILNEWS_VIEW_DEFAULT_CHARSET, gFolderCharsetObserver, false);
+        rv = prefBranch->AddObserver(kMAILNEWS_DEFAULT_CHARSET_OVERRIDE, gFolderCharsetObserver, false);
+
+        // also register for shutdown
+        nsCOMPtr<nsIObserverService> observerService =
+          mozilla::services::GetObserverService();
+        if (observerService)
+        {
+          rv = observerService->AddObserver(gFolderCharsetObserver, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+        }
+      }
+    }
+  }
+
+  m_mdb = mdb;
+  if (mdb)
+  {
+    nsresult err;
+
+    //		mdb->AddRef();
+    err = m_mdb->GetStore()->StringToToken(mdb->GetEnv(), kDBFolderInfoScope, &m_rowScopeToken);
+    if (NS_SUCCEEDED(err))
+    {
+      err = m_mdb->GetStore()->StringToToken(mdb->GetEnv(), kDBFolderInfoTableKind, &m_tableKindToken);
+      if (NS_SUCCEEDED(err))
+      {
+        gDBFolderInfoOID.mOid_Scope = m_rowScopeToken;
+        gDBFolderInfoOID.mOid_Id = 1;
+      }
+    }
+    InitMDBInfo();
+  }
+}
+
+nsDBFolderInfo::~nsDBFolderInfo()
+{
+  // nsMsgDatabase strictly owns nsDBFolderInfo, so don't ref-count db.
+  ReleaseExternalReferences();
+}
+
+// Release any objects we're holding onto. This needs to be safe
+// to call multiple times.
+void nsDBFolderInfo::ReleaseExternalReferences()
+{
+  if (m_mdb)
+  {
+    if (m_mdbTable)
+    {
+      NS_RELEASE(m_mdbTable);
+      m_mdbTable = nullptr;
+    }
+    if (m_mdbRow)
+    {
+      NS_RELEASE(m_mdbRow);
+      m_mdbRow = nullptr;
+    }
+    m_mdb = nullptr;
+  }
+}
+
+// this routine sets up a new db to know about the dbFolderInfo stuff...
+nsresult nsDBFolderInfo::AddToNewMDB()
+{
+  nsresult ret = NS_OK;
+  if (m_mdb && m_mdb->GetStore())
+  {
+    nsIMdbStore *store = m_mdb->GetStore();
+    // create the unique table for the dbFolderInfo.
+    nsresult err = store->NewTable(m_mdb->GetEnv(), m_rowScopeToken,
+      m_tableKindToken, true, nullptr, &m_mdbTable);
+
+    // create the singleton row for the dbFolderInfo.
+    err  = store->NewRowWithOid(m_mdb->GetEnv(),
+      &gDBFolderInfoOID, &m_mdbRow);
+
+    // add the row to the singleton table.
+    if (m_mdbRow && NS_SUCCEEDED(err))
+      err = m_mdbTable->AddRow(m_mdb->GetEnv(), m_mdbRow);
+
+    ret = err;	// what are we going to do about nsresult's?
+  }
+  return ret;
+}
+
+nsresult nsDBFolderInfo::InitFromExistingDB()
+{
+  nsresult ret = NS_OK;
+  if (m_mdb && m_mdb->GetStore())
+  {
+    nsIMdbStore *store = m_mdb->GetStore();
+    if (store)
+    {
+      mdb_pos		rowPos;
+      mdb_count outTableCount; // current number of such tables
+      mdb_bool mustBeUnique; // whether port can hold only one of these
+      mdb_bool hasOid;
+      ret = store->GetTableKind(m_mdb->GetEnv(), m_rowScopeToken, m_tableKindToken, &outTableCount,
+        &mustBeUnique, &m_mdbTable);
+      //			NS_ASSERTION(mustBeUnique && outTableCount == 1, "only one global db info allowed");
+
+      if (m_mdbTable)
+      {
+        // find singleton row for global info.
+        ret = m_mdbTable->HasOid(m_mdb->GetEnv(), &gDBFolderInfoOID, &hasOid);
+        if (NS_SUCCEEDED(ret))
+        {
+          nsIMdbTableRowCursor *rowCursor;
+          rowPos = -1;
+          ret= m_mdbTable->GetTableRowCursor(m_mdb->GetEnv(), rowPos, &rowCursor);
+          if (NS_SUCCEEDED(ret))
+          {
+            ret = rowCursor->NextRow(m_mdb->GetEnv(), &m_mdbRow, &rowPos);
+            NS_RELEASE(rowCursor);
+            if (!m_mdbRow)
+              ret = NS_ERROR_FAILURE;
+            if (NS_SUCCEEDED(ret))
+              LoadMemberVariables();
+          }
+        }
+      }
+      else
+        ret = NS_ERROR_FAILURE;
+    }
+  }
+  return ret;
+}
+
+nsresult nsDBFolderInfo::InitMDBInfo()
+{
+  nsresult ret = NS_OK;
+  if (!m_mdbTokensInitialized && m_mdb && m_mdb->GetStore())
+  {
+    nsIMdbStore *store = m_mdb->GetStore();
+    nsIMdbEnv	*env = m_mdb->GetEnv();
+
+    store->StringToToken(env,  kNumMessagesColumnName, &m_numMessagesColumnToken);
+    store->StringToToken(env,  kNumUnreadMessagesColumnName, &m_numUnreadMessagesColumnToken);
+    store->StringToToken(env,  kFlagsColumnName, &m_flagsColumnToken);
+    store->StringToToken(env,  kFolderSizeColumnName, &m_folderSizeColumnToken);
+    store->StringToToken(env,  kExpungedBytesColumnName, &m_expungedBytesColumnToken);
+    store->StringToToken(env,  kFolderDateColumnName, &m_folderDateColumnToken);
+
+    store->StringToToken(env,  kHighWaterMessageKeyColumnName, &m_highWaterMessageKeyColumnToken);
+    store->StringToToken(env,  kMailboxNameColumnName, &m_mailboxNameColumnToken);
+
+    store->StringToToken(env,  kImapUidValidityColumnName, &m_imapUidValidityColumnToken);
+    store->StringToToken(env,  kTotalPendingMessagesColumnName, &m_totalPendingMessagesColumnToken);
+    store->StringToToken(env,  kUnreadPendingMessagesColumnName, &m_unreadPendingMessagesColumnToken);
+    store->StringToToken(env,  kExpiredMarkColumnName, &m_expiredMarkColumnToken);
+    store->StringToToken(env,  kVersionColumnName, &m_versionColumnToken);
+    m_mdbTokensInitialized  = true;
+  }
+
+  return ret;
+}
+
+nsresult nsDBFolderInfo::LoadMemberVariables()
+{
+  // it's really not an error for these properties to not exist...
+  GetInt32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+  GetInt32PropertyWithToken(m_numUnreadMessagesColumnToken, m_numUnreadMessages);
+  GetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+  GetInt64PropertyWithToken(m_folderSizeColumnToken, m_folderSize);
+  GetUint32PropertyWithToken(m_folderDateColumnToken, m_folderDate);
+  GetInt32PropertyWithToken(m_imapUidValidityColumnToken, m_ImapUidValidity, kUidUnknown);
+  GetUint32PropertyWithToken(m_expiredMarkColumnToken, m_expiredMark);
+  GetInt64PropertyWithToken(m_expungedBytesColumnToken, m_expungedBytes);
+  GetUint32PropertyWithToken(m_highWaterMessageKeyColumnToken, m_highWaterMessageKey);
+  int32_t version;
+
+  GetInt32PropertyWithToken(m_versionColumnToken, version);
+  m_version = (uint16_t) version;
+  m_charSetOverride = gDefaultCharacterOverride;
+  uint32_t propertyValue;
+  nsresult rv = GetUint32Property(kCharacterSetOverrideColumnName, gDefaultCharacterOverride, &propertyValue);
+  if (NS_SUCCEEDED(rv))
+    m_charSetOverride = propertyValue;
+
+  m_mdb->GetProperty(m_mdbRow, kCharacterSetColumnName, getter_Copies(m_charSet));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetVersion(uint32_t version)
+{
+  m_version = version;
+  return SetUint32PropertyWithToken(m_versionColumnToken, (uint32_t) m_version);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetVersion(uint32_t *version)
+{
+  *version = m_version;
+  return NS_OK;
+}
+
+
+nsresult nsDBFolderInfo::AdjustHighWater(nsMsgKey highWater, bool force)
+{
+  if (force || m_highWaterMessageKey < highWater)
+  {
+    m_highWaterMessageKey = highWater;
+    SetUint32PropertyWithToken(m_highWaterMessageKeyColumnToken, highWater);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetHighWater(nsMsgKey highWater)
+{
+  return AdjustHighWater(highWater, true);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::OnKeyAdded(nsMsgKey aNewKey)
+{
+  return AdjustHighWater(aNewKey, false);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetFolderSize(int64_t *size)
+{
+  NS_ENSURE_ARG_POINTER(size);
+  *size = m_folderSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderSize(int64_t size)
+{
+  m_folderSize = size;
+  return SetInt64Property(kFolderSizeColumnName, m_folderSize);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetFolderDate(uint32_t *folderDate)
+{
+  NS_ENSURE_ARG_POINTER(folderDate);
+  *folderDate = m_folderDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderDate(uint32_t folderDate)
+{
+  m_folderDate = folderDate;
+  return SetUint32PropertyWithToken(m_folderDateColumnToken, folderDate);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetHighWater(nsMsgKey *result)
+{
+  // Sanity check highwater - if it gets too big, other code
+  // can fail. Look through last 100 messages to recalculate
+  // the highwater mark.
+  *result = m_highWaterMessageKey;
+  if (m_highWaterMessageKey > 0xFFFFFF00 && m_mdb)
+  {
+    nsCOMPtr <nsISimpleEnumerator> hdrs;
+    nsresult rv = m_mdb->ReverseEnumerateMessages(getter_AddRefs(hdrs));
+    if (NS_FAILED(rv))
+      return rv;
+    bool hasMore = false;
+    nsCOMPtr<nsIMsgDBHdr> pHeader;
+    nsMsgKey recalculatedHighWater = 1;
+    int32_t i = 0;
+    while(i++ < 100 && NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore))
+              && hasMore)
+    {
+      nsCOMPtr<nsISupports> supports;
+      (void) hdrs->GetNext(getter_AddRefs(supports));
+      pHeader = do_QueryInterface(supports);
+      if (pHeader)
+      {
+        nsMsgKey msgKey;
+        pHeader->GetMessageKey(&msgKey);
+        if (msgKey > recalculatedHighWater)
+          recalculatedHighWater = msgKey;
+      }
+    }
+    NS_ASSERTION(m_highWaterMessageKey >= recalculatedHighWater,
+                 "highwater incorrect");
+    m_highWaterMessageKey = recalculatedHighWater;
+  }
+  *result = m_highWaterMessageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetExpiredMark(nsMsgKey expiredKey)
+{
+  m_expiredMark = expiredKey;
+  return SetUint32PropertyWithToken(m_expiredMarkColumnToken, expiredKey);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetExpiredMark(nsMsgKey *result)
+{
+  *result = m_expiredMark;
+  return NS_OK;
+}
+
+// The size of the argument depends on the maximum size of a single message
+NS_IMETHODIMP nsDBFolderInfo::ChangeExpungedBytes(int32_t delta)
+{
+  return SetExpungedBytes(m_expungedBytes + delta);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetMailboxName(const nsAString &newBoxName)
+{
+  return SetPropertyWithToken(m_mailboxNameColumnToken, newBoxName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetMailboxName(nsAString &boxName)
+{
+  return GetPropertyWithToken(m_mailboxNameColumnToken, boxName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::ChangeNumUnreadMessages(int32_t delta)
+{
+  m_numUnreadMessages += delta;
+  // m_numUnreadMessages can never be set to negative.
+  if (m_numUnreadMessages < 0)
+  {
+#ifdef DEBUG_bienvenu1
+     NS_ASSERTION(false, "Hardcoded assertion");
+#endif
+      m_numUnreadMessages = 0;
+  }
+  return SetUint32PropertyWithToken(m_numUnreadMessagesColumnToken, m_numUnreadMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::ChangeNumMessages(int32_t delta)
+{
+  m_numMessages += delta;
+  // m_numMessages can never be set to negative.
+  if (m_numMessages < 0)
+  {
+#ifdef DEBUG_bienvenu
+    NS_ASSERTION(false, "num messages can't be < 0");
+#endif
+    m_numMessages = 0;
+  }
+  return SetUint32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+}
+
+
+NS_IMETHODIMP nsDBFolderInfo::GetNumUnreadMessages(int32_t *result)
+{
+  *result = m_numUnreadMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetNumUnreadMessages(int32_t numUnreadMessages)
+{
+  m_numUnreadMessages = numUnreadMessages;
+  return SetUint32PropertyWithToken(m_numUnreadMessagesColumnToken, m_numUnreadMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetNumMessages(int32_t *result)
+{
+  *result = m_numMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetNumMessages(int32_t numMessages)
+{
+  m_numMessages = numMessages;
+  return SetUint32PropertyWithToken(m_numMessagesColumnToken, m_numMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetExpungedBytes(int64_t *result)
+{
+  *result = m_expungedBytes;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetExpungedBytes(int64_t expungedBytes)
+{
+  m_expungedBytes = expungedBytes;
+  return SetInt64PropertyWithToken(m_expungedBytesColumnToken, m_expungedBytes);
+}
+
+
+NS_IMETHODIMP nsDBFolderInfo::GetFlags(int32_t *result)
+{
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFlags(int32_t flags)
+{
+  nsresult ret = NS_OK;
+
+  if (m_flags != flags)
+  {
+    NS_ASSERTION((m_flags & nsMsgFolderFlags::Inbox) == 0 || (flags & nsMsgFolderFlags::Inbox) != 0, "lost inbox flag");
+    m_flags = flags;
+    ret = SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+  }
+  return ret;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::OrFlags(int32_t flags, int32_t *result)
+{
+  m_flags |= flags;
+  *result = m_flags;
+  return SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::AndFlags(int32_t flags, int32_t *result)
+{
+  m_flags &= flags;
+  *result = m_flags;
+  return SetInt32PropertyWithToken(m_flagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP	nsDBFolderInfo::GetImapUidValidity(int32_t *result)
+{
+  *result = m_ImapUidValidity;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapUidValidity(int32_t uidValidity)
+{
+  m_ImapUidValidity = uidValidity;
+  return SetUint32PropertyWithToken(m_imapUidValidityColumnToken, m_ImapUidValidity);
+}
+
+bool nsDBFolderInfo::TestFlag(int32_t flags)
+{
+  return (m_flags & flags) != 0;
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetCharacterSet(nsACString &result)
+{
+  if (!m_charSet.IsEmpty())
+    result.Assign(m_charSet);
+  else if (gDefaultCharacterSet)
+    result.Assign(*gDefaultCharacterSet);
+  else
+    result.Truncate();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetEffectiveCharacterSet(nsACString &result)
+{
+  result.Truncate();
+  if (NS_FAILED(GetCharProperty(kCharacterSetColumnName, result)) ||
+      (result.IsEmpty() && gDefaultCharacterSet))
+    result = *gDefaultCharacterSet;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetCharacterSet(const nsACString &charSet)
+{
+  m_charSet.Assign(charSet);
+  return SetCharProperty(kCharacterSetColumnName, charSet);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetCharacterSetOverride(bool *characterSetOverride)
+{
+  NS_ENSURE_ARG_POINTER(characterSetOverride);
+  *characterSetOverride = m_charSetOverride;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetCharacterSetOverride(bool characterSetOverride)
+{
+  m_charSetOverride = characterSetOverride;
+  return SetUint32Property(kCharacterSetOverrideColumnName, characterSetOverride);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetLocale(nsAString &result)
+{
+  GetProperty(kLocaleColumnName, result);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetLocale(const nsAString &locale)
+{
+  return SetProperty(kLocaleColumnName, locale);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetImapTotalPendingMessages(int32_t *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_totalPendingMessages;
+  return NS_OK;
+}
+
+void nsDBFolderInfo::ChangeImapTotalPendingMessages(int32_t delta)
+{
+  m_totalPendingMessages+=delta;
+  SetInt32PropertyWithToken(m_totalPendingMessagesColumnToken, m_totalPendingMessages);
+}
+
+NS_IMETHODIMP
+nsDBFolderInfo::GetImapUnreadPendingMessages(int32_t *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_unreadPendingMessages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapUnreadPendingMessages(int32_t numUnreadPendingMessages)
+{
+  m_unreadPendingMessages = numUnreadPendingMessages;
+  return SetUint32PropertyWithToken(m_unreadPendingMessagesColumnToken, m_unreadPendingMessages);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetImapTotalPendingMessages(int32_t numTotalPendingMessages)
+{
+  m_totalPendingMessages = numTotalPendingMessages;
+  return SetUint32PropertyWithToken(m_totalPendingMessagesColumnToken, m_totalPendingMessages);
+}
+
+void nsDBFolderInfo::ChangeImapUnreadPendingMessages(int32_t delta)
+{
+  m_unreadPendingMessages+=delta;
+  SetInt32PropertyWithToken(m_unreadPendingMessagesColumnToken, m_unreadPendingMessages);
+}
+
+/* attribute nsMsgViewTypeValue viewType; */
+NS_IMETHODIMP nsDBFolderInfo::GetViewType(nsMsgViewTypeValue *aViewType)
+{
+  uint32_t viewTypeValue;
+  nsresult rv = GetUint32Property("viewType", nsMsgViewType::eShowAllThreads, &viewTypeValue);
+  *aViewType = viewTypeValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetViewType(nsMsgViewTypeValue aViewType)
+{
+  return SetUint32Property("viewType", aViewType);
+}
+
+/* attribute nsMsgViewFlagsTypeValue viewFlags; */
+NS_IMETHODIMP nsDBFolderInfo::GetViewFlags(nsMsgViewFlagsTypeValue *aViewFlags)
+{
+  nsMsgViewFlagsTypeValue defaultViewFlags;
+  nsresult rv = m_mdb->GetDefaultViewFlags(&defaultViewFlags);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  uint32_t viewFlagsValue;
+  rv = GetUint32Property("viewFlags", defaultViewFlags, &viewFlagsValue);
+  *aViewFlags = viewFlagsValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetViewFlags(nsMsgViewFlagsTypeValue aViewFlags)
+{
+  return SetUint32Property("viewFlags", aViewFlags);
+}
+
+/* attribute nsMsgViewSortTypeValue sortType; */
+NS_IMETHODIMP nsDBFolderInfo::GetSortType(nsMsgViewSortTypeValue *aSortType)
+{
+  nsMsgViewSortTypeValue defaultSortType;
+  nsresult rv = m_mdb->GetDefaultSortType(&defaultSortType);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  uint32_t sortTypeValue;
+  rv = GetUint32Property("sortType", defaultSortType, &sortTypeValue);
+  *aSortType = sortTypeValue;
+  return rv;
+}
+NS_IMETHODIMP nsDBFolderInfo::SetSortType(nsMsgViewSortTypeValue aSortType)
+{
+  return SetUint32Property("sortType", aSortType);
+}
+
+/* attribute nsMsgViewSortOrderValue sortOrder; */
+NS_IMETHODIMP nsDBFolderInfo::GetSortOrder(nsMsgViewSortOrderValue *aSortOrder)
+{
+  nsMsgViewSortOrderValue defaultSortOrder;
+  nsresult rv = m_mdb->GetDefaultSortOrder(&defaultSortOrder);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  uint32_t sortOrderValue;
+  rv = GetUint32Property("sortOrder", defaultSortOrder, &sortOrderValue);
+  *aSortOrder = sortOrderValue;
+  return rv;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetSortOrder(nsMsgViewSortOrderValue aSortOrder)
+{
+  return SetUint32Property("sortOrder", aSortOrder);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetKnownArtsSet(const char *newsArtSet)
+{
+  return m_mdb->SetProperty(m_mdbRow, kKnownArtsSetColumnName, newsArtSet);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetKnownArtsSet(char **newsArtSet)
+{
+  return m_mdb->GetProperty(m_mdbRow, kKnownArtsSetColumnName, newsArtSet);
+}
+
+// get arbitrary property, aka row cell value.
+NS_IMETHODIMP nsDBFolderInfo::GetProperty(const char *propertyName, nsAString &resultProperty)
+{
+  return m_mdb->GetPropertyAsNSString(m_mdbRow, propertyName, resultProperty);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetCharProperty(const char *aPropertyName,
+                                              const nsACString &aPropertyValue)
+{
+  return m_mdb->SetProperty(m_mdbRow, aPropertyName,
+                            nsCString(aPropertyValue).get());
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetCharProperty(const char *propertyName,
+                                              nsACString &resultProperty)
+{
+  nsCString result;
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, propertyName, getter_Copies(result));
+  if (NS_SUCCEEDED(rv))
+    resultProperty.Assign(result);
+  return rv;
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetUint32Property(const char *propertyName, uint32_t propertyValue)
+{
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName, propertyValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetInt64Property(const char *propertyName, int64_t propertyValue)
+{
+  return m_mdb->SetUint64Property(m_mdbRow, propertyName, (uint64_t) propertyValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetProperty(const char *propertyName, const nsAString &propertyStr)
+{
+  return m_mdb->SetPropertyFromNSString(m_mdbRow, propertyName, propertyStr);
+}
+
+nsresult nsDBFolderInfo::SetPropertyWithToken(mdb_token aProperty, const nsAString &propertyStr)
+{
+  return m_mdb->SetNSStringPropertyWithToken(m_mdbRow, aProperty, propertyStr);
+}
+
+nsresult nsDBFolderInfo::SetUint32PropertyWithToken(mdb_token aProperty, uint32_t propertyValue)
+{
+  return m_mdb->UInt32ToRowCellColumn(m_mdbRow, aProperty, propertyValue);
+}
+
+nsresult nsDBFolderInfo::SetInt64PropertyWithToken(mdb_token aProperty, int64_t propertyValue)
+{
+  return m_mdb->UInt64ToRowCellColumn(m_mdbRow, aProperty, (uint64_t) propertyValue);
+}
+
+nsresult nsDBFolderInfo::SetInt32PropertyWithToken(mdb_token aProperty, int32_t propertyValue)
+{
+  nsAutoString propertyStr;
+  propertyStr.AppendInt(propertyValue, 16);
+  return SetPropertyWithToken(aProperty, propertyStr);
+}
+
+nsresult nsDBFolderInfo::GetPropertyWithToken(mdb_token aProperty, nsAString &resultProperty)
+{
+  return m_mdb->RowCellColumnTonsString(m_mdbRow, aProperty, resultProperty);
+}
+
+nsresult nsDBFolderInfo::GetUint32PropertyWithToken(mdb_token aProperty, uint32_t &propertyValue, uint32_t defaultValue)
+{
+  return m_mdb->RowCellColumnToUInt32(m_mdbRow, aProperty, propertyValue, defaultValue);
+}
+
+nsresult nsDBFolderInfo::GetInt32PropertyWithToken(mdb_token aProperty, int32_t &propertyValue, int32_t defaultValue)
+{
+  return m_mdb->RowCellColumnToUInt32(m_mdbRow, aProperty, (uint32_t &) propertyValue, defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetUint32Property(const char *propertyName, uint32_t defaultValue, uint32_t *propertyValue)
+{
+  return m_mdb->GetUint32Property(m_mdbRow, propertyName, propertyValue, defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetInt64Property(const char *propertyName, int64_t defaultValue, int64_t *propertyValue)
+{
+  return m_mdb->GetUint64Property(m_mdbRow, propertyName, (uint64_t *) &propertyValue, defaultValue);
+}
+
+nsresult nsDBFolderInfo::GetInt64PropertyWithToken(mdb_token aProperty,
+                                                   int64_t &propertyValue,
+                                                   int64_t defaultValue)
+{
+  return m_mdb->RowCellColumnToUInt64(m_mdbRow, aProperty, (uint64_t *) &propertyValue, defaultValue);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetBooleanProperty(const char *propertyName, bool defaultValue, bool *propertyValue)
+{
+  uint32_t defaultUint32Value = (defaultValue) ? 1 : 0;
+  uint32_t returnValue;
+  nsresult rv = m_mdb->GetUint32Property(m_mdbRow, propertyName, &returnValue, defaultUint32Value);
+  *propertyValue = (returnValue != 0);
+  return rv;
+}
+NS_IMETHODIMP	nsDBFolderInfo::SetBooleanProperty(const char *propertyName, bool propertyValue)
+{
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName, propertyValue ? 1 : 0);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::GetFolderName(nsACString &folderName)
+{
+  return GetCharProperty("folderName", folderName);
+}
+
+NS_IMETHODIMP nsDBFolderInfo::SetFolderName(const nsACString &folderName)
+{
+  return SetCharProperty("folderName", folderName);
+}
+
+class nsTransferDBFolderInfo : public nsDBFolderInfo
+{
+public:
+  nsTransferDBFolderInfo();
+  virtual ~nsTransferDBFolderInfo();
+  // parallel arrays of properties and values
+  nsTArray<nsCString> m_properties;
+  nsTArray<nsCString> m_values;
+};
+
+nsTransferDBFolderInfo::nsTransferDBFolderInfo() : nsDBFolderInfo(nullptr)
+{
+}
+
+nsTransferDBFolderInfo::~nsTransferDBFolderInfo()
+{
+}
+
+/* void GetTransferInfo (out nsIDBFolderInfo transferInfo); */
+NS_IMETHODIMP nsDBFolderInfo::GetTransferInfo(nsIDBFolderInfo **transferInfo)
+{
+  NS_ENSURE_ARG_POINTER(transferInfo);
+
+  nsTransferDBFolderInfo *newInfo = new nsTransferDBFolderInfo;
+  *transferInfo = newInfo;
+  NS_ADDREF(newInfo);
+
+  mdb_count numCells;
+  mdbYarn cellYarn;
+  mdb_column cellColumn;
+  char columnName[100];
+  mdbYarn cellName = { columnName, 0, sizeof(columnName), 0, 0, nullptr };
+
+  NS_ASSERTION(m_mdbRow, "null row in getTransferInfo");
+  m_mdbRow->GetCount(m_mdb->GetEnv(), &numCells);
+  // iterate over the cells in the dbfolderinfo remembering attribute names and values.
+  for (mdb_count cellIndex = 0; cellIndex < numCells; cellIndex++)
+  {
+    nsresult err = m_mdbRow->SeekCellYarn(m_mdb->GetEnv(), cellIndex, &cellColumn, nullptr);
+    if (NS_SUCCEEDED(err))
+    {
+      err = m_mdbRow->AliasCellYarn(m_mdb->GetEnv(), cellColumn, &cellYarn);
+      if (NS_SUCCEEDED(err))
+      {
+        m_mdb->GetStore()->TokenToString(m_mdb->GetEnv(), cellColumn, &cellName);
+        newInfo->m_values.AppendElement(Substring((const char *)cellYarn.mYarn_Buf,
+                                        (const char *) cellYarn.mYarn_Buf + cellYarn.mYarn_Fill));
+        newInfo->m_properties.AppendElement(Substring((const char *) cellName.mYarn_Buf,
+                                            (const char *) cellName.mYarn_Buf + cellName.mYarn_Fill));
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+
+/* void InitFromTransferInfo (in nsIDBFolderInfo transferInfo); */
+NS_IMETHODIMP nsDBFolderInfo::InitFromTransferInfo(nsIDBFolderInfo *aTransferInfo)
+{
+  NS_ENSURE_ARG(aTransferInfo);
+
+  nsTransferDBFolderInfo *transferInfo = static_cast<nsTransferDBFolderInfo *>(aTransferInfo);
+
+  for (uint32_t i = 0; i < transferInfo->m_values.Length(); i++)
+    SetCharProperty(transferInfo->m_properties[i].get(), transferInfo->m_values[i]);
+
+  LoadMemberVariables();
+  return NS_OK;
+}
+
diff --git a/mailnews/db/msgdb/src/nsImapMailDatabase.cpp b/mailnews/db/msgdb/src/nsImapMailDatabase.cpp
new file mode 100644
index 000000000..84865eb80
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsImapMailDatabase.cpp
@@ -0,0 +1,249 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/stat.h>
+
+#include "msgCore.h"
+#include "nsImapMailDatabase.h"
+#include "nsDBFolderInfo.h"
+
+const char *kPendingHdrsScope = "ns:msg:db:row:scope:pending:all";	// scope for all offine ops table
+const char *kPendingHdrsTableKind = "ns:msg:db:table:kind:pending";
+struct mdbOid gAllPendingHdrsTableOID;
+
+nsImapMailDatabase::nsImapMailDatabase()
+{
+  m_mdbAllPendingHdrsTable = nullptr;
+}
+
+nsImapMailDatabase::~nsImapMailDatabase()
+{
+}
+
+NS_IMETHODIMP	nsImapMailDatabase::GetSummaryValid(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  if (m_dbFolderInfo)
+  {
+    uint32_t version;
+    m_dbFolderInfo->GetVersion(&version);
+    *aResult = (GetCurVersion() == version);
+  }
+  else
+      *aResult = false;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP	nsImapMailDatabase::SetSummaryValid(bool valid)
+{
+  if (m_dbFolderInfo)
+  {
+    m_dbFolderInfo->SetVersion(valid ? GetCurVersion() : 0);
+    Commit(nsMsgDBCommitType::kLargeCommit);
+  }
+  return NS_OK;
+}
+
+// IMAP does not set local file flags, override does nothing
+void nsImapMailDatabase::UpdateFolderFlag(nsIMsgDBHdr * /* msgHdr */, bool /* bSet */,
+                                          nsMsgMessageFlagType /* flag */, nsIOutputStream ** /* ppFileStream */)
+{
+}
+
+// We override this to avoid our parent class (nsMailDatabase)'s 
+// grabbing of the folder semaphore, and bailing on failure.
+NS_IMETHODIMP nsImapMailDatabase::DeleteMessages(uint32_t aNumKeys, nsMsgKey* nsMsgKeys, nsIDBChangeListener *instigator)
+{
+  return nsMsgDatabase::DeleteMessages(aNumKeys, nsMsgKeys, instigator);
+}
+
+// override so nsMailDatabase methods that deal with m_folderStream are *not* called
+NS_IMETHODIMP nsImapMailDatabase::StartBatch()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::EndBatch()
+{
+  return NS_OK;
+}
+
+nsresult nsImapMailDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr)
+{
+  uint32_t msgFlags;
+  msgHdr->GetFlags(&msgFlags);
+  if (msgFlags & nsMsgMessageFlags::Offline && m_dbFolderInfo)
+  {
+    uint32_t size = 0;
+    (void)msgHdr->GetOfflineMessageSize(&size);
+    return m_dbFolderInfo->ChangeExpungedBytes (size);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::ForceClosed()
+{
+  m_mdbAllPendingHdrsTable = nullptr;
+  return nsMailDatabase::ForceClosed();
+}
+
+nsresult nsImapMailDatabase::GetAllPendingHdrsTable()
+{
+  nsresult rv = NS_OK;
+  if (!m_mdbAllPendingHdrsTable)
+    rv = GetTableCreateIfMissing(kPendingHdrsScope, kPendingHdrsTableKind, getter_AddRefs(m_mdbAllPendingHdrsTable),
+                                                m_pendingHdrsRowScopeToken, m_pendingHdrsTableKindToken) ;
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::AddNewHdrToDB(nsIMsgDBHdr *newHdr, bool notify)
+{
+  nsresult rv = nsMsgDatabase::AddNewHdrToDB(newHdr, notify);
+  if (NS_SUCCEEDED(rv))
+    rv = UpdatePendingAttributes(newHdr);
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::UpdatePendingAttributes(nsIMsgDBHdr* aNewHdr)
+{
+  nsresult rv = GetAllPendingHdrsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  mdb_count numPendingHdrs = 0;
+  m_mdbAllPendingHdrsTable->GetCount(GetEnv(), &numPendingHdrs);
+  if (numPendingHdrs > 0)
+  {
+    mdbYarn messageIdYarn;
+    nsCOMPtr <nsIMdbRow> pendingRow;
+    mdbOid  outRowId;
+
+    nsCString messageId;
+    aNewHdr->GetMessageId(getter_Copies(messageId));
+    messageIdYarn.mYarn_Buf = (void*)messageId.get();
+    messageIdYarn.mYarn_Fill = messageId.Length();
+    messageIdYarn.mYarn_Form = 0;
+    messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+    m_mdbStore->FindRow(GetEnv(), m_pendingHdrsRowScopeToken,
+              m_messageIdColumnToken, &messageIdYarn, &outRowId, getter_AddRefs(pendingRow));
+    if (pendingRow)
+    {
+      mdb_count numCells;
+      mdbYarn cellYarn;
+      mdb_column cellColumn;
+      uint32_t existingFlags;
+
+      pendingRow->GetCount(GetEnv(), &numCells);
+      aNewHdr->GetFlags(&existingFlags);
+      // iterate over the cells in the pending hdr setting properties on the aNewHdr.
+      // we skip cell 0, which is the messageId;
+      nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(aNewHdr);      // closed system, cast ok
+      nsIMdbRow *row = msgHdr->GetMDBRow();
+      for (mdb_count cellIndex = 1; cellIndex < numCells; cellIndex++)
+      {
+        nsresult err = pendingRow->SeekCellYarn(GetEnv(), cellIndex, &cellColumn, nullptr);
+        if (NS_SUCCEEDED(err))
+        {
+          err = pendingRow->AliasCellYarn(GetEnv(), cellColumn, &cellYarn);
+          if (NS_SUCCEEDED(err))
+          {
+            if (row)
+              row->AddColumn(GetEnv(), cellColumn, &cellYarn);
+          }
+        }
+      }
+      // We might have changed some cached values, so force a refresh.
+      msgHdr->ClearCachedValues();
+      uint32_t resultFlags;
+      msgHdr->OrFlags(existingFlags, &resultFlags);
+      m_mdbAllPendingHdrsTable->CutRow(GetEnv(), pendingRow);
+      pendingRow->CutAllColumns(GetEnv());
+    }
+  }
+  return rv;
+}
+
+nsresult nsImapMailDatabase::GetRowForPendingHdr(nsIMsgDBHdr *pendingHdr,
+                                                 nsIMdbRow **row)
+{
+  nsresult rv = GetAllPendingHdrsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mdbYarn messageIdYarn;
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  mdbOid  outRowId;
+  nsCString messageId;
+  pendingHdr->GetMessageId(getter_Copies(messageId));
+  messageIdYarn.mYarn_Buf = (void*)messageId.get();
+  messageIdYarn.mYarn_Fill = messageId.Length();
+  messageIdYarn.mYarn_Form = 0;
+  messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+  rv = m_mdbStore->FindRow(GetEnv(), m_pendingHdrsRowScopeToken,
+            m_messageIdColumnToken, &messageIdYarn, &outRowId, getter_AddRefs(pendingRow));
+
+  if (!pendingRow)
+    rv  = m_mdbStore->NewRow(GetEnv(), m_pendingHdrsRowScopeToken, getter_AddRefs(pendingRow));
+
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (pendingRow)
+  {
+    // now we need to add cells to the row to remember the messageid, property and property value, and flags.
+    // Then, when hdrs are added to the db, we'll check if they have a matching message-id, and if so,
+    // set the property and flags
+    // XXX we already fetched messageId from the pending hdr, could it have changed by the time we get here? 
+    nsCString messageId;
+    pendingHdr->GetMessageId(getter_Copies(messageId));
+    // we're just going to ignore messages without a message-id. They should be rare. If SPAM messages often
+    // didn't have message-id's, they'd be filtered on the server, most likely, and spammers would then
+    // start putting in message-id's.
+    if (!messageId.IsEmpty())
+    {
+       extern const char *kMessageIdColumnName;
+       m_mdbAllPendingHdrsTable->AddRow(GetEnv(), pendingRow);
+       // make sure this is the first cell so that when we ignore the first
+       // cell in nsImapMailDatabase::AddNewHdrToDB, we're ignoring the right one
+      (void) SetProperty(pendingRow, kMessageIdColumnName, messageId.get());
+      pendingRow.forget(row);
+    }
+    else
+      return NS_ERROR_FAILURE;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsImapMailDatabase::SetAttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr, const char *property,
+                                  const char *propertyVal)
+{
+  NS_ENSURE_ARG_POINTER(pendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(pendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetProperty(pendingRow, property, propertyVal);
+}
+
+NS_IMETHODIMP
+nsImapMailDatabase::SetUint32AttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr,
+                                                   const char *property,
+                                                   uint32_t propertyVal)
+{
+  NS_ENSURE_ARG_POINTER(pendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(pendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetUint32Property(pendingRow, property, propertyVal);
+}
+
+NS_IMETHODIMP
+nsImapMailDatabase::SetUint64AttributeOnPendingHdr(nsIMsgDBHdr *aPendingHdr,
+                                                   const char *aProperty,
+                                                   uint64_t aPropertyVal)
+{
+  NS_ENSURE_ARG_POINTER(aPendingHdr);
+  nsCOMPtr<nsIMdbRow> pendingRow;
+  nsresult rv = GetRowForPendingHdr(aPendingHdr, getter_AddRefs(pendingRow));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return SetUint64Property(pendingRow, aProperty, aPropertyVal);
+}
diff --git a/mailnews/db/msgdb/src/nsMailDatabase.cpp b/mailnews/db/msgdb/src/nsMailDatabase.cpp
new file mode 100644
index 000000000..13a53485f
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMailDatabase.cpp
@@ -0,0 +1,444 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "nsMailDatabase.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgLocalFolderHdrs.h"
+#include "nsNetUtil.h"
+#include "nsISeekableStream.h"
+#include "nsMsgOfflineImapOperation.h"
+#include "nsMsgFolderFlags.h"
+#include "mozilla/Logging.h"
+#include "prprf.h"
+#include "nsMsgUtils.h"
+#include "nsIMsgPluggableStore.h"
+
+extern PRLogModuleInfo *IMAPOffline;
+
+using namespace mozilla;
+
+// scope for all offine ops table
+const char *kOfflineOpsScope = "ns:msg:db:row:scope:ops:all";
+const char *kOfflineOpsTableKind = "ns:msg:db:table:kind:ops";
+struct mdbOid gAllOfflineOpsTableOID;
+
+nsMailDatabase::nsMailDatabase() : m_reparse(false)
+{
+  m_mdbAllOfflineOpsTable = nullptr;
+  m_offlineOpsRowScopeToken = 0;
+  m_offlineOpsTableKindToken = 0;
+}
+
+nsMailDatabase::~nsMailDatabase()
+{
+}
+
+// caller passes in upgrading==true if they want back a db even if the db is out of date.
+// If so, they'll extract out the interesting info from the db, close it, delete it, and
+// then try to open the db again, prior to reparsing.
+nsresult nsMailDatabase::Open(nsMsgDBService* aDBService, nsIFile *aSummaryFile,
+                              bool aCreate, bool aUpgrading)
+{
+#ifdef DEBUG
+  nsString leafName;
+  aSummaryFile->GetLeafName(leafName);
+  if (!StringEndsWith(leafName, NS_LITERAL_STRING(".msf"),
+                     nsCaseInsensitiveStringComparator()))
+    NS_ERROR("non summary file passed into open\n");
+#endif
+  return nsMsgDatabase::Open(aDBService, aSummaryFile, aCreate, aUpgrading);
+}
+
+NS_IMETHODIMP nsMailDatabase::ForceClosed()
+{
+  m_mdbAllOfflineOpsTable = nullptr;
+  return nsMsgDatabase::ForceClosed();
+}
+
+// get this on demand so that only db's that have offline ops will
+// create the table.
+nsresult nsMailDatabase::GetAllOfflineOpsTable()
+{
+  nsresult rv = NS_OK;
+  if (!m_mdbAllOfflineOpsTable)
+    rv = GetTableCreateIfMissing(kOfflineOpsScope, kOfflineOpsTableKind, getter_AddRefs(m_mdbAllOfflineOpsTable), 
+                                                m_offlineOpsRowScopeToken, m_offlineOpsTableKindToken) ;
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::StartBatch()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMailDatabase::EndBatch()
+{
+  SetSummaryValid(true);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMailDatabase::DeleteMessages(uint32_t aNumKeys, nsMsgKey* nsMsgKeys, nsIDBChangeListener *instigator)
+{
+  nsresult rv;
+  if (m_folder)
+  {
+    bool isLocked;
+    m_folder->GetLocked(&isLocked);
+    if (isLocked)
+    {
+      NS_ASSERTION(false, "Some other operation is in progress");
+      return NS_MSG_FOLDER_BUSY;
+    }
+  }
+
+  rv = nsMsgDatabase::DeleteMessages(aNumKeys, nsMsgKeys, instigator);
+  SetSummaryValid(true);
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::GetSummaryValid(bool *aResult)
+{
+  uint32_t version;
+  m_dbFolderInfo->GetVersion(&version);
+  if (GetCurVersion() != version)
+  {
+    *aResult = false;
+    return NS_OK;
+  }
+  nsCOMPtr<nsIMsgPluggableStore> msgStore;
+  if (!m_folder) {
+    // If the folder is not set, we just return without checking the validity
+    // of the summary file. For now, this is an expected condition when the
+    // message database is being opened from a URL in 
+    // nsMailboxUrl::GetMsgHdrForKey() which calls
+    // nsMsgDBService::OpenMailDBFromFile() without a folder.
+    // Returning an error here would lead to the deletion of the MSF in the
+    // caller nsMsgDatabase::CheckForErrors().
+    *aResult = true;
+    return NS_OK;
+  }
+  nsresult rv = m_folder->GetMsgStore(getter_AddRefs(msgStore));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return msgStore->IsSummaryFileValid(m_folder, this, aResult);
+}
+
+NS_IMETHODIMP nsMailDatabase::SetSummaryValid(bool aValid)
+{
+  nsMsgDatabase::SetSummaryValid(aValid);
+
+  if (!m_folder)
+    return NS_ERROR_NULL_POINTER;
+
+  // If this is a virtual folder, there is no storage.
+  bool flag;
+  m_folder->GetFlag(nsMsgFolderFlags::Virtual, &flag);
+  if (flag)
+    return NS_OK;
+
+  nsCOMPtr<nsIMsgPluggableStore> msgStore;
+  nsresult rv = m_folder->GetMsgStore(getter_AddRefs(msgStore));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return msgStore->SetSummaryFileValid(m_folder, this, aValid);
+}
+
+NS_IMETHODIMP  nsMailDatabase::RemoveOfflineOp(nsIMsgOfflineImapOperation *op)
+{
+  
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  
+  if (!op || !m_mdbAllOfflineOpsTable)
+    return NS_ERROR_NULL_POINTER;
+  nsMsgOfflineImapOperation* offlineOp = static_cast<nsMsgOfflineImapOperation*>(op);  // closed system, so this is ok
+  nsIMdbRow* row = offlineOp->GetMDBRow();
+  rv = m_mdbAllOfflineOpsTable->CutRow(GetEnv(), row);
+  row->CutAllColumns(GetEnv());
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::GetOfflineOpForKey(nsMsgKey msgKey, bool create, nsIMsgOfflineImapOperation **offlineOp)
+{
+  mdb_bool	hasOid;
+  mdbOid		rowObjectId;
+  nsresult err;
+
+  if (!IMAPOffline)
+    IMAPOffline = PR_NewLogModule("IMAPOFFLINE");
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  
+  if (!offlineOp || !m_mdbAllOfflineOpsTable)
+    return NS_ERROR_NULL_POINTER;
+  
+  *offlineOp = NULL;
+  
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_offlineOpsRowScopeToken;
+  err = m_mdbAllOfflineOpsTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if (NS_SUCCEEDED(err) && m_mdbStore && (hasOid  || create))
+  {
+    nsCOMPtr <nsIMdbRow> offlineOpRow;
+    err = m_mdbStore->GetRow(GetEnv(), &rowObjectId, getter_AddRefs(offlineOpRow));
+    
+    if (create)
+    {
+      if (!offlineOpRow)
+      {
+        err  = m_mdbStore->NewRowWithOid(GetEnv(), &rowObjectId, getter_AddRefs(offlineOpRow));
+        NS_ENSURE_SUCCESS(err, err);
+      }
+      if (offlineOpRow && !hasOid)
+        m_mdbAllOfflineOpsTable->AddRow(GetEnv(), offlineOpRow);
+    }
+    
+    if (NS_SUCCEEDED(err) && offlineOpRow)
+    {
+      *offlineOp = new nsMsgOfflineImapOperation(this, offlineOpRow);
+      if (*offlineOp)
+        (*offlineOp)->SetMessageKey(msgKey);
+      NS_IF_ADDREF(*offlineOp);
+    }
+    if (!hasOid && m_dbFolderInfo)
+    {
+      // set initial value for flags so we don't lose them.
+      nsCOMPtr <nsIMsgDBHdr> msgHdr;
+      GetMsgHdrForKey(msgKey, getter_AddRefs(msgHdr));
+      if (msgHdr)
+      {
+        uint32_t flags;
+        msgHdr->GetFlags(&flags);
+        (*offlineOp)->SetNewFlags(flags);
+      }
+      int32_t newFlags;
+      m_dbFolderInfo->OrFlags(nsMsgFolderFlags::OfflineEvents, &newFlags);
+    }
+  }
+  
+  return err;
+}
+
+NS_IMETHODIMP nsMailDatabase::EnumerateOfflineOps(nsISimpleEnumerator **enumerator)
+{
+  NS_ASSERTION(false, "not impl yet");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+
+NS_IMETHODIMP nsMailDatabase::ListAllOfflineOpIds(nsTArray<nsMsgKey> *offlineOpIds)
+{
+  NS_ENSURE_ARG(offlineOpIds);
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsIMdbTableRowCursor *rowCursor;
+  if (!IMAPOffline)
+    IMAPOffline = PR_NewLogModule("IMAPOFFLINE");
+
+  if (m_mdbAllOfflineOpsTable)
+  {
+    nsresult err = m_mdbAllOfflineOpsTable->GetTableRowCursor(GetEnv(), -1, &rowCursor);
+    while (NS_SUCCEEDED(err) && rowCursor)
+    {
+      mdbOid outOid;
+      mdb_pos	outPos;
+      
+      err = rowCursor->NextRowOid(GetEnv(), &outOid, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || outOid.mOid_Id == (mdb_id) -1)
+        break;
+      if (NS_SUCCEEDED(err))
+      {
+        offlineOpIds->AppendElement(outOid.mOid_Id);
+        if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+        {
+          nsCOMPtr <nsIMsgOfflineImapOperation> offlineOp;
+          GetOfflineOpForKey(outOid.mOid_Id, false, getter_AddRefs(offlineOp));
+          if (offlineOp)
+          {
+            nsMsgOfflineImapOperation *logOp = static_cast<nsMsgOfflineImapOperation *>(static_cast<nsIMsgOfflineImapOperation *>(offlineOp.get()));
+            if (logOp)
+              logOp->Log(IMAPOffline);
+
+          }
+        }
+      }
+    }
+    // TODO: would it cause a problem to replace this with "rv = err;" ?
+    rv = (NS_SUCCEEDED(err)) ? NS_OK : NS_ERROR_FAILURE;
+    rowCursor->Release();
+  }
+
+  offlineOpIds->Sort();
+  return rv;
+}
+
+NS_IMETHODIMP nsMailDatabase::ListAllOfflineDeletes(nsTArray<nsMsgKey> *offlineDeletes)
+{
+  NS_ENSURE_ARG_POINTER(offlineDeletes);
+
+  nsresult rv = GetAllOfflineOpsTable();
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsIMdbTableRowCursor *rowCursor;
+  if (m_mdbAllOfflineOpsTable)
+  {
+    nsresult err = m_mdbAllOfflineOpsTable->GetTableRowCursor(GetEnv(), -1, &rowCursor);
+    while (NS_SUCCEEDED(err) && rowCursor)
+    {
+      mdbOid outOid;
+      mdb_pos outPos;
+      nsIMdbRow* offlineOpRow;
+
+      err = rowCursor->NextRow(GetEnv(), &offlineOpRow, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || offlineOpRow == nullptr)
+        break;
+      if (NS_SUCCEEDED(err))
+      {
+        offlineOpRow->GetOid(GetEnv(), &outOid);
+        nsIMsgOfflineImapOperation *offlineOp = new nsMsgOfflineImapOperation(this, offlineOpRow);
+        if (offlineOp)
+        {
+          NS_ADDREF(offlineOp);
+          imapMessageFlagsType newFlags;
+          nsOfflineImapOperationType opType;
+          
+          offlineOp->GetOperation(&opType);
+          offlineOp->GetNewFlags(&newFlags);
+          if (opType & nsIMsgOfflineImapOperation::kMsgMoved || 
+            ((opType & nsIMsgOfflineImapOperation::kFlagsChanged) 
+            && (newFlags & nsIMsgOfflineImapOperation::kMsgMarkedDeleted)))
+            offlineDeletes->AppendElement(outOid.mOid_Id);
+          NS_RELEASE(offlineOp);
+        }
+        offlineOpRow->Release();
+      }
+    }
+    // TODO: would it cause a problem to replace this with "rv = err;" ?
+    rv = (NS_SUCCEEDED(err)) ? NS_OK : NS_ERROR_FAILURE;
+    rowCursor->Release();
+  }
+  return rv;
+}
+
+// This is used to remember that the db is out of sync with the mail folder
+// and needs to be regenerated.
+void nsMailDatabase::SetReparse(bool reparse)
+{
+  m_reparse = reparse;
+}
+
+class nsMsgOfflineOpEnumerator : public nsISimpleEnumerator {
+public:
+  NS_DECL_ISUPPORTS
+
+  // nsISimpleEnumerator methods:
+  NS_DECL_NSISIMPLEENUMERATOR
+
+  nsMsgOfflineOpEnumerator(nsMailDatabase* db);
+
+protected:
+  virtual ~nsMsgOfflineOpEnumerator();
+  nsresult					GetRowCursor();
+  nsresult					PrefetchNext();
+  nsMailDatabase*              mDB;
+  nsIMdbTableRowCursor*       mRowCursor;
+  nsCOMPtr <nsIMsgOfflineImapOperation> mResultOp;
+  bool              mDone;
+  bool						mNextPrefetched;
+};
+
+nsMsgOfflineOpEnumerator::nsMsgOfflineOpEnumerator(nsMailDatabase* db)
+    : mDB(db), mRowCursor(nullptr), mDone(false)
+{
+  NS_ADDREF(mDB);
+  mNextPrefetched = false;
+}
+
+nsMsgOfflineOpEnumerator::~nsMsgOfflineOpEnumerator()
+{
+  NS_IF_RELEASE(mRowCursor);
+  NS_RELEASE(mDB);
+}
+
+NS_IMPL_ISUPPORTS(nsMsgOfflineOpEnumerator, nsISimpleEnumerator)
+
+nsresult nsMsgOfflineOpEnumerator::GetRowCursor()
+{
+  nsresult rv = NS_OK;
+  mDone = false;
+
+  if (!mDB || !mDB->m_mdbAllOfflineOpsTable)
+    return NS_ERROR_NULL_POINTER;
+
+  rv = mDB->m_mdbAllOfflineOpsTable->GetTableRowCursor(mDB->GetEnv(), -1, &mRowCursor);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineOpEnumerator::GetNext(nsISupports **aItem)
+{
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  nsresult rv = NS_OK;
+  if (!mNextPrefetched)
+    rv = PrefetchNext();
+  if (NS_SUCCEEDED(rv))
+  {
+    if (mResultOp) 
+    {
+      *aItem = mResultOp;
+      NS_ADDREF(*aItem);
+      mNextPrefetched = false;
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgOfflineOpEnumerator::PrefetchNext()
+{
+  nsresult rv = NS_OK;
+  nsIMdbRow* offlineOpRow;
+  mdb_pos rowPos;
+
+  if (!mRowCursor)
+  {
+    rv = GetRowCursor();
+    if (NS_FAILED(rv))
+      return rv;
+  }
+
+  rv = mRowCursor->NextRow(mDB->GetEnv(), &offlineOpRow, &rowPos);
+  if (!offlineOpRow) 
+  {
+    mDone = true;
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_FAILED(rv)) 
+  {
+    mDone = true;
+    return rv;
+  }
+
+  nsIMsgOfflineImapOperation *op = new nsMsgOfflineImapOperation(mDB, offlineOpRow);
+  mResultOp = op;
+  if (!op)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  if (mResultOp) 
+  {
+    mNextPrefetched = true;
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgOfflineOpEnumerator::HasMoreElements(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  if (!mNextPrefetched)
+    PrefetchNext();
+  *aResult = !mDone;
+  return NS_OK;
+}
diff --git a/mailnews/db/msgdb/src/nsMsgDatabase.cpp b/mailnews/db/msgdb/src/nsMsgDatabase.cpp
new file mode 100644
index 000000000..8b366ab5c
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMsgDatabase.cpp
@@ -0,0 +1,5915 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// this file implements the nsMsgDatabase interface using the MDB Interface.
+
+#include "nscore.h"
+#include "msgCore.h"
+#include "nsMailDatabase.h"
+#include "nsDBFolderInfo.h"
+#include "nsMsgKeySet.h"
+#include "nsMsgThread.h"
+#include "nsIMsgSearchTerm.h"
+#include "nsMsgBaseCID.h"
+#include "nsMorkCID.h"
+#include "nsIMdbFactoryFactory.h"
+#include "mozilla/Logging.h"
+#include "prprf.h"
+#include "nsMsgDBCID.h"
+#include "nsILocale.h"
+#include "nsMsgMimeCID.h"
+#include "nsILocaleService.h"
+#include "nsMsgFolderFlags.h"
+#include "nsIMsgAccountManager.h"
+#include "nsIMsgDBView.h"
+#include "nsIMsgFolderCache.h"
+#include "nsIMsgFolderCacheElement.h"
+#include "MailNewsTypes2.h"
+#include "nsMsgUtils.h"
+#include "nsMsgKeyArray.h"
+#include "nsIMutableArray.h"
+#include "nsComponentManagerUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsMemory.h"
+#include "nsICollation.h"
+#include "nsCollationCID.h"
+#include "nsIPrefService.h"
+#include "nsIPrefBranch.h"
+#include "nsIMsgPluggableStore.h"
+#include "nsAlgorithm.h"
+#include "nsArrayEnumerator.h"
+#include "nsIMemoryReporter.h"
+#include "mozilla/mailnews/MimeHeaderParser.h"
+#include "mozilla/mailnews/Services.h"
+#include <algorithm>
+
+using namespace mozilla::mailnews;
+using namespace mozilla;
+
+#if defined(DEBUG_sspitzer_) || defined(DEBUG_seth_)
+#define DEBUG_MSGKEYSET 1
+#endif
+
+#define MSG_HASH_SIZE 512
+
+// This will be used on discovery, since we don't know total.
+const int32_t kMaxHdrsInCache = 512;
+
+// special keys
+static const nsMsgKey kAllMsgHdrsTableKey = 1;
+static const nsMsgKey kTableKeyForThreadOne = 0xfffffffe;
+static const nsMsgKey kAllThreadsTableKey = 0xfffffffd;
+static const nsMsgKey kFirstPseudoKey = 0xfffffff0;
+static const nsMsgKey kIdStartOfFake = 0xffffff80;
+static const nsMsgKey kForceReparseKey = 0xfffffff0;
+
+static PRLogModuleInfo* DBLog;
+
+PRTime nsMsgDatabase::gLastUseTime;
+
+NS_IMPL_ISUPPORTS(nsMsgDBService, nsIMsgDBService)
+
+nsMsgDBService::nsMsgDBService()
+{
+  DBLog = PR_NewLogModule("MSGDB");
+}
+
+
+nsMsgDBService::~nsMsgDBService()
+{
+#ifdef DEBUG
+  // If you hit this warning, it means that some code is holding onto
+  // a db at shutdown.
+  NS_WARNING_ASSERTION(!m_dbCache.Length(), "some msg dbs left open");
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++)
+  {
+    nsMsgDatabase* pMessageDB = m_dbCache.ElementAt(i);
+    if (pMessageDB)
+      printf("db left open %s\n", (const char *) pMessageDB->m_dbName.get());
+  }
+#endif
+}
+
+NS_IMETHODIMP nsMsgDBService::OpenFolderDB(nsIMsgFolder *aFolder,
+                                           bool aLeaveInvalidDB,
+                                           nsIMsgDatabase **_retval)
+{
+  NS_ENSURE_ARG(aFolder);
+  nsCOMPtr<nsIMsgIncomingServer> incomingServer;
+  nsresult rv = aFolder->GetServer(getter_AddRefs(incomingServer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase *cacheDB = FindInCache(summaryFilePath);
+  if (cacheDB)
+  {
+    // this db could have ended up in the folder cache w/o an m_folder pointer via
+    // OpenMailDBFromFile. If so, take this chance to fix the folder.
+    if (!cacheDB->m_folder)
+      cacheDB->m_folder = aFolder;
+    cacheDB->RememberLastUseTime();
+    *_retval = cacheDB; // FindInCache already addRefed.
+    // if m_thumb is set, someone is asynchronously opening the db. But our
+    // caller wants to synchronously open it, so just do it.
+    if (cacheDB->m_thumb)
+      return cacheDB->Open(this, summaryFilePath, false, aLeaveInvalidDB);
+    return NS_OK;
+  }
+
+  nsCString localDatabaseType;
+  incomingServer->GetLocalDatabaseType(localDatabaseType);
+  nsAutoCString dbContractID(NS_MSGDB_CONTRACTID);
+  dbContractID.Append(localDatabaseType.get());
+  nsCOMPtr <nsIMsgDatabase> msgDB = do_CreateInstance(dbContractID.get(), &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Don't try to create the database yet--let the createNewDB call do that.
+  nsMsgDatabase *msgDatabase = static_cast<nsMsgDatabase *>(msgDB.get());
+  msgDatabase->m_folder = aFolder;
+  rv = msgDatabase->Open(this, summaryFilePath, false, aLeaveInvalidDB);
+  if (NS_FAILED(rv) && rv != NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+    return rv;
+
+  NS_ADDREF(*_retval = msgDB);
+
+  if (NS_FAILED(rv))
+  {
+#ifdef DEBUG
+    // Doing these checks for debug only as we don't want to report certain
+    // errors in debug mode, but in release mode we wouldn't report them either
+
+    // These errors are expected.
+    if (rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING ||
+        rv == NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+      return rv;
+
+    // If it isn't one of the expected errors, throw a warning.
+    NS_ENSURE_SUCCESS(rv, rv);
+#endif
+    return rv;
+  }
+
+  FinishDBOpen(aFolder, msgDatabase);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::AsyncOpenFolderDB(nsIMsgFolder *aFolder,
+                                                bool aLeaveInvalidDB,
+                                                nsIMsgDatabase **_retval)
+{
+  NS_ENSURE_ARG(aFolder);
+
+  nsCOMPtr <nsIFile> summaryFilePath;
+  nsresult rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase *cacheDB = FindInCache(summaryFilePath);
+  if (cacheDB)
+  {
+    // this db could have ended up in the folder cache w/o an m_folder pointer via
+    // OpenMailDBFromFile. If so, take this chance to fix the folder.
+    if (!cacheDB->m_folder)
+      cacheDB->m_folder = aFolder;
+    *_retval = cacheDB; // FindInCache already addRefed.
+    // We don't care if an other consumer is thumbing the store. In that
+    // case, they'll both thumb the store.
+    return NS_OK;
+  }
+
+  nsCOMPtr <nsIMsgIncomingServer> incomingServer;
+  rv = aFolder->GetServer(getter_AddRefs(incomingServer));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCString localDatabaseType;
+  incomingServer->GetLocalDatabaseType(localDatabaseType);
+  nsAutoCString dbContractID(NS_MSGDB_CONTRACTID);
+  dbContractID.Append(localDatabaseType.get());
+  nsCOMPtr <nsIMsgDatabase> msgDB = do_CreateInstance(dbContractID.get(), &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase *msgDatabase = static_cast<nsMsgDatabase *>(msgDB.get());
+  rv = msgDatabase->OpenInternal(this, summaryFilePath, false, aLeaveInvalidDB,
+                                 false /* open asynchronously */);
+
+  NS_ADDREF(*_retval = msgDB);
+  msgDatabase->m_folder = aFolder;
+
+  if (NS_FAILED(rv))
+  {
+#ifdef DEBUG
+    // Doing these checks for debug only as we don't want to report certain
+    // errors in debug mode, but in release mode we wouldn't report them either
+
+    // These errors are expected.
+    if (rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING ||
+        rv == NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+      return rv;
+
+    // If it isn't one of the expected errors, throw a warning.
+    NS_ENSURE_SUCCESS(rv, rv);
+#endif
+    return rv;
+  }
+
+  FinishDBOpen(aFolder, msgDatabase);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::OpenMore(nsIMsgDatabase *aDB,
+                                       uint32_t aTimeHint,
+                                       bool *_retval)
+{
+  NS_ENSURE_ARG_POINTER(_retval);
+  nsMsgDatabase *msgDatabase = static_cast<nsMsgDatabase *>(aDB);
+  NS_ENSURE_TRUE(msgDatabase, NS_ERROR_INVALID_ARG);
+  // Check if this db has been opened.
+  if (!msgDatabase->m_thumb)
+  {
+    *_retval = true;
+    return NS_OK;
+  }
+  nsresult rv;
+  *_retval = false;
+  PRIntervalTime startTime = PR_IntervalNow();
+  do
+  {
+    mdb_count outTotal;    // total somethings to do in operation
+    mdb_count outCurrent;  // subportion of total completed so far
+    mdb_bool outDone = false;      // is operation finished?
+    mdb_bool outBroken;     // is operation irreparably dead and broken?
+    rv = msgDatabase->m_thumb->DoMore(msgDatabase->m_mdbEnv,
+                                       &outTotal, &outCurrent, &outDone,
+                                       &outBroken);
+    if (NS_FAILED(rv))
+      break;
+    if (outDone)
+    {
+      nsCOMPtr<nsIMdbFactory> mdbFactory;
+      msgDatabase->GetMDBFactory(getter_AddRefs(mdbFactory));
+      NS_ENSURE_TRUE(mdbFactory, NS_ERROR_FAILURE);
+      rv = mdbFactory->ThumbToOpenStore(msgDatabase->m_mdbEnv, msgDatabase->m_thumb, &msgDatabase->m_mdbStore);
+      msgDatabase->m_thumb = nullptr;
+      nsCOMPtr<nsIFile> folderPath;
+      (void) msgDatabase->m_folder->GetFilePath(getter_AddRefs(folderPath));
+      nsCOMPtr <nsIFile> summaryFile;
+      (void) GetSummaryFileLocation(folderPath, getter_AddRefs(summaryFile));
+
+      if (NS_SUCCEEDED(rv))
+        rv = (msgDatabase->m_mdbStore) ? msgDatabase->InitExistingDB() : NS_ERROR_FAILURE;
+      if (NS_SUCCEEDED(rv))
+        rv = msgDatabase->CheckForErrors(rv, false, this, summaryFile);
+
+      FinishDBOpen(msgDatabase->m_folder, msgDatabase);
+      break;
+    }
+  }
+  while (PR_IntervalToMilliseconds(PR_IntervalNow() - startTime) <= aTimeHint);
+  *_retval = !msgDatabase->m_thumb;
+  return rv;
+}
+
+/**
+ * When a db is opened, we need to hook up any pending listeners for 
+ * that db, and notify them.
+ */
+void nsMsgDBService::HookupPendingListeners(nsIMsgDatabase *db,
+                                            nsIMsgFolder *folder)
+{
+  for (int32_t listenerIndex = 0;
+       listenerIndex < m_foldersPendingListeners.Count(); listenerIndex++)
+  {
+  //  check if we have a pending listener on this db, and if so, add it.
+    if (m_foldersPendingListeners[listenerIndex] == folder)
+    {
+      db->AddListener(m_pendingListeners.ObjectAt(listenerIndex));
+      m_pendingListeners.ObjectAt(listenerIndex)->OnEvent(db, "DBOpened");
+    }
+  }
+}
+
+void nsMsgDBService::FinishDBOpen(nsIMsgFolder *aFolder, nsMsgDatabase *aMsgDB)
+{
+  uint32_t folderFlags;
+  aFolder->GetFlags(&folderFlags);
+
+  if (! (folderFlags & nsMsgFolderFlags::Virtual) &&
+      aMsgDB->m_mdbAllMsgHeadersTable)
+  {
+    mdb_count numHdrsInTable = 0;
+    int32_t numMessages;
+    aMsgDB->m_mdbAllMsgHeadersTable->GetCount(aMsgDB->GetEnv(),
+                                              &numHdrsInTable);
+    aMsgDB->m_dbFolderInfo->GetNumMessages(&numMessages);
+    if (numMessages != (int32_t) numHdrsInTable)
+      aMsgDB->SyncCounts();
+  }
+  HookupPendingListeners(aMsgDB, aFolder);
+  aMsgDB->RememberLastUseTime();
+}
+
+//----------------------------------------------------------------------
+// FindInCache - this addrefs the db it finds.
+//----------------------------------------------------------------------
+nsMsgDatabase* nsMsgDBService::FindInCache(nsIFile *dbName)
+{
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++)
+  {
+    nsMsgDatabase* pMessageDB = m_dbCache[i];
+    if (pMessageDB->MatchDbName(dbName))
+    {
+      if (pMessageDB->m_mdbStore)  // don't return db without store
+      {
+        NS_ADDREF(pMessageDB);
+        return pMessageDB;
+      }
+    }
+  }
+  return nullptr;
+}
+
+// This method is called when the caller is trying to create a db without
+// having a corresponding nsIMsgFolder object.  This happens in a few
+// situations, including imap folder discovery, compacting local folders,
+// and copying local folders.
+NS_IMETHODIMP nsMsgDBService::OpenMailDBFromFile(nsIFile *aFolderName,
+                                                 nsIMsgFolder *aFolder,
+                                                 bool aCreate,
+                                                 bool aLeaveInvalidDB,
+                                                 nsIMsgDatabase** pMessageDB)
+{
+  if (!aFolderName)
+    return NS_ERROR_NULL_POINTER;
+
+  nsCOMPtr <nsIFile>  dbPath;
+  nsresult rv = GetSummaryFileLocation(aFolderName, getter_AddRefs(dbPath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *pMessageDB = FindInCache(dbPath);
+  if (*pMessageDB)
+    return NS_OK;
+
+  RefPtr<nsMailDatabase> msgDB = new nsMailDatabase;
+  NS_ENSURE_TRUE(msgDB, NS_ERROR_OUT_OF_MEMORY);
+  rv = msgDB->Open(this, dbPath, aCreate, aLeaveInvalidDB);
+  if (rv == NS_ERROR_FILE_TARGET_DOES_NOT_EXIST)
+    return rv;
+  NS_IF_ADDREF(*pMessageDB = msgDB);
+  if (aCreate && msgDB && rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING)
+    rv = NS_OK;
+  if (NS_SUCCEEDED(rv))
+    msgDB->m_folder = aFolder;
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::CreateNewDB(nsIMsgFolder *aFolder,
+                                          nsIMsgDatabase **_retval)
+{
+  NS_ENSURE_ARG(aFolder);
+  
+  nsCOMPtr <nsIMsgIncomingServer> incomingServer;
+  nsresult rv = aFolder->GetServer(getter_AddRefs(incomingServer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCString localDatabaseType;
+  incomingServer->GetLocalDatabaseType(localDatabaseType);
+  nsAutoCString dbContractID(NS_MSGDB_CONTRACTID);
+  dbContractID.Append(localDatabaseType.get());
+  
+  nsCOMPtr <nsIMsgDatabase> msgDB = do_CreateInstance(dbContractID.get(), &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMsgDatabase *msgDatabase = static_cast<nsMsgDatabase *>(msgDB.get());
+
+  msgDatabase->m_folder = aFolder;
+  rv = msgDatabase->Open(this, summaryFilePath, true, true);
+
+  // We are trying to create a new database, but that implies that it did not
+  // already exist. Open returns NS_MSG_ERROR_FOLDER_SUMMARY_MISSING for the
+  // successful creation of a new database. But if it existed for some
+  // reason, then we would get rv = NS_OK instead. That is a "failure"
+  // from our perspective, so we want to return a failure since we are not
+  // returning a valid database object.
+  NS_ENSURE_TRUE(rv == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING,
+                 NS_SUCCEEDED(rv) ? NS_ERROR_FILE_ALREADY_EXISTS : rv);
+
+  NS_ADDREF(*_retval = msgDB);
+
+  HookupPendingListeners(msgDB, aFolder);
+
+  msgDatabase->RememberLastUseTime();
+
+  return NS_OK;
+}
+
+/* void registerPendingListener (in nsIMsgFolder aFolder, in nsIDBChangeListener aListener); */
+NS_IMETHODIMP nsMsgDBService::RegisterPendingListener(nsIMsgFolder *aFolder, nsIDBChangeListener *aListener)
+{
+  // need to make sure we don't hold onto these forever. Maybe a shutdown listener?
+  // if there is a db open on this folder already, we should register the listener.
+  m_foldersPendingListeners.AppendObject(aFolder);
+  m_pendingListeners.AppendObject(aListener);
+  nsCOMPtr <nsIMsgDatabase> openDB;
+  CachedDBForFolder(aFolder, getter_AddRefs(openDB));
+  if (openDB)
+    openDB->AddListener(aListener);
+  return NS_OK;
+}
+
+/* void unregisterPendingListener (in nsIDBChangeListener aListener); */
+NS_IMETHODIMP nsMsgDBService::UnregisterPendingListener(nsIDBChangeListener *aListener)
+{
+  int32_t listenerIndex = m_pendingListeners.IndexOfObject(aListener);
+  if (listenerIndex != -1)
+  {
+    nsCOMPtr<nsIMsgDatabase> msgDB;
+    CachedDBForFolder(m_foldersPendingListeners[listenerIndex], getter_AddRefs(msgDB));
+    if (msgDB)
+      msgDB->RemoveListener(aListener);
+    m_foldersPendingListeners.RemoveObjectAt(listenerIndex);
+    m_pendingListeners.RemoveObjectAt(listenerIndex);
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgDBService::CachedDBForFolder(nsIMsgFolder *aFolder, nsIMsgDatabase **aRetDB)
+{
+  NS_ENSURE_ARG_POINTER(aFolder);
+  NS_ENSURE_ARG_POINTER(aRetDB);
+
+  nsCOMPtr<nsIFile> summaryFilePath;
+  nsresult rv = aFolder->GetSummaryFile(getter_AddRefs(summaryFilePath));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aRetDB = FindInCache(summaryFilePath);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBService::ForceFolderDBClosed(nsIMsgFolder *aFolder)
+{
+  nsCOMPtr<nsIMsgDatabase> mailDB;
+  nsresult rv = CachedDBForFolder(aFolder, getter_AddRefs(mailDB));
+  if (mailDB)
+  {
+    mailDB->ForceClosed();
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDBService::GetOpenDBs(nsIArray **aOpenDBs)
+{
+  NS_ENSURE_ARG_POINTER(aOpenDBs);
+  nsresult rv;
+  nsCOMPtr<nsIMutableArray> openDBs(do_CreateInstance(NS_ARRAY_CONTRACTID, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++)
+    openDBs->AppendElement(m_dbCache[i], false);
+
+  openDBs.forget(aOpenDBs);
+  return NS_OK;
+}
+
+static bool gGotGlobalPrefs = false;
+static bool gThreadWithoutRe = true;
+static bool gStrictThreading = false;
+static bool gCorrectThreading = false;
+
+void nsMsgDatabase::GetGlobalPrefs()
+{
+  if (!gGotGlobalPrefs)
+  {
+    GetBoolPref("mail.thread_without_re", &gThreadWithoutRe);
+    GetBoolPref("mail.strict_threading", &gStrictThreading);
+    GetBoolPref("mail.correct_threading", &gCorrectThreading);
+    gGotGlobalPrefs = true;
+  }
+}
+
+nsresult nsMsgDatabase::AddHdrToCache(nsIMsgDBHdr *hdr, nsMsgKey key) // do we want key? We could get it from hdr
+{
+  if (m_bCacheHeaders)
+  {
+    if (!m_cachedHeaders)
+      m_cachedHeaders = new PLDHashTable(&gMsgDBHashTableOps, sizeof(struct MsgHdrHashElement), m_cacheSize);
+    if (m_cachedHeaders)
+    {
+      if (key == nsMsgKey_None)
+        hdr->GetMessageKey(&key);
+      if (m_cachedHeaders->EntryCount() > m_cacheSize)
+        ClearHdrCache(true);
+      PLDHashEntryHdr *entry = m_cachedHeaders->Add((void *)(uintptr_t) key, mozilla::fallible);
+      if (!entry)
+        return NS_ERROR_OUT_OF_MEMORY; // XXX out of memory
+
+      MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+      element->mHdr = hdr;
+      element->mKey = key;
+      NS_ADDREF(hdr);     // make the cache hold onto the header
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_FAILURE;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgHdrCacheSize(uint32_t aSize)
+{
+  m_cacheSize = aSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrCacheSize(uint32_t *aSize)
+{
+  NS_ENSURE_ARG_POINTER(aSize);
+  *aSize = m_cacheSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetLastUseTime(PRTime *aTime)
+{
+  NS_ENSURE_ARG_POINTER(aTime);
+  *aTime = m_lastUseTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetLastUseTime(PRTime aTime)
+{
+  gLastUseTime = m_lastUseTime = aTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDatabaseSize(int64_t *_retval)
+{
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  nsresult rv;
+  nsCOMPtr<nsIFile> summaryFilePath = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = summaryFilePath->InitWithNativePath(m_dbName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool exists;
+  rv = summaryFilePath->Exists(&exists);
+  if (NS_SUCCEEDED(rv))
+  {
+    if (exists)
+      rv = summaryFilePath->GetFileSize(_retval);
+    else
+      *_retval = 0;
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ClearCachedHdrs()
+{
+  ClearCachedObjects(false);
+#ifdef DEBUG_bienvenu1
+  if (mRefCnt > 1)
+  {
+    NS_ASSERTION(false, "");
+    printf("someone's holding onto db - refs = %ld\n", mRefCnt);
+  }
+#endif
+  return NS_OK;
+}
+
+void nsMsgDatabase::ClearEnumerators()
+{
+  // clear out existing enumerators
+  nsTArray<nsMsgDBEnumerator *> copyEnumerators;
+  copyEnumerators.SwapElements(m_enumerators);
+
+  uint32_t numEnums = copyEnumerators.Length();
+  for (uint32_t i = 0; i < numEnums; i++)
+    copyEnumerators[i]->Clear();
+}
+
+nsMsgThread *nsMsgDatabase::FindExistingThread(nsMsgKey threadId)
+{
+  uint32_t numThreads = m_threads.Length();
+  for (uint32_t i = 0; i < numThreads; i++)
+    if (m_threads[i]->m_threadKey == threadId)
+      return m_threads[i];
+
+  return nullptr;
+}
+
+void nsMsgDatabase::ClearThreads()
+{
+  // clear out existing threads
+  nsTArray<nsMsgThread *> copyThreads;
+  copyThreads.SwapElements(m_threads);
+
+  uint32_t numThreads = copyThreads.Length();
+  for (uint32_t i = 0; i < numThreads; i++)
+    copyThreads[i]->Clear();
+}
+
+void nsMsgDatabase::ClearCachedObjects(bool dbGoingAway)
+{
+  ClearHdrCache(false);
+#ifdef DEBUG_DavidBienvenu
+  if (m_headersInUse && m_headersInUse->EntryCount() > 0)
+  {
+    NS_ASSERTION(false, "leaking headers");
+    printf("leaking %d headers in %s\n", m_headersInUse->EntryCount(), (const char *) m_dbName);
+  }
+#endif
+  m_cachedThread = nullptr;
+  m_cachedThreadId = nsMsgKey_None;
+  // We should only clear the use hdr cache when the db is going away, or we could
+  // end up with multiple copies of the same logical msg hdr, which will lead to
+  // ref-counting problems.
+  if (dbGoingAway)
+  {
+    ClearUseHdrCache();
+    ClearThreads();
+  }
+  m_thumb = nullptr;
+}
+
+nsresult nsMsgDatabase::ClearHdrCache(bool reInit)
+{
+  if (m_cachedHeaders)
+  {
+    // save this away in case we renter this code.
+    PLDHashTable  *saveCachedHeaders = m_cachedHeaders;
+    m_cachedHeaders = nullptr;
+    for (auto iter = saveCachedHeaders->Iter(); !iter.Done(); iter.Next()) {
+      auto element = static_cast<MsgHdrHashElement*>(iter.Get());
+      if (element)
+        NS_IF_RELEASE(element->mHdr);
+    }
+
+    if (reInit)
+    {
+      saveCachedHeaders->ClearAndPrepareForLength(m_cacheSize);
+      m_cachedHeaders = saveCachedHeaders;
+    }
+    else
+    {
+      delete saveCachedHeaders;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHdrFromCache(nsIMsgDBHdr *hdr, nsMsgKey key)
+{
+  if (m_cachedHeaders)
+  {
+    if (key == nsMsgKey_None)
+      hdr->GetMessageKey(&key);
+
+    PLDHashEntryHdr *entry =
+      m_cachedHeaders->Search((const void *)(uintptr_t) key);
+    if (entry)
+    {
+      m_cachedHeaders->Remove((void *)(uintptr_t) key);
+      NS_RELEASE(hdr); // get rid of extra ref the cache was holding.
+    }
+
+  }
+  return NS_OK;
+}
+
+
+nsresult nsMsgDatabase::GetHdrFromUseCache(nsMsgKey key, nsIMsgDBHdr* *result)
+{
+  if (!result)
+    return NS_ERROR_NULL_POINTER;
+
+  nsresult rv = NS_ERROR_FAILURE;
+
+  *result = nullptr;
+
+  if (m_headersInUse)
+  {
+    PLDHashEntryHdr *entry =
+      m_headersInUse->Search((const void *)(uintptr_t) key);
+    if (entry)
+    {
+      MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+      *result = element->mHdr;
+    }
+    if (*result)
+    {
+      NS_ADDREF(*result);
+      rv = NS_OK;
+    }
+  }
+  return rv;
+}
+
+PLDHashTableOps nsMsgDatabase::gMsgDBHashTableOps =
+{
+  HashKey,
+  MatchEntry,
+  MoveEntry,
+  ClearEntry,
+  nullptr
+};
+
+// HashKey is supposed to maximize entropy in the low order bits, and the key
+// as is, should do that.
+PLDHashNumber
+nsMsgDatabase::HashKey(const void* aKey)
+{
+  return PLDHashNumber(NS_PTR_TO_INT32(aKey));
+}
+
+bool
+nsMsgDatabase::MatchEntry(const PLDHashEntryHdr* aEntry, const void* aKey)
+{
+  const MsgHdrHashElement* hdr = static_cast<const MsgHdrHashElement*>(aEntry);
+  return aKey == (const void *)(uintptr_t) hdr->mKey; // ### or get the key from the hdr...
+}
+
+void
+nsMsgDatabase::MoveEntry(PLDHashTable* aTable, const PLDHashEntryHdr* aFrom, PLDHashEntryHdr* aTo)
+{
+  const MsgHdrHashElement* from = static_cast<const MsgHdrHashElement*>(aFrom);
+  MsgHdrHashElement* to = static_cast<MsgHdrHashElement*>(aTo);
+  // ### eh? Why is this needed? I don't think we have a copy operator?
+  *to = *from;
+}
+
+void
+nsMsgDatabase::ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry)
+{
+  MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(aEntry);
+  element->mHdr = nullptr; // eh? Need to release this or not?
+  element->mKey = nsMsgKey_None; // eh?
+}
+
+
+nsresult nsMsgDatabase::AddHdrToUseCache(nsIMsgDBHdr *hdr, nsMsgKey key)
+{
+  if (!m_headersInUse)
+  {
+    mdb_count numHdrs = MSG_HASH_SIZE;
+    if (m_mdbAllMsgHeadersTable)
+      m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrs);
+    m_headersInUse = new PLDHashTable(&gMsgDBHashTableOps, sizeof(struct MsgHdrHashElement), std::max((mdb_count)MSG_HASH_SIZE, numHdrs));
+  }
+  if (m_headersInUse)
+  {
+    if (key == nsMsgKey_None)
+      hdr->GetMessageKey(&key);
+    PLDHashEntryHdr *entry = m_headersInUse->Add((void *)(uintptr_t) key, mozilla::fallible);
+    if (!entry)
+      return NS_ERROR_OUT_OF_MEMORY; // XXX out of memory
+
+    MsgHdrHashElement* element = static_cast<MsgHdrHashElement*>(entry);
+    element->mHdr = hdr;
+    element->mKey = key;
+    // the hash table won't add ref, we'll do it ourselves
+    // stand for the addref that CreateMsgHdr normally does.
+    NS_ADDREF(hdr);
+    return NS_OK;
+  }
+
+  return NS_ERROR_OUT_OF_MEMORY;
+}
+
+nsresult nsMsgDatabase::ClearUseHdrCache()
+{
+  if (m_headersInUse)
+  {
+    // clear mdb row pointers of any headers still in use, because the
+    // underlying db is going away.
+    for (auto iter = m_headersInUse->Iter(); !iter.Done(); iter.Next()) {
+      auto element = static_cast<const MsgHdrHashElement*>(iter.Get());
+      if (element && element->mHdr) {
+        nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(element->mHdr);  // closed system, so this is ok
+        // clear out m_mdbRow member variable - the db is going away, which means that this member
+        // variable might very well point to a mork db that is gone.
+        NS_IF_RELEASE(msgHdr->m_mdbRow);
+    //    NS_IF_RELEASE(msgHdr->m_mdb);
+      }
+    }
+    delete m_headersInUse;
+    m_headersInUse = nullptr;
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHdrFromUseCache(nsIMsgDBHdr *hdr, nsMsgKey key)
+{
+  if (m_headersInUse)
+  {
+    if (key == nsMsgKey_None)
+      hdr->GetMessageKey(&key);
+
+    m_headersInUse->Remove((void *)(uintptr_t) key);
+  }
+  return NS_OK;
+}
+
+
+nsresult
+nsMsgDatabase::CreateMsgHdr(nsIMdbRow* hdrRow, nsMsgKey key, nsIMsgDBHdr* *result)
+{
+  NS_ENSURE_ARG_POINTER(hdrRow);
+  NS_ENSURE_ARG_POINTER(result);
+
+  nsresult rv = GetHdrFromUseCache(key, result);
+  if (NS_SUCCEEDED(rv) && *result)
+  {
+    hdrRow->Release();
+    return rv;
+  }
+
+  nsMsgHdr *msgHdr = new nsMsgHdr(this, hdrRow);
+  if(!msgHdr)
+    return NS_ERROR_OUT_OF_MEMORY;
+  msgHdr->SetMessageKey(key);
+  // don't need to addref here; GetHdrFromUseCache addrefs.
+  *result = msgHdr;
+
+  AddHdrToCache(msgHdr, key);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddListener(nsIDBChangeListener *aListener)
+{
+  NS_ENSURE_ARG_POINTER(aListener);
+  m_ChangeListeners.AppendElementUnlessExists(aListener);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RemoveListener(nsIDBChangeListener *aListener)
+{
+  NS_ENSURE_ARG_POINTER(aListener);
+  m_ChangeListeners.RemoveElement(aListener);
+  return NS_OK;
+}
+
+// XXX should we return rv for listener->propertyfunc_?
+#define NOTIFY_LISTENERS(propertyfunc_, params_) \
+  PR_BEGIN_MACRO \
+  nsTObserverArray<nsCOMPtr<nsIDBChangeListener> >::ForwardIterator iter(m_ChangeListeners); \
+  nsCOMPtr<nsIDBChangeListener> listener; \
+  while (iter.HasMore()) { \
+    listener = iter.GetNext(); \
+    listener->propertyfunc_ params_; \
+  } \
+  PR_END_MACRO
+
+// change announcer methods - just broadcast to all listeners.
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrChangeAll(nsIMsgDBHdr *aHdrChanged,
+                                                uint32_t aOldFlags,
+                                                uint32_t aNewFlags,
+                                                nsIDBChangeListener *aInstigator)
+{
+  // We will only notify the change if the header exists in the database.
+  // This allows database functions to be usable in both the case where the
+  // header is in the db, or the header is not so no notifications should be
+  // given.
+  nsMsgKey key;
+  bool inDb = false;
+  if (aHdrChanged)
+  {
+    aHdrChanged->GetMessageKey(&key);
+    ContainsKey(key, &inDb);
+  }
+  if (inDb)
+    NOTIFY_LISTENERS(OnHdrFlagsChanged,
+                     (aHdrChanged, aOldFlags, aNewFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyReadChanged(nsIDBChangeListener *aInstigator)
+{
+  NOTIFY_LISTENERS(OnReadChanged, (aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyJunkScoreChanged(nsIDBChangeListener *aInstigator)
+{
+  NOTIFY_LISTENERS(OnJunkScoreChanged, (aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrDeletedAll(nsIMsgDBHdr *aHdrDeleted,
+                                                 nsMsgKey aParentKey,
+                                                 int32_t aFlags,
+                                                 nsIDBChangeListener *aInstigator)
+{
+  NOTIFY_LISTENERS(OnHdrDeleted, (aHdrDeleted, aParentKey, aFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyHdrAddedAll(nsIMsgDBHdr *aHdrAdded,
+                                               nsMsgKey aParentKey,
+                                               int32_t aFlags,
+                                               nsIDBChangeListener *aInstigator)
+{
+#ifdef DEBUG_bienvenu1
+  printf("notifying add of %ld parent %ld\n", keyAdded, parentKey);
+#endif
+  NOTIFY_LISTENERS(OnHdrAdded, (aHdrAdded, aParentKey, aFlags, aInstigator));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::NotifyParentChangedAll(nsMsgKey aKeyReparented,
+                                                    nsMsgKey aOldParent,
+                                                    nsMsgKey aNewParent,
+                                                    nsIDBChangeListener *aInstigator)
+{
+  NOTIFY_LISTENERS(OnParentChanged,
+                   (aKeyReparented, aOldParent, aNewParent, aInstigator));
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::NotifyAnnouncerGoingAway(void)
+{
+  NOTIFY_LISTENERS(OnAnnouncerGoingAway, (this));
+  return NS_OK;
+}
+
+bool nsMsgDatabase::MatchDbName(nsIFile *dbName)  // returns true if they match
+{
+  nsCString dbPath;
+  dbName->GetNativePath(dbPath);
+  return dbPath.Equals(m_dbName);
+}
+
+void nsMsgDBService::AddToCache(nsMsgDatabase* pMessageDB)
+{
+#ifdef DEBUG_David_Bienvenu
+  NS_ASSERTION(m_dbCache.Length() < 50, "50 or more open db's");
+#endif
+#ifdef DEBUG
+  if (pMessageDB->m_folder)
+  {
+    nsCOMPtr<nsIMsgDatabase> msgDB;
+    CachedDBForFolder(pMessageDB->m_folder, getter_AddRefs(msgDB));
+    NS_ASSERTION(!msgDB, "shouldn't have db in cache");
+  }
+#endif
+  m_dbCache.AppendElement(pMessageDB);
+}
+
+/**
+ * Log the open db's, and how many headers are in memory.
+ */
+void nsMsgDBService::DumpCache()
+{
+  nsMsgDatabase* db = nullptr;
+  MOZ_LOG(DBLog, LogLevel::Info, ("%d open DB's\n", m_dbCache.Length()));
+  for (uint32_t i = 0; i < m_dbCache.Length(); i++)
+  {
+    db = m_dbCache.ElementAt(i);
+    MOZ_LOG(DBLog, LogLevel::Info, ("%s - %ld hdrs in use\n",
+      (const char*)db->m_dbName.get(),
+      db->m_headersInUse ? db->m_headersInUse->EntryCount() : 0));
+  }
+}
+
+// Memory Reporting implementations
+
+size_t nsMsgDatabase::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+{
+  size_t totalSize = 0;
+  if (m_dbFolderInfo)
+    totalSize += m_dbFolderInfo->SizeOfExcludingThis(aMallocSizeOf);
+  if (m_mdbEnv)
+  {
+    nsIMdbHeap *morkHeap = nullptr;
+    m_mdbEnv->GetHeap(&morkHeap);
+    if (morkHeap)
+      totalSize += morkHeap->GetUsedSize();
+  }
+  totalSize += m_newSet.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  totalSize += m_ChangeListeners.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  totalSize += m_threads.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  // We have two tables of header objects, but every header in m_cachedHeaders
+  // should be in m_headersInUse.
+  // double-counting...
+  size_t headerSize = 0;
+  if (m_headersInUse)
+  {
+    headerSize = m_headersInUse->ShallowSizeOfIncludingThis(aMallocSizeOf);
+    for (auto iter = m_headersInUse->Iter(); !iter.Done(); iter.Next()) {
+      auto entry = static_cast<MsgHdrHashElement*>(iter.Get());
+      // Sigh, this is dangerous, but so long as this is a closed system, this
+      // is safe.
+      headerSize += static_cast<nsMsgHdr*>(entry->mHdr)->SizeOfIncludingThis(aMallocSizeOf);
+    }
+  }
+  totalSize += headerSize;
+  if (m_msgReferences)
+    totalSize += m_msgReferences->ShallowSizeOfIncludingThis(aMallocSizeOf);
+  return totalSize;
+}
+
+namespace mozilla {
+namespace mailnews {
+
+MOZ_DEFINE_MALLOC_SIZE_OF(GetMallocSize)
+
+class MsgDBReporter final : public nsIMemoryReporter
+{
+  nsMsgDatabase *mDatabase;
+public:
+  MsgDBReporter(nsMsgDatabase *db) : mDatabase(db) {}
+
+  NS_DECL_ISUPPORTS
+  NS_IMETHOD GetName(nsACString &aName)
+  {
+    aName.AssignLiteral("msg-database-objects");
+    return NS_OK;
+  }
+
+  NS_IMETHOD CollectReports(nsIMemoryReporterCallback*aCb,
+                            nsISupports* aClosure,
+                            bool aAnonymize) override
+  {
+    nsCString path;
+    GetPath(path, aAnonymize);
+    return aCb->Callback(EmptyCString(), path,
+                         nsIMemoryReporter::KIND_HEAP,
+                         nsIMemoryReporter::UNITS_BYTES,
+                         mDatabase->SizeOfIncludingThis(GetMallocSize),           
+                         NS_LITERAL_CSTRING("Memory used for the folder database."),
+                         aClosure);
+  }
+
+  void GetPath(nsACString &memoryPath, bool aAnonymize)
+  {
+    memoryPath.AssignLiteral("explicit/maildb/database(");
+    nsCOMPtr<nsIMsgFolder> folder;
+    mDatabase->GetFolder(getter_AddRefs(folder));
+    if (folder)
+    {
+      if (aAnonymize)
+        memoryPath.AppendLiteral("<anonymized>");
+      else
+      {
+        nsAutoCString folderURL;
+        folder->GetFolderURL(folderURL);
+        MsgReplaceChar(folderURL, '/', '\\');
+        memoryPath += folderURL;
+      }
+    } else {
+      memoryPath.AppendLiteral("UNKNOWN-FOLDER");
+    }
+    memoryPath.Append(')');
+  }
+
+private:
+  ~MsgDBReporter() {}
+};
+
+NS_IMPL_ISUPPORTS(MsgDBReporter, nsIMemoryReporter)
+}
+}
+
+nsMsgDatabase::nsMsgDatabase()
+        : m_dbFolderInfo(nullptr),
+        m_nextPseudoMsgKey(kFirstPseudoKey),
+        m_mdbEnv(nullptr), m_mdbStore(nullptr),
+        m_mdbAllMsgHeadersTable(nullptr), m_mdbAllThreadsTable(nullptr),
+        m_create(false),
+        m_leaveInvalidDB(false),
+        m_dbName(""),
+        m_mdbTokensInitialized(false),
+        m_hdrRowScopeToken(0),
+        m_hdrTableKindToken(0),
+        m_threadTableKindToken(0),
+        m_subjectColumnToken(0),
+        m_senderColumnToken(0),
+        m_messageIdColumnToken(0),
+        m_referencesColumnToken(0),
+        m_recipientsColumnToken(0),
+        m_dateColumnToken(0),
+        m_messageSizeColumnToken(0),
+        m_flagsColumnToken(0),
+        m_priorityColumnToken(0),
+        m_labelColumnToken(0),
+        m_statusOffsetColumnToken(0),
+        m_numLinesColumnToken(0),
+        m_ccListColumnToken(0),
+        m_bccListColumnToken(0),
+        m_threadFlagsColumnToken(0),
+        m_threadIdColumnToken(0),
+        m_threadChildrenColumnToken(0),
+        m_threadUnreadChildrenColumnToken(0),
+        m_messageThreadIdColumnToken(0),
+        m_threadSubjectColumnToken(0),
+        m_messageCharSetColumnToken(0),
+        m_threadParentColumnToken(0),
+        m_threadRootKeyColumnToken(0),
+        m_threadNewestMsgDateColumnToken(0),
+        m_offlineMsgOffsetColumnToken(0),
+        m_offlineMessageSizeColumnToken(0),
+        m_headersInUse(nullptr),
+        m_cachedHeaders(nullptr),
+        m_bCacheHeaders(true),
+        m_cachedThreadId(nsMsgKey_None),
+        m_msgReferences(nullptr),
+        m_cacheSize(kMaxHdrsInCache)
+{
+  mMemReporter = new mozilla::mailnews::MsgDBReporter(this);
+  mozilla::RegisterWeakMemoryReporter(mMemReporter);
+}
+
+nsMsgDatabase::~nsMsgDatabase()
+{
+  mozilla::UnregisterWeakMemoryReporter(mMemReporter);
+  //  Close(FALSE);  // better have already been closed.
+  ClearCachedObjects(true);
+  ClearEnumerators();
+  delete m_cachedHeaders;
+  delete m_headersInUse;
+
+  if (m_msgReferences)
+  {
+    delete m_msgReferences;
+    m_msgReferences = nullptr;
+  }
+
+  MOZ_LOG(DBLog, LogLevel::Info, ("closing database    %s\n",
+    (const char*)m_dbName.get()));
+
+  nsCOMPtr<nsIMsgDBService> serv(do_GetService(NS_MSGDB_SERVICE_CONTRACTID));
+  if (serv)
+    static_cast<nsMsgDBService*>(serv.get())->RemoveFromCache(this);
+
+  // if the db folder info refers to the mdb db, we must clear it because
+  // the reference will be a dangling one soon.
+  if (m_dbFolderInfo)
+    m_dbFolderInfo->ReleaseExternalReferences();
+
+  NS_IF_RELEASE(m_dbFolderInfo);
+  if (m_mdbAllMsgHeadersTable)
+    m_mdbAllMsgHeadersTable->Release();
+
+  if (m_mdbAllThreadsTable)
+    m_mdbAllThreadsTable->Release();
+
+  if (m_mdbStore)
+    m_mdbStore->Release();
+
+  if (m_mdbEnv)
+  {
+    m_mdbEnv->Release(); //??? is this right?
+    m_mdbEnv = nullptr;
+  }
+  m_ChangeListeners.Clear();
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDatabase, nsIMsgDatabase, nsIDBChangeAnnouncer)
+
+void nsMsgDatabase::GetMDBFactory(nsIMdbFactory ** aMdbFactory)
+{
+  if (!mMdbFactory)
+  {
+    nsresult rv;
+    nsCOMPtr <nsIMdbFactoryService> mdbFactoryService = do_GetService(NS_MORK_CONTRACTID, &rv);
+    if (NS_SUCCEEDED(rv) && mdbFactoryService)
+      mdbFactoryService->GetMdbFactory(getter_AddRefs(mMdbFactory));
+  }
+  NS_IF_ADDREF(*aMdbFactory = mMdbFactory);
+}
+
+// aLeaveInvalidDB: true if caller wants back a db even out of date.
+// If so, they'll extract out the interesting info from the db, close it,
+// delete it, and then try to open the db again, prior to reparsing.
+nsresult nsMsgDatabase::Open(nsMsgDBService *aDBService, nsIFile *aFolderName,
+                             bool aCreate, bool aLeaveInvalidDB)
+{
+  return nsMsgDatabase::OpenInternal(aDBService, aFolderName, aCreate, aLeaveInvalidDB,
+                                     true /* open synchronously */);
+}
+
+nsresult nsMsgDatabase::OpenInternal(nsMsgDBService *aDBService,
+                                     nsIFile *summaryFile, bool aCreate,
+                                     bool aLeaveInvalidDB, bool sync)
+{
+  nsAutoCString summaryFilePath;
+  summaryFile->GetNativePath(summaryFilePath);
+
+  MOZ_LOG(DBLog, LogLevel::Info, ("nsMsgDatabase::Open(%s, %s, %p, %s)\n",
+    (const char*)summaryFilePath.get(), aCreate ? "TRUE":"FALSE",
+    this, aLeaveInvalidDB ? "TRUE":"FALSE"));
+
+
+  nsresult rv = OpenMDB(summaryFilePath.get(), aCreate, sync);
+  if (NS_FAILED(rv))
+    MOZ_LOG(DBLog, LogLevel::Info, ("error opening db %lx", rv));
+
+  if (MOZ_LOG_TEST(DBLog, LogLevel::Debug))
+    aDBService->DumpCache();
+
+  if (rv == NS_ERROR_FILE_TARGET_DOES_NOT_EXIST)
+    return rv;
+
+  m_create = aCreate;
+  m_leaveInvalidDB = aLeaveInvalidDB;
+  if (!sync && NS_SUCCEEDED(rv))
+  {
+    aDBService->AddToCache(this);
+    // remember open options for when the parsing is complete.
+    return rv;
+  }
+  return CheckForErrors(rv, true, aDBService, summaryFile);
+}
+
+nsresult nsMsgDatabase::CheckForErrors(nsresult err, bool sync,
+                                       nsMsgDBService *aDBService,
+                                       nsIFile *summaryFile)
+{
+  nsCOMPtr<nsIDBFolderInfo> folderInfo;
+  bool summaryFileExists;
+  bool newFile = false;
+  bool deleteInvalidDB = false;
+
+  bool exists;
+  int64_t fileSize;
+  summaryFile->Exists(&exists);
+  summaryFile->GetFileSize(&fileSize);
+  // if the old summary doesn't exist, we're creating a new one.
+  if ((!exists || !fileSize) && m_create)
+    newFile = true;
+
+  summaryFileExists = exists && fileSize > 0;
+
+  if (NS_SUCCEEDED(err))
+  {
+    if (!m_dbFolderInfo)
+    {
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    }
+    else
+    {
+      if (!newFile && summaryFileExists)
+      {
+        bool valid = false;
+        nsresult rv = GetSummaryValid(&valid);
+        if (NS_FAILED(rv) || !valid)
+          err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+      }
+      // compare current version of db versus filed out version info.
+      uint32_t version;
+      m_dbFolderInfo->GetVersion(&version);
+      if (GetCurVersion() != version)
+        err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+
+      // Check if we should force a reparse because, for example, we have
+      // reached the key limit.
+      bool forceReparse;
+      m_dbFolderInfo->GetBooleanProperty("forceReparse", false, &forceReparse);
+      if (forceReparse)
+      {
+        NS_WARNING("Forcing a reparse presumably because key limit reached");
+        err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+      }
+
+    }
+    if (NS_FAILED(err) && !m_leaveInvalidDB)
+      deleteInvalidDB = true;
+  }
+  else
+  {
+    err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    deleteInvalidDB = true;
+  }
+
+  if (deleteInvalidDB)
+  {
+    // this will make the db folder info release its ref to the mail db...
+    NS_IF_RELEASE(m_dbFolderInfo);
+    ForceClosed();
+    if (err == NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+      summaryFile->Remove(false);
+  }
+  if (NS_FAILED(err) || newFile)
+  {
+    // if we couldn't open file, or we have a blank one, and we're supposed
+    // to upgrade, updgrade it.
+    if (newFile && !m_leaveInvalidDB)  // caller is upgrading, and we have empty summary file,
+    {          // leave db around and open so caller can upgrade it.
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+    }
+    else if (NS_FAILED(err) && err != NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE)
+    {
+      Close(false);
+      summaryFile->Remove(false);  // blow away the db if it's corrupt.
+    }
+  }
+  if (sync && (NS_SUCCEEDED(err) || err == NS_MSG_ERROR_FOLDER_SUMMARY_MISSING))
+    aDBService->AddToCache(this);
+  return (summaryFileExists) ? err : NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+}
+
+/**
+ * Open the MDB database synchronously or async based on sync argument.
+ * If successful, this routine will set up the m_mdbStore and m_mdbEnv of
+ * the database object so other database calls can work.
+ */
+nsresult nsMsgDatabase::OpenMDB(const char *dbName, bool create, bool sync)
+{
+  nsresult ret = NS_OK;
+  nsCOMPtr<nsIMdbFactory> mdbFactory;
+  GetMDBFactory(getter_AddRefs(mdbFactory));
+  if (mdbFactory)
+  {
+    ret = mdbFactory->MakeEnv(NULL, &m_mdbEnv);
+    if (NS_SUCCEEDED(ret))
+    {
+      nsIMdbHeap* dbHeap = nullptr;
+
+      if (m_mdbEnv)
+        m_mdbEnv->SetAutoClear(true);
+      m_dbName = dbName;
+      bool exists = false;
+      nsCOMPtr<nsIFile> dbFile = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &ret);
+      if (NS_SUCCEEDED(ret) && dbFile) {
+        ret = dbFile->InitWithNativePath(m_dbName);
+        if (NS_SUCCEEDED(ret))
+          ret = dbFile->Exists(&exists);
+      }
+      if (!exists)
+      {
+        ret = NS_MSG_ERROR_FOLDER_SUMMARY_MISSING;
+      }
+      // If m_thumb is set, we're asynchronously opening the db already.
+      else if (!m_thumb) 
+      {
+        mdbOpenPolicy inOpenPolicy;
+        mdb_bool  canOpen;
+        mdbYarn    outFormatVersion;
+
+        nsIMdbFile* oldFile = nullptr;
+        ret = mdbFactory->OpenOldFile(m_mdbEnv, dbHeap, dbName,
+                                      mdbBool_kFalse, // not readonly, we want modifiable
+                                      &oldFile);
+        if (oldFile)
+        {
+          if (NS_SUCCEEDED(ret))
+          {
+            ret = mdbFactory->CanOpenFilePort(m_mdbEnv, oldFile, // the file to investigate
+              &canOpen, &outFormatVersion);
+            if (NS_SUCCEEDED(ret) && canOpen)
+            {
+              inOpenPolicy.mOpenPolicy_ScopePlan.mScopeStringSet_Count = 0;
+              inOpenPolicy.mOpenPolicy_MinMemory = 0;
+              inOpenPolicy.mOpenPolicy_MaxLazy = 0;
+
+              ret = mdbFactory->OpenFileStore(m_mdbEnv, dbHeap,
+                oldFile, &inOpenPolicy, getter_AddRefs(m_thumb));
+            }
+            else
+              ret = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+          }
+          NS_RELEASE(oldFile); // always release our file ref, store has own
+        }
+      }
+      if (NS_SUCCEEDED(ret) && m_thumb && sync)
+      {
+        mdb_count outTotal;    // total somethings to do in operation
+        mdb_count outCurrent;  // subportion of total completed so far
+        mdb_bool outDone = false;      // is operation finished?
+        mdb_bool outBroken;     // is operation irreparably dead and broken?
+        do
+        {
+          ret = m_thumb->DoMore(m_mdbEnv, &outTotal, &outCurrent, &outDone, &outBroken);
+          if (NS_FAILED(ret))
+          {// mork isn't really doing NS errors yet.
+            outDone = true;
+            break;
+          }
+        }
+        while (NS_SUCCEEDED(ret) && !outBroken && !outDone);
+        //        m_mdbEnv->ClearErrors(); // ### temporary...
+        // only 0 is a non-error return.
+        if (NS_SUCCEEDED(ret) && outDone)
+        {
+          ret = mdbFactory->ThumbToOpenStore(m_mdbEnv, m_thumb, &m_mdbStore);
+          if (NS_SUCCEEDED(ret))
+            ret = (m_mdbStore) ? InitExistingDB() : NS_ERROR_FAILURE;
+        }
+#ifdef DEBUG_bienvenu1
+        DumpContents();
+#endif
+        m_thumb = nullptr;
+      }
+      else if (create)  // ### need error code saying why open file store failed
+      {
+        nsIMdbFile* newFile = 0;
+        ret = mdbFactory->CreateNewFile(m_mdbEnv, dbHeap, dbName, &newFile);
+        if (NS_FAILED(ret))
+          ret = NS_ERROR_FILE_TARGET_DOES_NOT_EXIST;
+        if ( newFile )
+        {
+          if (NS_SUCCEEDED(ret))
+          {
+            mdbOpenPolicy inOpenPolicy;
+
+            inOpenPolicy.mOpenPolicy_ScopePlan.mScopeStringSet_Count = 0;
+            inOpenPolicy.mOpenPolicy_MinMemory = 0;
+            inOpenPolicy.mOpenPolicy_MaxLazy = 0;
+
+            ret = mdbFactory->CreateNewFileStore(m_mdbEnv, dbHeap,
+              newFile, &inOpenPolicy, &m_mdbStore);
+            if (NS_SUCCEEDED(ret))
+              ret = (m_mdbStore) ? InitNewDB() : NS_ERROR_FAILURE;
+          }
+          NS_RELEASE(newFile); // always release our file ref, store has own
+        }
+      }
+    }
+  }
+#ifdef DEBUG_David_Bienvenu
+//  NS_ASSERTION(NS_SUCCEEDED(ret), "failed opening mdb");
+#endif
+  return ret;
+}
+
+nsresult nsMsgDatabase::CloseMDB(bool commit)
+{
+  if (commit)
+    Commit(nsMsgDBCommitType::kSessionCommit);
+  return(NS_OK);
+}
+
+
+// force the database to close - this'll flush out anybody holding onto
+// a database without having a listener!
+// This is evil in the com world, but there are times we need to delete the file.
+NS_IMETHODIMP nsMsgDatabase::ForceClosed()
+{
+  nsresult  err = NS_OK;
+
+  // make sure someone has a reference so object won't get deleted out from under us.
+  AddRef();
+  NotifyAnnouncerGoingAway();
+  // make sure dbFolderInfo isn't holding onto mork stuff because mork db is going away
+  if (m_dbFolderInfo)
+    m_dbFolderInfo->ReleaseExternalReferences();
+  NS_IF_RELEASE(m_dbFolderInfo);
+
+  err = CloseMDB(true);  // Backup DB will try to recover info, so commit
+  ClearCachedObjects(true);
+  ClearEnumerators();
+if (m_mdbAllMsgHeadersTable)
+  {
+    m_mdbAllMsgHeadersTable->Release();
+    m_mdbAllMsgHeadersTable = nullptr;
+  }
+  if (m_mdbAllThreadsTable)
+  {
+    m_mdbAllThreadsTable->Release();
+    m_mdbAllThreadsTable = nullptr;
+  }
+  if (m_mdbStore)
+  {
+    m_mdbStore->Release();
+    m_mdbStore = nullptr;
+  }
+
+  // better not be any listeners, because we're going away.
+  NS_ASSERTION(m_ChangeListeners.IsEmpty(), "shouldn't have any listeners left");
+
+  Release();
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDBFolderInfo(nsIDBFolderInfo  **result)
+{
+  if (!m_dbFolderInfo)
+  {
+    NS_ERROR("db must be corrupt");
+    return NS_ERROR_NULL_POINTER;
+  }
+  NS_ADDREF(*result = m_dbFolderInfo);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetFolder(nsIMsgFolder **aFolder)
+{
+  NS_ENSURE_ARG_POINTER(aFolder);
+  NS_IF_ADDREF(*aFolder = m_folder);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::Commit(nsMsgDBCommit commitType)
+{
+  nsresult  err = NS_OK;
+  nsCOMPtr<nsIMdbThumb> commitThumb;
+
+  RememberLastUseTime();
+  if (commitType == nsMsgDBCommitType::kLargeCommit || commitType == nsMsgDBCommitType::kSessionCommit)
+  {
+    mdb_percent outActualWaste = 0;
+    mdb_bool outShould;
+    if (m_mdbStore) {
+      err = m_mdbStore->ShouldCompress(GetEnv(), 30, &outActualWaste, &outShould);
+      if (NS_SUCCEEDED(err) && outShould)
+        commitType = nsMsgDBCommitType::kCompressCommit;
+    }
+  }
+  //  commitType = nsMsgDBCommitType::kCompressCommit;  // ### until incremental writing works.
+
+  if (m_mdbStore)
+  {
+    switch (commitType)
+    {
+    case nsMsgDBCommitType::kLargeCommit:
+      err = m_mdbStore->LargeCommit(GetEnv(), getter_AddRefs(commitThumb));
+      break;
+    case nsMsgDBCommitType::kSessionCommit:
+      err = m_mdbStore->SessionCommit(GetEnv(), getter_AddRefs(commitThumb));
+      break;
+    case nsMsgDBCommitType::kCompressCommit:
+      err = m_mdbStore->CompressCommit(GetEnv(), getter_AddRefs(commitThumb));
+      break;
+    }
+  }
+  if (commitThumb)
+  {
+    mdb_count outTotal = 0;    // total somethings to do in operation
+    mdb_count outCurrent = 0;  // subportion of total completed so far
+    mdb_bool outDone = false;      // is operation finished?
+    mdb_bool outBroken = false;     // is operation irreparably dead and broken?
+    while (!outDone && !outBroken && NS_SUCCEEDED(err))
+    {
+      err = commitThumb->DoMore(GetEnv(), &outTotal, &outCurrent, &outDone, &outBroken);
+    }
+
+  }
+  // ### do something with error, but clear it now because mork errors out on commits.
+  if (GetEnv())
+    GetEnv()->ClearErrors();
+
+  nsresult rv;
+  nsCOMPtr<nsIMsgAccountManager> accountManager =
+    do_GetService(NS_MSGACCOUNTMANAGER_CONTRACTID, &rv);
+  if (NS_SUCCEEDED(rv) && accountManager)
+  {
+    nsCOMPtr<nsIMsgFolderCache> folderCache;
+
+    rv = accountManager->GetFolderCache(getter_AddRefs(folderCache));
+    if (NS_SUCCEEDED(rv) && folderCache)
+    {
+      nsCOMPtr <nsIMsgFolderCacheElement> cacheElement;
+      rv = folderCache->GetCacheElement(m_dbName, false, getter_AddRefs(cacheElement));
+      if (NS_SUCCEEDED(rv) && cacheElement && m_dbFolderInfo)
+      {
+        int32_t totalMessages, unreadMessages, pendingMessages, pendingUnreadMessages;
+
+        m_dbFolderInfo->GetNumMessages(&totalMessages);
+        m_dbFolderInfo->GetNumUnreadMessages(&unreadMessages);
+        m_dbFolderInfo->GetImapUnreadPendingMessages(&pendingUnreadMessages);
+        m_dbFolderInfo->GetImapTotalPendingMessages(&pendingMessages);
+        cacheElement->SetInt32Property("totalMsgs", totalMessages);
+        cacheElement->SetInt32Property("totalUnreadMsgs", unreadMessages);
+        cacheElement->SetInt32Property("pendingMsgs", pendingMessages);
+        cacheElement->SetInt32Property("pendingUnreadMsgs", pendingUnreadMessages);
+        folderCache->Commit(false);
+      }
+    }
+  }
+
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::Close(bool forceCommit /* = TRUE */)
+{
+  return CloseMDB(forceCommit);
+}
+
+const char *kMsgHdrsScope = "ns:msg:db:row:scope:msgs:all";  // scope for all headers table
+const char *kMsgHdrsTableKind = "ns:msg:db:table:kind:msgs";
+const char *kThreadTableKind = "ns:msg:db:table:kind:thread";
+const char *kThreadHdrsScope = "ns:msg:db:row:scope:threads:all"; // scope for all threads table
+const char *kAllThreadsTableKind = "ns:msg:db:table:kind:allthreads"; // kind for table of all threads
+const char *kSubjectColumnName = "subject";
+const char *kSenderColumnName = "sender";
+const char *kMessageIdColumnName = "message-id";
+const char *kReferencesColumnName = "references";
+const char *kRecipientsColumnName = "recipients";
+const char *kDateColumnName = "date";
+const char *kMessageSizeColumnName = "size";
+const char *kFlagsColumnName = "flags";
+const char *kPriorityColumnName = "priority";
+const char *kLabelColumnName = "label";
+const char *kStatusOffsetColumnName = "statusOfset";
+const char *kNumLinesColumnName = "numLines";
+const char *kCCListColumnName = "ccList";
+const char *kBCCListColumnName = "bccList";
+const char *kMessageThreadIdColumnName = "msgThreadId";
+const char *kThreadFlagsColumnName = "threadFlags";
+const char *kThreadIdColumnName = "threadId";
+const char *kThreadChildrenColumnName = "children";
+const char *kThreadUnreadChildrenColumnName = "unreadChildren";
+const char *kThreadSubjectColumnName = "threadSubject";
+const char *kMessageCharSetColumnName = "msgCharSet";
+const char *kThreadParentColumnName = "threadParent";
+const char *kThreadRootColumnName = "threadRoot";
+const char *kThreadNewestMsgDateColumnName = "threadNewestMsgDate";
+const char *kOfflineMsgOffsetColumnName = "msgOffset";
+const char *kOfflineMsgSizeColumnName = "offlineMsgSize";
+struct mdbOid gAllMsgHdrsTableOID;
+struct mdbOid gAllThreadsTableOID;
+const char *kFixedBadRefThreadingProp = "fixedBadRefThreading";
+
+// set up empty tables, dbFolderInfo, etc.
+nsresult nsMsgDatabase::InitNewDB()
+{
+  nsresult err = NS_OK;
+
+  err = InitMDBInfo();
+  if (NS_SUCCEEDED(err))
+  {
+    nsDBFolderInfo *dbFolderInfo = new nsDBFolderInfo(this);
+    if (dbFolderInfo)
+    {
+      NS_ADDREF(dbFolderInfo);
+      err = dbFolderInfo->AddToNewMDB();
+      dbFolderInfo->SetVersion(GetCurVersion());
+      dbFolderInfo->SetBooleanProperty("forceReparse", false);
+      dbFolderInfo->SetBooleanProperty(kFixedBadRefThreadingProp, true);
+      nsIMdbStore *store = GetStore();
+      // create the unique table for the dbFolderInfo.
+      struct mdbOid allMsgHdrsTableOID;
+      struct mdbOid allThreadsTableOID;
+      if (!store)
+        return NS_ERROR_NULL_POINTER;
+
+      allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+      allMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+      allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+      allThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+
+      // TODO: check this error value?
+      (void) store->NewTableWithOid(GetEnv(), &allMsgHdrsTableOID, m_hdrTableKindToken,
+        false, nullptr, &m_mdbAllMsgHeadersTable);
+
+      // error here is not fatal.
+      (void) store->NewTableWithOid(GetEnv(), &allThreadsTableOID, m_allThreadsTableKindToken,
+        false, nullptr, &m_mdbAllThreadsTable);
+
+      m_dbFolderInfo = dbFolderInfo;
+
+    }
+    else
+      err = NS_ERROR_OUT_OF_MEMORY;
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetTableCreateIfMissing(const char *scope, const char *kind, nsIMdbTable **table,
+                                                mdb_token &scopeToken, mdb_token &kindToken)
+{
+  struct mdbOid tableOID;
+
+  if (!m_mdbStore)
+    return NS_ERROR_FAILURE;
+  (void) m_mdbStore->StringToToken(GetEnv(), scope, &scopeToken);
+  (void) m_mdbStore->StringToToken(GetEnv(), kind, &kindToken);
+  tableOID.mOid_Scope = scopeToken;
+  tableOID.mOid_Id = 1;
+
+  nsresult rv = m_mdbStore->GetTable(GetEnv(), &tableOID, table);
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);
+
+  // create new all all offline ops table, if it doesn't exist.
+  if (NS_SUCCEEDED(rv) && !*table)
+  {
+    rv = m_mdbStore->NewTable(GetEnv(), scopeToken,kindToken,
+                              false, nullptr, table);
+    if (NS_FAILED(rv) || !*table)
+      rv = NS_ERROR_FAILURE;
+  }
+  NS_ASSERTION(NS_SUCCEEDED(rv), "couldn't create offline ops table");
+  return rv;
+}
+
+nsresult nsMsgDatabase::InitExistingDB()
+{
+  nsresult err = NS_OK;
+
+  err = InitMDBInfo();
+  if (NS_SUCCEEDED(err))
+  {
+    err = GetStore()->GetTable(GetEnv(), &gAllMsgHdrsTableOID, &m_mdbAllMsgHeadersTable);
+    if (NS_SUCCEEDED(err))
+    {
+      m_dbFolderInfo = new nsDBFolderInfo(this);
+      if (m_dbFolderInfo)
+      {
+        NS_ADDREF(m_dbFolderInfo);
+        err = m_dbFolderInfo->InitFromExistingDB();
+      }
+    }
+    else
+      err = NS_ERROR_FAILURE;
+
+    NS_ASSERTION(NS_SUCCEEDED(err), "failed initing existing db");
+    NS_ENSURE_SUCCESS(err, err);
+    // create new all msg hdrs table, if it doesn't exist.
+    if (NS_SUCCEEDED(err) && !m_mdbAllMsgHeadersTable)
+    {
+      struct mdbOid allMsgHdrsTableOID;
+      allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+      allMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+
+      nsresult mdberr = GetStore()->NewTableWithOid(GetEnv(), &allMsgHdrsTableOID, m_hdrTableKindToken,
+        false, nullptr, &m_mdbAllMsgHeadersTable);
+      if (NS_FAILED(mdberr) || !m_mdbAllMsgHeadersTable)
+        err = NS_ERROR_FAILURE;
+    }
+    struct mdbOid allThreadsTableOID;
+    allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+    allThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+    err = GetStore()->GetTable(GetEnv(), &gAllThreadsTableOID, &m_mdbAllThreadsTable);
+    if (!m_mdbAllThreadsTable)
+    {
+
+      nsresult mdberr = GetStore()->NewTableWithOid(GetEnv(), &allThreadsTableOID, m_allThreadsTableKindToken,
+        false, nullptr, &m_mdbAllThreadsTable);
+      if (NS_FAILED(mdberr) || !m_mdbAllThreadsTable)
+        err = NS_ERROR_FAILURE;
+    }
+  }
+  if (NS_SUCCEEDED(err) && m_dbFolderInfo)
+  {
+    bool fixedBadRefThreading;
+    m_dbFolderInfo->GetBooleanProperty(kFixedBadRefThreadingProp, false, &fixedBadRefThreading);
+    if (!fixedBadRefThreading)
+    {
+      nsCOMPtr <nsISimpleEnumerator> enumerator;
+      err = EnumerateMessages(getter_AddRefs(enumerator));
+      if (NS_SUCCEEDED(err) && enumerator)
+      {
+        bool hasMore;
+
+        while (NS_SUCCEEDED(err = enumerator->HasMoreElements(&hasMore)) &&
+               hasMore)
+        {
+          nsCOMPtr <nsISupports> supports;
+          err = enumerator->GetNext(getter_AddRefs(supports));
+          NS_ASSERTION(NS_SUCCEEDED(err), "nsMsgDBEnumerator broken");
+          nsCOMPtr <nsIMsgDBHdr> msgHdr = do_QueryInterface(supports);
+          if (msgHdr && NS_SUCCEEDED(err))
+          {
+            nsCString messageId;
+            nsAutoCString firstReference;
+            msgHdr->GetMessageId(getter_Copies(messageId));
+            msgHdr->GetStringReference(0, firstReference);
+            if (messageId.Equals(firstReference))
+            {
+              err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+              break;
+            }
+          }
+        }
+      }
+
+      m_dbFolderInfo->SetBooleanProperty(kFixedBadRefThreadingProp, true);
+    }
+
+  }
+  return err;
+}
+
+// initialize the various tokens and tables in our db's env
+nsresult nsMsgDatabase::InitMDBInfo()
+{
+  nsresult err = NS_OK;
+
+  if (!m_mdbTokensInitialized && GetStore())
+  {
+    m_mdbTokensInitialized = true;
+    err  = GetStore()->StringToToken(GetEnv(), kMsgHdrsScope, &m_hdrRowScopeToken);
+    if (NS_SUCCEEDED(err))
+    {
+      GetStore()->StringToToken(GetEnv(),  kSubjectColumnName, &m_subjectColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kSenderColumnName, &m_senderColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kMessageIdColumnName, &m_messageIdColumnToken);
+      // if we just store references as a string, we won't get any savings from the
+      // fact there's a lot of duplication. So we may want to break them up into
+      // multiple columns, r1, r2, etc.
+      GetStore()->StringToToken(GetEnv(),  kReferencesColumnName, &m_referencesColumnToken);
+      // similarly, recipients could be tokenized properties
+      GetStore()->StringToToken(GetEnv(),  kRecipientsColumnName, &m_recipientsColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kDateColumnName, &m_dateColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kMessageSizeColumnName, &m_messageSizeColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kFlagsColumnName, &m_flagsColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kPriorityColumnName, &m_priorityColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kLabelColumnName, &m_labelColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kStatusOffsetColumnName, &m_statusOffsetColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kNumLinesColumnName, &m_numLinesColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kCCListColumnName, &m_ccListColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kBCCListColumnName, &m_bccListColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kMessageThreadIdColumnName, &m_messageThreadIdColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadIdColumnName, &m_threadIdColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadFlagsColumnName, &m_threadFlagsColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadNewestMsgDateColumnName, &m_threadNewestMsgDateColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadChildrenColumnName, &m_threadChildrenColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadUnreadChildrenColumnName, &m_threadUnreadChildrenColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kThreadSubjectColumnName, &m_threadSubjectColumnToken);
+      GetStore()->StringToToken(GetEnv(),  kMessageCharSetColumnName, &m_messageCharSetColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kMsgHdrsTableKind, &m_hdrTableKindToken);
+      if (NS_SUCCEEDED(err))
+        err = GetStore()->StringToToken(GetEnv(), kThreadTableKind, &m_threadTableKindToken);
+      err = GetStore()->StringToToken(GetEnv(), kAllThreadsTableKind, &m_allThreadsTableKindToken);
+      err  = GetStore()->StringToToken(GetEnv(), kThreadHdrsScope, &m_threadRowScopeToken);
+      err  = GetStore()->StringToToken(GetEnv(), kThreadParentColumnName, &m_threadParentColumnToken);
+      err  = GetStore()->StringToToken(GetEnv(), kThreadRootColumnName, &m_threadRootKeyColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kOfflineMsgOffsetColumnName, &m_offlineMsgOffsetColumnToken);
+      err = GetStore()->StringToToken(GetEnv(), kOfflineMsgSizeColumnName, &m_offlineMessageSizeColumnToken);
+
+      if (NS_SUCCEEDED(err))
+      {
+        // The table of all message hdrs will have table id 1.
+        gAllMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+        gAllMsgHdrsTableOID.mOid_Id = kAllMsgHdrsTableKey;
+        gAllThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+        gAllThreadsTableOID.mOid_Id = kAllThreadsTableKey;
+
+      }
+    }
+  }
+  return err;
+}
+
+// Returns if the db contains this key
+NS_IMETHODIMP nsMsgDatabase::ContainsKey(nsMsgKey key, bool *containsKey)
+{
+
+  nsresult  err = NS_OK;
+  mdb_bool  hasOid;
+  mdbOid    rowObjectId;
+
+  if (!containsKey || !m_mdbAllMsgHeadersTable)
+    return NS_ERROR_NULL_POINTER;
+  *containsKey = false;
+
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  err = m_mdbAllMsgHeadersTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if(NS_SUCCEEDED(err))
+    *containsKey = hasOid;
+
+  return err;
+}
+
+// get a message header for the given key. Caller must release()!
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForKey(nsMsgKey key, nsIMsgDBHdr **pmsgHdr)
+{
+  nsresult  err = NS_OK;
+  mdb_bool  hasOid;
+  mdbOid    rowObjectId;
+
+  // Because this may be called a lot, and we don't want gettimeofday() to show
+  // up in trace logs, we just remember the most recent time any db was used,
+  // which should be close enough for our purposes.
+  m_lastUseTime = gLastUseTime;
+
+#ifdef DEBUG_bienvenu1
+  NS_ASSERTION(m_folder, "folder should be set");
+#endif
+
+  if (!pmsgHdr || !m_mdbAllMsgHeadersTable || !m_mdbStore)
+    return NS_ERROR_NULL_POINTER;
+
+  *pmsgHdr = NULL;
+  err = GetHdrFromUseCache(key, pmsgHdr);
+  if (NS_SUCCEEDED(err) && *pmsgHdr)
+    return err;
+
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  err = m_mdbAllMsgHeadersTable->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  if (NS_SUCCEEDED(err) /* && hasOid */)
+  {
+    nsIMdbRow *hdrRow;
+    err = m_mdbStore->GetRow(GetEnv(), &rowObjectId, &hdrRow);
+
+    if (NS_SUCCEEDED(err))
+    {
+      if (!hdrRow)
+      {
+        err = NS_ERROR_NULL_POINTER;
+      }
+      else
+      {
+        //        NS_ASSERTION(hasOid, "we had oid, right?");
+        err = CreateMsgHdr(hdrRow,  key, pmsgHdr);
+      }
+    }
+  }
+
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::StartBatch()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::EndBatch()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::DeleteMessage(nsMsgKey key, nsIDBChangeListener *instigator, bool commit)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (!msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+
+  rv = DeleteHeader(msgHdr, instigator, commit, true);
+  return rv;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::DeleteMessages(uint32_t aNumKeys, nsMsgKey* nsMsgKeys, nsIDBChangeListener *instigator)
+{
+  nsresult  err = NS_OK;
+
+  uint32_t kindex;
+  for (kindex = 0; kindex < aNumKeys; kindex++)
+  {
+    nsMsgKey key = nsMsgKeys[kindex];
+    nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+    bool hasKey;
+
+    if (NS_SUCCEEDED(ContainsKey(key, &hasKey)) && hasKey)
+    {
+      err = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+      if (NS_FAILED(err))
+      {
+        err = NS_MSG_MESSAGE_NOT_FOUND;
+        break;
+      }
+      if (msgHdr)
+        err = DeleteHeader(msgHdr, instigator, kindex % 300 == 0, true);
+      if (NS_FAILED(err))
+        break;
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr)
+{
+  uint32_t size = 0;
+  (void)msgHdr->GetMessageSize(&size);
+  return m_dbFolderInfo->ChangeExpungedBytes (size);
+}
+
+NS_IMETHODIMP nsMsgDatabase::DeleteHeader(nsIMsgDBHdr *msg, nsIDBChangeListener *instigator, bool commit, bool notify)
+{
+  if (!msg)
+    return NS_ERROR_NULL_POINTER;
+
+  nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(msg);  // closed system, so this is ok
+  nsMsgKey key;
+  (void)msg->GetMessageKey(&key);
+  // only need to do this for mail - will this speed up news expiration?
+  SetHdrFlag(msg, true, nsMsgMessageFlags::Expunged);  // tell mailbox (mail)
+
+  bool hdrWasNew = m_newSet.BinaryIndexOf(key) != m_newSet.NoIndex;
+  m_newSet.RemoveElement(key);
+
+  if (m_dbFolderInfo != NULL)
+  {
+    bool isRead;
+    m_dbFolderInfo->ChangeNumMessages(-1);
+    IsRead(key, &isRead);
+    if (!isRead)
+      m_dbFolderInfo->ChangeNumUnreadMessages(-1);
+    AdjustExpungedBytesOnDelete(msg);
+  }
+
+  uint32_t flags;
+  nsMsgKey threadParent;
+
+  //Save off flags and threadparent since they will no longer exist after we remove the header from the db.
+  if (notify)
+  {
+    (void)msg->GetFlags(&flags);
+    msg->GetThreadParent(&threadParent);
+  }
+
+  RemoveHeaderFromThread(msgHdr);
+  if (notify)
+  {
+    // If deleted hdr was new, restore the new flag on flags 
+    // so saved searches will know to reduce their new msg count.
+    if (hdrWasNew)
+      flags |= nsMsgMessageFlags::New;
+    NotifyHdrDeletedAll(msg, threadParent, flags, instigator); // tell listeners
+  }
+  //  if (!onlyRemoveFromThread)  // to speed up expiration, try this. But really need to do this in RemoveHeaderFromDB
+  nsresult ret = RemoveHeaderFromDB(msgHdr);
+
+
+  if (commit)
+    Commit(nsMsgDBCommitType::kLargeCommit);      // ### dmb is this a good time to commit?
+  return ret;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::UndoDelete(nsIMsgDBHdr *aMsgHdr)
+{
+    if (aMsgHdr)
+    {
+        nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(aMsgHdr);  // closed system, so this is ok
+        // force deleted flag, so SetHdrFlag won't bail out because  deleted flag isn't set
+        msgHdr->m_flags |= nsMsgMessageFlags::Expunged;
+        SetHdrFlag(msgHdr, false, nsMsgMessageFlags::Expunged); // clear deleted flag in db
+    }
+    return NS_OK;
+}
+
+nsresult nsMsgDatabase::RemoveHeaderFromThread(nsMsgHdr *msgHdr)
+{
+  if (!msgHdr)
+    return NS_ERROR_NULL_POINTER;
+  nsresult ret = NS_OK;
+  nsCOMPtr <nsIMsgThread> thread ;
+  ret = GetThreadContainingMsgHdr(msgHdr, getter_AddRefs(thread));
+  if (NS_SUCCEEDED(ret) && thread)
+  {
+    nsCOMPtr <nsIDBChangeAnnouncer> announcer = do_QueryInterface(this);
+    ret = thread->RemoveChildHdr(msgHdr, announcer);
+  }
+  return ret;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RemoveHeaderMdbRow(nsIMsgDBHdr *msg)
+{
+  NS_ENSURE_ARG_POINTER(msg);
+  nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(msg);  // closed system, so this is ok
+  return RemoveHeaderFromDB(msgHdr);
+}
+
+// This is a lower level routine which doesn't send notifcations or
+// update folder info. One use is when a rule fires moving a header
+// from one db to another, to remove it from the first db.
+
+nsresult nsMsgDatabase::RemoveHeaderFromDB(nsMsgHdr *msgHdr)
+{
+  if (!msgHdr)
+    return NS_ERROR_NULL_POINTER;
+  nsresult ret = NS_OK;
+
+  RemoveHdrFromCache(msgHdr, nsMsgKey_None);
+  if (UseCorrectThreading())
+    RemoveMsgRefsFromHash(msgHdr);
+  nsIMdbRow* row = msgHdr->GetMDBRow();
+  if (row)
+  {
+    ret = m_mdbAllMsgHeadersTable->CutRow(GetEnv(), row);
+    row->CutAllColumns(GetEnv());
+  }
+  msgHdr->m_initedValues = 0; // invalidate cached values.
+  return ret;
+}
+
+nsresult nsMsgDatabase::IsRead(nsMsgKey key, bool *pRead)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+  rv = IsHeaderRead(msgHdr, pRead);
+  return rv;
+}
+
+uint32_t  nsMsgDatabase::GetStatusFlags(nsIMsgDBHdr *msgHdr, uint32_t origFlags)
+{
+  uint32_t  statusFlags = origFlags;
+  bool    isRead = true;
+
+  nsMsgKey key;
+  (void)msgHdr->GetMessageKey(&key);
+  if ((!m_newSet.IsEmpty() && m_newSet[m_newSet.Length() - 1] == key) ||
+      (m_newSet.BinaryIndexOf(key) != m_newSet.NoIndex))
+    statusFlags |= nsMsgMessageFlags::New;
+  if (NS_SUCCEEDED(IsHeaderRead(msgHdr, &isRead)) && isRead)
+    statusFlags |= nsMsgMessageFlags::Read;
+  return statusFlags;
+}
+
+nsresult nsMsgDatabase::IsHeaderRead(nsIMsgDBHdr *msgHdr, bool *pRead)
+{
+  if (!msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(msgHdr);          // closed system, cast ok
+  // can't call GetFlags, because it will be recursive.
+  uint32_t flags;
+  hdr->GetRawFlags(&flags);
+  *pRead = !!(flags & nsMsgMessageFlags::Read);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsMarked(nsMsgKey key, bool *pMarked)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv))
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pMarked = !!(flags & nsMsgMessageFlags::Marked);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsIgnored(nsMsgKey key, bool *pIgnored)
+{
+  NS_ENSURE_ARG_POINTER(pIgnored);
+
+  nsCOMPtr <nsIMsgThread> threadHdr;
+
+  nsresult rv = GetThreadForMsgKey(key, getter_AddRefs(threadHdr));
+  // This should be very surprising, but we leave that up to the caller
+  // to determine for now.
+  if (!threadHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t threadFlags;
+  threadHdr->GetFlags(&threadFlags);
+  *pIgnored = !!(threadFlags & nsMsgMessageFlags::Ignored);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsWatched(nsMsgKey key, bool *pWatched)
+{
+  NS_ENSURE_ARG_POINTER(pWatched);
+
+  nsCOMPtr <nsIMsgThread> threadHdr;
+
+  nsresult rv = GetThreadForMsgKey(key, getter_AddRefs(threadHdr));
+  // This should be very surprising, but we leave that up to the caller
+  // to determine for now.
+  if (!threadHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+
+  uint32_t threadFlags;
+  threadHdr->GetFlags(&threadFlags);
+  *pWatched = !!(threadFlags & nsMsgMessageFlags::Watched);
+  return rv;
+}
+
+nsresult nsMsgDatabase::HasAttachments(nsMsgKey key, bool *pHasThem)
+{
+  NS_ENSURE_ARG_POINTER(pHasThem);
+
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv))
+    return rv;
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pHasThem = !!(flags & nsMsgMessageFlags::Attachment);
+  return rv;
+}
+
+bool nsMsgDatabase::SetHdrReadFlag(nsIMsgDBHdr *msgHdr, bool bRead)
+{
+  return SetHdrFlag(msgHdr, bRead, nsMsgMessageFlags::Read);
+}
+
+nsresult nsMsgDatabase::MarkHdrReadInDB(nsIMsgDBHdr *msgHdr, bool bRead,
+                                             nsIDBChangeListener *instigator)
+{
+  nsresult rv;
+  nsMsgKey key;
+  uint32_t oldFlags;
+  bool     hdrInDB;
+  (void)msgHdr->GetMessageKey(&key);
+  msgHdr->GetFlags(&oldFlags);
+
+  m_newSet.RemoveElement(key);
+  (void) ContainsKey(key, &hdrInDB);
+  if (hdrInDB && m_dbFolderInfo)
+  {
+    if (bRead)
+      m_dbFolderInfo->ChangeNumUnreadMessages(-1);
+    else
+      m_dbFolderInfo->ChangeNumUnreadMessages(1);
+  }
+
+  SetHdrReadFlag(msgHdr, bRead); // this will cause a commit, at least for local mail, so do it after we change
+  // the folder counts above, so they will get committed too.
+  uint32_t flags;
+  rv = msgHdr->GetFlags(&flags);
+  flags &= ~nsMsgMessageFlags::New;
+  msgHdr->SetFlags(flags);
+  if (NS_FAILED(rv)) return rv;
+
+  if (oldFlags == flags)
+    return NS_OK;
+
+  return NotifyHdrChangeAll(msgHdr, oldFlags, flags, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkRead(nsMsgKey key, bool bRead,
+                                      nsIDBChangeListener *instigator)
+{
+  nsresult rv;
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+
+  rv = MarkHdrRead(msgHdr, bRead, instigator);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkReplied(nsMsgKey key, bool bReplied,
+                                         nsIDBChangeListener *instigator /* = NULL */)
+{
+  return SetKeyFlag(key, bReplied, nsMsgMessageFlags::Replied, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkForwarded(nsMsgKey key, bool bForwarded,
+                                           nsIDBChangeListener *instigator /* = NULL */)
+{
+  return SetKeyFlag(key, bForwarded, nsMsgMessageFlags::Forwarded, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHasAttachments(nsMsgKey key, bool bHasAttachments,
+                                                nsIDBChangeListener *instigator)
+{
+  return SetKeyFlag(key, bHasAttachments, nsMsgMessageFlags::Attachment, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadRead(nsIMsgThread *thread, nsIDBChangeListener *instigator,
+                              uint32_t *aNumMarked, nsMsgKey **aThoseMarked)
+{
+  NS_ENSURE_ARG_POINTER(thread);
+  NS_ENSURE_ARG_POINTER(aNumMarked);
+  NS_ENSURE_ARG_POINTER(aThoseMarked);
+  nsresult rv = NS_OK;
+
+  uint32_t numChildren;
+  nsTArray<nsMsgKey> thoseMarked;
+  thread->GetNumChildren(&numChildren);
+  for (uint32_t curChildIndex = 0; curChildIndex < numChildren; curChildIndex++)
+  {
+    nsCOMPtr <nsIMsgDBHdr> child;
+
+    rv = thread->GetChildHdrAt(curChildIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child)
+    {
+      bool isRead = true;
+      IsHeaderRead(child, &isRead);
+      if (!isRead)
+      {
+        nsMsgKey key;
+        if (NS_SUCCEEDED(child->GetMessageKey(&key)))
+          thoseMarked.AppendElement(key);
+        MarkHdrRead(child, true, instigator);
+      }
+    }
+  }
+
+  *aNumMarked = thoseMarked.Length();
+
+  if (thoseMarked.Length())
+  {
+    *aThoseMarked =
+      (nsMsgKey *) nsMemory::Clone(&thoseMarked[0],
+                                   thoseMarked.Length() * sizeof(nsMsgKey));
+    if (!*aThoseMarked)
+      return NS_ERROR_OUT_OF_MEMORY;
+  }
+  else
+    *aThoseMarked = nullptr;
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadIgnored(nsIMsgThread *thread, nsMsgKey threadKey, bool bIgnored,
+                                 nsIDBChangeListener *instigator)
+{
+  NS_ENSURE_ARG(thread);
+  uint32_t threadFlags;
+  thread->GetFlags(&threadFlags);
+  uint32_t oldThreadFlags = threadFlags; // not quite right, since we probably want msg hdr flags.
+  if (bIgnored)
+  {
+    threadFlags |= nsMsgMessageFlags::Ignored;
+    threadFlags &= ~nsMsgMessageFlags::Watched;  // ignore is implicit un-watch
+  }
+  else
+    threadFlags &= ~nsMsgMessageFlags::Ignored;
+  thread->SetFlags(threadFlags);
+
+  nsCOMPtr <nsIMsgDBHdr> msg;
+  nsresult rv = GetMsgHdrForKey(threadKey, getter_AddRefs(msg));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NotifyHdrChangeAll(msg, oldThreadFlags, threadFlags, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkHeaderKilled(nsIMsgDBHdr *msg, bool bIgnored,
+                           nsIDBChangeListener *instigator)
+{
+  uint32_t msgFlags;
+  msg->GetFlags(&msgFlags);
+  uint32_t oldFlags = msgFlags;
+  if (bIgnored)
+    msgFlags |= nsMsgMessageFlags::Ignored;
+  else
+    msgFlags &= ~nsMsgMessageFlags::Ignored;
+  msg->SetFlags(msgFlags);
+
+  return NotifyHdrChangeAll(msg, oldFlags, msgFlags, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkThreadWatched(nsIMsgThread *thread, nsMsgKey threadKey, bool bWatched,
+                                 nsIDBChangeListener *instigator)
+{
+  NS_ENSURE_ARG(thread);
+  uint32_t threadFlags;
+  thread->GetFlags(&threadFlags);
+  uint32_t oldThreadFlags = threadFlags; // not quite right, since we probably want msg hdr flags.
+  if (bWatched)
+  {
+    threadFlags |= nsMsgMessageFlags::Watched;
+    threadFlags &= ~nsMsgMessageFlags::Ignored;  // watch is implicit un-ignore
+  }
+  else
+    threadFlags &= ~nsMsgMessageFlags::Watched;
+
+  nsCOMPtr <nsIMsgDBHdr> msg;
+  GetMsgHdrForKey(threadKey, getter_AddRefs(msg));
+
+  nsresult rv  = NotifyHdrChangeAll(msg, oldThreadFlags, threadFlags, instigator);
+  thread->SetFlags(threadFlags);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkMarked(nsMsgKey key, bool mark,
+                                        nsIDBChangeListener *instigator)
+{
+  return SetKeyFlag(key, mark, nsMsgMessageFlags::Marked, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkOffline(nsMsgKey key, bool offline,
+                                         nsIDBChangeListener *instigator)
+{
+  return SetKeyFlag(key, offline, nsMsgMessageFlags::Offline, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetStringProperty(nsMsgKey aKey, const char *aProperty, const char *aValue)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+  nsresult rv = GetMsgHdrForKey(aKey, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+  return SetStringPropertyByHdr(msgHdr, aProperty, aValue);
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetStringPropertyByHdr(nsIMsgDBHdr *msgHdr, const char *aProperty, const char *aValue)
+{
+  // don't do notifications if message not yet added to database.
+  // Ignore errors (consequences of failure are minor).
+  bool notify = true;
+  nsMsgKey key = nsMsgKey_None;
+  msgHdr->GetMessageKey(&key);
+  ContainsKey(key, &notify);
+
+  nsCString oldValue;
+  nsresult rv = msgHdr->GetStringProperty(aProperty, getter_Copies(oldValue));
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  // if no change to this string property, bail out
+  if (oldValue.Equals(aValue))
+    return NS_OK;
+
+  // Precall OnHdrPropertyChanged to store prechange status
+  nsTArray<uint32_t> statusArray(m_ChangeListeners.Length());
+  uint32_t status;
+  nsCOMPtr<nsIDBChangeListener> listener;
+  if (notify)
+  {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener> >::ForwardIterator listeners(m_ChangeListeners);
+    while (listeners.HasMore())
+    {
+      listener = listeners.GetNext();
+      listener->OnHdrPropertyChanged(msgHdr, true, &status, nullptr);
+      // ignore errors, but append element to keep arrays in sync
+      statusArray.AppendElement(status);
+    }
+  }
+
+  rv = msgHdr->SetStringProperty(aProperty, aValue);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  //Postcall OnHdrPropertyChanged to process the change
+  if (notify)
+  {
+    // if this is the junk score property notify, as long as we're not going
+    // from no value to non junk
+    if (!strcmp(aProperty, "junkscore") && !(oldValue.IsEmpty() && !strcmp(aValue, "0")))
+      NotifyJunkScoreChanged(nullptr);
+
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener> >::ForwardIterator listeners(m_ChangeListeners);
+    for (uint32_t i = 0; listeners.HasMore(); i++)
+    {
+      listener = listeners.GetNext();
+      status = statusArray[i];
+      listener->OnHdrPropertyChanged(msgHdr, false, &status, nullptr);
+      // ignore errors
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SetUint32PropertyByHdr(nsIMsgDBHdr *aMsgHdr,
+                                      const char *aProperty,
+                                      uint32_t aValue)
+{
+  // If no change to this property, bail out.
+  uint32_t oldValue;
+  nsresult rv = aMsgHdr->GetUint32Property(aProperty, &oldValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (oldValue == aValue)
+    return NS_OK;
+
+  // Don't do notifications if message not yet added to database.
+  bool notify = true;  
+  nsMsgKey key = nsMsgKey_None;
+  aMsgHdr->GetMessageKey(&key);
+  ContainsKey(key, &notify);
+
+  // Precall OnHdrPropertyChanged to store prechange status.
+  nsTArray<uint32_t> statusArray(m_ChangeListeners.Length());
+  uint32_t status;
+  nsCOMPtr<nsIDBChangeListener> listener;
+  if (notify)
+  {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener> >::ForwardIterator listeners(m_ChangeListeners);
+    while (listeners.HasMore())
+    {
+      listener = listeners.GetNext();
+      listener->OnHdrPropertyChanged(aMsgHdr, true, &status, nullptr);
+      // Ignore errors, but append element to keep arrays in sync.
+      statusArray.AppendElement(status);
+    }
+  }
+
+  rv = aMsgHdr->SetUint32Property(aProperty, aValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Postcall OnHdrPropertyChanged to process the change.
+  if (notify)
+  {
+    nsTObserverArray<nsCOMPtr<nsIDBChangeListener> >::ForwardIterator listeners(m_ChangeListeners);
+    for (uint32_t i = 0; listeners.HasMore(); i++)
+    {
+      listener = listeners.GetNext();
+      status = statusArray[i];
+      listener->OnHdrPropertyChanged(aMsgHdr, false, &status, nullptr);
+      // Ignore errors.
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetLabel(nsMsgKey key, nsMsgLabelValue label)
+{
+  nsresult rv;
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+  nsMsgLabelValue oldLabel;
+  msgHdr->GetLabel(&oldLabel);
+
+  msgHdr->SetLabel(label);
+  // clear old label
+  if (oldLabel != label)
+  {
+    if (oldLabel != 0)
+      rv = SetKeyFlag(key, false, oldLabel << 25, nullptr);
+    // set the flag in the x-mozilla-status2 line.
+    rv = SetKeyFlag(key, true, label << 25, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkImapDeleted(nsMsgKey key, bool deleted,
+                                             nsIDBChangeListener *instigator)
+{
+  return SetKeyFlag(key, deleted, nsMsgMessageFlags::IMAPDeleted, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkMDNNeeded(nsMsgKey key, bool bNeeded,
+                                           nsIDBChangeListener *instigator /* = NULL */)
+{
+  return SetKeyFlag(key, bNeeded, nsMsgMessageFlags::MDNReportNeeded, instigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::IsMDNNeeded(nsMsgKey key, bool *pNeeded)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pNeeded = !!(flags & nsMsgMessageFlags::MDNReportNeeded);
+  return rv;
+}
+
+
+nsresult nsMsgDatabase::MarkMDNSent(nsMsgKey key, bool bSent,
+                                    nsIDBChangeListener *instigator /* = NULL */)
+{
+  return SetKeyFlag(key, bSent, nsMsgMessageFlags::MDNReportSent, instigator);
+}
+
+
+nsresult nsMsgDatabase::IsMDNSent(nsMsgKey key, bool *pSent)
+{
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  nsresult rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+  *pSent = !!(flags & nsMsgMessageFlags::MDNReportSent);
+  return rv;
+}
+
+
+nsresult  nsMsgDatabase::SetKeyFlag(nsMsgKey key, bool set, uint32_t flag,
+                                     nsIDBChangeListener *instigator)
+{
+  nsresult rv;
+  nsCOMPtr <nsIMsgDBHdr> msgHdr;
+
+  rv = GetMsgHdrForKey(key, getter_AddRefs(msgHdr));
+  if (NS_FAILED(rv) || !msgHdr)
+    return NS_MSG_MESSAGE_NOT_FOUND; // XXX return rv?
+
+  uint32_t oldFlags;
+  msgHdr->GetFlags(&oldFlags);
+
+  SetHdrFlag(msgHdr, set, flag);
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+
+  if (oldFlags == flags)
+    return NS_OK;
+
+  return NotifyHdrChangeAll(msgHdr, oldFlags, flags, instigator);
+}
+
+nsresult nsMsgDatabase::SetMsgHdrFlag(nsIMsgDBHdr *msgHdr, bool set, uint32_t flag, nsIDBChangeListener *instigator)
+{
+  uint32_t oldFlags;
+  msgHdr->GetFlags(&oldFlags);
+
+  SetHdrFlag(msgHdr, set, flag);
+
+  uint32_t flags;
+  (void)msgHdr->GetFlags(&flags);
+
+  if (oldFlags == flags)
+    return NS_OK;
+
+  return NotifyHdrChangeAll(msgHdr, oldFlags, flags, instigator);
+}
+
+// Helper routine - lowest level of flag setting - returns true if flags change,
+// false otherwise.
+bool nsMsgDatabase::SetHdrFlag(nsIMsgDBHdr *msgHdr, bool bSet, nsMsgMessageFlagType flag)
+{
+  uint32_t statusFlags;
+  (void)msgHdr->GetFlags(&statusFlags);
+  uint32_t currentStatusFlags = GetStatusFlags(msgHdr, statusFlags);
+  bool flagAlreadySet = (currentStatusFlags & flag) != 0;
+
+  if ((flagAlreadySet && !bSet) || (!flagAlreadySet && bSet))
+  {
+    uint32_t resultFlags;
+    if (bSet)
+      msgHdr->OrFlags(flag, &resultFlags);
+    else
+      msgHdr->AndFlags(~flag, &resultFlags);
+    return true;
+  }
+  return false;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrRead(nsIMsgDBHdr *msgHdr, bool bRead,
+                                         nsIDBChangeListener *instigator)
+{
+  bool isReadInDB = true;
+  nsresult rv = nsMsgDatabase::IsHeaderRead(msgHdr, &isReadInDB);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isRead = true;
+  rv = IsHeaderRead(msgHdr, &isRead);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // if the flag is already correct in the db, don't change it.
+  // Check msg flags as well as IsHeaderRead in case it's a newsgroup
+  // and the msghdr flags are out of sync with the newsrc settings.
+  // (we could override this method for news db's, but it's a trivial fix here.
+  if (bRead != isRead || isRead != isReadInDB)
+  {
+    nsMsgKey msgKey;
+    msgHdr->GetMessageKey(&msgKey);
+    
+    bool inDB = false;
+    (void)ContainsKey(msgKey, &inDB);
+
+    if (inDB)
+    {
+      nsCOMPtr <nsIMsgThread> threadHdr;
+      rv = GetThreadForMsgKey(msgKey, getter_AddRefs(threadHdr));
+      if (threadHdr)
+        threadHdr->MarkChildRead(bRead);
+    }
+    return MarkHdrReadInDB(msgHdr, bRead, instigator);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrReplied(nsIMsgDBHdr *msgHdr, bool bReplied,
+                         nsIDBChangeListener *instigator)
+{
+  return SetMsgHdrFlag(msgHdr, bReplied, nsMsgMessageFlags::Replied, instigator);
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::MarkHdrMarked(nsIMsgDBHdr *msgHdr, bool mark,
+                         nsIDBChangeListener *instigator)
+{
+  return SetMsgHdrFlag(msgHdr, mark, nsMsgMessageFlags::Marked, instigator);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::MarkHdrNotNew(nsIMsgDBHdr *aMsgHdr,
+                             nsIDBChangeListener *aInstigator)
+{
+  NS_ENSURE_ARG_POINTER(aMsgHdr);
+  nsMsgKey msgKey;
+  aMsgHdr->GetMessageKey(&msgKey);
+  m_newSet.RemoveElement(msgKey);
+  return SetMsgHdrFlag(aMsgHdr, false, nsMsgMessageFlags::New, aInstigator);
+}
+
+NS_IMETHODIMP nsMsgDatabase::MarkAllRead(uint32_t *aNumKeys, nsMsgKey **aThoseMarked)
+{
+  NS_ENSURE_ARG_POINTER(aNumKeys);
+  NS_ENSURE_ARG_POINTER(aThoseMarked);
+  nsMsgHdr  *pHeader;
+
+  nsCOMPtr<nsISimpleEnumerator> hdrs;
+  nsTArray<nsMsgKey> thoseMarked;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv))
+    return rv;
+  bool hasMore = false;
+
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore)
+  {
+    rv = hdrs->GetNext((nsISupports**)&pHeader);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    if (NS_FAILED(rv))
+      break;
+
+    bool isRead;
+    IsHeaderRead(pHeader, &isRead);
+
+    if (!isRead)
+    {
+      nsMsgKey key;
+      (void)pHeader->GetMessageKey(&key);
+      thoseMarked.AppendElement(key);
+      rv = MarkHdrRead(pHeader, true, nullptr);   // ### dmb - blow off error?
+    }
+    NS_RELEASE(pHeader);
+  }
+
+  *aNumKeys = thoseMarked.Length();
+
+  if (thoseMarked.Length())
+  {
+    *aThoseMarked = (nsMsgKey *) nsMemory::Clone(&thoseMarked[0],
+                                                 thoseMarked.Length() * sizeof(nsMsgKey));
+    if (!*aThoseMarked)
+      return NS_ERROR_OUT_OF_MEMORY;
+  }
+  else
+    *aThoseMarked = nullptr;
+
+  // force num new to 0.
+  int32_t numUnreadMessages;
+
+  rv = m_dbFolderInfo->GetNumUnreadMessages(&numUnreadMessages);
+  if (NS_SUCCEEDED(rv))
+    m_dbFolderInfo->ChangeNumUnreadMessages(-numUnreadMessages);
+  // caller will Commit the db, so no need to do it here.
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddToNewList(nsMsgKey key)
+{
+  // we add new keys in increasing order...
+  if (m_newSet.IsEmpty() || (m_newSet[m_newSet.Length() - 1] < key))
+    m_newSet.AppendElement(key);
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::ClearNewList(bool notify /* = FALSE */)
+{
+  nsresult err = NS_OK;
+  if (notify && !m_newSet.IsEmpty())  // need to update view
+  {
+    nsTArray<nsMsgKey> saveNewSet;
+    // clear m_newSet so that the code that's listening to the key change
+    // doesn't think we have new messages and send notifications all over
+    // that we have new messages.
+    saveNewSet.SwapElements(m_newSet);
+    for (uint32_t elementIndex = saveNewSet.Length() - 1; ; elementIndex--)
+    {
+      nsMsgKey lastNewKey = saveNewSet.ElementAt(elementIndex);
+      nsCOMPtr <nsIMsgDBHdr> msgHdr;
+      err = GetMsgHdrForKey(lastNewKey, getter_AddRefs(msgHdr));
+      if (NS_SUCCEEDED(err))
+      {
+        uint32_t flags;
+        (void)msgHdr->GetFlags(&flags);
+
+        if ((flags | nsMsgMessageFlags::New) != flags)
+        {
+          msgHdr->AndFlags(~nsMsgMessageFlags::New, &flags);
+          NotifyHdrChangeAll(msgHdr, flags | nsMsgMessageFlags::New, flags, nullptr);
+        }
+      }
+      if (elementIndex == 0)
+        break;
+    }
+  }
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::HasNew(bool *_retval)
+{
+  if (!_retval) return NS_ERROR_NULL_POINTER;
+
+  *_retval = (m_newSet.Length() > 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetFirstNew(nsMsgKey *result)
+{
+  bool hasnew;
+  nsresult rv = HasNew(&hasnew);
+  if (NS_FAILED(rv)) return rv;
+  *result = (hasnew) ? m_newSet.ElementAt(0) : nsMsgKey_None;
+  return NS_OK;
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+
+nsMsgDBEnumerator::nsMsgDBEnumerator(nsMsgDatabase* db,
+                                     nsIMdbTable *table,
+                                     nsMsgDBEnumeratorFilter filter,
+                                     void* closure,
+                                     bool iterateForwards)
+    : mDB(db),
+      mDone(false),
+      mIterateForwards(iterateForwards),
+      mFilter(filter),
+      mClosure(closure),
+      mStopPos(-1)
+{
+  mNextPrefetched = false;
+  mTable = table;
+  mRowPos = 0;
+  mDB->m_enumerators.AppendElement(this);
+}
+
+nsMsgDBEnumerator::~nsMsgDBEnumerator()
+{
+  Clear();
+}
+
+void nsMsgDBEnumerator::Clear()
+{
+  mRowCursor = nullptr;
+  mTable = nullptr;
+  mResultHdr = nullptr;
+  if (mDB)
+    mDB->m_enumerators.RemoveElement(this);
+  mDB = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDBEnumerator, nsISimpleEnumerator)
+
+nsresult nsMsgDBEnumerator::GetRowCursor()
+{
+  mDone = false;
+
+  if (!mDB || !mTable)
+    return NS_ERROR_NULL_POINTER;
+
+  if (mIterateForwards)
+  {
+    mRowPos = -1;
+  }
+  else
+  {
+    mdb_count numRows;
+    mTable->GetCount(mDB->GetEnv(), &numRows);
+    mRowPos = numRows; // startPos is 0 relative.
+  }
+  return mTable->GetTableRowCursor(mDB->GetEnv(), mRowPos, getter_AddRefs(mRowCursor));
+}
+
+NS_IMETHODIMP nsMsgDBEnumerator::GetNext(nsISupports **aItem)
+{
+  if (!aItem)
+    return NS_ERROR_NULL_POINTER;
+  nsresult rv = NS_OK;
+  if (!mNextPrefetched)
+    rv = PrefetchNext();
+  if (NS_SUCCEEDED(rv))
+  {
+    if (mResultHdr)
+    {
+      *aItem = mResultHdr;
+      NS_ADDREF(*aItem);
+      mNextPrefetched = false;
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgDBEnumerator::PrefetchNext()
+{
+  nsresult rv = NS_OK;
+  nsIMdbRow* hdrRow;
+  uint32_t flags;
+
+  if (!mRowCursor)
+  {
+    rv = GetRowCursor();
+    if (NS_FAILED(rv))
+      return rv;
+  }
+
+  do
+  {
+    mResultHdr = nullptr;
+    if (mIterateForwards)
+      rv = mRowCursor->NextRow(mDB->GetEnv(), &hdrRow, &mRowPos);
+    else
+      rv = mRowCursor->PrevRow(mDB->GetEnv(), &hdrRow, &mRowPos);
+    if (!hdrRow)
+    {
+      mDone = true;
+      return NS_ERROR_FAILURE;
+    }
+    if (NS_FAILED(rv))
+    {
+      mDone = true;
+      return rv;
+    }
+    //Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(mDB->GetEnv(), &outOid);
+    if (NS_WARN_IF(NS_FAILED(rv)))
+      return rv;
+    key = outOid.mOid_Id;
+
+    rv = mDB->GetHdrFromUseCache(key, getter_AddRefs(mResultHdr));
+    if (NS_SUCCEEDED(rv) && mResultHdr)
+      hdrRow->Release();
+    else {
+      rv = mDB->CreateMsgHdr(hdrRow, key, getter_AddRefs(mResultHdr));
+      if (NS_WARN_IF(NS_FAILED(rv)))
+        return rv;
+    }
+
+    if (mResultHdr)
+      mResultHdr->GetFlags(&flags);
+    else
+      flags = 0;
+  }
+  while (mFilter && NS_FAILED(mFilter(mResultHdr, mClosure)) && !(flags & nsMsgMessageFlags::Expunged));
+
+  if (mResultHdr)
+  {
+    mNextPrefetched = true;
+    return NS_OK;
+  }
+  else
+    mNextPrefetched = false;
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgDBEnumerator::HasMoreElements(bool *aResult)
+{
+  if (!aResult)
+    return NS_ERROR_NULL_POINTER;
+
+  if (!mNextPrefetched && (NS_FAILED(PrefetchNext())))
+    mDone = true;
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+nsMsgFilteredDBEnumerator::nsMsgFilteredDBEnumerator(nsMsgDatabase* db,
+                                                     nsIMdbTable *table,
+                                                     bool reverse,
+                                                     nsIArray *searchTerms)
+   : nsMsgDBEnumerator(db, table, nullptr, nullptr, !reverse)
+{
+}
+
+nsMsgFilteredDBEnumerator::~nsMsgFilteredDBEnumerator()
+{
+}
+
+/**
+ * Create the search session for the enumerator,
+ * add the scope term for "folder" to the search session, and add the search
+ * terms in the array to the search session.
+ */
+nsresult nsMsgFilteredDBEnumerator::InitSearchSession(nsIArray *searchTerms, nsIMsgFolder *folder)
+{
+  nsresult rv;
+  m_searchSession = do_CreateInstance(NS_MSGSEARCHSESSION_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  m_searchSession->AddScopeTerm(nsMsgSearchScope::offlineMail, folder);
+  // add each item in termsArray to the search session
+  uint32_t numTerms;
+  rv = searchTerms->GetLength(&numTerms);
+  NS_ENSURE_SUCCESS(rv, rv);
+  for (uint32_t i = 0; i < numTerms; i++)
+  {
+    nsCOMPtr <nsIMsgSearchTerm> searchTerm;
+    searchTerms->QueryElementAt(i, NS_GET_IID(nsIMsgSearchTerm), getter_AddRefs(searchTerm));
+    m_searchSession->AppendTerm(searchTerm);
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgFilteredDBEnumerator::PrefetchNext()
+{
+  nsresult rv;
+  do
+  {
+    rv = nsMsgDBEnumerator::PrefetchNext();
+    if (NS_SUCCEEDED(rv) && mResultHdr)
+    {
+      bool matches;
+      rv  = m_searchSession->MatchHdr(mResultHdr, mDB, &matches);
+      if (NS_SUCCEEDED(rv) && matches)
+        break;
+      mResultHdr = nullptr;
+    }
+    else
+      break;
+  } while (mStopPos == -1 || mRowPos != mStopPos);
+
+  if (!mResultHdr)
+    mNextPrefetched = false;
+
+  return rv;
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMETHODIMP
+nsMsgDatabase::EnumerateMessages(nsISimpleEnumerator* *result)
+{
+  RememberLastUseTime();
+  NS_ENSURE_ARG_POINTER(result);
+  nsMsgDBEnumerator* e = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                               nullptr, nullptr);
+  if (!e)
+    return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*result = e);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::ReverseEnumerateMessages(nsISimpleEnumerator* *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  nsMsgDBEnumerator* e = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable,
+                                               nullptr, nullptr, false);
+  if (!e)
+    return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*result = e);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::GetFilterEnumerator(nsIArray *searchTerms, bool aReverse,
+                                   nsISimpleEnumerator **aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  RefPtr<nsMsgFilteredDBEnumerator> e = 
+    new nsMsgFilteredDBEnumerator(this, m_mdbAllMsgHeadersTable, aReverse,
+                                  searchTerms);
+
+  NS_ENSURE_TRUE(e, NS_ERROR_OUT_OF_MEMORY);
+  nsresult rv = e->InitSearchSession(searchTerms, m_folder);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return CallQueryInterface(e.get(), aResult);
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::NextMatchingHdrs(nsISimpleEnumerator *aEnumerator,
+                                int32_t aNumHdrsToLookAt, int32_t aMaxResults,
+                                nsIMutableArray *aMatchingHdrs,
+                                int32_t *aNumMatches, bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aEnumerator);
+  NS_ENSURE_ARG_POINTER(aResult);
+  nsMsgFilteredDBEnumerator *enumerator =
+    static_cast<nsMsgFilteredDBEnumerator *> (aEnumerator);
+
+  // Force mRowPos to be initialized.
+  if (!enumerator->mRowCursor)
+    enumerator->GetRowCursor();
+
+  if (aNumHdrsToLookAt)
+  {
+    enumerator->mStopPos = enumerator->mIterateForwards ?
+      enumerator->mRowPos + aNumHdrsToLookAt :
+      enumerator->mRowPos - aNumHdrsToLookAt;
+    if (enumerator->mStopPos < 0)
+      enumerator->mStopPos = 0;
+  }
+  int32_t numMatches = 0;
+  nsresult rv;
+  do
+  {
+    nsCOMPtr <nsISupports> supports;
+    rv = enumerator->GetNext(getter_AddRefs(supports));
+    nsCOMPtr <nsIMsgDBHdr> nextMessage = do_QueryInterface(supports);
+    if (NS_SUCCEEDED(rv) && nextMessage)
+    {
+      if (aMatchingHdrs)
+        aMatchingHdrs->AppendElement(nextMessage, false);
+      ++numMatches;
+      if (aMaxResults && numMatches == aMaxResults)
+        break;
+    }
+    else
+      break;
+  }
+  while (true);
+
+  if (aNumMatches)
+    *aNumMatches = numMatches;
+
+  *aResult = !enumerator->mDone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SyncCounts()
+{
+  nsCOMPtr <nsISimpleEnumerator> hdrs;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv))
+    return rv;
+  bool hasMore = false;
+
+  mdb_count numHdrsInTable = 0;
+  int32_t numUnread = 0;
+  int32_t numHdrs = 0;
+
+  if (m_mdbAllMsgHeadersTable)
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrsInTable);
+  else
+    return NS_ERROR_NULL_POINTER;
+
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore)
+  {
+    nsCOMPtr <nsISupports> supports;
+    rv = hdrs->GetNext(getter_AddRefs(supports));
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    if (NS_FAILED(rv))
+      break;
+
+    nsCOMPtr <nsIMsgDBHdr> pHeader = do_QueryInterface(supports);
+
+    bool isRead;
+    IsHeaderRead(pHeader, &isRead);
+    if (!isRead)
+      numUnread++;
+    numHdrs++;
+  }
+
+  int32_t oldTotal, oldUnread;
+  (void) m_dbFolderInfo->GetNumUnreadMessages(&oldUnread);
+  (void) m_dbFolderInfo->GetNumMessages(&oldTotal);
+  if (oldUnread != numUnread)
+    m_dbFolderInfo->ChangeNumUnreadMessages(numUnread - oldUnread);
+  if (oldTotal != numHdrs)
+    m_dbFolderInfo->ChangeNumMessages(numHdrs - oldTotal);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllKeys(nsIMsgKeyArray *aKeys)
+{
+  NS_ENSURE_ARG_POINTER(aKeys);
+  nsresult  rv = NS_OK;
+  nsCOMPtr<nsIMdbTableRowCursor> rowCursor;
+
+  RememberLastUseTime();
+
+  if (m_mdbAllMsgHeadersTable)
+  {
+    uint32_t numMsgs = 0;
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numMsgs);
+    aKeys->SetCapacity(numMsgs);
+    rv = m_mdbAllMsgHeadersTable->GetTableRowCursor(GetEnv(), -1,
+                                                     getter_AddRefs(rowCursor));
+    while (NS_SUCCEEDED(rv) && rowCursor)
+    {
+      mdbOid outOid;
+      mdb_pos  outPos;
+
+      rv = rowCursor->NextRowOid(GetEnv(), &outOid, &outPos);
+      // is this right? Mork is returning a 0 id, but that should valid.
+      if (outPos < 0 || outOid.mOid_Id == (mdb_id) -1)
+        break;
+      if (NS_SUCCEEDED(rv))
+        aKeys->AppendElement(outOid.mOid_Id);
+    }
+  }
+  return rv;
+}
+
+class nsMsgDBThreadEnumerator : public nsISimpleEnumerator, public nsIDBChangeListener
+{
+public:
+    NS_DECL_ISUPPORTS
+
+    // nsISimpleEnumerator methods:
+    NS_DECL_NSISIMPLEENUMERATOR
+
+    NS_DECL_NSIDBCHANGELISTENER
+
+    // nsMsgDBEnumerator methods:
+    typedef nsresult (*nsMsgDBThreadEnumeratorFilter)(nsIMsgThread* thread);
+
+    nsMsgDBThreadEnumerator(nsMsgDatabase* db, nsMsgDBThreadEnumeratorFilter filter);
+
+protected:
+    virtual ~nsMsgDBThreadEnumerator();
+    nsresult          GetTableCursor(void);
+    nsresult          PrefetchNext();
+    nsMsgDatabase*              mDB;
+    nsCOMPtr <nsIMdbPortTableCursor>  mTableCursor;
+    nsIMsgThread*                 mResultThread;
+    bool                        mDone;
+    bool              mNextPrefetched;
+    nsMsgDBThreadEnumeratorFilter     mFilter;
+};
+
+nsMsgDBThreadEnumerator::nsMsgDBThreadEnumerator(nsMsgDatabase* db,
+                                     nsMsgDBThreadEnumeratorFilter filter)
+    : mDB(db), mTableCursor(nullptr), mResultThread(nullptr), mDone(false),
+      mFilter(filter)
+{
+    mDB->AddListener(this);
+    mNextPrefetched = false;
+}
+
+nsMsgDBThreadEnumerator::~nsMsgDBThreadEnumerator()
+{
+  mTableCursor = nullptr;
+  NS_IF_RELEASE(mResultThread);
+  if (mDB)
+    mDB->RemoveListener(this);
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDBThreadEnumerator, nsISimpleEnumerator, nsIDBChangeListener)
+
+
+/* void OnHdrFlagsChanged (in nsIMsgDBHdr aHdrChanged, in unsigned long aOldFlags, in unsigned long aNewFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrFlagsChanged(nsIMsgDBHdr *aHdrChanged, uint32_t aOldFlags, uint32_t aNewFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+//void OnHdrPropertyChanged(in nsIMsgDBHdr aHdrToChange, in bool aPreChange, 
+// inout uint32_t aStatus, in nsIDBChangeListener aInstigator);
+NS_IMETHODIMP
+nsMsgDBThreadEnumerator::OnHdrPropertyChanged(nsIMsgDBHdr *aHdrToChange, bool aPreChange, uint32_t *aStatus, 
+                                         nsIDBChangeListener * aInstigator)
+{
+  return NS_OK;
+}
+
+/* void onHdrDeleted (in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrDeleted(nsIMsgDBHdr *aHdrChanged, nsMsgKey aParentKey, int32_t aFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onHdrAdded (in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrAdded(nsIMsgDBHdr *aHdrChanged, nsMsgKey aParentKey, int32_t aFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onParentChanged (in nsMsgKey aKeyChanged, in nsMsgKey oldParent, in nsMsgKey newParent, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnParentChanged(nsMsgKey aKeyChanged, nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onAnnouncerGoingAway (in nsIDBChangeAnnouncer instigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnAnnouncerGoingAway(nsIDBChangeAnnouncer *instigator)
+{
+  mTableCursor = nullptr;
+  NS_IF_RELEASE(mResultThread);
+  mDB->RemoveListener(this);
+  mDB = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnEvent(nsIMsgDatabase *aDB, const char *aEvent)
+{
+  return NS_OK;
+}
+
+/* void onReadChanged (in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnReadChanged(nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onJunkScoreChanged (in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnJunkScoreChanged(nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+nsresult nsMsgDBThreadEnumerator::GetTableCursor(void)
+{
+  nsresult rv = NS_OK;
+
+  if (!mDB || !mDB->m_mdbStore)
+    return NS_ERROR_NULL_POINTER;
+
+  mDB->m_mdbStore->GetPortTableCursor(mDB->GetEnv(),   mDB->m_hdrRowScopeToken, mDB->m_threadTableKindToken,
+    getter_AddRefs(mTableCursor));
+
+  if (NS_FAILED(rv))
+    return rv;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDBThreadEnumerator::GetNext(nsISupports **aItem)
+{
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  *aItem = nullptr;
+  nsresult rv = NS_OK;
+  if (!mNextPrefetched)
+    rv = PrefetchNext();
+  if (NS_SUCCEEDED(rv))
+  {
+    if (mResultThread)
+    {
+      *aItem = mResultThread;
+      NS_ADDREF(mResultThread);
+      mNextPrefetched = false;
+    }
+  }
+  return rv;
+}
+
+
+nsresult nsMsgDBThreadEnumerator::PrefetchNext()
+{
+  nsresult rv;
+  nsCOMPtr<nsIMdbTable> table;
+
+  if (!mDB)
+    return NS_ERROR_NULL_POINTER;
+
+  if (!mTableCursor)
+  {
+    rv = GetTableCursor();
+    if (NS_FAILED(rv))
+      return rv;
+  }
+  while (true)
+  {
+    NS_IF_RELEASE(mResultThread);
+    mResultThread = nullptr;
+    rv = mTableCursor->NextTable(mDB->GetEnv(), getter_AddRefs(table));
+    if (!table)
+    {
+      mDone = true;
+      return NS_ERROR_FAILURE;
+    }
+    if (NS_FAILED(rv))
+    {
+      mDone = true;
+      return rv;
+    }
+
+    mdbOid tableId;
+    table->GetOid(mDB->GetEnv(), &tableId);
+
+    mResultThread = mDB->FindExistingThread(tableId.mOid_Id);
+    if (!mResultThread)
+      mResultThread = new nsMsgThread(mDB, table);
+
+    if (mResultThread)
+    {
+      uint32_t numChildren = 0;
+      NS_ADDREF(mResultThread);
+      mResultThread->GetNumChildren(&numChildren);
+      // we've got empty thread; don't tell caller about it.
+      if (numChildren == 0)
+        continue;
+    }
+    if (mFilter && NS_FAILED(mFilter(mResultThread)))
+      continue;
+    else
+      break;
+  }
+  if (mResultThread)
+  {
+    mNextPrefetched = true;
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsMsgDBThreadEnumerator::HasMoreElements(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  if (!mNextPrefetched)
+    PrefetchNext();
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::EnumerateThreads(nsISimpleEnumerator* *result)
+{
+  RememberLastUseTime();
+  nsMsgDBThreadEnumerator* e = new nsMsgDBThreadEnumerator(this, nullptr);
+  if (e == nullptr)
+    return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*result = e);
+  return NS_OK;
+}
+
+// only return headers with a particular flag set
+static nsresult
+nsMsgFlagSetFilter(nsIMsgDBHdr *msg, void *closure)
+{
+  uint32_t msgFlags, desiredFlags;
+  desiredFlags = * (uint32_t *) closure;
+  msg->GetFlags(&msgFlags);
+  return (msgFlags & desiredFlags) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult
+nsMsgDatabase::EnumerateMessagesWithFlag(nsISimpleEnumerator* *result, uint32_t *pFlag)
+{
+  RememberLastUseTime();
+
+  nsMsgDBEnumerator* e = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable, nsMsgFlagSetFilter, pFlag);
+  if (!e)
+    return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*result = e);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::CreateNewHdr(nsMsgKey key, nsIMsgDBHdr **pnewHdr)
+{
+  nsresult  err = NS_OK;
+  nsIMdbRow    *hdrRow = nullptr;
+  struct mdbOid allMsgHdrsTableOID;
+
+  if (!pnewHdr || !m_mdbAllMsgHeadersTable || !m_mdbStore)
+    return NS_ERROR_NULL_POINTER;
+
+  if (key != nsMsgKey_None)
+  {
+  allMsgHdrsTableOID.mOid_Scope = m_hdrRowScopeToken;
+  allMsgHdrsTableOID.mOid_Id = key;  // presumes 0 is valid key value
+
+  err = m_mdbStore->GetRow(GetEnv(), &allMsgHdrsTableOID, &hdrRow);
+  if (!hdrRow)
+    err  = m_mdbStore->NewRowWithOid(GetEnv(), &allMsgHdrsTableOID, &hdrRow);
+  }
+  else
+  {
+    // Mork will assign an ID to the new row, generally the next available ID.
+    err  = m_mdbStore->NewRow(GetEnv(), m_hdrRowScopeToken, &hdrRow);
+    if (hdrRow)
+    {
+      struct mdbOid oid;
+      hdrRow->GetOid(GetEnv(), &oid);
+      key = oid.mOid_Id;
+    }
+    else
+    {
+      // We failed to create a new row. That can happen if we run out of keys,
+      // which will force a reparse.
+      RefPtr<nsMsgKeyArray> keys = new nsMsgKeyArray;
+      if (NS_SUCCEEDED(ListAllKeys(keys)))
+      {
+        uint32_t numKeys;
+        keys->GetLength(&numKeys);
+        for (uint32_t i = 0; i < numKeys; i++)
+        {
+          if (keys->m_keys[i] >= kForceReparseKey)
+          {
+            // Force a reparse.
+            if (m_dbFolderInfo)
+              m_dbFolderInfo->SetBooleanProperty("forceReparse", true);
+            break;
+          }
+        }
+      }
+      err = NS_MSG_ERROR_FOLDER_SUMMARY_OUT_OF_DATE;
+    }
+  }
+  if (NS_FAILED(err))
+    return err;
+  err = CreateMsgHdr(hdrRow, key, pnewHdr);
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::AddNewHdrToDB(nsIMsgDBHdr *newHdr, bool notify)
+{
+  NS_ENSURE_ARG_POINTER(newHdr);
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(newHdr);          // closed system, cast ok
+  bool newThread;
+  bool hasKey;
+  ContainsKey(hdr->m_messageKey, &hasKey);
+  if (hasKey)
+  {
+    NS_ERROR("adding hdr that already exists");
+    return NS_ERROR_FAILURE;
+  }
+  nsresult err = ThreadNewHdr(hdr, newThread);
+  // we thread header before we add it to the all headers table
+  // so that subject and reference threading will work (otherwise,
+  // when we try to find the first header with the same subject or
+  // reference, we get the new header!)
+  if (NS_SUCCEEDED(err))
+  {
+    nsMsgKey key;
+    uint32_t flags;
+
+    newHdr->GetMessageKey(&key);
+    hdr->GetRawFlags(&flags);
+    // use raw flags instead of GetFlags, because GetFlags will
+    // pay attention to what's in m_newSet, and this new hdr isn't
+    // in m_newSet yet.
+    if (flags & nsMsgMessageFlags::New)
+    {
+      uint32_t newFlags;
+      newHdr->AndFlags(~nsMsgMessageFlags::New, &newFlags);  // make sure not filed out
+      AddToNewList(key);
+    }
+    if (m_dbFolderInfo != NULL)
+    {
+      m_dbFolderInfo->ChangeNumMessages(1);
+      bool isRead = true;
+      IsHeaderRead(newHdr, &isRead);
+      if (!isRead)
+        m_dbFolderInfo->ChangeNumUnreadMessages(1);
+      m_dbFolderInfo->OnKeyAdded(key);
+    }
+
+    err = m_mdbAllMsgHeadersTable->AddRow(GetEnv(), hdr->GetMDBRow());
+    if (notify)
+    {
+      nsMsgKey threadParent;
+
+      newHdr->GetThreadParent(&threadParent);
+      NotifyHdrAddedAll(newHdr, threadParent, flags, NULL);
+    }
+
+    if (UseCorrectThreading())
+      err = AddMsgRefsToHash(newHdr);
+  }
+  NS_ASSERTION(NS_SUCCEEDED(err), "error creating thread");
+  return err;
+}
+
+NS_IMETHODIMP nsMsgDatabase::CopyHdrFromExistingHdr(nsMsgKey key, nsIMsgDBHdr *existingHdr, bool addHdrToDB, nsIMsgDBHdr **newHdr)
+{
+  nsresult  err = NS_OK;
+
+  if (existingHdr)
+  {
+    nsMsgHdr* sourceMsgHdr = static_cast<nsMsgHdr*>(existingHdr);      // closed system, cast ok
+    nsMsgHdr *destMsgHdr = nullptr;
+    CreateNewHdr(key, (nsIMsgDBHdr **) &destMsgHdr);
+    nsIMdbRow  *sourceRow = sourceMsgHdr->GetMDBRow();
+    if (!destMsgHdr || !sourceRow)
+      return NS_MSG_MESSAGE_NOT_FOUND;
+
+    nsIMdbRow  *destRow = destMsgHdr->GetMDBRow();
+    if (!destRow)
+      return NS_ERROR_UNEXPECTED;
+
+    err = destRow->SetRow(GetEnv(), sourceRow);
+    if (NS_SUCCEEDED(err))
+    {
+      // we may have gotten the header from a cache - calling SetRow
+      // basically invalidates any cached values, so invalidate them.
+      destMsgHdr->m_initedValues = 0;
+      if(addHdrToDB)
+        err = AddNewHdrToDB(destMsgHdr, true);
+      if (NS_SUCCEEDED(err) && newHdr)
+        *newHdr = destMsgHdr;
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnTonsString(nsIMdbRow *hdrRow, mdb_token columnToken, nsAString &resultStr)
+{
+  NS_ENSURE_ARG_POINTER(hdrRow);
+
+  struct mdbYarn yarn;
+  nsresult rv = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  YarnTonsString(&yarn, resultStr);
+  return NS_OK;
+}
+
+// as long as the row still exists, and isn't changed, the returned const char ** will be valid.
+// But be very careful using this data - the caller should never return it in turn to another caller.
+nsresult nsMsgDatabase::RowCellColumnToConstCharPtr(nsIMdbRow *hdrRow, mdb_token columnToken, const char **ptr)
+{
+  NS_ENSURE_ARG_POINTER(hdrRow);
+
+  struct mdbYarn yarn;
+  nsresult rv = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  *ptr = (const char*)yarn.mYarn_Buf;
+  return NS_OK;
+}
+
+nsIMimeConverter *nsMsgDatabase::GetMimeConverter()
+{
+  if (!m_mimeConverter)
+  {
+    // apply mime decode
+    m_mimeConverter = do_GetService(NS_MIME_CONVERTER_CONTRACTID);
+  }
+  return m_mimeConverter;
+}
+
+nsresult nsMsgDatabase::GetEffectiveCharset(nsIMdbRow *row, nsACString &resultCharset)
+{
+  resultCharset.Truncate();
+  bool characterSetOverride;
+  m_dbFolderInfo->GetCharacterSetOverride(&characterSetOverride);
+  nsresult rv = RowCellColumnToCharPtr(row, m_messageCharSetColumnToken, getter_Copies(resultCharset));
+  if (NS_FAILED(rv) || resultCharset.IsEmpty() ||
+      resultCharset.Equals("us-ascii") || characterSetOverride)
+  {
+    rv = m_dbFolderInfo->GetEffectiveCharacterSet(resultCharset);
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToMime2DecodedString(nsIMdbRow *row, mdb_token columnToken, nsAString &resultStr)
+{
+  nsresult err = NS_OK;
+  const char *nakedString = nullptr;
+  err = RowCellColumnToConstCharPtr(row, columnToken, &nakedString);
+  if (NS_SUCCEEDED(err) && nakedString && strlen(nakedString))
+  {
+    GetMimeConverter();
+    if (m_mimeConverter)
+    {
+      nsAutoString decodedStr;
+      nsCString charSet;
+      GetEffectiveCharset(row, charSet);
+
+      err = m_mimeConverter->DecodeMimeHeader(nakedString, charSet.get(),
+        false, true, resultStr);
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToAddressCollationKey(nsIMdbRow *row, mdb_token colToken, uint8_t **result, uint32_t *len)
+{
+  nsString sender;
+  nsresult rv = RowCellColumnToMime2DecodedString(row, colToken, sender);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsString name;
+  ExtractName(DecodedHeader(sender), name);
+  return CreateCollationKey(name, len, result);
+}
+
+nsresult nsMsgDatabase::GetCollationKeyGenerator()
+{
+  nsresult err = NS_OK;
+  if (!m_collationKeyGenerator)
+  {
+    nsCOMPtr <nsILocale> locale;
+    nsAutoString localeName;
+
+    // get a locale service
+    nsCOMPtr <nsILocaleService> localeService = do_GetService(NS_LOCALESERVICE_CONTRACTID, &err);
+    if (NS_SUCCEEDED(err))
+    {
+      // do this for a new db if no UI to be provided for locale selection
+      err = localeService->GetApplicationLocale(getter_AddRefs(locale));
+
+      if (locale)
+      {
+        // or generate a locale from a stored locale name ("en_US", "fr_FR")
+        //err = localeFactory->NewLocale(&localeName, &locale);
+
+        nsCOMPtr <nsICollationFactory> f = do_CreateInstance(NS_COLLATIONFACTORY_CONTRACTID, &err);
+        if (NS_SUCCEEDED(err) && f)
+        {
+          // get a collation interface instance
+          err = f->CreateCollation(locale, getter_AddRefs(m_collationKeyGenerator));
+        }
+      }
+    }
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToCollationKey(nsIMdbRow *row, mdb_token columnToken, uint8_t **result, uint32_t *len)
+{
+  const char *nakedString = nullptr;
+  nsresult err;
+
+  err = RowCellColumnToConstCharPtr(row, columnToken, &nakedString);
+  if (!nakedString)
+    nakedString = "";
+  if (NS_SUCCEEDED(err))
+  {
+    GetMimeConverter();
+    if (m_mimeConverter)
+    {
+      nsCString decodedStr;
+      nsCString charSet;
+      GetEffectiveCharset(row, charSet);
+
+      err = m_mimeConverter->DecodeMimeHeaderToUTF8(
+        nsDependentCString(nakedString), charSet.get(), false,
+        true, decodedStr);
+      if (NS_SUCCEEDED(err))
+        err = CreateCollationKey(NS_ConvertUTF8toUTF16(decodedStr), len, result);
+    }
+  }
+  return err;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::CompareCollationKeys(uint32_t len1, uint8_t *key1, uint32_t len2,
+                                    uint8_t *key2, int32_t *result)
+{
+  nsresult rv = GetCollationKeyGenerator();
+  NS_ENSURE_SUCCESS(rv,rv);
+  if (!m_collationKeyGenerator) return NS_ERROR_FAILURE;
+
+  rv = m_collationKeyGenerator->CompareRawSortKey(key1,len1,key2,len2,result);
+  NS_ENSURE_SUCCESS(rv,rv);
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::CreateCollationKey(const nsAString& sourceString, uint32_t *len,
+                                  uint8_t **result)
+{
+  nsresult err = GetCollationKeyGenerator();
+  NS_ENSURE_SUCCESS(err,err);
+  if (!m_collationKeyGenerator) return NS_ERROR_FAILURE;
+
+  err = m_collationKeyGenerator->AllocateRawSortKey(nsICollation::kCollationCaseInSensitive, sourceString, result, len);
+  NS_ENSURE_SUCCESS(err,err);
+  return err;
+}
+
+nsresult nsMsgDatabase::RowCellColumnToUInt32(nsIMdbRow *hdrRow, mdb_token columnToken, uint32_t &uint32Result, uint32_t defaultValue)
+{
+  return RowCellColumnToUInt32(hdrRow, columnToken, &uint32Result, defaultValue);
+}
+
+nsresult nsMsgDatabase::RowCellColumnToUInt32(nsIMdbRow *hdrRow, mdb_token columnToken, uint32_t *uint32Result, uint32_t defaultValue)
+{
+  nsresult  err = NS_OK;
+
+  if (uint32Result)
+    *uint32Result = defaultValue;
+  if (hdrRow)  // ### probably should be an error if hdrRow is NULL...
+  {
+    struct mdbYarn yarn;
+    err = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err))
+      YarnToUInt32(&yarn, uint32Result);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::UInt32ToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, uint32_t value)
+{
+  struct mdbYarn yarn;
+  char  yarnBuf[100];
+
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  yarn.mYarn_Buf = (void *) yarnBuf;
+  yarn.mYarn_Size = sizeof(yarnBuf);
+  yarn.mYarn_Fill = yarn.mYarn_Size;
+  yarn.mYarn_Form = 0;
+  yarn.mYarn_Grow = NULL;
+  return row->AddColumn(GetEnv(),  columnToken, UInt32ToYarn(&yarn, value));
+}
+
+nsresult nsMsgDatabase::UInt64ToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, uint64_t value)
+{
+  NS_ENSURE_ARG_POINTER(row);
+  struct mdbYarn yarn;
+  char  yarnBuf[17]; // max string is 16 bytes, + 1 for null.
+
+  yarn.mYarn_Buf = (void *) yarnBuf;
+  yarn.mYarn_Size = sizeof(yarnBuf);
+  yarn.mYarn_Form = 0;
+  yarn.mYarn_Grow = NULL;
+  PR_snprintf((char *) yarn.mYarn_Buf, yarn.mYarn_Size, "%llx", value);
+  yarn.mYarn_Fill = PL_strlen((const char *) yarn.mYarn_Buf);
+  return row->AddColumn(GetEnv(),  columnToken, &yarn);
+}
+
+nsresult
+nsMsgDatabase::RowCellColumnToUInt64(nsIMdbRow *hdrRow, mdb_token columnToken,
+                                     uint64_t *uint64Result,
+                                     uint64_t defaultValue)
+{
+  nsresult  err = NS_OK;
+
+  if (uint64Result)
+    *uint64Result = defaultValue;
+  if (hdrRow)  // ### probably should be an error if hdrRow is NULL...
+  {
+    struct mdbYarn yarn;
+    err = hdrRow->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err))
+      YarnToUInt64(&yarn, uint64Result);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::CharPtrToRowCellColumn(nsIMdbRow *row, mdb_token columnToken, const char *charPtr)
+{
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  struct mdbYarn yarn;
+  yarn.mYarn_Buf = (void *) charPtr;
+  yarn.mYarn_Size = PL_strlen((const char *) yarn.mYarn_Buf) + 1;
+  yarn.mYarn_Fill = yarn.mYarn_Size - 1;
+  yarn.mYarn_Form = 0;  // what to do with this? we're storing csid in the msg hdr...
+
+  return row->AddColumn(GetEnv(),  columnToken, &yarn);
+}
+
+// caller must NS_Free result
+nsresult nsMsgDatabase::RowCellColumnToCharPtr(nsIMdbRow *row, mdb_token columnToken, char **result)
+{
+  nsresult  err = NS_ERROR_NULL_POINTER;
+
+  if (row && result)
+  {
+    struct mdbYarn yarn;
+    err = row->AliasCellYarn(GetEnv(), columnToken, &yarn);
+    if (NS_SUCCEEDED(err))
+    {
+      *result = (char *)NS_Alloc(yarn.mYarn_Fill + 1);
+      if (*result)
+      {
+        if (yarn.mYarn_Fill > 0)
+          memcpy(*result, yarn.mYarn_Buf, yarn.mYarn_Fill);
+        (*result)[yarn.mYarn_Fill] = '\0';
+      }
+      else
+        err = NS_ERROR_OUT_OF_MEMORY;
+
+    }
+  }
+  return err;
+}
+
+
+
+/* static */struct mdbYarn *nsMsgDatabase::nsStringToYarn(struct mdbYarn *yarn, const nsAString &str)
+{
+  yarn->mYarn_Buf = ToNewCString(NS_ConvertUTF16toUTF8(str));
+  yarn->mYarn_Size = str.Length() + 1;
+  yarn->mYarn_Fill = yarn->mYarn_Size - 1;
+  yarn->mYarn_Form = 0;  // what to do with this? we're storing csid in the msg hdr...
+  return yarn;
+}
+
+/* static */struct mdbYarn *nsMsgDatabase::UInt32ToYarn(struct mdbYarn *yarn, uint32_t i)
+{
+  PR_snprintf((char *) yarn->mYarn_Buf, yarn->mYarn_Size, "%lx", i);
+  yarn->mYarn_Fill = PL_strlen((const char *) yarn->mYarn_Buf);
+  yarn->mYarn_Form = 0;  // what to do with this? Should be parsed out of the mime2 header?
+  return yarn;
+}
+
+/* static */struct mdbYarn *nsMsgDatabase::UInt64ToYarn(struct mdbYarn *yarn, uint64_t i)
+{
+  PR_snprintf((char *) yarn->mYarn_Buf, yarn->mYarn_Size, "%llx", i);
+  yarn->mYarn_Fill = PL_strlen((const char *) yarn->mYarn_Buf);
+  yarn->mYarn_Form = 0;
+  return yarn;
+}
+
+/* static */void nsMsgDatabase::YarnTonsString(struct mdbYarn *yarn, nsAString &str)
+{
+  const char* buf = (const char*)yarn->mYarn_Buf;
+  if (buf)
+    CopyASCIItoUTF16(Substring(buf, buf + yarn->mYarn_Fill), str);
+  else
+    str.Truncate();
+}
+
+/* static */void nsMsgDatabase::YarnTonsCString(struct mdbYarn *yarn, nsACString &str)
+{
+    const char* buf = (const char*)yarn->mYarn_Buf;
+    if (buf)
+        str.Assign(buf, yarn->mYarn_Fill);
+    else
+        str.Truncate();
+}
+
+// WARNING - if yarn is empty, *pResult will not be changed!!!!
+// this is so we can leave default values as they were.
+/* static */void nsMsgDatabase::YarnToUInt32(struct mdbYarn *yarn, uint32_t *pResult)
+{
+  uint8_t numChars = std::min<mdb_fill>(8, yarn->mYarn_Fill);
+
+  if (numChars == 0)
+    return;
+
+  *pResult = MsgUnhex((char *) yarn->mYarn_Buf, numChars);
+}
+
+// WARNING - if yarn is empty, *pResult will not be changed!!!!
+// this is so we can leave default values as they were.
+/* static */void nsMsgDatabase::YarnToUInt64(struct mdbYarn *yarn, uint64_t *pResult)
+{
+  uint8_t numChars = std::min<mdb_fill>(16, yarn->mYarn_Fill);
+
+  if (numChars == 0)
+    return;
+
+  *pResult = MsgUnhex((char *) yarn->mYarn_Buf, numChars);
+}
+
+nsresult nsMsgDatabase::GetProperty(nsIMdbRow *row, const char *propertyName, char **result)
+{
+  nsresult err = NS_OK;
+  mdb_token  property_token;
+
+  if (m_mdbStore)
+    err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  else
+    err = NS_ERROR_NULL_POINTER;
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToCharPtr(row, property_token, result);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetProperty(nsIMdbRow *row, const char *propertyName, const char *propertyVal)
+{
+  nsresult err = NS_OK;
+  mdb_token  property_token;
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    CharPtrToRowCellColumn(row, property_token, propertyVal);
+  return err;
+}
+
+nsresult nsMsgDatabase::GetPropertyAsNSString(nsIMdbRow *row, const char *propertyName, nsAString &result)
+{
+  nsresult err = NS_OK;
+  mdb_token  property_token;
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnTonsString(row, property_token, result);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetPropertyFromNSString(nsIMdbRow *row, const char *propertyName, const nsAString &propertyVal)
+{
+  nsresult err = NS_OK;
+  mdb_token  property_token;
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    return SetNSStringPropertyWithToken(row, property_token, propertyVal);
+
+  return err;
+}
+
+
+nsresult nsMsgDatabase::GetUint32Property(nsIMdbRow *row, const char *propertyName, uint32_t *result, uint32_t defaultValue)
+{
+  nsresult err = NS_OK;
+  mdb_token  property_token;
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToUInt32(row, property_token, result, defaultValue);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::GetUint64Property(nsIMdbRow *row, const char *propertyName, uint64_t *result, uint64_t defaultValue)
+{
+  nsresult err = NS_OK;
+  mdb_token property_token;
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  err = m_mdbStore->StringToToken(GetEnv(), propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+    err = RowCellColumnToUInt64(row, property_token, result, defaultValue);
+
+  return err;
+}
+
+nsresult nsMsgDatabase::SetUint32Property(nsIMdbRow *row, const char *propertyName, uint32_t propertyVal)
+{
+  struct mdbYarn yarn;
+  char  int32StrBuf[20];
+  yarn.mYarn_Buf = int32StrBuf;
+  yarn.mYarn_Size = sizeof(int32StrBuf);
+  yarn.mYarn_Fill = sizeof(int32StrBuf);
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  mdb_token  property_token;
+
+  nsresult err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+  {
+    UInt32ToYarn(&yarn, propertyVal);
+    err = row->AddColumn(GetEnv(), property_token, &yarn);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::SetUint64Property(nsIMdbRow *row,
+                                          const char *propertyName,
+                                          uint64_t propertyVal)
+{
+  struct mdbYarn yarn;
+  char  int64StrBuf[100];
+  yarn.mYarn_Buf = int64StrBuf;
+  yarn.mYarn_Size = sizeof(int64StrBuf);
+  yarn.mYarn_Fill = sizeof(int64StrBuf);
+
+  NS_ENSURE_STATE(m_mdbStore); // db might have been closed out from under us.
+  if (!row)
+    return NS_ERROR_NULL_POINTER;
+
+  mdb_token  property_token;
+
+  nsresult err = m_mdbStore->StringToToken(GetEnv(),  propertyName, &property_token);
+  if (NS_SUCCEEDED(err))
+  {
+    UInt64ToYarn(&yarn, propertyVal);
+    err = row->AddColumn(GetEnv(), property_token, &yarn);
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetBooleanProperty(nsIMdbRow *row, const char *propertyName, 
+                                     bool *result, 
+                                     bool defaultValue /* = false */)
+{
+  uint32_t res;
+  nsresult rv = GetUint32Property(row, propertyName, &res, (uint32_t) defaultValue);
+  *result = !!res;
+  return rv;
+}
+
+nsresult nsMsgDatabase::SetBooleanProperty(nsIMdbRow *row, const char *propertyName, 
+                                    bool propertyVal)
+{
+  return SetUint32Property(row, propertyName, (uint32_t) propertyVal);
+}
+
+nsresult nsMsgDatabase::SetNSStringPropertyWithToken(nsIMdbRow *row, mdb_token aProperty, const nsAString &propertyStr)
+{
+  NS_ENSURE_ARG(row);
+  struct mdbYarn yarn;
+
+  yarn.mYarn_Grow = NULL;
+  nsresult err = row->AddColumn(GetEnv(), aProperty, nsStringToYarn(&yarn, propertyStr));
+  free((char *)yarn.mYarn_Buf);  // won't need this when we have nsCString
+  return err;
+}
+
+
+uint32_t nsMsgDatabase::GetCurVersion()
+{
+  return kMsgDBVersion;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetSummaryValid(bool valid /* = true */)
+{
+  // If the file was invalid when opened (for example in folder compact), then it may
+  //  not have been added to the cache. Add it now if missing.
+  if (valid)
+  {
+    nsCOMPtr<nsIMsgDBService> serv(mozilla::services::GetDBService());
+    static_cast<nsMsgDBService*>(serv.get())->EnsureCached(this);
+  }
+  // setting the version to 0 ought to make it pretty invalid.
+  if (m_dbFolderInfo)
+    m_dbFolderInfo->SetVersion(valid ? GetCurVersion() : 0);
+
+  // for default db (and news), there's no nothing to set to make it it valid
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP  nsMsgDatabase::GetSummaryValid(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  *aResult = true;
+  return NS_OK;
+}
+
+
+// protected routines
+
+// should we thread messages with common subjects that don't start with Re: together?
+// I imagine we might have separate preferences for mail and news, so this is a virtual method.
+bool    nsMsgDatabase::ThreadBySubjectWithoutRe()
+{
+  GetGlobalPrefs();
+  return gThreadWithoutRe;
+}
+
+bool nsMsgDatabase::UseStrictThreading()
+{
+  GetGlobalPrefs();
+  return gStrictThreading;
+}
+
+// Should we make sure messages are always threaded correctly (see bug 181446)
+bool nsMsgDatabase::UseCorrectThreading()
+{
+  GetGlobalPrefs();
+  return gCorrectThreading;
+}
+
+// adapted from removed PL_DHashFreeStringKey
+static void
+msg_DHashFreeStringKey(PLDHashTable* aTable, PLDHashEntryHdr* aEntry)
+{
+  const PLDHashEntryStub* stub = (const PLDHashEntryStub*)aEntry;
+  free((void*)stub->key);
+  PLDHashTable::ClearEntryStub(aTable, aEntry);
+}
+
+PLDHashTableOps nsMsgDatabase::gRefHashTableOps =
+{
+  PLDHashTable::HashStringKey,
+  PLDHashTable::MatchStringKey,
+  PLDHashTable::MoveEntryStub,
+  msg_DHashFreeStringKey,
+  nullptr
+};
+
+nsresult nsMsgDatabase::GetRefFromHash(nsCString &reference, nsMsgKey *threadId)
+{
+  // Initialize the reference hash
+  if (!m_msgReferences)
+  {
+    nsresult rv = InitRefHash();
+    if (NS_FAILED(rv))
+      return rv;
+  }
+
+  // Find reference from the hash
+  PLDHashEntryHdr *entry =
+    m_msgReferences->Search((const void *) reference.get());
+  if (entry)
+  {
+    RefHashElement *element = static_cast<RefHashElement *>(entry);
+    *threadId = element->mThreadId;
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::AddRefToHash(nsCString &reference, nsMsgKey threadId)
+{
+  if (m_msgReferences)
+  {
+    PLDHashEntryHdr *entry = m_msgReferences->Add((void *) reference.get(), mozilla::fallible);
+    if (!entry)
+      return NS_ERROR_OUT_OF_MEMORY; // XXX out of memory
+
+    RefHashElement *element = static_cast<RefHashElement *>(entry);
+    if (!element->mRef)
+    {
+      element->mRef = ToNewCString(reference);  // Will be freed in msg_DHashFreeStringKey()
+      element->mThreadId = threadId;
+      element->mCount = 1;
+    }
+    else
+      element->mCount++;
+  }
+
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::AddMsgRefsToHash(nsIMsgDBHdr *msgHdr)
+{
+  uint16_t numReferences = 0;
+  nsMsgKey threadId;
+  nsresult rv = NS_OK;
+
+  msgHdr->GetThreadId(&threadId);
+  msgHdr->GetNumReferences(&numReferences);
+
+  for (int32_t i = 0; i < numReferences; i++)
+  {
+    nsAutoCString reference;
+    
+    msgHdr->GetStringReference(i, reference);
+    if (reference.IsEmpty())
+      break;
+
+    rv = AddRefToHash(reference, threadId);
+    if (NS_FAILED(rv))
+      break;
+  }
+
+  return rv;
+}
+
+nsresult nsMsgDatabase::RemoveRefFromHash(nsCString &reference)
+{
+  if (m_msgReferences)
+  {
+    PLDHashEntryHdr *entry =
+     m_msgReferences->Search((const void *) reference.get());
+    if (entry)
+    {
+      RefHashElement *element = static_cast<RefHashElement *>(entry);
+      if (--element->mCount == 0)
+        m_msgReferences->Remove((void *) reference.get());
+    }
+  }
+  return NS_OK;
+}
+
+// Filter only messages with one or more references
+nsresult nsMsgDatabase::RemoveMsgRefsFromHash(nsIMsgDBHdr *msgHdr)
+{
+  uint16_t numReferences = 0;
+  nsresult rv = NS_OK;
+
+  msgHdr->GetNumReferences(&numReferences);
+
+  for (int32_t i = 0; i < numReferences; i++)
+  {
+    nsAutoCString reference;
+    
+    msgHdr->GetStringReference(i, reference);
+    if (reference.IsEmpty())
+      break;
+
+    rv = RemoveRefFromHash(reference);
+    if (NS_FAILED(rv))
+      break;
+  }
+
+  return rv;
+}
+
+static nsresult nsReferencesOnlyFilter(nsIMsgDBHdr *msg, void *closure)
+{
+  uint16_t numReferences = 0;
+  msg->GetNumReferences(&numReferences);
+  return (numReferences) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsMsgDatabase::InitRefHash()
+{
+  // Delete an existing table just in case
+  if (m_msgReferences)
+    delete m_msgReferences;
+
+  // Create new table
+  m_msgReferences = new PLDHashTable(&gRefHashTableOps, sizeof(struct RefHashElement), MSG_HASH_SIZE);
+  if (!m_msgReferences)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  // Create enumerator to go through all messages with references
+  nsCOMPtr <nsISimpleEnumerator> enumerator;
+  enumerator = new nsMsgDBEnumerator(this, m_mdbAllMsgHeadersTable, nsReferencesOnlyFilter, nullptr);
+  if (enumerator == nullptr)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  // Populate table with references of existing messages
+  bool hasMore;
+  nsresult rv = NS_OK;
+  while (NS_SUCCEEDED(rv = enumerator->HasMoreElements(&hasMore)) && hasMore)
+  {
+    nsCOMPtr <nsISupports> supports;
+    rv = enumerator->GetNext(getter_AddRefs(supports));
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    nsCOMPtr <nsIMsgDBHdr> msgHdr = do_QueryInterface(supports);
+    if (msgHdr && NS_SUCCEEDED(rv))
+      rv = AddMsgRefsToHash(msgHdr);
+    if (NS_FAILED(rv))
+      break;
+  }
+
+  return rv;
+}
+
+nsresult nsMsgDatabase::CreateNewThread(nsMsgKey threadId, const char *subject, nsMsgThread **pnewThread)
+{
+  nsresult  err = NS_OK;
+  nsCOMPtr<nsIMdbTable> threadTable;
+  struct mdbOid threadTableOID;
+  struct mdbOid allThreadsTableOID;
+
+  if (!pnewThread || !m_mdbStore)
+    return NS_ERROR_NULL_POINTER;
+
+  threadTableOID.mOid_Scope = m_hdrRowScopeToken;
+  threadTableOID.mOid_Id = threadId;
+
+  // Under some circumstances, mork seems to reuse an old table when we create one.
+  // Prevent problems from that by finding any old table first, and deleting its rows.
+  nsresult res = GetStore()->GetTable(GetEnv(), &threadTableOID, getter_AddRefs(threadTable));
+  if (NS_SUCCEEDED(res) && threadTable)
+    threadTable->CutAllRows(GetEnv());
+
+  err  = GetStore()->NewTableWithOid(GetEnv(), &threadTableOID, m_threadTableKindToken,
+    false, nullptr, getter_AddRefs(threadTable));
+  if (NS_FAILED(err))
+    return err;
+
+  allThreadsTableOID.mOid_Scope = m_threadRowScopeToken;
+  allThreadsTableOID.mOid_Id = threadId;
+
+  // add a row for this thread in the table of all threads that we'll use
+  // to do our mapping between subject strings and threads.
+  nsCOMPtr<nsIMdbRow> threadRow;
+
+  err = m_mdbStore->GetRow(GetEnv(), &allThreadsTableOID,
+                           getter_AddRefs(threadRow));
+  if (!threadRow)
+  {
+    err  = m_mdbStore->NewRowWithOid(GetEnv(), &allThreadsTableOID,
+                                     getter_AddRefs(threadRow));
+    if (NS_SUCCEEDED(err) && threadRow)
+    {
+      if (m_mdbAllThreadsTable)
+        m_mdbAllThreadsTable->AddRow(GetEnv(), threadRow);
+      err = CharPtrToRowCellColumn(threadRow, m_threadSubjectColumnToken, subject);
+    }
+  }
+  else
+  {
+#ifdef DEBUG_David_Bienvenu
+    NS_WARNING("odd that thread row already exists");
+#endif
+    threadRow->CutAllColumns(GetEnv());
+    nsCOMPtr<nsIMdbRow> metaRow;
+    threadTable->GetMetaRow(GetEnv(), nullptr, nullptr, getter_AddRefs(metaRow));
+    if (metaRow)
+      metaRow->CutAllColumns(GetEnv());
+
+    CharPtrToRowCellColumn(threadRow, m_threadSubjectColumnToken, subject);
+  }
+
+
+  *pnewThread = new nsMsgThread(this, threadTable);
+  if (*pnewThread)
+  {
+    (*pnewThread)->SetThreadKey(threadId);
+     m_cachedThread = *pnewThread;
+     m_cachedThreadId = threadId;
+  }
+  return err;
+}
+
+
+nsIMsgThread *nsMsgDatabase::GetThreadForReference(nsCString &msgID, nsIMsgDBHdr **pMsgHdr)
+{
+  nsMsgKey threadId;
+  nsIMsgDBHdr  *msgHdr = nullptr;
+  GetMsgHdrForMessageID(msgID.get(), &msgHdr);
+  nsIMsgThread *thread = NULL;
+
+  if (msgHdr != NULL)
+  {
+    if (NS_SUCCEEDED(msgHdr->GetThreadId(&threadId)))
+    {
+      // find thread header for header whose message id we matched.
+      thread = GetThreadForThreadId(threadId);
+    }
+    if (pMsgHdr)
+      *pMsgHdr = msgHdr;
+    else
+      msgHdr->Release();
+  }
+  // Referenced message not found, check if there are messages that reference same message
+  else if (UseCorrectThreading())
+  {
+	if (NS_SUCCEEDED(GetRefFromHash(msgID, &threadId)))
+	  thread = GetThreadForThreadId(threadId);
+  }
+
+  return thread;
+}
+
+nsIMsgThread *  nsMsgDatabase::GetThreadForSubject(nsCString &subject)
+{
+  nsIMsgThread *thread = nullptr;
+
+  mdbYarn  subjectYarn;
+
+  subjectYarn.mYarn_Buf = (void*)subject.get();
+  subjectYarn.mYarn_Fill = PL_strlen(subject.get());
+  subjectYarn.mYarn_Form = 0;
+  subjectYarn.mYarn_Size = subjectYarn.mYarn_Fill;
+
+  nsCOMPtr <nsIMdbRow>  threadRow;
+  mdbOid    outRowId;
+  if (m_mdbStore)
+  {
+    nsresult result = m_mdbStore->FindRow(GetEnv(), m_threadRowScopeToken,
+      m_threadSubjectColumnToken, &subjectYarn,  &outRowId, getter_AddRefs(threadRow));
+    if (NS_SUCCEEDED(result) && threadRow)
+    {
+      //Get key from row
+      mdbOid outOid;
+      nsMsgKey key = nsMsgKey_None;
+      if (NS_SUCCEEDED(threadRow->GetOid(GetEnv(), &outOid)))
+        key = outOid.mOid_Id;
+      // find thread header for header whose message id we matched.
+      // It is fine if key was not found,
+      // GetThreadForThreadId(nsMsgKey_None) returns nullptr.
+      thread = GetThreadForThreadId(key);
+    }
+#ifdef DEBUG_bienvenu1
+    else
+    {
+      nsresult  rv;
+      RefPtr<nsMsgThread> pThread;
+
+      nsCOMPtr <nsIMdbPortTableCursor> tableCursor;
+      m_mdbStore->GetPortTableCursor(GetEnv(), m_hdrRowScopeToken, m_threadTableKindToken,
+                                     getter_AddRefs(tableCursor));
+
+        nsCOMPtr<nsIMdbTable> table;
+
+        while (true)
+        {
+          rv = tableCursor->NextTable(GetEnv(), getter_AddRefs(table));
+          if (!table)
+            break;
+          if (NS_FAILED(rv))
+            break;
+
+          pThread = new nsMsgThread(this, table);
+          if (pThread)
+          {
+            nsCString curSubject;
+            pThread->GetSubject(curSubject);
+            if (subject.Equals(curSubject))
+            {
+              NS_ERROR("thread with subject exists, but FindRow didn't find it\n");
+              break;
+            }
+          }
+          else
+            break;
+        }
+      }
+#endif
+  }
+  return thread;
+}
+
+// Returns thread that contains a message that references the passed message ID
+nsIMsgThread *nsMsgDatabase::GetThreadForMessageId(nsCString &msgId)
+{
+  nsIMsgThread *thread = NULL;
+  nsMsgKey threadId;
+  
+  if (NS_SUCCEEDED(GetRefFromHash(msgId, &threadId)))
+    thread = GetThreadForThreadId(threadId);
+
+  return thread;
+}
+
+nsresult nsMsgDatabase::ThreadNewHdr(nsMsgHdr* newHdr, bool &newThread)
+{
+  nsresult result=NS_ERROR_UNEXPECTED;
+  nsCOMPtr <nsIMsgThread> thread;
+  nsCOMPtr <nsIMsgDBHdr> replyToHdr;
+  nsMsgKey threadId = nsMsgKey_None, newHdrKey;
+
+  if (!newHdr)
+    return NS_ERROR_NULL_POINTER;
+
+  newHdr->SetThreadParent(nsMsgKey_None); // if we're undoing, could have a thread parent
+  uint16_t numReferences = 0;
+  uint32_t newHdrFlags = 0;
+
+  // use raw flags instead of GetFlags, because GetFlags will
+  // pay attention to what's in m_newSet, and this new hdr isn't
+  // in m_newSet yet.
+  newHdr->GetRawFlags(&newHdrFlags);
+  newHdr->GetNumReferences(&numReferences);
+  newHdr->GetMessageKey(&newHdrKey);
+
+  // try reference threading first
+  for (int32_t i = numReferences - 1; i >= 0;  i--)
+  {
+    nsAutoCString reference;
+
+    newHdr->GetStringReference(i, reference);
+    // first reference we have hdr for is best top-level hdr.
+    // but we have to handle case of promoting new header to top-level
+    // in case the top-level header comes after a reply.
+
+    if (reference.IsEmpty())
+      break;
+
+    thread = dont_AddRef(GetThreadForReference(reference, getter_AddRefs(replyToHdr))) ;
+    if (thread)
+    {
+      if (replyToHdr)
+      {
+        nsMsgKey replyToKey;
+        replyToHdr->GetMessageKey(&replyToKey);
+        // message claims to be a reply to itself - ignore that since it leads to corrupt threading.
+        if (replyToKey == newHdrKey)
+        {
+          // bad references - throw them all away.
+          newHdr->SetMessageId("");
+          thread = nullptr;
+          break;
+        }
+      }
+      thread->GetThreadKey(&threadId);
+      newHdr->SetThreadId(threadId);
+      result = AddToThread(newHdr, thread, replyToHdr, true);
+      break;
+    }
+  }
+  // if user hasn't said "only thread by ref headers", thread by subject
+  if (!thread && !UseStrictThreading())
+  {
+    // try subject threading if we couldn't find a reference and the subject starts with Re:
+    nsCString subject;
+    newHdr->GetSubject(getter_Copies(subject));
+    if (ThreadBySubjectWithoutRe() || (newHdrFlags & nsMsgMessageFlags::HasRe))
+    {
+      nsAutoCString cSubject(subject);
+      thread = dont_AddRef(GetThreadForSubject(cSubject));
+      if(thread)
+      {
+        thread->GetThreadKey(&threadId);
+        newHdr->SetThreadId(threadId);
+        //TRACE("threading based on subject %s\n", (const char *) msgHdr->m_subject);
+        // if we move this and do subject threading after, ref threading,
+        // don't thread within children, since we know it won't work. But for now, pass TRUE.
+        result = AddToThread(newHdr, thread, nullptr, true);
+      }
+    }
+  }
+
+  // Check if this is a new parent to an existing message (that has a reference to this message)
+  if (!thread && UseCorrectThreading())
+  {
+    nsCString msgId;
+    newHdr->GetMessageId(getter_Copies(msgId));
+
+    thread = dont_AddRef(GetThreadForMessageId(msgId));
+    if (thread)
+    {
+      thread->GetThreadKey(&threadId);
+      newHdr->SetThreadId(threadId);
+      result = AddToThread(newHdr, thread, nullptr, true);
+    }
+  }
+
+  if (!thread)
+  {
+    // Not a parent or child, make it a new thread for now
+    result = AddNewThread(newHdr);
+    newThread = true;
+  }
+  else
+  {
+    newThread = false;
+  }
+  return result;
+}
+
+nsresult nsMsgDatabase::AddToThread(nsMsgHdr *newHdr, nsIMsgThread *thread, nsIMsgDBHdr *inReplyTo, bool threadInThread)
+{
+  // don't worry about real threading yet.
+  nsCOMPtr <nsIDBChangeAnnouncer> announcer = do_QueryInterface(this);
+
+  return thread->AddChild(newHdr, inReplyTo, threadInThread, announcer);
+}
+
+nsMsgHdr * nsMsgDatabase::GetMsgHdrForReference(nsCString &reference)
+{
+  NS_ASSERTION(false, "not implemented yet.");
+  return nullptr;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForMessageID(const char *aMsgID, nsIMsgDBHdr **aHdr)
+{
+  NS_ENSURE_ARG_POINTER(aHdr);
+  NS_ENSURE_ARG_POINTER(aMsgID);
+  nsIMsgDBHdr  *msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn  messageIdYarn;
+
+  messageIdYarn.mYarn_Buf = (void *) aMsgID;
+  messageIdYarn.mYarn_Fill = PL_strlen(aMsgID);
+  messageIdYarn.mYarn_Form = 0;
+  messageIdYarn.mYarn_Size = messageIdYarn.mYarn_Fill;
+
+  nsIMdbRow *hdrRow;
+  mdbOid outRowId;
+  nsresult result;
+  if (m_mdbStore)
+    result = m_mdbStore->FindRow(GetEnv(), m_hdrRowScopeToken,
+      m_messageIdColumnToken, &messageIdYarn,  &outRowId,
+      &hdrRow);
+  else
+    return NS_ERROR_FAILURE;
+  if (NS_SUCCEEDED(result) && hdrRow)
+  {
+    //Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    if (NS_WARN_IF(NS_FAILED(rv)))
+      return rv;
+    key = outOid.mOid_Id;
+
+    rv = GetHdrFromUseCache(key, &msgHdr);
+    if (NS_SUCCEEDED(rv) && msgHdr)
+      hdrRow->Release();
+    else {
+      rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+      if (NS_WARN_IF(NS_FAILED(rv)))
+        return rv;
+    }
+  }
+  *aHdr = msgHdr; // already addreffed above.
+  return NS_OK; // it's not an error not to find a msg hdr.
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgHdrForGMMsgID(const char *aGMMsgId, nsIMsgDBHdr **aHdr)
+{
+  NS_ENSURE_ARG_POINTER(aGMMsgId);
+  NS_ENSURE_ARG_POINTER(aHdr);
+  nsIMsgDBHdr *msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn gMailMessageIdYarn;
+  gMailMessageIdYarn.mYarn_Buf = (void *) aGMMsgId;
+  gMailMessageIdYarn.mYarn_Fill = strlen(aGMMsgId);
+  gMailMessageIdYarn.mYarn_Form = 0;
+  gMailMessageIdYarn.mYarn_Size = gMailMessageIdYarn.mYarn_Fill;
+
+  nsIMdbRow *hdrRow;
+  mdbOid outRowId;
+  nsresult result;
+  mdb_token property_token;
+  NS_ENSURE_TRUE(m_mdbStore, NS_ERROR_NULL_POINTER);
+  result = m_mdbStore->StringToToken(GetEnv(), "X-GM-MSGID",
+    &property_token);
+  NS_ENSURE_SUCCESS(result, result);
+  result = m_mdbStore->FindRow(GetEnv(), m_hdrRowScopeToken,
+    property_token, &gMailMessageIdYarn, &outRowId, &hdrRow);
+  if (NS_SUCCEEDED(result) && hdrRow)
+  {
+    // Get key from row
+    mdbOid outOid;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsMsgKey key = outOid.mOid_Id;
+    rv = GetHdrFromUseCache(key, &msgHdr);
+    if ((NS_SUCCEEDED(rv) && msgHdr))
+      hdrRow->Release();
+    else {
+      rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+      if (NS_WARN_IF(NS_FAILED(rv)))
+        return rv;
+    }
+  }
+  *aHdr = msgHdr;
+  return NS_OK; // it's not an error not to find a msg hdr.
+}
+
+nsIMsgDBHdr *nsMsgDatabase::GetMsgHdrForSubject(nsCString &subject)
+{
+  nsIMsgDBHdr *msgHdr = nullptr;
+  nsresult rv = NS_OK;
+  mdbYarn subjectYarn;
+
+  subjectYarn.mYarn_Buf = (void*)subject.get();
+  subjectYarn.mYarn_Fill = PL_strlen(subject.get());
+  subjectYarn.mYarn_Form = 0;
+  subjectYarn.mYarn_Size = subjectYarn.mYarn_Fill;
+
+  nsIMdbRow *hdrRow;
+  mdbOid outRowId;
+  nsresult result = GetStore()->FindRow(GetEnv(), m_hdrRowScopeToken,
+    m_subjectColumnToken, &subjectYarn,  &outRowId,
+    &hdrRow);
+  if (NS_SUCCEEDED(result) && hdrRow)
+  {
+    //Get key from row
+    mdbOid outOid;
+    nsMsgKey key = nsMsgKey_None;
+    rv = hdrRow->GetOid(GetEnv(), &outOid);
+    if (NS_WARN_IF(NS_FAILED(rv)))
+      return nullptr;
+    key = outOid.mOid_Id;
+
+    rv = GetHdrFromUseCache(key, &msgHdr);
+    if (NS_SUCCEEDED(rv) && msgHdr)
+      hdrRow->Release();
+    else {
+      rv = CreateMsgHdr(hdrRow, key, &msgHdr);
+      if (NS_WARN_IF(NS_FAILED(rv)))
+        return nullptr;
+    }
+  }
+  return msgHdr;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetThreadContainingMsgHdr(nsIMsgDBHdr *msgHdr, nsIMsgThread **result)
+{
+  NS_ENSURE_ARG_POINTER(msgHdr);
+  NS_ENSURE_ARG_POINTER(result);
+
+  *result = nullptr;
+  nsMsgKey threadId = nsMsgKey_None;
+  (void)msgHdr->GetThreadId(&threadId);
+  if (threadId != nsMsgKey_None)
+    *result = GetThreadForThreadId(threadId);
+
+  // if we can't find the thread, try using the msg key as the thread id,
+  // because the msg hdr might not have the thread id set correctly
+  // Or maybe the message was deleted?
+  if (!*result)
+  {
+    nsMsgKey msgKey;
+    msgHdr->GetMessageKey(&msgKey);
+    *result = GetThreadForThreadId(msgKey);
+  }
+  // failure is normal when message was deleted
+  return (*result) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+
+nsresult nsMsgDatabase::GetThreadForMsgKey(nsMsgKey msgKey, nsIMsgThread **aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  nsCOMPtr <nsIMsgDBHdr> msg;
+  nsresult rv = GetMsgHdrForKey(msgKey, getter_AddRefs(msg));
+
+  if (NS_SUCCEEDED(rv) && msg)
+    rv = GetThreadContainingMsgHdr(msg, aResult);
+
+  return rv;
+}
+
+// caller needs to unrefer.
+nsIMsgThread *  nsMsgDatabase::GetThreadForThreadId(nsMsgKey threadId)
+{
+
+  nsIMsgThread *retThread = (threadId == m_cachedThreadId && m_cachedThread) ?
+    m_cachedThread.get() : FindExistingThread(threadId);
+  if (retThread)
+  {
+    NS_ADDREF(retThread);
+    return retThread;
+  }
+  if (m_mdbStore)
+  {
+    mdbOid tableId;
+    tableId.mOid_Id = threadId;
+    tableId.mOid_Scope = m_hdrRowScopeToken;
+
+    nsCOMPtr<nsIMdbTable> threadTable;
+    nsresult res = m_mdbStore->GetTable(GetEnv(), &tableId,
+                                        getter_AddRefs(threadTable));
+
+    if (NS_SUCCEEDED(res) && threadTable)
+    {
+      retThread = new nsMsgThread(this, threadTable);
+      if (retThread)
+      {
+        NS_ADDREF(retThread);
+        m_cachedThread = retThread;
+        m_cachedThreadId = threadId;
+      }
+    }
+  }
+  return retThread;
+}
+
+// make the passed in header a thread header
+nsresult nsMsgDatabase::AddNewThread(nsMsgHdr *msgHdr)
+{
+
+  if (!msgHdr)
+    return NS_ERROR_NULL_POINTER;
+
+  nsMsgThread *threadHdr = nullptr;
+
+  nsCString subject;
+  nsMsgKey threadKey = msgHdr->m_messageKey;
+  // can't have a thread with key 1 since that's the table id of the all msg hdr table,
+  // so give it kTableKeyForThreadOne (0xfffffffe).
+  if (threadKey == kAllMsgHdrsTableKey)
+    threadKey = kTableKeyForThreadOne;
+
+  nsresult err = msgHdr->GetSubject(getter_Copies(subject));
+
+  err = CreateNewThread(threadKey, subject.get(), &threadHdr);
+  msgHdr->SetThreadId(threadKey);
+  if (threadHdr)
+  {
+    threadHdr->AddRef();
+    // err = msgHdr->GetSubject(subject);
+    // threadHdr->SetThreadKey(msgHdr->m_messageKey);
+    // threadHdr->SetSubject(subject.get());
+    // need to add the thread table to the db.
+    AddToThread(msgHdr, threadHdr, nullptr, false);
+    threadHdr->Release();
+  }
+  return err;
+}
+
+nsresult nsMsgDatabase::GetBoolPref(const char *prefName, bool *result)
+{
+  bool prefValue = false;
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> pPrefBranch(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  if (pPrefBranch)
+  {
+    rv = pPrefBranch->GetBoolPref(prefName, &prefValue);
+    *result = prefValue;
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::GetIntPref(const char *prefName, int32_t *result)
+{
+  int32_t prefValue = 0;
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> pPrefBranch(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
+  if (pPrefBranch)
+  {
+    rv = pPrefBranch->GetIntPref(prefName, &prefValue);
+    *result = prefValue;
+  }
+  return rv;
+}
+
+
+nsresult nsMsgDatabase::ListAllThreads(nsTArray<nsMsgKey> *threadIds)
+{
+  nsresult rv;
+  nsMsgThread *pThread;
+
+  nsCOMPtr <nsISimpleEnumerator> threads;
+  rv = EnumerateThreads(getter_AddRefs(threads));
+  if (NS_FAILED(rv)) return rv;
+  bool hasMore = false;
+
+  while (NS_SUCCEEDED(rv = threads->HasMoreElements(&hasMore)) && hasMore)
+  {
+    rv = threads->GetNext((nsISupports**)&pThread);
+    NS_ENSURE_SUCCESS(rv,rv);
+
+    if (threadIds) {
+      nsMsgKey key;
+      (void)pThread->GetThreadKey(&key);
+      threadIds->AppendElement(key);
+    }
+    // NS_RELEASE(pThread);
+    pThread = nullptr;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetAttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr, const char *property,
+                                  const char *propertyVal)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetUint32AttributeOnPendingHdr(nsIMsgDBHdr *pendingHdr, const char *property,
+                                  uint32_t propertyVal)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::SetUint64AttributeOnPendingHdr(nsIMsgDBHdr *aPendingHdr,
+                                              const char *aProperty,
+                                              uint64_t aPropertyVal)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::UpdatePendingAttributes(nsIMsgDBHdr *aNewHdr)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetOfflineOpForKey(nsMsgKey msgKey, bool create, nsIMsgOfflineImapOperation **offlineOp)
+{
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP  nsMsgDatabase::RemoveOfflineOp(nsIMsgOfflineImapOperation *op)
+{
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineMsgs(nsIMsgKeyArray *aKeys)
+{
+  NS_ENSURE_ARG_POINTER(aKeys);
+  nsCOMPtr <nsISimpleEnumerator> enumerator;
+  uint32_t flag = nsMsgMessageFlags::Offline;
+  // if we change this routine to return an enumerator that generates the keys
+  // one by one, we'll need to somehow make a copy of flag for the enumerator
+  // to own, since the enumerator will persist past the life of flag on the stack.
+  nsresult rv = EnumerateMessagesWithFlag(getter_AddRefs(enumerator), &flag);
+  if (NS_SUCCEEDED(rv) && enumerator)
+  {
+    bool hasMoreElements;
+    while(NS_SUCCEEDED(enumerator->HasMoreElements(&hasMoreElements)) && hasMoreElements)
+    {
+      nsCOMPtr<nsISupports> childSupports;
+      rv = enumerator->GetNext(getter_AddRefs(childSupports));
+      if(NS_FAILED(rv))
+        return rv;
+
+      // clear out db hdr, because it won't be valid when we get rid of the .msf file
+      nsCOMPtr<nsIMsgDBHdr> dbMessage(do_QueryInterface(childSupports, &rv));
+      if(NS_SUCCEEDED(rv) && dbMessage)
+      {
+        nsMsgKey msgKey;
+        dbMessage->GetMessageKey(&msgKey);
+        aKeys->AppendElement(msgKey);
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgDatabase::EnumerateOfflineOps(nsISimpleEnumerator **enumerator)
+{
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineOpIds(nsTArray<nsMsgKey> *offlineOpIds)
+{
+  NS_ASSERTION(false, "overridden by nsMailDatabase");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ListAllOfflineDeletes(nsTArray<nsMsgKey> *offlineDeletes)
+{
+  nsresult ret = NS_OK;
+  if (!offlineDeletes)
+    return NS_ERROR_NULL_POINTER;
+
+  // technically, notimplemented, but no one's putting offline ops in anyway.
+  return ret;
+}
+NS_IMETHODIMP nsMsgDatabase::GetHighWaterArticleNum(nsMsgKey *key)
+{
+  if (!m_dbFolderInfo)
+    return NS_ERROR_NULL_POINTER;
+  return m_dbFolderInfo->GetHighWater(key);
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetLowWaterArticleNum(nsMsgKey *key)
+{
+    return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* attribute nsMsgKey NextPseudoMsgKey */
+
+NS_IMETHODIMP nsMsgDatabase::GetNextPseudoMsgKey(nsMsgKey *nextPseudoMsgKey)
+{
+  NS_ENSURE_ARG_POINTER(nextPseudoMsgKey);
+  *nextPseudoMsgKey = m_nextPseudoMsgKey--;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetNextPseudoMsgKey(nsMsgKey nextPseudoMsgKey)
+{
+  m_nextPseudoMsgKey = nextPseudoMsgKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetNextFakeOfflineMsgKey(nsMsgKey *nextFakeOfflineMsgKey)
+{
+  NS_ENSURE_ARG_POINTER(nextFakeOfflineMsgKey);
+  // iterate over hdrs looking for first non-existant fake offline msg key
+  nsMsgKey fakeMsgKey = kIdStartOfFake;
+
+  bool containsKey;
+  do
+  {
+     ContainsKey(fakeMsgKey, &containsKey);
+     if (!containsKey)
+       break;
+     fakeMsgKey--;
+  }
+  while (containsKey);
+
+  *nextFakeOfflineMsgKey = fakeMsgKey;
+  return NS_OK;
+}
+
+#ifdef DEBUG
+nsresult nsMsgDatabase::DumpContents()
+{
+  nsMsgKey key;
+  uint32_t i;
+
+  RefPtr<nsMsgKeyArray> keys = new nsMsgKeyArray;
+  if (!keys)
+    return NS_ERROR_OUT_OF_MEMORY;
+  nsresult rv = ListAllKeys(keys);
+  uint32_t numKeys;
+  keys->GetLength(&numKeys);
+  for (i = 0; i < numKeys; i++) {
+    key = keys->m_keys[i];
+    nsIMsgDBHdr *msg = NULL;
+    rv = GetMsgHdrForKey(key, &msg);
+    nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(msg);      // closed system, cast ok
+    if (NS_SUCCEEDED(rv))
+    {
+      nsCString author;
+      nsCString subject;
+
+      msgHdr->GetMessageKey(&key);
+      msgHdr->GetAuthor(getter_Copies(author));
+      msgHdr->GetSubject(getter_Copies(subject));
+      printf("hdr key = %u, author = %s subject = %s\n", key, author.get(), subject.get());
+      NS_RELEASE(msgHdr);
+    }
+  }
+  nsTArray<nsMsgKey> threads;
+  rv = ListAllThreads(&threads);
+  for ( i = 0; i < threads.Length(); i++)
+  {
+    key = threads[i];
+    printf("thread key = %u\n", key);
+    // DumpThread(key);
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::DumpMsgChildren(nsIMsgDBHdr *msgHdr)
+{
+  return NS_OK;
+}
+
+nsresult nsMsgDatabase::DumpThread(nsMsgKey threadId)
+{
+  nsresult rv = NS_OK;
+  nsIMsgThread *thread = nullptr;
+
+  thread = GetThreadForThreadId(threadId);
+  if (thread)
+  {
+    nsISimpleEnumerator *enumerator = nullptr;
+
+    rv = thread->EnumerateMessages(nsMsgKey_None, &enumerator);
+    if (NS_SUCCEEDED(rv) && enumerator)
+    {
+      bool hasMore = false;
+
+      while (NS_SUCCEEDED(rv = enumerator->HasMoreElements(&hasMore)) &&
+             hasMore)
+      {
+        nsCOMPtr <nsISupports> supports;
+        rv = enumerator->GetNext(getter_AddRefs(supports));
+        NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+        nsCOMPtr <nsIMsgDBHdr> pMessage = do_QueryInterface(supports);
+        if (NS_FAILED(rv) || !pMessage)
+          break;
+      }
+      NS_RELEASE(enumerator);
+
+    }
+  }
+  return rv;
+}
+#endif /* DEBUG */
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgRetentionSettings(nsIMsgRetentionSettings *retentionSettings)
+{
+  m_retentionSettings = retentionSettings;
+  if (retentionSettings && m_dbFolderInfo)
+  {
+    nsresult rv;
+
+    nsMsgRetainByPreference retainByPreference;
+    uint32_t daysToKeepHdrs;
+    uint32_t numHeadersToKeep;
+    uint32_t daysToKeepBodies;
+    bool cleanupBodiesByDays;
+    bool useServerDefaults;
+    bool applyToFlaggedMessages;
+
+    rv = retentionSettings->GetRetainByPreference(&retainByPreference);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetDaysToKeepHdrs(&daysToKeepHdrs);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetNumHeadersToKeep(&numHeadersToKeep);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = retentionSettings->GetDaysToKeepBodies(&daysToKeepBodies);
+    NS_ENSURE_SUCCESS(rv, rv);
+    (void) retentionSettings->GetCleanupBodiesByDays(&cleanupBodiesByDays);
+    (void) retentionSettings->GetUseServerDefaults(&useServerDefaults);
+    rv = retentionSettings->GetApplyToFlaggedMessages(&applyToFlaggedMessages);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // need to write this to the db. We'll just use the dbfolderinfo to write properties.
+    m_dbFolderInfo->SetUint32Property("retainBy", retainByPreference);
+    m_dbFolderInfo->SetUint32Property("daysToKeepHdrs", daysToKeepHdrs);
+    m_dbFolderInfo->SetUint32Property("numHdrsToKeep", numHeadersToKeep);
+    m_dbFolderInfo->SetUint32Property("daysToKeepBodies", daysToKeepBodies);
+    m_dbFolderInfo->SetBooleanProperty("cleanupBodies", cleanupBodiesByDays);
+    m_dbFolderInfo->SetBooleanProperty("useServerDefaults", useServerDefaults);
+    m_dbFolderInfo->SetBooleanProperty("applyToFlaggedMessages", applyToFlaggedMessages);
+  }
+  Commit(nsMsgDBCommitType::kLargeCommit);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgRetentionSettings(nsIMsgRetentionSettings **retentionSettings)
+{
+  NS_ENSURE_ARG_POINTER(retentionSettings);
+  if (!m_retentionSettings)
+  {
+    // create a new one, and initialize it from the db.
+    m_retentionSettings = new nsMsgRetentionSettings;
+    if (m_retentionSettings && m_dbFolderInfo)
+    {
+      nsMsgRetainByPreference retainByPreference;
+      uint32_t daysToKeepHdrs = 0;
+      uint32_t numHeadersToKeep = 0;
+      bool useServerDefaults;
+      uint32_t daysToKeepBodies = 0;
+      bool cleanupBodiesByDays = false;
+      bool applyToFlaggedMessages;
+
+      m_dbFolderInfo->GetUint32Property("retainBy", nsIMsgRetentionSettings::nsMsgRetainAll, &retainByPreference);
+      m_dbFolderInfo->GetUint32Property("daysToKeepHdrs", 0, &daysToKeepHdrs);
+      m_dbFolderInfo->GetUint32Property("numHdrsToKeep", 0, &numHeadersToKeep);
+      m_dbFolderInfo->GetUint32Property("daysToKeepBodies", 0, &daysToKeepBodies);
+      m_dbFolderInfo->GetBooleanProperty("useServerDefaults", true, &useServerDefaults);
+      m_dbFolderInfo->GetBooleanProperty("cleanupBodies", false, &cleanupBodiesByDays);
+      m_dbFolderInfo->GetBooleanProperty("applyToFlaggedMessages", false,
+                                         &applyToFlaggedMessages);
+      m_retentionSettings->SetRetainByPreference(retainByPreference);
+      m_retentionSettings->SetDaysToKeepHdrs(daysToKeepHdrs);
+      m_retentionSettings->SetNumHeadersToKeep(numHeadersToKeep);
+      m_retentionSettings->SetDaysToKeepBodies(daysToKeepBodies);
+      m_retentionSettings->SetUseServerDefaults(useServerDefaults);
+      m_retentionSettings->SetCleanupBodiesByDays(cleanupBodiesByDays);
+      m_retentionSettings->SetApplyToFlaggedMessages(applyToFlaggedMessages);
+    }
+  }
+  *retentionSettings = m_retentionSettings;
+  NS_IF_ADDREF(*retentionSettings);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::SetMsgDownloadSettings(nsIMsgDownloadSettings *downloadSettings)
+{
+  m_downloadSettings = downloadSettings;
+  if (downloadSettings && m_dbFolderInfo)
+  {
+    nsresult rv;
+
+    bool useServerDefaults;
+    bool downloadByDate;
+    uint32_t ageLimitOfMsgsToDownload;
+    bool downloadUnreadOnly;
+
+    rv = downloadSettings->GetUseServerDefaults(&useServerDefaults);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetDownloadByDate(&downloadByDate);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetDownloadUnreadOnly(&downloadUnreadOnly);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = downloadSettings->GetAgeLimitOfMsgsToDownload(&ageLimitOfMsgsToDownload);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // need to write this to the db. We'll just use the dbfolderinfo to write properties.
+    m_dbFolderInfo->SetBooleanProperty("useServerDefaults", useServerDefaults);
+    m_dbFolderInfo->SetBooleanProperty("downloadByDate", downloadByDate);
+    m_dbFolderInfo->SetBooleanProperty("downloadUnreadOnly", downloadUnreadOnly);
+    m_dbFolderInfo->SetUint32Property("ageLimit", ageLimitOfMsgsToDownload);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetMsgDownloadSettings(nsIMsgDownloadSettings **downloadSettings)
+{
+  NS_ENSURE_ARG_POINTER(downloadSettings);
+  if (!m_downloadSettings)
+  {
+    // create a new one, and initialize it from the db.
+    m_downloadSettings = new nsMsgDownloadSettings;
+    if (m_downloadSettings && m_dbFolderInfo)
+    {
+      bool useServerDefaults;
+      bool downloadByDate;
+      uint32_t ageLimitOfMsgsToDownload;
+      bool downloadUnreadOnly;
+
+      m_dbFolderInfo->GetBooleanProperty("useServerDefaults", true, &useServerDefaults);
+      m_dbFolderInfo->GetBooleanProperty("downloadByDate", false, &downloadByDate);
+      m_dbFolderInfo->GetBooleanProperty("downloadUnreadOnly", false, &downloadUnreadOnly);
+      m_dbFolderInfo->GetUint32Property("ageLimit", 0, &ageLimitOfMsgsToDownload);
+
+      m_downloadSettings->SetUseServerDefaults(useServerDefaults);
+      m_downloadSettings->SetDownloadByDate(downloadByDate);
+      m_downloadSettings->SetDownloadUnreadOnly(downloadUnreadOnly);
+      m_downloadSettings->SetAgeLimitOfMsgsToDownload(ageLimitOfMsgsToDownload);
+    }
+  }
+  *downloadSettings = m_downloadSettings;
+  NS_IF_ADDREF(*downloadSettings);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ApplyRetentionSettings(nsIMsgRetentionSettings *aMsgRetentionSettings,
+                                                    bool aDeleteViaFolder)
+{
+  NS_ENSURE_ARG_POINTER(aMsgRetentionSettings);
+  nsresult rv = NS_OK;
+
+  if (!m_folder)
+    return NS_ERROR_NULL_POINTER;
+
+  bool isDraftsTemplatesOutbox;
+  uint32_t dtoFlags = nsMsgFolderFlags::Drafts | nsMsgFolderFlags::Templates |
+                        nsMsgFolderFlags::Queue;
+  (void) m_folder->IsSpecialFolder(dtoFlags, true, &isDraftsTemplatesOutbox);
+  // Never apply retention settings to Drafts/Templates/Outbox.
+  if (isDraftsTemplatesOutbox)
+    return NS_OK;
+
+  nsCOMPtr <nsIMutableArray> msgHdrsToDelete;
+  if (aDeleteViaFolder)
+  {
+    msgHdrsToDelete = do_CreateInstance(NS_ARRAY_CONTRACTID, &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  nsMsgRetainByPreference retainByPreference;
+  aMsgRetentionSettings->GetRetainByPreference(&retainByPreference);
+
+  bool applyToFlaggedMessages = false;
+  aMsgRetentionSettings->GetApplyToFlaggedMessages(&applyToFlaggedMessages);
+
+  uint32_t daysToKeepHdrs = 0;
+  uint32_t numHeadersToKeep = 0;
+  switch (retainByPreference)
+  {
+  case nsIMsgRetentionSettings::nsMsgRetainAll:
+    break;
+  case nsIMsgRetentionSettings::nsMsgRetainByAge:
+    aMsgRetentionSettings->GetDaysToKeepHdrs(&daysToKeepHdrs);
+    rv = PurgeMessagesOlderThan(daysToKeepHdrs,
+                                applyToFlaggedMessages, msgHdrsToDelete);
+    break;
+  case nsIMsgRetentionSettings::nsMsgRetainByNumHeaders:
+    aMsgRetentionSettings->GetNumHeadersToKeep(&numHeadersToKeep);
+    rv = PurgeExcessMessages(numHeadersToKeep,
+                             applyToFlaggedMessages, msgHdrsToDelete);
+    break;
+  }
+  if (m_folder)
+  {
+    // update the time we attempted to purge this folder
+    char dateBuf[100];
+    dateBuf[0] = '\0';
+    PRExplodedTime exploded;
+    PR_ExplodeTime(PR_Now(), PR_LocalTimeParameters, &exploded);
+    PR_FormatTimeUSEnglish(dateBuf, sizeof(dateBuf), "%a %b %d %H:%M:%S %Y", &exploded);
+    m_folder->SetStringProperty("LastPurgeTime", nsDependentCString(dateBuf));
+  }
+  if (msgHdrsToDelete)
+  {
+    uint32_t count;
+    msgHdrsToDelete->GetLength(&count);
+    if (count > 0)
+      rv = m_folder->DeleteMessages(msgHdrsToDelete, nullptr, true, false, nullptr, false);
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::PurgeMessagesOlderThan(uint32_t daysToKeepHdrs,
+                                               bool applyToFlaggedMessages,
+                                               nsIMutableArray *hdrsToDelete)
+{
+  nsresult rv = NS_OK;
+  nsMsgHdr *pHeader;
+  nsCOMPtr <nsISimpleEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  nsTArray<nsMsgKey> keysToDelete;
+
+  if (NS_FAILED(rv))
+    return rv;
+  bool hasMore = false;
+
+  PRTime cutOffDay = PR_Now() - daysToKeepHdrs * PR_USEC_PER_DAY;
+
+  // so now cutOffDay is the PRTime cut-off point. Any msg with a date less than that will get purged.
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore)
+  {
+    bool purgeHdr = false;
+
+    rv = hdrs->GetNext((nsISupports**)&pHeader);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    if (NS_FAILED(rv))
+      break;
+
+    if (!applyToFlaggedMessages)
+    {
+      uint32_t flags;
+      (void)pHeader->GetFlags(&flags);
+      if (flags & nsMsgMessageFlags::Marked)
+        continue;
+    }
+
+    if (!purgeHdr)
+    {
+      PRTime date;
+      pHeader->GetDate(&date);
+      if (date < cutOffDay)
+        purgeHdr = true;
+    }
+    if (purgeHdr)
+    {
+      nsMsgKey msgKey;
+      pHeader->GetMessageKey(&msgKey);
+      keysToDelete.AppendElement(msgKey);
+      if (hdrsToDelete)
+        hdrsToDelete->AppendElement(pHeader, false);
+    }
+    NS_RELEASE(pHeader);
+  }
+
+  if (!hdrsToDelete)
+  {
+    DeleteMessages(keysToDelete.Length(), keysToDelete.Elements(), nullptr);
+
+    if (keysToDelete.Length() > 10) // compress commit if we deleted more than 10
+      Commit(nsMsgDBCommitType::kCompressCommit);
+    else if (!keysToDelete.IsEmpty())
+      Commit(nsMsgDBCommitType::kLargeCommit);
+  }
+  return rv;
+}
+
+nsresult nsMsgDatabase::PurgeExcessMessages(uint32_t numHeadersToKeep,
+                                            bool applyToFlaggedMessages,
+                                            nsIMutableArray *hdrsToDelete)
+{
+  nsresult rv = NS_OK;
+  nsMsgHdr    *pHeader;
+  nsCOMPtr <nsISimpleEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv))
+    return rv;
+  bool hasMore = false;
+  nsTArray<nsMsgKey> keysToDelete;
+
+  mdb_count numHdrs = 0;
+  if (m_mdbAllMsgHeadersTable)
+    m_mdbAllMsgHeadersTable->GetCount(GetEnv(), &numHdrs);
+  else
+    return NS_ERROR_NULL_POINTER;
+
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore)
+  {
+    bool purgeHdr = false;
+    rv = hdrs->GetNext((nsISupports**)&pHeader);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+    if (NS_FAILED(rv))
+      break;
+
+    if (!applyToFlaggedMessages)
+    {
+      uint32_t flags;
+      (void)pHeader->GetFlags(&flags);
+      if (flags & nsMsgMessageFlags::Marked)
+        continue;
+    }
+
+    // this isn't quite right - we want to prefer unread messages (keep all of those we can)
+    if (numHdrs > numHeadersToKeep)
+      purgeHdr = true;
+
+    if (purgeHdr)
+    {
+      nsMsgKey msgKey;
+      pHeader->GetMessageKey(&msgKey);
+      keysToDelete.AppendElement(msgKey);
+      numHdrs--;
+      if (hdrsToDelete)
+        hdrsToDelete->AppendElement(pHeader, false);
+    }
+    NS_RELEASE(pHeader);
+  }
+
+  if (!hdrsToDelete)
+  {
+    int32_t numKeysToDelete = keysToDelete.Length();
+    if (numKeysToDelete > 0)
+    {
+      DeleteMessages(keysToDelete.Length(), keysToDelete.Elements(), nullptr);
+      if (numKeysToDelete > 10)  // compress commit if we deleted more than 10
+        Commit(nsMsgDBCommitType::kCompressCommit);
+      else
+        Commit(nsMsgDBCommitType::kLargeCommit);
+    }
+  }
+  return rv;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgRetentionSettings, nsIMsgRetentionSettings)
+
+// Initialise the member variables to resonable defaults.
+nsMsgRetentionSettings::nsMsgRetentionSettings()
+: m_retainByPreference(1),
+  m_daysToKeepHdrs(0),
+  m_numHeadersToKeep(0),
+  m_useServerDefaults(true),
+  m_cleanupBodiesByDays(false),
+  m_daysToKeepBodies(0),
+  m_applyToFlaggedMessages(false)
+{
+}
+
+nsMsgRetentionSettings::~nsMsgRetentionSettings()
+{
+}
+
+/* attribute unsigned long retainByPreference */
+
+NS_IMETHODIMP nsMsgRetentionSettings::GetRetainByPreference(nsMsgRetainByPreference *retainByPreference)
+{
+  NS_ENSURE_ARG_POINTER(retainByPreference);
+  *retainByPreference = m_retainByPreference;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgRetentionSettings::SetRetainByPreference(nsMsgRetainByPreference retainByPreference)
+{
+  m_retainByPreference = retainByPreference;
+  return NS_OK;
+}
+
+/* attribute long daysToKeepHdrs; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetDaysToKeepHdrs(uint32_t *aDaysToKeepHdrs)
+{
+  NS_ENSURE_ARG_POINTER(aDaysToKeepHdrs);
+  *aDaysToKeepHdrs = m_daysToKeepHdrs;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgRetentionSettings::SetDaysToKeepHdrs(uint32_t aDaysToKeepHdrs)
+{
+  m_daysToKeepHdrs = aDaysToKeepHdrs;
+  return NS_OK;
+}
+
+/* attribute long numHeadersToKeep; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetNumHeadersToKeep(uint32_t *aNumHeadersToKeep)
+{
+  NS_ENSURE_ARG_POINTER(aNumHeadersToKeep);
+  *aNumHeadersToKeep = m_numHeadersToKeep;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetNumHeadersToKeep(uint32_t aNumHeadersToKeep)
+{
+  m_numHeadersToKeep = aNumHeadersToKeep;
+  return NS_OK;
+}
+/* attribute boolean useServerDefaults; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetUseServerDefaults(bool *aUseServerDefaults)
+{
+  NS_ENSURE_ARG_POINTER(aUseServerDefaults);
+  *aUseServerDefaults = m_useServerDefaults;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetUseServerDefaults(bool aUseServerDefaults)
+{
+  m_useServerDefaults = aUseServerDefaults;
+  return NS_OK;
+}
+
+/* attribute boolean cleanupBodiesByDays; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetCleanupBodiesByDays(bool *aCleanupBodiesByDays)
+{
+  NS_ENSURE_ARG_POINTER(aCleanupBodiesByDays);
+  *aCleanupBodiesByDays = m_cleanupBodiesByDays;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetCleanupBodiesByDays(bool aCleanupBodiesByDays)
+{
+  m_cleanupBodiesByDays = aCleanupBodiesByDays;
+  return NS_OK;
+}
+
+/* attribute long daysToKeepBodies; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetDaysToKeepBodies(uint32_t *aDaysToKeepBodies)
+{
+  NS_ENSURE_ARG_POINTER(aDaysToKeepBodies);
+  *aDaysToKeepBodies = m_daysToKeepBodies;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetDaysToKeepBodies(uint32_t aDaysToKeepBodies)
+{
+  m_daysToKeepBodies = aDaysToKeepBodies;
+  return NS_OK;
+}
+
+/* attribute boolean applyToFlaggedMessages; */
+NS_IMETHODIMP nsMsgRetentionSettings::GetApplyToFlaggedMessages(bool *aApplyToFlaggedMessages)
+{
+  NS_ENSURE_ARG_POINTER(aApplyToFlaggedMessages);
+  *aApplyToFlaggedMessages = m_applyToFlaggedMessages;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgRetentionSettings::SetApplyToFlaggedMessages(bool aApplyToFlaggedMessages)
+{
+  m_applyToFlaggedMessages = aApplyToFlaggedMessages;
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgDownloadSettings, nsIMsgDownloadSettings)
+
+nsMsgDownloadSettings::nsMsgDownloadSettings()
+{
+  m_useServerDefaults = false;
+  m_downloadUnreadOnly = false;
+  m_downloadByDate = false;
+  m_ageLimitOfMsgsToDownload = 0;
+}
+
+nsMsgDownloadSettings::~nsMsgDownloadSettings()
+{
+}
+
+/* attribute boolean useServerDefaults; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetUseServerDefaults(bool *aUseServerDefaults)
+{
+  NS_ENSURE_ARG_POINTER(aUseServerDefaults);
+  *aUseServerDefaults = m_useServerDefaults;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetUseServerDefaults(bool aUseServerDefaults)
+{
+  m_useServerDefaults = aUseServerDefaults;
+  return NS_OK;
+}
+
+
+/* attribute boolean downloadUnreadOnly; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetDownloadUnreadOnly(bool *aDownloadUnreadOnly)
+{
+  NS_ENSURE_ARG_POINTER(aDownloadUnreadOnly);
+  *aDownloadUnreadOnly = m_downloadUnreadOnly;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetDownloadUnreadOnly(bool aDownloadUnreadOnly)
+{
+  m_downloadUnreadOnly = aDownloadUnreadOnly;
+  return NS_OK;
+}
+
+/* attribute boolean downloadByDate; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetDownloadByDate(bool *aDownloadByDate)
+{
+  NS_ENSURE_ARG_POINTER(aDownloadByDate);
+  *aDownloadByDate = m_downloadByDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDownloadSettings::SetDownloadByDate(bool aDownloadByDate)
+{
+  m_downloadByDate = aDownloadByDate;
+  return NS_OK;
+}
+
+
+/* attribute long ageLimitOfMsgsToDownload; */
+NS_IMETHODIMP nsMsgDownloadSettings::GetAgeLimitOfMsgsToDownload(uint32_t *ageLimitOfMsgsToDownload)
+{
+  NS_ENSURE_ARG_POINTER(ageLimitOfMsgsToDownload);
+  *ageLimitOfMsgsToDownload = m_ageLimitOfMsgsToDownload;
+  return NS_OK;
+}
+NS_IMETHODIMP nsMsgDownloadSettings::SetAgeLimitOfMsgsToDownload(uint32_t ageLimitOfMsgsToDownload)
+{
+  m_ageLimitOfMsgsToDownload = ageLimitOfMsgsToDownload;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultViewFlags(nsMsgViewFlagsTypeValue *aDefaultViewFlags)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultViewFlags);
+  GetIntPref("mailnews.default_view_flags", aDefaultViewFlags);
+  if (*aDefaultViewFlags < nsMsgViewFlagsType::kNone ||
+      *aDefaultViewFlags > (nsMsgViewFlagsType::kThreadedDisplay |
+                            nsMsgViewFlagsType::kShowIgnored |
+                            nsMsgViewFlagsType::kUnreadOnly |
+                            nsMsgViewFlagsType::kExpandAll |
+                            nsMsgViewFlagsType::kGroupBySort))
+    *aDefaultViewFlags = nsMsgViewFlagsType::kNone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultSortType(nsMsgViewSortTypeValue *aDefaultSortType)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultSortType);
+  GetIntPref("mailnews.default_sort_type", aDefaultSortType);
+  if (*aDefaultSortType < nsMsgViewSortType::byDate ||
+      *aDefaultSortType > nsMsgViewSortType::byAccount)
+    *aDefaultSortType = nsMsgViewSortType::byDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::GetDefaultSortOrder(nsMsgViewSortOrderValue *aDefaultSortOrder)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultSortOrder);
+  GetIntPref("mailnews.default_sort_order", aDefaultSortOrder);
+  if (*aDefaultSortOrder != nsMsgViewSortOrder::descending)
+    *aDefaultSortOrder = nsMsgViewSortOrder::ascending;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::ResetHdrCacheSize(uint32_t aSize)
+{
+  if (m_cacheSize > aSize)
+  {
+    m_cacheSize = aSize;
+    ClearHdrCache(false);
+  }
+  return NS_OK;
+}
+
+/**
+  void getNewList(out unsigned long count, [array, size_is(count)] out long newKeys);
+ */
+NS_IMETHODIMP
+nsMsgDatabase::GetNewList(uint32_t *aCount, nsMsgKey **aNewKeys)
+{
+    NS_ENSURE_ARG_POINTER(aCount);
+    NS_ENSURE_ARG_POINTER(aNewKeys);
+
+    *aCount = m_newSet.Length();
+    if (*aCount > 0)
+    {
+      *aNewKeys = static_cast<nsMsgKey *>(moz_xmalloc(*aCount * sizeof(nsMsgKey)));
+      if (!*aNewKeys)
+        return NS_ERROR_OUT_OF_MEMORY;
+      memcpy(*aNewKeys, m_newSet.Elements(), *aCount * sizeof(nsMsgKey));
+      return NS_OK;
+    }
+    // if there were no new messages, signal this by returning a null pointer
+    //
+    *aNewKeys = nullptr;
+    return NS_OK;
+}
+
+nsresult nsMsgDatabase::GetSearchResultsTable(const char *searchFolderUri, bool createIfMissing, nsIMdbTable **table)
+{
+  mdb_kind kindToken;
+  mdb_count numTables;
+  mdb_bool mustBeUnique;
+  NS_ENSURE_TRUE(m_mdbStore, NS_ERROR_NULL_POINTER);
+
+  nsresult err = m_mdbStore->StringToToken(GetEnv(), searchFolderUri, &kindToken);
+  err = m_mdbStore->GetTableKind(GetEnv(), m_hdrRowScopeToken,  kindToken,
+                                  &numTables, &mustBeUnique, table);
+  if ((!*table || NS_FAILED(err)) && createIfMissing)
+    err = m_mdbStore->NewTable(GetEnv(), m_hdrRowScopeToken, kindToken, true, nullptr, table);
+
+  return *table ? err : NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsMsgDatabase::GetCachedHits(const char *aSearchFolderUri, nsISimpleEnumerator **aEnumerator)
+{
+  nsCOMPtr <nsIMdbTable> table;
+  (void) GetSearchResultsTable(aSearchFolderUri, false, getter_AddRefs(table));
+  if (!table)
+    return NS_ERROR_FAILURE; // expected result for no cached hits
+  nsMsgDBEnumerator* e = new nsMsgDBEnumerator(this, table, nullptr, nullptr);
+  if (e == nullptr)
+      return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(*aEnumerator = e);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgDatabase::RefreshCache(const char *aSearchFolderUri, uint32_t aNumKeys, nsMsgKey *aNewHits, uint32_t *aNumBadHits, nsMsgKey **aStaleHits)
+{
+  nsCOMPtr <nsIMdbTable> table;
+  nsresult err = GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  // update the table so that it just contains aNewHits.
+  // And, keep track of the headers in the original table but not in aNewHits, so we
+  // can put those in aStaleHits.
+  // both aNewHits and the db table are sorted by uid/key.
+  // So, start at the beginning of the table and the aNewHits array.
+  uint32_t newHitIndex = 0;
+  uint32_t tableRowIndex = 0;
+
+  uint32_t rowCount;
+  table->GetCount(GetEnv(), &rowCount);
+  nsTArray<nsMsgKey> staleHits;
+  // should assert that each array is sorted
+  while (newHitIndex < aNumKeys || tableRowIndex < rowCount)
+  {
+    mdbOid oid;
+    nsMsgKey tableRowKey = nsMsgKey_None;
+    if (tableRowIndex < rowCount)
+    {
+      nsresult ret = table->PosToOid (GetEnv(), tableRowIndex, &oid);
+      if (NS_FAILED(ret))
+      {
+        tableRowIndex++;
+        continue;
+      }
+      tableRowKey = oid.mOid_Id;  // ### TODO need the real key for the 0th key problem.
+    }
+
+    if (newHitIndex < aNumKeys && aNewHits[newHitIndex] == tableRowKey)
+    {
+      newHitIndex++;
+      tableRowIndex++;
+      continue;
+    }
+    else if (tableRowIndex >= rowCount || (newHitIndex < aNumKeys && aNewHits[newHitIndex] < tableRowKey))
+    {
+      nsCOMPtr <nsIMdbRow> hdrRow;
+      mdbOid rowObjectId;
+
+      rowObjectId.mOid_Id = aNewHits[newHitIndex];
+      rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+      err = m_mdbStore->GetRow(GetEnv(), &rowObjectId, getter_AddRefs(hdrRow));
+      if (hdrRow)
+      {
+        table->AddRow(GetEnv(), hdrRow);
+        mdb_pos newPos;
+        table->MoveRow(GetEnv(), hdrRow, rowCount, tableRowIndex, &newPos);
+        rowCount++;
+        tableRowIndex++;
+      }
+      newHitIndex++;
+      continue;
+    }
+    else if (newHitIndex >= aNumKeys || aNewHits[newHitIndex] > tableRowKey)
+    {
+      staleHits.AppendElement(tableRowKey);
+      table->CutOid(GetEnv(), &oid);
+      rowCount--;
+      continue; // don't increment tableRowIndex since we removed that row.
+    }
+   }
+   *aNumBadHits = staleHits.Length();
+   if (*aNumBadHits)
+   {
+     *aStaleHits = static_cast<nsMsgKey *>(moz_xmalloc(*aNumBadHits * sizeof(nsMsgKey)));
+     if (!*aStaleHits)
+       return NS_ERROR_OUT_OF_MEMORY;
+     memcpy(*aStaleHits, staleHits.Elements(), *aNumBadHits * sizeof(nsMsgKey));
+   }
+   else
+     *aStaleHits = nullptr;
+
+#ifdef DEBUG_David_Bienvenu
+  printf("after refreshing cache\n");
+  // iterate over table and assert that it's in id order
+  table->GetCount(GetEnv(), &rowCount);
+  mdbOid oid;
+  tableRowIndex = 0;
+  mdb_id prevId = 0;
+  while (tableRowIndex < rowCount)
+  {
+    nsresult ret = table->PosToOid (m_mdbEnv, tableRowIndex++, &oid);
+    if (tableRowIndex > 1 && oid.mOid_Id <= prevId)
+    {
+      NS_ASSERTION(false, "inserting row into cached hits table, not sorted correctly");
+      printf("key %lx is before or equal %lx\n", prevId, oid.mOid_Id);
+    }
+    prevId = oid.mOid_Id;
+  }
+
+#endif
+  Commit(nsMsgDBCommitType::kLargeCommit);
+  return NS_OK;
+}
+
+// search sorted table
+mdb_pos nsMsgDatabase::FindInsertIndexInSortedTable(nsIMdbTable *table, mdb_id idToInsert)
+{
+  mdb_pos searchPos = 0;
+  uint32_t rowCount;
+  table->GetCount(GetEnv(), &rowCount);
+  mdb_pos hi = rowCount;
+  mdb_pos lo = 0;
+
+  while (hi > lo)
+  {
+    mdbOid outOid;
+    searchPos = (lo + hi - 1) / 2;
+    table->PosToOid(GetEnv(), searchPos, &outOid);
+    if (outOid.mOid_Id == idToInsert)
+    {
+      NS_ASSERTION(false, "id shouldn't be in table");
+      return hi;
+    }
+    if (outOid.mOid_Id > idToInsert)
+      hi = searchPos;
+    else // if (outOid.mOid_Id <  idToInsert)
+      lo = searchPos + 1;
+  }
+  return hi;
+}
+NS_IMETHODIMP
+nsMsgDatabase::UpdateHdrInCache(const char *aSearchFolderUri, nsIMsgDBHdr *aHdr, bool aAdd)
+{
+  nsCOMPtr <nsIMdbTable> table;
+  nsresult err = GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  nsMsgKey key;
+  aHdr->GetMessageKey(&key);
+  nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(aHdr);  // closed system, so this is ok
+  if (NS_SUCCEEDED(err) && m_mdbStore && msgHdr->m_mdbRow)
+  {
+    if (!aAdd)
+    {
+      table->CutRow(m_mdbEnv, msgHdr->m_mdbRow);
+    }
+    else
+    {
+      mdbOid rowId;
+      msgHdr->m_mdbRow->GetOid(m_mdbEnv, &rowId);
+      mdb_pos insertPos = FindInsertIndexInSortedTable(table, rowId.mOid_Id);
+      uint32_t rowCount;
+      table->GetCount(m_mdbEnv, &rowCount);
+      table->AddRow(m_mdbEnv, msgHdr->m_mdbRow);
+      mdb_pos newPos;
+      table->MoveRow(m_mdbEnv, msgHdr->m_mdbRow, rowCount, insertPos, &newPos);
+    }
+  }
+
+//  if (aAdd)
+ // if we need to add this hdr, we need to insert it in key order.
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsMsgDatabase::HdrIsInCache(const char* aSearchFolderUri, nsIMsgDBHdr *aHdr, bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  nsCOMPtr <nsIMdbTable> table;
+  nsresult err = GetSearchResultsTable(aSearchFolderUri, true, getter_AddRefs(table));
+  NS_ENSURE_SUCCESS(err, err);
+  nsMsgKey key;
+  aHdr->GetMessageKey(&key);
+  mdbOid rowObjectId;
+  rowObjectId.mOid_Id = key;
+  rowObjectId.mOid_Scope = m_hdrRowScopeToken;
+  mdb_bool hasOid;
+  err =  table->HasOid(GetEnv(), &rowObjectId, &hasOid);
+  *aResult = hasOid;
+  return err;
+}
+
diff --git a/mailnews/db/msgdb/src/nsMsgHdr.cpp b/mailnews/db/msgdb/src/nsMsgHdr.cpp
new file mode 100644
index 000000000..ba1663e3b
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMsgHdr.cpp
@@ -0,0 +1,1098 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "mozilla/mailnews/MimeHeaderParser.h"
+#include "nsMsgHdr.h"
+#include "nsMsgDatabase.h"
+#include "nsMsgUtils.h"
+#include "nsIMsgThread.h"
+#include "nsMsgMimeCID.h"
+#include "nsIMimeConverter.h"
+#include "mozilla/Attributes.h"
+
+using namespace mozilla::mailnews;
+
+NS_IMPL_ISUPPORTS(nsMsgHdr, nsIMsgDBHdr)
+
+#define FLAGS_INITED 0x1
+#define CACHED_VALUES_INITED 0x2
+#define REFERENCES_INITED 0x4
+#define THREAD_PARENT_INITED 0x8
+
+nsMsgHdr::nsMsgHdr(nsMsgDatabase *db, nsIMdbRow *dbRow)
+{
+  m_mdb = db;
+  Init();
+  m_mdbRow = dbRow;
+  if(m_mdb)
+  {
+    m_mdb->AddRef();
+    mdbOid outOid;
+    if (dbRow && NS_SUCCEEDED(dbRow->GetOid(m_mdb->GetEnv(), &outOid)))
+    {
+      m_messageKey = outOid.mOid_Id;
+      m_mdb->AddHdrToUseCache((nsIMsgDBHdr *) this, m_messageKey);
+    }
+  }
+}
+
+
+void nsMsgHdr::Init()
+{
+  m_initedValues = 0;
+  m_statusOffset = 0xffffffff;
+  m_messageKey = nsMsgKey_None;
+  m_messageSize = 0;
+  m_date = 0;
+  m_flags = 0;
+  m_mdbRow = NULL;
+  m_threadId = nsMsgKey_None;
+  m_threadParent = nsMsgKey_None;
+}
+
+nsresult nsMsgHdr::InitCachedValues()
+{
+  nsresult err = NS_OK;
+
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+
+  if (!(m_initedValues & CACHED_VALUES_INITED))
+  {
+    uint32_t uint32Value;
+    mdbOid outOid;
+    if (NS_SUCCEEDED(m_mdbRow->GetOid(m_mdb->GetEnv(), &outOid)))
+      m_messageKey = outOid.mOid_Id;
+
+    err = GetUInt32Column(m_mdb->m_messageSizeColumnToken, &m_messageSize);
+
+    err = GetUInt32Column(m_mdb->m_dateColumnToken, &uint32Value);
+    Seconds2PRTime(uint32Value, &m_date);
+
+    err = GetUInt32Column(m_mdb->m_messageThreadIdColumnToken, &m_threadId);
+
+    if (NS_SUCCEEDED(err))
+      m_initedValues |= CACHED_VALUES_INITED;
+  }
+  return err;
+}
+
+nsresult nsMsgHdr::InitFlags()
+{
+
+  nsresult err = NS_OK;
+
+  if (!m_mdb)
+    return NS_ERROR_NULL_POINTER;
+
+  if(!(m_initedValues & FLAGS_INITED))
+  {
+    err = GetUInt32Column(m_mdb->m_flagsColumnToken, &m_flags);
+    m_flags &= ~nsMsgMessageFlags::New; // don't get new flag from MDB
+
+    if(NS_SUCCEEDED(err))
+      m_initedValues |= FLAGS_INITED;
+  }
+
+  return err;
+
+}
+
+nsMsgHdr::~nsMsgHdr()
+{
+  if (m_mdbRow)
+  {
+    if (m_mdb)
+    {
+      NS_RELEASE(m_mdbRow);
+      m_mdb->RemoveHdrFromUseCache((nsIMsgDBHdr *) this, m_messageKey);
+    }
+  }
+  NS_IF_RELEASE(m_mdb);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageKey(nsMsgKey *result)
+{
+  if (m_messageKey == nsMsgKey_None && m_mdbRow != NULL)
+  {
+    mdbOid outOid;
+    if (NS_SUCCEEDED(m_mdbRow->GetOid(m_mdb->GetEnv(), &outOid)))
+      m_messageKey = outOid.mOid_Id;
+
+  }
+  *result = m_messageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetThreadId(nsMsgKey *result)
+{
+
+  if (!(m_initedValues & CACHED_VALUES_INITED))
+    InitCachedValues();
+
+  if (result)
+  {
+    *result = m_threadId;
+    return NS_OK;
+  }
+  return NS_ERROR_NULL_POINTER;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetThreadId(nsMsgKey inKey)
+{
+  m_threadId = inKey;
+  return SetUInt32Column(m_threadId, m_mdb->m_messageThreadIdColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageKey(nsMsgKey value)
+{
+  m_messageKey = value;
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::GetRawFlags(uint32_t *result)
+{
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetFlags(uint32_t *result)
+{
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  if (m_mdb)
+    *result = m_mdb->GetStatusFlags(this, m_flags);
+  else
+    *result = m_flags;
+#ifdef DEBUG_bienvenu
+  NS_ASSERTION(! (*result & (nsMsgMessageFlags::Elided)), "shouldn't be set in db");
+#endif
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetFlags(uint32_t flags)
+{
+#ifdef DEBUG_bienvenu
+  NS_ASSERTION(! (flags & (nsMsgMessageFlags::Elided)), "shouldn't set this flag on db");
+#endif
+  m_initedValues |= FLAGS_INITED;
+  m_flags = flags;
+  // don't write out nsMsgMessageFlags::New to MDB.
+  return SetUInt32Column(m_flags & ~nsMsgMessageFlags::New, m_mdb->m_flagsColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::OrFlags(uint32_t flags, uint32_t *result)
+{
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  if ((m_flags & flags) != flags)
+    SetFlags (m_flags | flags);
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::AndFlags(uint32_t flags, uint32_t *result)
+{
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  if ((m_flags & flags) != m_flags)
+    SetFlags (m_flags & flags);
+  *result = m_flags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkHasAttachments(bool bHasAttachments)
+{
+  nsresult rv = NS_OK;
+
+  if(m_mdb)
+  {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if(NS_SUCCEEDED(rv))
+      rv = m_mdb->MarkHasAttachments(key, bHasAttachments, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkRead(bool bRead)
+{
+  nsresult rv = NS_OK;
+
+  if(m_mdb)
+  {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if(NS_SUCCEEDED(rv))
+      rv = m_mdb->MarkRead(key, bRead, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::MarkFlagged(bool bFlagged)
+{
+  nsresult rv = NS_OK;
+
+  if(m_mdb)
+  {
+    nsMsgKey key;
+    rv = GetMessageKey(&key);
+    if(NS_SUCCEEDED(rv))
+      rv = m_mdb->MarkMarked(key, bFlagged, nullptr);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetProperty(const char *propertyName, nsAString &resultProperty)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->GetPropertyAsNSString(m_mdbRow, propertyName, resultProperty);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetProperty(const char *propertyName, const nsAString &propertyStr)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->SetPropertyFromNSString(m_mdbRow, propertyName, propertyStr);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetStringProperty(const char *propertyName, const char *propertyValue)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->SetProperty(m_mdbRow, propertyName, propertyValue);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetStringProperty(const char *propertyName, char **aPropertyValue)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->GetProperty(m_mdbRow, propertyName, aPropertyValue);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetUint32Property(const char *propertyName, uint32_t *pResult)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->GetUint32Property(m_mdbRow, propertyName, pResult);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetUint32Property(const char *propertyName, uint32_t value)
+{
+  NS_ENSURE_ARG_POINTER(propertyName);
+  if (!m_mdb || !m_mdbRow)
+    return NS_ERROR_NULL_POINTER;
+  return m_mdb->SetUint32Property(m_mdbRow, propertyName, value);
+}
+
+
+NS_IMETHODIMP nsMsgHdr::GetNumReferences(uint16_t *result)
+{
+  if (!(m_initedValues & REFERENCES_INITED))
+  {
+    const char *references;
+    if (NS_SUCCEEDED(m_mdb->RowCellColumnToConstCharPtr(GetMDBRow(),
+                       m_mdb->m_referencesColumnToken, &references)))
+      ParseReferences(references);
+    m_initedValues |= REFERENCES_INITED;
+  }
+
+  if (result)
+    *result = m_references.Length();
+  // there is no real failure here; if there are no references, there are no
+  //  references.
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::ParseReferences(const char *references)
+{
+  const char *startNextRef = references;
+  nsAutoCString resultReference;
+  nsCString messageId;
+  GetMessageId(getter_Copies(messageId));
+
+  while (startNextRef && *startNextRef)
+  {
+    startNextRef = GetNextReference(startNextRef, resultReference,
+                                    startNextRef == references);
+    // Don't add self-references.
+    if (!resultReference.IsEmpty() && !resultReference.Equals(messageId))
+      m_references.AppendElement(resultReference);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetStringReference(int32_t refNum, nsACString& resultReference)
+{
+  nsresult err = NS_OK;
+
+  if(!(m_initedValues & REFERENCES_INITED))
+    GetNumReferences(nullptr); // it can handle the null
+
+  if ((uint32_t)refNum < m_references.Length())
+    resultReference = m_references.ElementAt(refNum);
+  else
+    err = NS_ERROR_ILLEGAL_VALUE;
+  return err;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetDate(PRTime *result)
+{
+  if (!(m_initedValues & CACHED_VALUES_INITED))
+    InitCachedValues();
+
+  *result = m_date;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetDateInSeconds(uint32_t *aResult)
+{
+  return GetUInt32Column(m_mdb->m_dateColumnToken, aResult);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageId(const char *messageId)
+{
+  if (messageId && *messageId == '<')
+  {
+    nsAutoCString tempMessageID(messageId + 1);
+    if (tempMessageID.CharAt(tempMessageID.Length() - 1) == '>')
+      tempMessageID.SetLength(tempMessageID.Length() - 1);
+    return SetStringColumn(tempMessageID.get(), m_mdb->m_messageIdColumnToken);
+  }
+  return SetStringColumn(messageId, m_mdb->m_messageIdColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetSubject(const char *subject)
+{
+	return SetStringColumn(subject, m_mdb->m_subjectColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetAuthor(const char *author)
+{
+	return SetStringColumn(author, m_mdb->m_senderColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetReferences(const char *references)
+{
+  NS_ENSURE_ARG_POINTER(references);
+  m_references.Clear();
+  ParseReferences(references);
+
+  m_initedValues |= REFERENCES_INITED;
+
+  return SetStringColumn(references, m_mdb->m_referencesColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetRecipients(const char *recipients)
+{
+  // need to put in rfc822 address parsing code here (or make caller do it...)
+  return SetStringColumn(recipients, m_mdb->m_recipientsColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetCcList(const char *ccList)
+{
+	return SetStringColumn(ccList, m_mdb->m_ccListColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetBccList(const char *bccList)
+{
+  return SetStringColumn(bccList, m_mdb->m_bccListColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageSize(uint32_t messageSize)
+{
+  SetUInt32Column(messageSize, m_mdb->m_messageSizeColumnToken);
+  m_messageSize = messageSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetOfflineMessageSize(uint32_t *result)
+{
+  uint32_t size;
+  nsresult res = GetUInt32Column(m_mdb->m_offlineMessageSizeColumnToken, &size);
+
+  *result = size;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetOfflineMessageSize(uint32_t messageSize)
+{
+  return SetUInt32Column(messageSize, m_mdb->m_offlineMessageSizeColumnToken);
+}
+
+
+NS_IMETHODIMP nsMsgHdr::SetLineCount(uint32_t lineCount)
+{
+  SetUInt32Column(lineCount, m_mdb->m_numLinesColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetStatusOffset(uint32_t statusOffset)
+{
+  return SetUInt32Column(statusOffset, m_mdb->m_statusOffsetColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetDate(PRTime date)
+{
+  m_date = date;
+  uint32_t seconds;
+  PRTime2Seconds(date, &seconds);
+  return SetUInt32Column((uint32_t) seconds, m_mdb->m_dateColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetStatusOffset(uint32_t *result)
+{
+  uint32_t offset = 0;
+  nsresult res = GetUInt32Column(m_mdb->m_statusOffsetColumnToken, &offset);
+
+  *result = offset;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetPriority(nsMsgPriorityValue priority)
+{
+  SetUInt32Column((uint32_t) priority, m_mdb->m_priorityColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetPriority(nsMsgPriorityValue *result)
+{
+  if (!result)
+    return NS_ERROR_NULL_POINTER;
+
+  uint32_t priority = 0;
+  nsresult rv = GetUInt32Column(m_mdb->m_priorityColumnToken, &priority);
+  if (NS_FAILED(rv)) return rv;
+
+  *result = (nsMsgPriorityValue) priority;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetLabel(nsMsgLabelValue label)
+{
+  SetUInt32Column((uint32_t) label, m_mdb->m_labelColumnToken);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetLabel(nsMsgLabelValue *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+
+  return GetUInt32Column(m_mdb->m_labelColumnToken, result);
+}
+
+// I'd like to not store the account key, if the msg is in
+// the same account as it was received in, to save disk space and memory.
+// This might be problematic when a message gets moved...
+// And I'm not sure if we should short circuit it here,
+// or at a higher level where it might be more efficient.
+NS_IMETHODIMP nsMsgHdr::SetAccountKey(const char *aAccountKey)
+{
+  return SetStringProperty("account", aAccountKey);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetAccountKey(char **aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  return GetStringProperty("account", aResult);
+}
+
+
+NS_IMETHODIMP nsMsgHdr::GetMessageOffset(uint64_t *result)
+{
+  NS_ENSURE_ARG(result);
+
+  // if there is a message offset, use it, otherwise, we'll use the message key.
+  (void) GetUInt64Column(m_mdb->m_offlineMsgOffsetColumnToken, result, (unsigned)-1);
+  if (*result == (unsigned)-1)
+    *result = m_messageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetMessageOffset(uint64_t offset)
+{
+  SetUInt64Column(offset, m_mdb->m_offlineMsgOffsetColumnToken);
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP nsMsgHdr::GetMessageSize(uint32_t *result)
+{
+  uint32_t size;
+  nsresult res = GetUInt32Column(m_mdb->m_messageSizeColumnToken, &size);
+
+  *result = size;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetLineCount(uint32_t *result)
+{
+  uint32_t linecount;
+  nsresult res = GetUInt32Column(m_mdb->m_numLinesColumnToken, &linecount);
+  *result = linecount;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgHdr::SetPriorityString(const char *priority)
+{
+  nsMsgPriorityValue priorityVal = nsMsgPriority::Default;
+
+  // We can ignore |NS_MsgGetPriorityFromString()| return value,
+  // since we set a default value for |priorityVal|.
+  NS_MsgGetPriorityFromString(priority, priorityVal);
+
+  return SetPriority(priorityVal);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetAuthor(char* *resultAuthor)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_senderColumnToken, resultAuthor);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetSubject(char* *resultSubject)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_subjectColumnToken, resultSubject);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetRecipients(char* *resultRecipients)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetCcList(char * *resultCCList)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_ccListColumnToken, resultCCList);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetBccList(char * *resultBCCList)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_bccListColumnToken, resultBCCList);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMessageId(char * *resultMessageId)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_messageIdColumnToken, resultMessageId);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedAuthor(nsAString &resultAuthor)
+{
+  return m_mdb->RowCellColumnToMime2DecodedString(GetMDBRow(), m_mdb->m_senderColumnToken, resultAuthor);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedSubject(nsAString &resultSubject)
+{
+  return m_mdb->RowCellColumnToMime2DecodedString(GetMDBRow(), m_mdb->m_subjectColumnToken, resultSubject);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetMime2DecodedRecipients(nsAString &resultRecipients)
+{
+  return m_mdb->RowCellColumnToMime2DecodedString(GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients);
+}
+
+
+NS_IMETHODIMP nsMsgHdr::GetAuthorCollationKey(uint32_t *len, uint8_t **resultAuthor)
+{
+  return m_mdb->RowCellColumnToAddressCollationKey(GetMDBRow(), m_mdb->m_senderColumnToken, resultAuthor, len);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetSubjectCollationKey(uint32_t *len, uint8_t **resultSubject)
+{
+  return m_mdb->RowCellColumnToCollationKey(GetMDBRow(), m_mdb->m_subjectColumnToken, resultSubject, len);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetRecipientsCollationKey(uint32_t *len, uint8_t **resultRecipients)
+{
+  return m_mdb->RowCellColumnToCollationKey(GetMDBRow(), m_mdb->m_recipientsColumnToken, resultRecipients, len);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetCharset(char **aCharset)
+{
+  return m_mdb->RowCellColumnToCharPtr(GetMDBRow(), m_mdb->m_messageCharSetColumnToken, aCharset);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetCharset(const char *aCharset)
+{
+  return SetStringColumn(aCharset, m_mdb->m_messageCharSetColumnToken);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetEffectiveCharset(nsACString &resultCharset)
+{
+  return m_mdb->GetEffectiveCharset(m_mdbRow, resultCharset);
+}
+
+NS_IMETHODIMP nsMsgHdr::SetThreadParent(nsMsgKey inKey)
+{
+  m_threadParent = inKey;
+  if (inKey == m_messageKey)
+    NS_ASSERTION(false, "can't be your own parent");
+  SetUInt32Column(m_threadParent, m_mdb->m_threadParentColumnToken);
+  m_initedValues |= THREAD_PARENT_INITED;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetThreadParent(nsMsgKey *result)
+{
+  nsresult res;
+  if(!(m_initedValues & THREAD_PARENT_INITED))
+  {
+    res = GetUInt32Column(m_mdb->m_threadParentColumnToken, &m_threadParent, nsMsgKey_None);
+    if (NS_SUCCEEDED(res))
+      m_initedValues |= THREAD_PARENT_INITED;
+  }
+  *result = m_threadParent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetFolder(nsIMsgFolder **result)
+{
+  NS_ENSURE_ARG(result);
+
+  if (m_mdb && m_mdb->m_folder)
+  {
+    *result = m_mdb->m_folder;
+    NS_ADDREF(*result);
+  }
+  else
+    *result = nullptr;
+  return NS_OK;
+}
+
+nsresult nsMsgHdr::SetStringColumn(const char *str, mdb_token token)
+{
+  NS_ENSURE_ARG_POINTER(str);
+  return m_mdb->CharPtrToRowCellColumn(m_mdbRow, token, str);
+}
+
+nsresult nsMsgHdr::SetUInt32Column(uint32_t value, mdb_token token)
+{
+  return m_mdb->UInt32ToRowCellColumn(m_mdbRow, token, value);
+}
+
+nsresult nsMsgHdr::GetUInt32Column(mdb_token token, uint32_t *pvalue, uint32_t defaultValue)
+{
+  return m_mdb->RowCellColumnToUInt32(GetMDBRow(), token, pvalue, defaultValue);
+}
+
+nsresult nsMsgHdr::SetUInt64Column(uint64_t value, mdb_token token)
+{
+  return m_mdb->UInt64ToRowCellColumn(m_mdbRow, token, value);
+}
+
+nsresult nsMsgHdr::GetUInt64Column(mdb_token token, uint64_t *pvalue, uint64_t defaultValue)
+{
+  return m_mdb->RowCellColumnToUInt64(GetMDBRow(), token, pvalue, defaultValue);
+}
+
+/**
+ * Roughly speaking, get the next message-id (starts with a '<' ends with a
+ *  '>').  Except, we also try to handle the case where your reference is of
+ *  a prehistoric vintage that just stuck any old random junk in there.  Our
+ *  old logic would (unintentionally?) just trim the whitespace off the front
+ *  and hand you everything after that.  We change things at all because that
+ *  same behaviour does not make sense if we have already seen a proper message
+ *  id.  We keep the old behaviour at all because it would seem to have
+ *  benefits.  (See jwz's non-zero stats: http://www.jwz.org/doc/threading.html) 
+ * So, to re-state, if there is a valid message-id in there at all, we only
+ *  return valid message-id's (sans bracketing '<' and '>').  If there isn't,
+ *  our result (via "references") is a left-trimmed copy of the string.  If
+ *  there is nothing in there, our result is an empty string.)  We do require
+ *  that you pass allowNonDelimitedReferences what it demands, though.
+ * For example: "<valid@stuff> this stuff is invalid" would net you
+ *  "valid@stuff" and "this stuff is invalid" as results.  We now only would
+ *  provide "valid-stuff" and an empty string (which you should ignore) as
+ *  results.  However "this stuff is invalid" would return itself, allowing
+ *  anything relying on that behaviour to keep working.
+ * 
+ * Note: We accept anything inside the '<' and '>'; technically, we should want
+ *  at least a '@' in there (per rfc 2822).  But since we're going out of our
+ *  way to support weird things...
+ * 
+ * @param startNextRef The position to start at; this should either be the start
+ *     of your references string or our return value from a previous call.
+ * @param reference You pass a nsCString by reference, we put the reference we
+ *     find in it, if we find one.  It may be empty!  Beware!
+ * @param allowNonDelimitedReferences Should we support the
+ *     pre-reasonable-standards form of In-Reply-To where it could be any
+ *     arbitrary string and our behaviour was just to take off leading
+ *     whitespace.  It only makes sense to pass true for your first call to this
+ *     function, as if you are around to make a second call, it means we found
+ *     a properly formatted message-id and so we should only look for more
+ *     properly formatted message-ids.
+ * @returns The next starting position of this routine, which may be pointing at
+ *     a nul '\0' character to indicate termination.
+ */ 
+const char *nsMsgHdr::GetNextReference(const char *startNextRef,
+                                       nsCString &reference,
+                                       bool acceptNonDelimitedReferences)
+{
+  const char *ptr = startNextRef;
+  const char *whitespaceEndedAt = nullptr;
+  const char *firstMessageIdChar = nullptr;
+
+  // make the reference result string empty by default; we will set it to
+  //  something valid if the time comes.
+  reference.Truncate();
+
+  // walk until we find a '<', but keep track of the first point we found that
+  //  was not whitespace (as defined by previous versions of this code.)
+  for (bool foundLessThan = false; !foundLessThan; ptr++)
+  {
+    switch (*ptr)
+    {
+      case '\0':
+        // if we are at the end of the string, we found some non-whitespace, and
+        //  the caller requested that we accept non-delimited whitespace,
+        //  give them that as their reference.  (otherwise, leave it empty)
+        if (acceptNonDelimitedReferences && whitespaceEndedAt)
+          reference = whitespaceEndedAt;
+        return ptr;
+      case ' ':
+      case '\r':
+      case '\n':
+      case '\t':
+        // do nothing, make default case mean you didn't get whitespace
+        break;
+      case '<':
+        firstMessageIdChar = ++ptr; // skip over the '<'
+        foundLessThan = true; // (flag to stop)
+        // intentional fallthrough so whitespaceEndedAt will definitely have
+        //  a non-NULL value, just in case the message-id is not valid (no '>')
+        //  and the old-school support is desired.
+        MOZ_FALLTHROUGH;
+      default:
+        if (!whitespaceEndedAt)
+            whitespaceEndedAt = ptr;
+        break;
+    }
+  }
+
+  // keep going until we hit a '>' or hit the end of the string 
+  for(; *ptr ; ptr++)
+  {
+    if (*ptr == '>')
+    {
+      // it's valid, update reference, making sure to stop before the '>'
+      reference.Assign(firstMessageIdChar, ptr - firstMessageIdChar);
+      // and return a start point just after the '>'
+      return ++ptr;
+    }
+  }
+
+  // we did not have a fully-formed, valid message-id, so consider falling back
+  if (acceptNonDelimitedReferences && whitespaceEndedAt)
+    reference = whitespaceEndedAt;
+  return ptr;
+}
+
+bool nsMsgHdr::IsParentOf(nsIMsgDBHdr *possibleChild)
+{
+  uint16_t referenceToCheck = 0;
+  possibleChild->GetNumReferences(&referenceToCheck);
+  nsAutoCString reference;
+
+  nsCString messageId;
+  GetMessageId(getter_Copies(messageId));
+
+  while (referenceToCheck > 0)
+  {
+    possibleChild->GetStringReference(referenceToCheck - 1, reference);
+
+    if (reference.Equals(messageId))
+      return true;
+    // if reference didn't match, check if this ref is for a non-existent
+    // header. If it is, continue looking at ancestors.
+    nsCOMPtr <nsIMsgDBHdr> refHdr;
+    if (!m_mdb)
+      break;
+    (void) m_mdb->GetMsgHdrForMessageID(reference.get(), getter_AddRefs(refHdr));
+    if (refHdr)
+      break;
+    referenceToCheck--;
+  }
+  return false;
+}
+
+bool nsMsgHdr::IsAncestorOf(nsIMsgDBHdr *possibleChild)
+{
+  const char *references;
+  nsMsgHdr* curHdr = static_cast<nsMsgHdr*>(possibleChild);      // closed system, cast ok
+  m_mdb->RowCellColumnToConstCharPtr(curHdr->GetMDBRow(), m_mdb->m_referencesColumnToken, &references);
+  if (!references)
+    return false;
+
+  nsCString messageId;
+  // should put < > around message id to make strstr strictly match
+  GetMessageId(getter_Copies(messageId));
+  return (strstr(references, messageId.get()) != nullptr);
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsRead(bool *isRead)
+{
+  NS_ENSURE_ARG_POINTER(isRead);
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  *isRead = !!(m_flags & nsMsgMessageFlags::Read);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsFlagged(bool *isFlagged)
+{
+  NS_ENSURE_ARG_POINTER(isFlagged);
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  *isFlagged = !!(m_flags & nsMsgMessageFlags::Marked);
+  return NS_OK;
+}
+
+void nsMsgHdr::ReparentInThread(nsIMsgThread *thread)
+{
+  NS_WARNING("Borked message header, attempting to fix!");
+  uint32_t numChildren;
+  thread->GetNumChildren(&numChildren);
+  // bail out early for the singleton thread case.
+  if (numChildren == 1)
+  {
+    SetThreadParent(nsMsgKey_None);
+    return;
+  }
+  else
+  {
+    nsCOMPtr<nsIMsgDBHdr> curHdr;
+    // loop through thread, looking for our proper parent.
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      thread->GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      // closed system, cast ok
+      nsMsgHdr* curMsgHdr = static_cast<nsMsgHdr*>(curHdr.get());
+      if (curHdr && curMsgHdr->IsParentOf(this))
+      {
+        nsMsgKey curHdrKey;
+        curHdr->GetMessageKey(&curHdrKey);
+        SetThreadParent(curHdrKey);
+        return;
+      }
+    }
+    // we didn't find it. So either the root header is our parent,
+    // or we're the root.
+    int32_t rootIndex;
+    nsCOMPtr<nsIMsgDBHdr> rootHdr;
+    thread->GetRootHdr(&rootIndex, getter_AddRefs(rootHdr));
+    NS_ASSERTION(rootHdr, "thread has no root hdr - shouldn't happen");
+    if (rootHdr)
+    {
+      nsMsgKey rootKey;
+      rootHdr->GetMessageKey(&rootKey);
+      // if we're the root, our thread parent is -1.
+      SetThreadParent(rootKey == m_messageKey ? nsMsgKey_None : rootKey);
+    }
+  }
+}
+
+bool nsMsgHdr::IsAncestorKilled(uint32_t ancestorsToCheck)
+{
+  if (!(m_initedValues & FLAGS_INITED))
+    InitFlags();
+  bool isKilled = m_flags & nsMsgMessageFlags::Ignored;
+
+  if (!isKilled)
+  {
+    nsMsgKey threadParent;
+    GetThreadParent(&threadParent);
+
+    if (threadParent == m_messageKey)
+    {
+      // isKilled is false by virtue of the enclosing if statement
+      NS_ERROR("Thread is parent of itself, please fix!");
+      nsCOMPtr<nsIMsgThread> thread;
+      (void) m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+      if (!thread)
+        return false;
+      ReparentInThread(thread);
+      // Something's wrong, but the problem happened some time ago, so erroring
+      // out now is probably not a good idea. Ergo, we'll pretend to be OK, show
+      // the user the thread (err on the side of caution), and let the assertion
+      // alert debuggers to a problem.
+      return false;
+    }
+    if (threadParent != nsMsgKey_None)
+    {
+      nsCOMPtr<nsIMsgDBHdr> parentHdr;
+      (void) m_mdb->GetMsgHdrForKey(threadParent, getter_AddRefs(parentHdr));
+
+      if (parentHdr)
+      {
+        // More proofing against crashers. This crasher was derived from the
+        // fact that something got borked, leaving is in hand with a circular
+        // reference to borked headers inducing these loops. The defining
+        // characteristic of these headers is that they don't actually seat
+        // themselves in the thread properly.
+        nsCOMPtr<nsIMsgThread> thread;
+        (void) m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+        if (thread)
+        {
+          nsCOMPtr<nsIMsgDBHdr> claimant;
+          (void) thread->GetChild(threadParent, getter_AddRefs(claimant));
+          if (!claimant)
+          {
+            // attempt to reparent, and say the thread isn't killed,
+            // erring on the side of safety.
+            ReparentInThread(thread);
+            return false;
+          }
+        }
+
+        if (!ancestorsToCheck)
+        {
+          // We think we have a parent, but we have no more ancestors to check
+          NS_ASSERTION(false, "cycle in parent relationship, please fix!");
+          return false;
+        }
+        // closed system, cast ok
+        nsMsgHdr* parent = static_cast<nsMsgHdr*>(parentHdr.get());
+        return parent->IsAncestorKilled(ancestorsToCheck - 1);
+      }
+    }
+  }
+  return isKilled;
+}
+
+NS_IMETHODIMP nsMsgHdr::GetIsKilled(bool *isKilled)
+{
+  NS_ENSURE_ARG_POINTER(isKilled);
+  *isKilled = false;
+  nsCOMPtr<nsIMsgThread> thread;
+  (void) m_mdb->GetThreadContainingMsgHdr(this, getter_AddRefs(thread));
+  // if we can't find the thread, let's at least check one level; maybe
+  // the header hasn't been added to a thread yet.
+  uint32_t numChildren = 1;
+  if (thread)
+    thread->GetNumChildren(&numChildren);
+  if (!numChildren)
+    return NS_ERROR_FAILURE;
+  // We can't have as many ancestors as there are messages in the thread,
+  // so tell IsAncestorKilled to only check numChildren - 1 ancestors.
+  *isKilled = IsAncestorKilled(numChildren - 1);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#include "nsIStringEnumerator.h"
+#include "nsAutoPtr.h"
+#define NULL_MORK_COLUMN 0
+class nsMsgPropertyEnumerator : public nsIUTF8StringEnumerator
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIUTF8STRINGENUMERATOR
+
+  nsMsgPropertyEnumerator(nsMsgHdr* aHdr);
+  void PrefetchNext();
+
+protected:
+  virtual ~nsMsgPropertyEnumerator();
+  nsCOMPtr<nsIMdbRowCellCursor> mRowCellCursor;
+  nsCOMPtr<nsIMdbEnv> m_mdbEnv;
+  nsCOMPtr<nsIMdbStore> m_mdbStore;
+  // Hold a reference to the hdr so it will hold an xpcom reference to the
+  // underlying mdb row. The row cell cursor will crash if the underlying
+  // row goes away.
+  RefPtr<nsMsgHdr> m_hdr;
+  bool mNextPrefetched;
+  mdb_column mNextColumn;
+};
+
+nsMsgPropertyEnumerator::nsMsgPropertyEnumerator(nsMsgHdr* aHdr)
+  :  mNextPrefetched(false),
+     mNextColumn(NULL_MORK_COLUMN)
+{
+  RefPtr<nsMsgDatabase> mdb;
+  nsCOMPtr<nsIMdbRow> mdbRow;
+
+  if (aHdr &&
+      (mdbRow = aHdr->GetMDBRow()) &&
+      (m_hdr = aHdr) &&
+      (mdb = aHdr->m_mdb) &&
+      (m_mdbEnv = mdb->m_mdbEnv) &&
+      (m_mdbStore = mdb->m_mdbStore))
+  {
+    mdbRow->GetRowCellCursor(m_mdbEnv, -1, getter_AddRefs(mRowCellCursor));
+  }
+}
+
+nsMsgPropertyEnumerator::~nsMsgPropertyEnumerator()
+{
+  // Need to clear this before the nsMsgHdr and its corresponding
+  // nsIMdbRow potentially go away.
+  mRowCellCursor = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsMsgPropertyEnumerator, nsIUTF8StringEnumerator)
+
+NS_IMETHODIMP nsMsgPropertyEnumerator::GetNext(nsACString& aItem)
+{
+  PrefetchNext();
+  if (mNextColumn == NULL_MORK_COLUMN)
+    return NS_ERROR_FAILURE; // call HasMore first
+  if (!m_mdbStore || !m_mdbEnv)
+    return NS_ERROR_NOT_INITIALIZED;
+  mNextPrefetched = false;
+  char columnName[100];
+  struct mdbYarn colYarn = {columnName, 0, sizeof(columnName), 0, 0, nullptr};
+  // Get the column of the cell
+  nsresult rv = m_mdbStore->TokenToString(m_mdbEnv, mNextColumn, &colYarn);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aItem.Assign(static_cast<char *>(colYarn.mYarn_Buf), colYarn.mYarn_Fill);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgPropertyEnumerator::HasMore(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  PrefetchNext();
+  *aResult = (mNextColumn != NULL_MORK_COLUMN);
+  return NS_OK;
+}
+
+void nsMsgPropertyEnumerator::PrefetchNext(void)
+{
+  if (!mNextPrefetched && m_mdbEnv && mRowCellCursor)
+  {
+    mNextPrefetched = true;
+    nsCOMPtr<nsIMdbCell> cell;
+    mRowCellCursor->NextCell(m_mdbEnv, getter_AddRefs(cell), &mNextColumn, nullptr);
+    if (mNextColumn == NULL_MORK_COLUMN)
+    {
+      // free up references
+      m_mdbStore = nullptr;
+      m_mdbEnv = nullptr;
+      mRowCellCursor = nullptr;
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMETHODIMP nsMsgHdr::GetPropertyEnumerator(nsIUTF8StringEnumerator** _result)
+{
+  nsMsgPropertyEnumerator* enumerator = new nsMsgPropertyEnumerator(this);
+  if (!enumerator)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  NS_ADDREF(*_result = enumerator);
+  return NS_OK;
+}
diff --git a/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp b/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp
new file mode 100644
index 000000000..2ce35047a
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.cpp
@@ -0,0 +1,378 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "nsMsgOfflineImapOperation.h"
+#include "nsMsgUtils.h"
+#include "mozilla/Logging.h"
+
+using namespace mozilla;
+
+PRLogModuleInfo *IMAPOffline;
+
+/* Implementation file */
+NS_IMPL_ISUPPORTS(nsMsgOfflineImapOperation, nsIMsgOfflineImapOperation)
+
+// property names for offine imap operation fields.
+#define PROP_OPERATION "op"
+#define PROP_OPERATION_FLAGS "opFlags"
+#define PROP_NEW_FLAGS "newFlags"
+#define PROP_MESSAGE_KEY "msgKey"
+#define PROP_SRC_MESSAGE_KEY "srcMsgKey"
+#define PROP_SRC_FOLDER_URI "srcFolderURI"
+#define PROP_MOVE_DEST_FOLDER_URI "moveDest"
+#define PROP_NUM_COPY_DESTS "numCopyDests"
+#define PROP_COPY_DESTS "copyDests" // how to delimit these? Or should we do the "dest1","dest2" etc trick? But then we'd need to shuffle
+                                    // them around since we delete off the front first.
+#define PROP_KEYWORD_ADD "addedKeywords"
+#define PROP_KEYWORD_REMOVE "removedKeywords"
+#define PROP_MSG_SIZE "msgSize"
+#define PROP_PLAYINGBACK "inPlayback"
+
+nsMsgOfflineImapOperation::nsMsgOfflineImapOperation(nsMsgDatabase *db, nsIMdbRow *row)
+{
+  NS_ASSERTION(db, "can't have null db");
+  NS_ASSERTION(row, "can't have null row");
+  m_operation = 0;
+  m_operationFlags = 0;
+  m_messageKey = nsMsgKey_None;
+  m_sourceMessageKey = nsMsgKey_None;
+  m_mdb = db;
+  NS_ADDREF(m_mdb);
+  m_mdbRow = row;
+  m_newFlags = 0;
+  m_mdb->GetUint32Property(m_mdbRow, PROP_OPERATION, (uint32_t *) &m_operation, 0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_MESSAGE_KEY, &m_messageKey, 0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_OPERATION_FLAGS, &m_operationFlags, 0);
+  m_mdb->GetUint32Property(m_mdbRow, PROP_NEW_FLAGS, (uint32_t *) &m_newFlags, 0);
+}
+
+nsMsgOfflineImapOperation::~nsMsgOfflineImapOperation()
+{
+  // clear the row first, in case we're holding the last reference
+  // to the db.
+  m_mdbRow = nullptr;
+  NS_IF_RELEASE(m_mdb);
+}
+
+/* attribute nsOfflineImapOperationType operation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetOperation(nsOfflineImapOperationType *aOperation)
+{
+  NS_ENSURE_ARG(aOperation);
+  *aOperation = m_operation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetOperation(nsOfflineImapOperationType aOperation)
+{
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x setOperation was %x add %x", m_messageKey, m_operation, aOperation));
+
+  m_operation |= aOperation;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION, m_operation);
+}
+
+/* void clearOperation (in nsOfflineImapOperationType operation); */
+NS_IMETHODIMP nsMsgOfflineImapOperation::ClearOperation(nsOfflineImapOperationType aOperation)
+{
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x clearOperation was %x clear %x", m_messageKey, m_operation, aOperation));
+  m_operation &= ~aOperation;
+  switch (aOperation)
+  {
+  case kMsgMoved:
+  case kAppendTemplate:
+  case kAppendDraft:
+    m_moveDestination.Truncate();
+    break;
+  case kMsgCopy:
+    m_copyDestinations.RemoveElementAt(0);
+    break;
+  }
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION, m_operation);
+}
+
+/* attribute nsMsgKey messageKey; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetMessageKey(nsMsgKey *aMessageKey)
+{
+  NS_ENSURE_ARG(aMessageKey);
+  *aMessageKey = m_messageKey;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetMessageKey(nsMsgKey aMessageKey)
+{
+  m_messageKey = aMessageKey;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_MESSAGE_KEY, m_messageKey);
+}
+
+/* attribute nsMsgKey srcMessageKey; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetSrcMessageKey(nsMsgKey *aMessageKey)
+{
+  NS_ENSURE_ARG(aMessageKey);
+  return m_mdb->GetUint32Property(m_mdbRow, PROP_SRC_MESSAGE_KEY, aMessageKey, nsMsgKey_None);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetSrcMessageKey(nsMsgKey aMessageKey)
+{
+  m_messageKey = aMessageKey;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_SRC_MESSAGE_KEY, m_messageKey);
+}
+
+/* attribute imapMessageFlagsType flagOperation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetFlagOperation(imapMessageFlagsType *aFlagOperation)
+{
+  NS_ENSURE_ARG(aFlagOperation);
+  *aFlagOperation = m_operationFlags;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetFlagOperation(imapMessageFlagsType aFlagOperation)
+{
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x setFlagOperation was %x add %x", m_messageKey, m_operationFlags, aFlagOperation));
+  SetOperation(kFlagsChanged);
+  nsresult rv = SetNewFlags(aFlagOperation);
+  NS_ENSURE_SUCCESS(rv, rv);
+  m_operationFlags |= aFlagOperation;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_OPERATION_FLAGS, m_operationFlags);
+}
+
+/* attribute imapMessageFlagsType flagOperation; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetNewFlags(imapMessageFlagsType *aNewFlags)
+{
+  NS_ENSURE_ARG(aNewFlags);
+  uint32_t flags;
+  nsresult rv = m_mdb->GetUint32Property(m_mdbRow, PROP_NEW_FLAGS, &flags, 0);
+  *aNewFlags = m_newFlags = (imapMessageFlagsType) flags;
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetNewFlags(imapMessageFlagsType aNewFlags)
+{
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info) && m_newFlags != aNewFlags)
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x SetNewFlags was %x to %x", m_messageKey, m_newFlags, aNewFlags));
+  m_newFlags = aNewFlags;
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_NEW_FLAGS, m_newFlags);
+}
+
+
+/* attribute string destinationFolderURI; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetDestinationFolderURI(char * *aDestinationFolderURI)
+{
+  NS_ENSURE_ARG(aDestinationFolderURI);
+  (void) m_mdb->GetProperty(m_mdbRow, PROP_MOVE_DEST_FOLDER_URI, getter_Copies(m_moveDestination));
+  *aDestinationFolderURI = ToNewCString(m_moveDestination);
+  return (*aDestinationFolderURI) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetDestinationFolderURI(const char * aDestinationFolderURI)
+{
+  if (MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x SetDestinationFolderURI to %s", m_messageKey, aDestinationFolderURI));
+  m_moveDestination = aDestinationFolderURI ? aDestinationFolderURI : 0;
+  return m_mdb->SetProperty(m_mdbRow, PROP_MOVE_DEST_FOLDER_URI, aDestinationFolderURI);
+}
+
+/* attribute string sourceFolderURI; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetSourceFolderURI(char * *aSourceFolderURI)
+{
+  NS_ENSURE_ARG(aSourceFolderURI);
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_SRC_FOLDER_URI, getter_Copies(m_sourceFolder));
+  *aSourceFolderURI = ToNewCString(m_sourceFolder);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetSourceFolderURI(const char * aSourceFolderURI)
+{
+  m_sourceFolder = aSourceFolderURI ? aSourceFolderURI : 0;
+  SetOperation(kMoveResult);
+
+  return m_mdb->SetProperty(m_mdbRow, PROP_SRC_FOLDER_URI, aSourceFolderURI);
+}
+
+/* attribute string keyword; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetKeywordsToAdd(char * *aKeywords)
+{
+  NS_ENSURE_ARG(aKeywords);
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_KEYWORD_ADD, getter_Copies(m_keywordsToAdd));
+  *aKeywords = ToNewCString(m_keywordsToAdd);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddKeywordToAdd(const char * aKeyword)
+{
+  SetOperation(kAddKeywords);
+  return AddKeyword(aKeyword, m_keywordsToAdd, PROP_KEYWORD_ADD, m_keywordsToRemove, PROP_KEYWORD_REMOVE);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetKeywordsToRemove(char * *aKeywords)
+{
+  NS_ENSURE_ARG(aKeywords);
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_KEYWORD_REMOVE, getter_Copies(m_keywordsToRemove));
+  *aKeywords = ToNewCString(m_keywordsToRemove);
+  return rv;
+}
+
+nsresult nsMsgOfflineImapOperation::AddKeyword(const char *aKeyword, nsCString &addList, const char *addProp,
+                                               nsCString &removeList, const char *removeProp)
+{
+  int32_t startOffset, keywordLength;
+  if (!MsgFindKeyword(nsDependentCString(aKeyword), addList, &startOffset, &keywordLength))
+  {
+    if (!addList.IsEmpty())
+      addList.Append(' ');
+    addList.Append(aKeyword);
+  }
+  // if the keyword we're removing was in the list of keywords to add,
+  // cut it from that list.
+  if (MsgFindKeyword(nsDependentCString(aKeyword), removeList, &startOffset, &keywordLength))
+  {
+    removeList.Cut(startOffset, keywordLength);
+    m_mdb->SetProperty(m_mdbRow, removeProp, removeList.get());
+  }
+  return m_mdb->SetProperty(m_mdbRow, addProp, addList.get());
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddKeywordToRemove(const char * aKeyword)
+{
+  SetOperation(kRemoveKeywords);
+  return AddKeyword(aKeyword, m_keywordsToRemove, PROP_KEYWORD_REMOVE, m_keywordsToAdd, PROP_KEYWORD_ADD);
+}
+
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::AddMessageCopyOperation(const char *destinationBox)
+{
+  SetOperation(kMsgCopy);
+  nsAutoCString newDest(destinationBox);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  m_copyDestinations.AppendElement(newDest);
+  return SetCopiesToDB();
+}
+
+// we write out the folders as one string, separated by 0x1.
+#define FOLDER_SEP_CHAR '\001'
+
+nsresult nsMsgOfflineImapOperation::GetCopiesFromDB()
+{
+  nsCString copyDests;
+  m_copyDestinations.Clear();
+  nsresult rv = m_mdb->GetProperty(m_mdbRow, PROP_COPY_DESTS, getter_Copies(copyDests));
+  // use 0x1 as the delimiter between folder names since it's not a legal character
+  if (NS_SUCCEEDED(rv) && !copyDests.IsEmpty())
+  {
+    int32_t curCopyDestStart = 0;
+    int32_t nextCopyDestPos = 0;
+
+    while (nextCopyDestPos != -1)
+    {
+      nsCString curDest;
+      nextCopyDestPos = copyDests.FindChar(FOLDER_SEP_CHAR, curCopyDestStart);
+      if (nextCopyDestPos > 0)
+        curDest = Substring(copyDests, curCopyDestStart, nextCopyDestPos - curCopyDestStart);
+      else
+        curDest = Substring(copyDests, curCopyDestStart, copyDests.Length() - curCopyDestStart);
+      curCopyDestStart = nextCopyDestPos + 1;
+      m_copyDestinations.AppendElement(curDest);
+    }
+  }
+  return rv;
+}
+
+nsresult nsMsgOfflineImapOperation::SetCopiesToDB()
+{
+  nsAutoCString copyDests;
+
+  // use 0x1 as the delimiter between folders
+  for (uint32_t i = 0; i < m_copyDestinations.Length(); i++)
+  {
+    if (i > 0)
+      copyDests.Append(FOLDER_SEP_CHAR);
+    copyDests.Append(m_copyDestinations.ElementAt(i));
+  }
+  return m_mdb->SetProperty(m_mdbRow, PROP_COPY_DESTS, copyDests.get());
+}
+
+/* attribute long numberOfCopies; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetNumberOfCopies(int32_t *aNumberOfCopies)
+{
+  NS_ENSURE_ARG(aNumberOfCopies);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  *aNumberOfCopies = m_copyDestinations.Length();
+  return NS_OK;
+}
+
+/* string getCopyDestination (in long copyIndex); */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetCopyDestination(int32_t copyIndex, char **retval)
+{
+  NS_ENSURE_ARG(retval);
+  nsresult rv = GetCopiesFromDB();
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (copyIndex >= (int32_t)m_copyDestinations.Length())
+    return NS_ERROR_ILLEGAL_VALUE;
+  *retval = ToNewCString(m_copyDestinations.ElementAt(copyIndex));
+  return (*retval) ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
+}
+
+/* attribute unsigned log msgSize; */
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetMsgSize(uint32_t *aMsgSize)
+{
+  NS_ENSURE_ARG(aMsgSize);
+  return m_mdb->GetUint32Property(m_mdbRow, PROP_MSG_SIZE, aMsgSize, 0);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetMsgSize(uint32_t aMsgSize)
+{
+  return m_mdb->SetUint32Property(m_mdbRow, PROP_MSG_SIZE, aMsgSize);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::SetPlayingBack(bool aPlayingBack)
+{
+  return m_mdb->SetBooleanProperty(m_mdbRow, PROP_PLAYINGBACK, aPlayingBack);
+}
+
+NS_IMETHODIMP nsMsgOfflineImapOperation::GetPlayingBack(bool *aPlayingBack)
+{
+  NS_ENSURE_ARG(aPlayingBack);
+  return m_mdb->GetBooleanProperty(m_mdbRow, PROP_PLAYINGBACK, aPlayingBack);
+}
+
+
+void nsMsgOfflineImapOperation::Log(PRLogModuleInfo *logFile)
+{
+  if (!IMAPOffline)
+    IMAPOffline = PR_NewLogModule("IMAPOFFLINE");
+  if (!MOZ_LOG_TEST(IMAPOffline, LogLevel::Info))
+    return;
+  //  const long kMoveResult              = 0x8;
+  //  const long kAppendDraft           = 0x10;
+  //  const long kAddedHeader           = 0x20;
+  //  const long kDeletedMsg              = 0x40;
+  //  const long kMsgMarkedDeleted = 0x80;
+  //  const long kAppendTemplate      = 0x100;
+  //  const long kDeleteAllMsgs          = 0x200;
+  if (m_operation & nsIMsgOfflineImapOperation::kFlagsChanged)
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x changeFlag:%x", m_messageKey, m_newFlags));
+  if (m_operation & nsIMsgOfflineImapOperation::kMsgMoved)
+  {
+    nsCString moveDestFolder;
+    GetDestinationFolderURI(getter_Copies(moveDestFolder));
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x moveTo:%s", m_messageKey, moveDestFolder.get()));
+  }
+  if (m_operation & nsIMsgOfflineImapOperation::kMsgCopy)
+  {
+    nsCString copyDests;
+    m_mdb->GetProperty(m_mdbRow, PROP_COPY_DESTS, getter_Copies(copyDests));
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x moveTo:%s", m_messageKey, copyDests.get()));
+  }
+  if (m_operation & nsIMsgOfflineImapOperation::kAppendDraft)
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x append draft", m_messageKey));
+  if (m_operation & nsIMsgOfflineImapOperation::kAddKeywords)
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x add keyword:%s", m_messageKey, m_keywordsToAdd.get()));
+  if (m_operation & nsIMsgOfflineImapOperation::kRemoveKeywords)
+    MOZ_LOG(IMAPOffline, LogLevel::Info, ("msg id %x remove keyword:%s", m_messageKey, m_keywordsToRemove.get()));
+}
diff --git a/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h b/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h
new file mode 100644
index 000000000..e892a253a
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMsgOfflineImapOperation.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _nsMsgOfflineImapOperation_H_
+
+#include "nsIMsgOfflineImapOperation.h"
+#include "mdb.h"
+#include "nsMsgDatabase.h"
+#include "prlog.h"
+
+class nsMsgOfflineImapOperation : public nsIMsgOfflineImapOperation
+{
+public:
+  /** Instance Methods **/
+  nsMsgOfflineImapOperation(nsMsgDatabase *db, nsIMdbRow *row);
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMSGOFFLINEIMAPOPERATION
+
+
+  nsIMdbRow   *GetMDBRow() {return m_mdbRow;}
+  nsresult    GetCopiesFromDB();
+  nsresult    SetCopiesToDB();
+  void        Log(PRLogModuleInfo *logFile);
+protected:
+  virtual ~nsMsgOfflineImapOperation();
+  nsresult AddKeyword(const char *aKeyword, nsCString &addList, const char *addProp,
+                      nsCString &removeList, const char *removeProp);
+
+  nsOfflineImapOperationType m_operation;
+  nsMsgKey          m_messageKey;
+  nsMsgKey          m_sourceMessageKey;
+  uint32_t          m_operationFlags; // what to do on sync
+  imapMessageFlagsType m_newFlags; // used for kFlagsChanged
+
+  // these are URI's, and are escaped. Thus, we can use a delimter like ' '
+  // because the real spaces should be escaped.
+  nsCString  m_sourceFolder;
+  nsCString  m_moveDestination;
+  nsTArray<nsCString>  m_copyDestinations;
+
+  nsCString      m_keywordsToAdd;
+  nsCString      m_keywordsToRemove;
+
+  // nsMsgOfflineImapOperation will have to know what db and row they belong to, since they are really
+  // just a wrapper around the offline operation row in the mdb.
+  // though I hope not.
+  nsMsgDatabase    *m_mdb;
+  nsCOMPtr <nsIMdbRow> m_mdbRow;
+};
+
+
+
+#endif /* _nsMsgOfflineImapOperation_H_ */
+
diff --git a/mailnews/db/msgdb/src/nsMsgThread.cpp b/mailnews/db/msgdb/src/nsMsgThread.cpp
new file mode 100644
index 000000000..0d8ad3d85
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsMsgThread.cpp
@@ -0,0 +1,1180 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "nsMsgDatabase.h"
+#include "nsCOMPtr.h"
+#include "nsMsgThread.h"
+#include "MailNewsTypes2.h"
+#include "mozilla/DebugOnly.h"
+
+NS_IMPL_ISUPPORTS(nsMsgThread, nsIMsgThread)
+
+nsMsgThread::nsMsgThread()
+{
+  MOZ_COUNT_CTOR(nsMsgThread);
+  Init();
+}
+nsMsgThread::nsMsgThread(nsMsgDatabase *db, nsIMdbTable *table)
+{
+  MOZ_COUNT_CTOR(nsMsgThread);
+  Init();
+  m_mdbTable = table;
+  m_mdbDB = db;
+  if (db)
+    db->m_threads.AppendElement(this);
+  else
+    NS_ERROR("no db for thread");
+#ifdef DEBUG_David_Bienvenu
+  if (m_mdbDB->m_threads.Length() > 5)
+    printf("more than five outstanding threads\n");
+#endif
+  if (table && db)
+  {
+    table->GetMetaRow(db->GetEnv(), nullptr, nullptr, getter_AddRefs(m_metaRow));
+    InitCachedValues();
+  }
+}
+
+void nsMsgThread::Init()
+{
+  m_threadKey = nsMsgKey_None;
+  m_threadRootKey = nsMsgKey_None;
+  m_numChildren = 0;
+  m_numUnreadChildren = 0;
+  m_flags = 0;
+  m_newestMsgDate = 0;
+  m_cachedValuesInitialized = false;
+}
+
+nsMsgThread::~nsMsgThread()
+{
+  MOZ_COUNT_DTOR(nsMsgThread);
+  if (m_mdbDB)
+  {
+    mozilla::DebugOnly<bool> found = m_mdbDB->m_threads.RemoveElement(this);
+    NS_ASSERTION(found, "removing thread not in threads array");
+  }
+  else // This can happen if db is forced closed
+    NS_WARNING("null db in thread");
+  Clear();
+}
+
+void nsMsgThread::Clear()
+{
+  m_mdbTable = nullptr;
+  m_metaRow = nullptr;
+  m_mdbDB = nullptr;
+}
+
+nsresult nsMsgThread::InitCachedValues()
+{
+  nsresult err = NS_OK;
+
+  NS_ENSURE_TRUE(m_mdbDB && m_metaRow, NS_ERROR_INVALID_POINTER);
+
+  if (!m_cachedValuesInitialized)
+  {
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadFlagsColumnToken, &m_flags);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadChildrenColumnToken, &m_numChildren);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadIdColumnToken, &m_threadKey, nsMsgKey_None);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken, &m_numUnreadChildren);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadRootKeyColumnToken, &m_threadRootKey, nsMsgKey_None);
+    err = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadNewestMsgDateColumnToken, &m_newestMsgDate, 0);
+    // fix num children if it's wrong. this doesn't work - some DB's have a bogus thread table
+    // that is full of bogus headers - don't know why.
+    uint32_t rowCount = 0;
+    m_mdbTable->GetCount(m_mdbDB->GetEnv(), &rowCount);
+    //    NS_ASSERTION(m_numChildren <= rowCount, "num children wrong - fixing");
+    if (m_numChildren > rowCount)
+      ChangeChildCount((int32_t) rowCount - (int32_t) m_numChildren);
+    if ((int32_t) m_numUnreadChildren < 0)
+      ChangeUnreadChildCount(- (int32_t) m_numUnreadChildren);
+    if (NS_SUCCEEDED(err))
+      m_cachedValuesInitialized = true;
+  }
+  return err;
+}
+
+NS_IMETHODIMP nsMsgThread::SetThreadKey(nsMsgKey threadKey)
+{
+  NS_ASSERTION(m_threadKey == nsMsgKey_None || m_threadKey == threadKey,
+               "shouldn't be changing thread key");
+  m_threadKey = threadKey;
+  // by definition, the initial thread key is also the thread root key.
+  SetThreadRootKey(threadKey);
+  // gotta set column in meta row here.
+  return m_mdbDB->UInt32ToRowCellColumn(
+                    m_metaRow, m_mdbDB->m_threadIdColumnToken, threadKey);
+}
+
+NS_IMETHODIMP nsMsgThread::GetThreadKey(nsMsgKey *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  nsresult res = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadIdColumnToken, &m_threadKey);
+  *result = m_threadKey;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgThread::GetFlags(uint32_t *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  nsresult res = m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadFlagsColumnToken, &m_flags);
+  *result = m_flags;
+  return res;
+}
+
+NS_IMETHODIMP nsMsgThread::SetFlags(uint32_t flags)
+{
+  m_flags = flags;
+  return m_mdbDB->UInt32ToRowCellColumn(
+                    m_metaRow, m_mdbDB->m_threadFlagsColumnToken, m_flags);
+}
+
+NS_IMETHODIMP nsMsgThread::SetSubject(const nsACString& aSubject)
+{
+  return m_mdbDB->CharPtrToRowCellColumn(m_metaRow, m_mdbDB->m_threadSubjectColumnToken, nsCString(aSubject).get());
+}
+
+NS_IMETHODIMP nsMsgThread::GetSubject(nsACString& aSubject)
+{
+  nsCString subjectStr;
+  nsresult rv = m_mdbDB->RowCellColumnToCharPtr(m_metaRow, m_mdbDB->m_threadSubjectColumnToken, 
+                                                getter_Copies(subjectStr));
+
+  aSubject.Assign(subjectStr);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetNumChildren(uint32_t *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_numChildren;
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP nsMsgThread::GetNumUnreadChildren (uint32_t *result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  *result = m_numUnreadChildren;
+  return NS_OK;
+}
+
+nsresult nsMsgThread::RerootThread(nsIMsgDBHdr *newParentOfOldRoot, nsIMsgDBHdr *oldRoot, nsIDBChangeAnnouncer *announcer)
+{
+  nsresult rv = NS_OK;
+  mdb_pos outPos;
+  nsMsgKey newHdrAncestor;
+  nsCOMPtr <nsIMsgDBHdr> ancestorHdr = newParentOfOldRoot;
+  nsMsgKey newRoot;
+
+  ancestorHdr->GetMessageKey(&newRoot);
+  // loop trying to find the oldest ancestor of this msg
+  // that is a parent of the root. The oldest ancestor will
+  // become the root of the thread.
+  do
+  {
+    ancestorHdr->GetThreadParent(&newHdrAncestor);
+    if (newHdrAncestor != nsMsgKey_None && newHdrAncestor != m_threadRootKey && newHdrAncestor != newRoot)
+    {
+      newRoot = newHdrAncestor;
+      rv = m_mdbDB->GetMsgHdrForKey(newRoot, getter_AddRefs(ancestorHdr));
+    }
+  }
+  while (NS_SUCCEEDED(rv) && ancestorHdr && newHdrAncestor != nsMsgKey_None && newHdrAncestor != m_threadRootKey
+    && newHdrAncestor != newRoot);
+  SetThreadRootKey(newRoot);
+  ReparentNonReferenceChildrenOf(oldRoot, newRoot, announcer);
+  if (ancestorHdr)
+  {
+    nsIMsgDBHdr *msgHdr = ancestorHdr;
+    nsMsgHdr* rootMsgHdr = static_cast<nsMsgHdr*>(msgHdr);          // closed system, cast ok
+    nsIMdbRow *newRootHdrRow = rootMsgHdr->GetMDBRow();
+    // move the  root hdr to pos 0.
+    m_mdbTable->MoveRow(m_mdbDB->GetEnv(), newRootHdrRow, -1, 0, &outPos);
+    ancestorHdr->SetThreadParent(nsMsgKey_None);
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::AddChild(nsIMsgDBHdr *child, nsIMsgDBHdr *inReplyTo, bool threadInThread,
+                                    nsIDBChangeAnnouncer *announcer)
+{
+  nsresult rv = NS_OK;
+  nsMsgHdr* hdr = static_cast<nsMsgHdr*>(child);          // closed system, cast ok
+  uint32_t newHdrFlags = 0;
+  uint32_t msgDate;
+  nsMsgKey newHdrKey = 0;
+  bool parentKeyNeedsSetting = true;
+
+  nsIMdbRow *hdrRow = hdr->GetMDBRow();
+  NS_ENSURE_STATE(hdrRow);
+  hdr->GetRawFlags(&newHdrFlags);
+  hdr->GetMessageKey(&newHdrKey);
+  hdr->GetDateInSeconds(&msgDate);
+  if (msgDate > m_newestMsgDate)
+    SetNewestMsgDate(msgDate);
+
+  if (newHdrFlags & nsMsgMessageFlags::Watched)
+    SetFlags(m_flags | nsMsgMessageFlags::Watched);
+
+  child->AndFlags(~(nsMsgMessageFlags::Watched), &newHdrFlags);
+  
+  // These are threading flags that the child may have set before being added
+  // to the database.
+  uint32_t protoThreadFlags;
+  child->GetUint32Property("ProtoThreadFlags", &protoThreadFlags);
+  SetFlags(m_flags | protoThreadFlags);
+  // Clear the flag so that it doesn't fudge anywhere else
+  child->SetUint32Property("ProtoThreadFlags", 0);
+
+  uint32_t numChildren;
+  uint32_t childIndex = 0;
+
+  // get the num children before we add the new header.
+  GetNumChildren(&numChildren);
+
+  // if this is an empty thread, set the root key to this header's key
+  if (numChildren == 0)
+    SetThreadRootKey(newHdrKey);
+
+  if (m_mdbTable)
+  {
+    m_mdbTable->AddRow(m_mdbDB->GetEnv(), hdrRow);
+    ChangeChildCount(1);
+    if (! (newHdrFlags & nsMsgMessageFlags::Read))
+      ChangeUnreadChildCount(1);
+  }
+  if (inReplyTo)
+  {
+    nsMsgKey parentKey;
+    inReplyTo->GetMessageKey(&parentKey);
+    child->SetThreadParent(parentKey);
+    parentKeyNeedsSetting = false;
+  }
+
+  // check if this header is a parent of one of the messages in this thread
+  bool hdrMoved = false;
+  nsCOMPtr <nsIMsgDBHdr> curHdr;
+  uint32_t moveIndex = 0;
+
+  PRTime newHdrDate;
+  child->GetDate(&newHdrDate);
+
+  // This is an ugly but simple fix for a difficult problem. Basically, when we add
+  // a message to a thread, we have to run through the thread to see if the new
+  // message is a parent of an existing message in the thread, and adjust things
+  // accordingly. If you thread by subject, and you have a large folder with
+  // messages w/ all the same subject, this code can take a really long time. So the
+  // pragmatic thing is to say that for threads with more than 1000 messages, it's
+  // simply not worth dealing with the case where the parent comes in after the
+  // child. Threads with more than 1000 messages are pretty unwieldy anyway.
+  // See Bug 90452
+
+  if (numChildren < 1000)
+  {
+    for (childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      nsMsgKey msgKey = nsMsgKey_None;
+
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      if (NS_SUCCEEDED(rv) && curHdr)
+      {
+        if (hdr->IsParentOf(curHdr))
+        {
+          nsMsgKey oldThreadParent;
+          mdb_pos outPos;
+          // move this hdr before the current header.
+          if (!hdrMoved)
+          {
+            m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, childIndex, &outPos);
+            hdrMoved = true;
+            curHdr->GetThreadParent(&oldThreadParent);
+            curHdr->GetMessageKey(&msgKey);
+            nsCOMPtr <nsIMsgDBHdr> curParent;
+            m_mdbDB->GetMsgHdrForKey(oldThreadParent, getter_AddRefs(curParent));
+            if (curParent && hdr->IsAncestorOf(curParent))
+            {
+              nsMsgKey curParentKey;
+              curParent->GetMessageKey(&curParentKey);
+              if (curParentKey == m_threadRootKey)
+              {
+                m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, 0, &outPos);
+                RerootThread(child, curParent, announcer);
+                parentKeyNeedsSetting = false;
+              }
+            }
+            else if (msgKey == m_threadRootKey)
+            {
+              RerootThread(child, curHdr, announcer);
+              parentKeyNeedsSetting = false;
+            }
+          }
+          curHdr->SetThreadParent(newHdrKey);
+          // TODO: what should be msgKey if hdrMoved was true above?
+          if (msgKey == newHdrKey)
+            parentKeyNeedsSetting = false;
+
+          // OK, this is a reparenting - need to send notification
+          if (announcer)
+            announcer->NotifyParentChangedAll(msgKey, oldThreadParent, newHdrKey, nullptr);
+#ifdef DEBUG_bienvenu1
+          if (newHdrKey != m_threadKey)
+            printf("adding second level child\n");
+#endif
+        }
+        // Calculate a position for this child in date order
+        else if (!hdrMoved && childIndex > 0 && moveIndex == 0)
+        {
+          PRTime curHdrDate;
+
+          curHdr->GetDate(&curHdrDate);
+          if (newHdrDate < curHdrDate)
+            moveIndex = childIndex;
+        }
+      }
+    }
+  }
+  // If this header is not a reply to a header in the thread, and isn't a parent
+  // check to see if it starts with Re: - if not, and the first header does start
+  // with re, should we make this header the top level header?
+  // If it's date is less (or it's ID?), then yes.
+  if (numChildren > 0 && !(newHdrFlags & nsMsgMessageFlags::HasRe) && !inReplyTo)
+  {
+    PRTime topLevelHdrDate;
+
+    nsCOMPtr <nsIMsgDBHdr> topLevelHdr;
+    rv = GetRootHdr(nullptr, getter_AddRefs(topLevelHdr));
+    if (NS_SUCCEEDED(rv) && topLevelHdr)
+    {
+      topLevelHdr->GetDate(&topLevelHdrDate);
+      if (newHdrDate < topLevelHdrDate)
+      {
+        RerootThread(child, topLevelHdr, announcer);
+        mdb_pos outPos;
+        m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, 0, &outPos);
+        hdrMoved = true;
+        topLevelHdr->SetThreadParent(newHdrKey);
+        parentKeyNeedsSetting = false;
+        // ### need to get ancestor of new hdr here too.
+        SetThreadRootKey(newHdrKey);
+        child->SetThreadParent(nsMsgKey_None);
+        // argh, here we'd need to adjust all the headers that listed
+        // the demoted header as their thread parent, but only because
+        // of subject threading. Adjust them to point to the new parent,
+        // that is.
+        ReparentNonReferenceChildrenOf(topLevelHdr, newHdrKey, announcer);
+      }
+    }
+  }
+  // OK, check to see if we added this header, and didn't parent it.
+
+  if (numChildren > 0 && parentKeyNeedsSetting)
+    child->SetThreadParent(m_threadRootKey);
+
+  // Move child to keep thread sorted in ascending date order
+  if (!hdrMoved && moveIndex > 0)
+  {
+    mdb_pos outPos;
+    m_mdbTable->MoveRow(m_mdbDB->GetEnv(), hdrRow, -1, moveIndex, &outPos);
+  }
+
+  // do this after we've put the new hdr in the thread
+  bool isKilled;
+  child->GetIsKilled(&isKilled);
+  if ((m_flags & nsMsgMessageFlags::Ignored || isKilled) && m_mdbDB)
+    m_mdbDB->MarkHdrRead(child, true, nullptr);
+#ifdef DEBUG_David_Bienvenu
+  nsMsgKey msgHdrThreadKey;
+  child->GetThreadId(&msgHdrThreadKey);
+  NS_ASSERTION(msgHdrThreadKey == m_threadKey, "adding msg to thread it doesn't belong to");
+#endif
+#ifdef DEBUG_bienvenu1
+  nsMsgDatabase *msgDB = static_cast<nsMsgDatabase*>(m_mdbDB);
+  msgDB->DumpThread(m_threadRootKey);
+#endif
+  return rv;
+}
+
+nsresult nsMsgThread::ReparentNonReferenceChildrenOf(nsIMsgDBHdr *oldTopLevelHdr, nsMsgKey newParentKey,
+                                                            nsIDBChangeAnnouncer *announcer)
+{
+  nsCOMPtr <nsIMsgDBHdr> curHdr;
+  uint32_t numChildren;
+  uint32_t childIndex = 0;
+
+  GetNumChildren(&numChildren);
+  for (childIndex = 0; childIndex < numChildren; childIndex++)
+  {
+    nsMsgKey oldTopLevelHdrKey;
+
+    oldTopLevelHdr->GetMessageKey(&oldTopLevelHdrKey);
+    nsresult rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+    if (NS_SUCCEEDED(rv) && curHdr)
+    {
+      nsMsgKey oldThreadParent, curHdrKey;
+      nsMsgHdr* oldTopLevelMsgHdr = static_cast<nsMsgHdr*>(oldTopLevelHdr);      // closed system, cast ok
+      curHdr->GetThreadParent(&oldThreadParent);
+      curHdr->GetMessageKey(&curHdrKey);
+      if (oldThreadParent == oldTopLevelHdrKey && curHdrKey != newParentKey && !oldTopLevelMsgHdr->IsParentOf(curHdr))
+      {
+        curHdr->GetThreadParent(&oldThreadParent);
+        curHdr->SetThreadParent(newParentKey);
+        // OK, this is a reparenting - need to send notification
+        if (announcer)
+          announcer->NotifyParentChangedAll(curHdrKey, oldThreadParent, newParentKey, nullptr);
+      }
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChildKeyAt(uint32_t aIndex, nsMsgKey *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  nsresult rv;
+
+  if (aIndex >= m_numChildren)
+  {
+    *aResult = nsMsgKey_None;
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  mdbOid oid;
+  rv = m_mdbTable->PosToOid( m_mdbDB->GetEnv(), aIndex, &oid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aResult = oid.mOid_Id;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChildHdrAt(uint32_t aIndex, nsIMsgDBHdr **result)
+{
+  // mork doesn't seem to handle this correctly, so deal with going off
+  // the end here.
+  if (aIndex >= m_numChildren)
+    return NS_MSG_MESSAGE_NOT_FOUND;
+  mdbOid oid;
+  nsresult rv = m_mdbTable->PosToOid( m_mdbDB->GetEnv(), aIndex, &oid);
+  NS_ENSURE_SUCCESS(rv, NS_MSG_MESSAGE_NOT_FOUND);
+  nsIMdbRow *hdrRow = nullptr;
+  rv = m_mdbTable->PosToRow(m_mdbDB->GetEnv(), aIndex, &hdrRow);
+  NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hdrRow, NS_ERROR_FAILURE);
+  // CreateMsgHdr takes ownership of the hdrRow reference.
+  rv = m_mdbDB->CreateMsgHdr(hdrRow,  oid.mOid_Id , result);
+  return (NS_SUCCEEDED(rv)) ? NS_OK : NS_MSG_MESSAGE_NOT_FOUND;
+}
+
+NS_IMETHODIMP nsMsgThread::GetChild(nsMsgKey msgKey, nsIMsgDBHdr **result)
+{
+  nsresult rv;
+
+  mdb_bool hasOid;
+  mdbOid rowObjectId;
+
+  NS_ENSURE_ARG_POINTER(result);
+  NS_ENSURE_TRUE(m_mdbTable, NS_ERROR_INVALID_POINTER);
+
+  *result = NULL;
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_mdbDB->m_hdrRowScopeToken;
+  rv = m_mdbTable->HasOid(m_mdbDB->GetEnv(), &rowObjectId, &hasOid);
+
+  if (NS_SUCCEEDED(rv) && hasOid && m_mdbDB && m_mdbDB->m_mdbStore)
+  {
+    nsIMdbRow *hdrRow = nullptr;
+    rv = m_mdbDB->m_mdbStore->GetRow(m_mdbDB->GetEnv(), &rowObjectId,  &hdrRow);
+    NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hdrRow, NS_ERROR_FAILURE);
+    rv = m_mdbDB->CreateMsgHdr(hdrRow,  msgKey, result);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::RemoveChildAt(uint32_t aIndex)
+{
+  return NS_OK;
+}
+
+nsresult nsMsgThread::RemoveChild(nsMsgKey msgKey)
+{
+  nsresult rv;
+
+  mdbOid  rowObjectId;
+  rowObjectId.mOid_Id = msgKey;
+  rowObjectId.mOid_Scope = m_mdbDB->m_hdrRowScopeToken;
+  rv = m_mdbTable->CutOid(m_mdbDB->GetEnv(), &rowObjectId);
+  // if this thread is empty, remove it from the all threads table.
+  if (m_numChildren == 0 && m_mdbDB->m_mdbAllThreadsTable)
+  {
+    mdbOid rowID;
+    rowID.mOid_Id = m_threadKey;
+    rowID.mOid_Scope = m_mdbDB->m_threadRowScopeToken;
+
+    m_mdbDB->m_mdbAllThreadsTable->CutOid(m_mdbDB->GetEnv(), &rowID);
+  }
+#if 0 // this seems to cause problems
+  if (m_numChildren == 0 && m_metaRow && m_mdbDB)
+    m_metaRow->CutAllColumns(m_mdbDB->GetEnv());
+#endif
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::RemoveChildHdr(nsIMsgDBHdr *child, nsIDBChangeAnnouncer *announcer)
+{
+  uint32_t flags;
+  nsMsgKey key;
+  nsMsgKey threadParent;
+
+  NS_ENSURE_ARG_POINTER(child);
+
+  child->GetFlags(&flags);
+  child->GetMessageKey(&key);
+
+  child->GetThreadParent(&threadParent);
+  ReparentChildrenOf(key, threadParent, announcer);
+
+  // if this was the newest msg, clear the newest msg date so we'll recalc.
+  uint32_t date;
+  child->GetDateInSeconds(&date);
+  if (date == m_newestMsgDate)
+    SetNewestMsgDate(0);
+
+ if (!(flags & nsMsgMessageFlags::Read))
+    ChangeUnreadChildCount(-1);
+  ChangeChildCount(-1);
+  return RemoveChild(key);
+}
+
+nsresult nsMsgThread::ReparentChildrenOf(nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeAnnouncer *announcer)
+{
+  nsresult rv = NS_OK;
+
+  uint32_t numChildren;
+  uint32_t childIndex = 0;
+
+  GetNumChildren(&numChildren);
+
+  nsCOMPtr <nsIMsgDBHdr> curHdr;
+  if (numChildren > 0)
+  {
+    for (childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(curHdr));
+      if (NS_SUCCEEDED(rv) && curHdr)
+      {
+        nsMsgKey threadParent;
+
+        curHdr->GetThreadParent(&threadParent);
+        if (threadParent == oldParent)
+        {
+          nsMsgKey curKey;
+
+          curHdr->SetThreadParent(newParent);
+          curHdr->GetMessageKey(&curKey);
+          if (announcer)
+            announcer->NotifyParentChangedAll(curKey, oldParent, newParent, nullptr);
+          // if the old parent was the root of the thread, then only the first child gets
+          // promoted to root, and other children become children of the new root.
+          if (newParent == nsMsgKey_None)
+          {
+            SetThreadRootKey(curKey);
+            newParent = curKey;
+          }
+        }
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::MarkChildRead(bool bRead)
+{
+  ChangeUnreadChildCount(bRead ? -1 : 1);
+  return NS_OK;
+}
+
+class nsMsgThreadEnumerator : public nsISimpleEnumerator {
+public:
+  NS_DECL_ISUPPORTS
+
+  // nsISimpleEnumerator methods:
+  NS_DECL_NSISIMPLEENUMERATOR
+
+  // nsMsgThreadEnumerator methods:
+  typedef nsresult (*nsMsgThreadEnumeratorFilter)(nsIMsgDBHdr* hdr, void* closure);
+
+  nsMsgThreadEnumerator(nsMsgThread *thread, nsMsgKey startKey,
+  nsMsgThreadEnumeratorFilter filter, void* closure);
+  int32_t MsgKeyFirstChildIndex(nsMsgKey inMsgKey);
+
+protected:
+  virtual ~nsMsgThreadEnumerator();
+
+  nsresult                Prefetch();
+
+  nsIMdbTableRowCursor*   mRowCursor;
+  nsCOMPtr <nsIMsgDBHdr>  mResultHdr;
+  nsMsgThread*            mThread;
+  nsMsgKey                mThreadParentKey;
+  nsMsgKey                mFirstMsgKey;
+  int32_t                 mChildIndex;
+  bool                    mDone;
+  bool                    mNeedToPrefetch;
+  nsMsgThreadEnumeratorFilter     mFilter;
+  void*                   mClosure;
+  bool                    mFoundChildren;
+};
+
+nsMsgThreadEnumerator::nsMsgThreadEnumerator(nsMsgThread *thread, nsMsgKey startKey,
+                                             nsMsgThreadEnumeratorFilter filter, void* closure)
+                                             : mRowCursor(nullptr), mDone(false),
+                                             mFilter(filter), mClosure(closure), mFoundChildren(false)
+{
+  mThreadParentKey = startKey;
+  mChildIndex = 0;
+  mThread = thread;
+  mNeedToPrefetch = true;
+  mFirstMsgKey = nsMsgKey_None;
+
+  nsresult rv = mThread->GetRootHdr(nullptr, getter_AddRefs(mResultHdr));
+
+  if (NS_SUCCEEDED(rv) && mResultHdr)
+    mResultHdr->GetMessageKey(&mFirstMsgKey);
+
+  uint32_t numChildren;
+  mThread->GetNumChildren(&numChildren);
+
+  if (mThreadParentKey != nsMsgKey_None)
+  {
+    nsMsgKey msgKey = nsMsgKey_None;
+    uint32_t childIndex = 0;
+
+
+    for (childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      rv = mThread->GetChildHdrAt(childIndex, getter_AddRefs(mResultHdr));
+      if (NS_SUCCEEDED(rv) && mResultHdr)
+      {
+        mResultHdr->GetMessageKey(&msgKey);
+
+        if (msgKey == startKey)
+        {
+          mChildIndex = MsgKeyFirstChildIndex(msgKey);
+          mDone = (mChildIndex < 0);
+          break;
+        }
+
+        if (mDone)
+          break;
+
+      }
+      else
+        NS_ASSERTION(false, "couldn't get child from thread");
+    }
+  }
+
+#ifdef DEBUG_bienvenu1
+  nsCOMPtr <nsIMsgDBHdr> child;
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+  {
+    rv = mThread->GetChildHdrAt(childIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child)
+    {
+      nsMsgKey threadParent;
+      nsMsgKey msgKey;
+      // we're only doing one level of threading, so check if caller is
+      // asking for children of the first message in the thread or not.
+      // if not, we will tell him there are no children.
+      child->GetMessageKey(&msgKey);
+      child->GetThreadParent(&threadParent);
+
+      printf("index = %ld key = %ld parent = %lx\n", childIndex, msgKey, threadParent);
+    }
+  }
+#endif
+  NS_ADDREF(thread);
+}
+
+nsMsgThreadEnumerator::~nsMsgThreadEnumerator()
+{
+    NS_RELEASE(mThread);
+}
+
+NS_IMPL_ISUPPORTS(nsMsgThreadEnumerator, nsISimpleEnumerator)
+
+
+int32_t nsMsgThreadEnumerator::MsgKeyFirstChildIndex(nsMsgKey inMsgKey)
+{
+  //	if (msgKey != mThreadParentKey)
+  //		mDone = true;
+  // look through rest of thread looking for a child of this message.
+  // If the inMsgKey is the first message in the thread, then all children
+  // without parents are considered to be children of inMsgKey.
+  // Otherwise, only true children qualify.
+  uint32_t numChildren;
+  nsCOMPtr <nsIMsgDBHdr> curHdr;
+  int32_t firstChildIndex = -1;
+
+  mThread->GetNumChildren(&numChildren);
+
+  // if this is the first message in the thread, just check if there's more than
+  // one message in the thread.
+  // if (inMsgKey == mThread->m_threadRootKey)
+  // return (numChildren > 1) ? 1 : -1;
+
+  for (uint32_t curChildIndex = 0; curChildIndex < numChildren; curChildIndex++)
+  {
+    nsresult rv = mThread->GetChildHdrAt(curChildIndex, getter_AddRefs(curHdr));
+    if (NS_SUCCEEDED(rv) && curHdr)
+    {
+      nsMsgKey parentKey;
+
+      curHdr->GetThreadParent(&parentKey);
+      if (parentKey == inMsgKey)
+      {
+        firstChildIndex = curChildIndex;
+        break;
+      }
+    }
+  }
+#ifdef DEBUG_bienvenu1
+  printf("first child index of %ld = %ld\n", inMsgKey, firstChildIndex);
+#endif
+  return firstChildIndex;
+}
+
+NS_IMETHODIMP nsMsgThreadEnumerator::GetNext(nsISupports **aItem)
+{
+  NS_ENSURE_ARG_POINTER(aItem);
+  nsresult rv;
+
+  if (mNeedToPrefetch)
+  {
+    rv = Prefetch();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }  
+
+  if (mResultHdr)
+  {
+    *aItem = mResultHdr;
+    NS_ADDREF(*aItem);
+    mNeedToPrefetch = true;
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgThreadEnumerator::Prefetch()
+{
+  nsresult rv=NS_OK;          // XXX or should this default to an error?
+  mResultHdr = nullptr;
+  if (mThreadParentKey == nsMsgKey_None)
+  {
+    rv = mThread->GetRootHdr(&mChildIndex, getter_AddRefs(mResultHdr));
+    NS_ASSERTION(NS_SUCCEEDED(rv) && mResultHdr, "better be able to get root hdr");
+    mChildIndex = 0; // since root can be anywhere, set mChildIndex to 0.
+  }
+  else if (!mDone)
+  {
+    uint32_t numChildren;
+    mThread->GetNumChildren(&numChildren);
+
+    while (mChildIndex < (int32_t) numChildren)
+    {
+      rv  = mThread->GetChildHdrAt(mChildIndex++, getter_AddRefs(mResultHdr));
+      if (NS_SUCCEEDED(rv) && mResultHdr)
+      {
+        nsMsgKey parentKey;
+        nsMsgKey curKey;
+
+        if (mFilter && NS_FAILED(mFilter(mResultHdr, mClosure))) {
+          mResultHdr = nullptr;
+          continue;
+        }
+
+        mResultHdr->GetThreadParent(&parentKey);
+        mResultHdr->GetMessageKey(&curKey);
+        // if the parent is the same as the msg we're enumerating over,
+        // or the parentKey isn't set, and we're iterating over the top
+        // level message in the thread, then leave mResultHdr set to cur msg.
+        if (parentKey == mThreadParentKey ||
+          (parentKey == nsMsgKey_None
+          && mThreadParentKey == mFirstMsgKey && curKey != mThreadParentKey))
+          break;
+        mResultHdr = nullptr;
+      }
+      else
+        NS_ASSERTION(false, "better be able to get child");
+    }
+    if (!mResultHdr && mThreadParentKey == mFirstMsgKey && !mFoundChildren && numChildren > 1)
+      mThread->ReparentMsgsWithInvalidParent(numChildren, mThreadParentKey);
+  }
+  if (!mResultHdr)
+  {
+    mDone = true;
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_FAILED(rv))
+  {
+    mDone = true;
+    return rv;
+  }
+  else
+    mNeedToPrefetch = false;
+  mFoundChildren = true;
+
+#ifdef DEBUG_bienvenu1
+	nsMsgKey debugMsgKey;
+	mResultHdr->GetMessageKey(&debugMsgKey);
+	printf("next for %ld = %ld\n", mThreadParentKey, debugMsgKey);
+#endif
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThreadEnumerator::HasMoreElements(bool *aResult)
+{
+  NS_ENSURE_ARG_POINTER(aResult);
+  if (mNeedToPrefetch)
+    Prefetch();
+  *aResult = !mDone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsMsgThread::EnumerateMessages(nsMsgKey parentKey, nsISimpleEnumerator* *result)
+{
+  nsMsgThreadEnumerator* e = new nsMsgThreadEnumerator(this, parentKey, nullptr, nullptr);
+  NS_ENSURE_TRUE(e, NS_ERROR_OUT_OF_MEMORY);
+  NS_ADDREF(*result = e);
+  return NS_OK;
+}
+
+nsresult nsMsgThread::ReparentMsgsWithInvalidParent(uint32_t numChildren, nsMsgKey threadParentKey)
+{
+  nsresult rv = NS_OK;
+  // run through looking for messages that don't have a correct parent,
+  // i.e., a parent that's in the thread!
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+  {
+    nsCOMPtr <nsIMsgDBHdr> curChild;
+    rv  = GetChildHdrAt(childIndex, getter_AddRefs(curChild));
+    if (NS_SUCCEEDED(rv) && curChild)
+    {
+      nsMsgKey parentKey;
+      nsCOMPtr <nsIMsgDBHdr> parent;
+
+      curChild->GetThreadParent(&parentKey);
+
+      if (parentKey != nsMsgKey_None)
+      {
+        GetChild(parentKey, getter_AddRefs(parent));
+        if (!parent)
+          curChild->SetThreadParent(threadParentKey);
+        else
+        {
+          nsMsgKey childKey;
+          curChild->GetMessageKey(&childKey);
+          // can't be your own parent; set parent to thread parent,
+          // or make ourselves the root if we are the root.
+          if (childKey == parentKey)
+            curChild->SetThreadParent(m_threadRootKey == childKey ? 
+                                      nsMsgKey_None : m_threadRootKey);
+        }
+      }
+    }
+  }
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetRootHdr(int32_t *resultIndex, nsIMsgDBHdr **result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+
+  *result = nullptr;
+  nsresult rv = NS_OK;
+
+  if (m_threadRootKey != nsMsgKey_None)
+  {
+    rv = GetChildHdrForKey(m_threadRootKey, result, resultIndex);
+    if (NS_SUCCEEDED(rv) && *result)
+    {
+      // check that we're really the root key.
+      nsMsgKey parentKey;
+      (*result)->GetThreadParent(&parentKey);
+      if (parentKey == nsMsgKey_None)
+        return rv;
+      NS_RELEASE(*result);
+    }
+#ifdef DEBUG_David_Bienvenu
+    printf("need to reset thread root key\n");
+#endif
+    uint32_t numChildren;
+    nsMsgKey threadParentKey = nsMsgKey_None;
+    GetNumChildren(&numChildren);
+
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      nsCOMPtr <nsIMsgDBHdr> curChild;
+      rv  = GetChildHdrAt(childIndex, getter_AddRefs(curChild));
+      if (NS_SUCCEEDED(rv) && curChild)
+      {
+        nsMsgKey parentKey;
+
+        curChild->GetThreadParent(&parentKey);
+        if (parentKey == nsMsgKey_None)
+        {
+          curChild->GetMessageKey(&threadParentKey);
+          if (*result)
+          {
+            NS_WARNING("two top level msgs, not good");
+            continue;
+          }
+          SetThreadRootKey(threadParentKey);
+          if (resultIndex)
+            *resultIndex = childIndex;
+          NS_ADDREF(*result = curChild);
+          ReparentMsgsWithInvalidParent(numChildren, threadParentKey);
+          //            return NS_OK;
+        }
+      }
+    }
+  }
+  if (!*result)
+  {
+    // if we can't get the thread root key, we'll just get the first hdr.
+    // there's a bug where sometimes we weren't resetting the thread root key
+    // when removing the thread root key.
+    if (resultIndex)
+      *resultIndex = 0;
+    rv = GetChildHdrAt(0, result);
+  }
+  if (!*result)
+    return rv;
+  // Check that the thread id of the message is this thread.
+  nsMsgKey threadId = nsMsgKey_None;
+  (void)(*result)->GetThreadId(&threadId);
+  if (threadId != m_threadKey)
+    (*result)->SetThreadId(m_threadKey);
+  return rv;
+}
+
+nsresult nsMsgThread::ChangeChildCount(int32_t delta)
+{
+  nsresult rv;
+
+  uint32_t childCount = 0;
+  m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadChildrenColumnToken, childCount);
+
+  NS_WARNING_ASSERTION(childCount != 0 || delta > 0, "child count gone negative");
+  childCount += delta;
+
+  NS_WARNING_ASSERTION((int32_t) childCount >= 0, "child count gone to 0 or below");
+  if ((int32_t) childCount < 0)	// force child count to >= 0
+    childCount = 0;
+
+  rv = m_mdbDB->UInt32ToRowCellColumn(m_metaRow, m_mdbDB->m_threadChildrenColumnToken, childCount);
+  m_numChildren = childCount;
+  return rv;
+}
+
+nsresult nsMsgThread::ChangeUnreadChildCount(int32_t delta)
+{
+  nsresult rv;
+
+  uint32_t childCount = 0;
+  m_mdbDB->RowCellColumnToUInt32(m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken, childCount);
+  childCount += delta;
+  if ((int32_t) childCount < 0)
+  {
+#ifdef DEBUG_bienvenu1
+    NS_ASSERTION(false, "negative unread child count");
+#endif
+    childCount = 0;
+  }
+  rv = m_mdbDB->UInt32ToRowCellColumn(m_metaRow, m_mdbDB->m_threadUnreadChildrenColumnToken, childCount);
+  m_numUnreadChildren = childCount;
+  return rv;
+}
+
+nsresult nsMsgThread::SetThreadRootKey(nsMsgKey threadRootKey)
+{
+  m_threadRootKey = threadRootKey;
+  return m_mdbDB->UInt32ToRowCellColumn(m_metaRow, m_mdbDB->m_threadRootKeyColumnToken, threadRootKey);
+}
+
+nsresult nsMsgThread::GetChildHdrForKey(nsMsgKey desiredKey, nsIMsgDBHdr **result, int32_t *resultIndex)
+{
+  uint32_t numChildren;
+  uint32_t childIndex = 0;
+  nsresult rv = NS_OK;        // XXX or should this default to an error?
+
+  NS_ENSURE_ARG_POINTER(result);
+
+  GetNumChildren(&numChildren);
+
+  if ((int32_t) numChildren < 0)
+    numChildren = 0;
+
+  for (childIndex = 0; childIndex < numChildren; childIndex++)
+  {
+    rv = GetChildHdrAt(childIndex, result);
+    if (NS_SUCCEEDED(rv) && *result)
+    {
+      nsMsgKey msgKey;
+      // we're only doing one level of threading, so check if caller is
+      // asking for children of the first message in the thread or not.
+      // if not, we will tell him there are no children.
+      (*result)->GetMessageKey(&msgKey);
+
+      if (msgKey == desiredKey)
+      {
+        nsMsgKey threadKey;
+        (*result)->GetThreadId(&threadKey);
+        if (threadKey != m_threadKey) // this msg isn't in this thread
+        {
+          NS_WARNING("msg in wrong thread - this shouldn't happen");
+          uint32_t msgSize;
+          (*result)->GetMessageSize(&msgSize);
+          if (msgSize == 0) // this is a phantom message - let's get rid of it.
+          {
+            RemoveChild(msgKey);
+            rv = NS_ERROR_UNEXPECTED;
+          }
+          else
+          {
+            // otherwise, let's try to figure out which thread
+            // this message really belongs to.
+            nsCOMPtr<nsIMsgThread> threadKeyThread = 
+                  dont_AddRef(m_mdbDB->GetThreadForThreadId(threadKey));
+            if (threadKeyThread)
+            {
+              nsCOMPtr<nsIMsgDBHdr> otherThreadHdr;
+              threadKeyThread->GetChild(msgKey, getter_AddRefs(otherThreadHdr));
+              if (otherThreadHdr)
+              {
+                // Message is in one thread but has a different thread id.
+                // Remove it from the thread and then rethread it.
+                RemoveChild(msgKey);
+                threadKeyThread->RemoveChildHdr(otherThreadHdr, nullptr);
+                bool newThread;
+                nsMsgHdr* msgHdr = static_cast<nsMsgHdr*>(otherThreadHdr.get());
+                m_mdbDB->ThreadNewHdr(msgHdr, newThread);
+              }
+              else
+              {
+                (*result)->SetThreadId(m_threadKey);
+              }
+            }
+          }
+        }
+        break;
+      }
+      NS_RELEASE(*result);
+    }
+  }
+  if (resultIndex)
+    *resultIndex = (int32_t) childIndex;
+
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetFirstUnreadChild(nsIMsgDBHdr **result)
+{
+  NS_ENSURE_ARG_POINTER(result);
+  uint32_t numChildren;
+  nsresult rv = NS_OK;
+  uint8_t minLevel = 0xff;
+
+  GetNumChildren(&numChildren);
+
+  if ((int32_t) numChildren < 0)
+    numChildren = 0;
+
+  nsCOMPtr <nsIMsgDBHdr> retHdr;
+
+  for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+  {
+    nsCOMPtr <nsIMsgDBHdr> child;
+    rv = GetChildHdrAt(childIndex, getter_AddRefs(child));
+    if (NS_SUCCEEDED(rv) && child)
+    {
+      nsMsgKey msgKey;
+      child->GetMessageKey(&msgKey);
+
+      bool isRead;
+      rv = m_mdbDB->IsRead(msgKey, &isRead);
+      if (NS_SUCCEEDED(rv) && !isRead)
+      {
+        // this is the root, so it's the best we're going to do.
+        if (msgKey == m_threadRootKey)
+        {
+          retHdr = child;
+          break;
+        }
+        uint8_t level = 0;
+        nsMsgKey parentId;
+        child->GetThreadParent(&parentId);
+        nsCOMPtr <nsIMsgDBHdr> parent;
+        // count number of ancestors - that's our level
+        while (parentId != nsMsgKey_None)
+        {
+          rv = m_mdbDB->GetMsgHdrForKey(parentId, getter_AddRefs(parent));
+          if (parent)
+          {
+            parent->GetThreadParent(&parentId);
+            level++;
+          }
+        }
+        if (level < minLevel)
+        {
+          minLevel = level;
+          retHdr = child;
+        }
+      }
+    }
+  }
+
+  NS_IF_ADDREF(*result = retHdr);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgThread::GetNewestMsgDate(uint32_t *aResult)
+{
+  // if this hasn't been set, figure it out by enumerating the msgs in the thread.
+  if (!m_newestMsgDate)
+  {
+    uint32_t numChildren;
+    nsresult rv;
+
+    GetNumChildren(&numChildren);
+
+    if ((int32_t) numChildren < 0)
+      numChildren = 0;
+
+    for (uint32_t childIndex = 0; childIndex < numChildren; childIndex++)
+    {
+      nsCOMPtr <nsIMsgDBHdr> child;
+      rv = GetChildHdrAt(childIndex, getter_AddRefs(child));
+      if (NS_SUCCEEDED(rv))
+      {
+        uint32_t msgDate;
+        child->GetDateInSeconds(&msgDate);
+        if (msgDate > m_newestMsgDate)
+          m_newestMsgDate = msgDate;
+      }
+    }
+
+  }
+  *aResult = m_newestMsgDate;
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP nsMsgThread::SetNewestMsgDate(uint32_t aNewestMsgDate)
+{
+  m_newestMsgDate = aNewestMsgDate;
+  return m_mdbDB->UInt32ToRowCellColumn(m_metaRow, m_mdbDB->m_threadNewestMsgDateColumnToken, aNewestMsgDate);
+}
diff --git a/mailnews/db/msgdb/src/nsNewsDatabase.cpp b/mailnews/db/msgdb/src/nsNewsDatabase.cpp
new file mode 100644
index 000000000..3fb3dbb2b
--- /dev/null
+++ b/mailnews/db/msgdb/src/nsNewsDatabase.cpp
@@ -0,0 +1,360 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "msgCore.h"
+#include "nsIMsgDBView.h"
+#include "nsIMsgThread.h"
+#include "nsNewsDatabase.h"
+#include "nsMsgKeySet.h"
+#include "nsCOMPtr.h"
+#include "prlog.h"
+
+#if defined(DEBUG_sspitzer_) || defined(DEBUG_seth_)
+#define DEBUG_NEWS_DATABASE 1
+#endif
+
+nsNewsDatabase::nsNewsDatabase()
+{
+  m_readSet = nullptr;
+}
+
+nsNewsDatabase::~nsNewsDatabase()
+{
+}
+
+NS_IMPL_ADDREF_INHERITED(nsNewsDatabase, nsMsgDatabase)
+NS_IMPL_RELEASE_INHERITED(nsNewsDatabase, nsMsgDatabase)
+
+NS_IMETHODIMP nsNewsDatabase::QueryInterface(REFNSIID aIID, void** aInstancePtr)
+{
+  if (!aInstancePtr) return NS_ERROR_NULL_POINTER;
+  *aInstancePtr = nullptr;
+
+  if (aIID.Equals(NS_GET_IID(nsINewsDatabase)))
+  {
+    *aInstancePtr = static_cast<nsINewsDatabase *>(this);
+  }
+
+  if(*aInstancePtr)
+  {
+    AddRef();
+    return NS_OK;
+  }
+
+  return nsMsgDatabase::QueryInterface(aIID, aInstancePtr);
+}
+
+nsresult nsNewsDatabase::Close(bool forceCommit)
+{
+  return nsMsgDatabase::Close(forceCommit);
+}
+
+nsresult nsNewsDatabase::ForceClosed()
+{
+  return nsMsgDatabase::ForceClosed();
+}
+
+nsresult nsNewsDatabase::Commit(nsMsgDBCommit commitType)
+{
+  if (m_dbFolderInfo && m_readSet)
+  {
+    // let's write out our idea of the read set so we can compare it with that of
+    // the .rc file next time we start up.
+    nsCString readSet;
+    m_readSet->Output(getter_Copies(readSet));
+    m_dbFolderInfo->SetCharProperty("readSet", readSet);
+  }
+  return nsMsgDatabase::Commit(commitType);
+}
+
+
+uint32_t nsNewsDatabase::GetCurVersion()
+{
+  return kMsgDBVersion;
+}
+
+NS_IMETHODIMP nsNewsDatabase::IsRead(nsMsgKey key, bool *pRead)
+{
+  NS_ASSERTION(pRead, "null out param in IsRead");
+  if (!pRead) return NS_ERROR_NULL_POINTER;
+
+  if (!m_readSet) return NS_ERROR_FAILURE;
+
+  *pRead = m_readSet->IsMember(key);
+  return NS_OK;
+}
+
+nsresult nsNewsDatabase::IsHeaderRead(nsIMsgDBHdr *msgHdr, bool *pRead)
+{
+    nsresult rv;
+    nsMsgKey messageKey;
+
+    if (!msgHdr || !pRead) return NS_ERROR_NULL_POINTER;
+
+    rv = msgHdr->GetMessageKey(&messageKey);
+    if (NS_FAILED(rv)) return rv;
+
+    rv = IsRead(messageKey,pRead);
+    return rv;
+}
+
+// return highest article number we've seen.
+NS_IMETHODIMP nsNewsDatabase::GetHighWaterArticleNum(nsMsgKey *key)
+{
+  NS_ASSERTION(m_dbFolderInfo, "null db folder info");
+  if (!m_dbFolderInfo)
+    return NS_ERROR_FAILURE;
+  return m_dbFolderInfo->GetHighWater(key);
+}
+
+// return the key of the first article number we know about.
+// Since the iterator iterates in id order, we can just grab the
+// messagekey of the first header it returns.
+// ### dmb
+// This will not deal with the situation where we get holes in
+// the headers we know about. Need to figure out how and when
+// to solve that. This could happen if a transfer is interrupted.
+// Do we need to keep track of known arts permanently?
+NS_IMETHODIMP nsNewsDatabase::GetLowWaterArticleNum(nsMsgKey *key)
+{
+  nsresult  rv;
+  nsMsgHdr  *pHeader;
+
+  nsCOMPtr<nsISimpleEnumerator> hdrs;
+  rv = EnumerateMessages(getter_AddRefs(hdrs));
+  if (NS_FAILED(rv))
+    return rv;
+
+  rv = hdrs->GetNext((nsISupports**)&pHeader);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "nsMsgDBEnumerator broken");
+  if (NS_FAILED(rv))
+    return rv;
+
+  return pHeader->GetMessageKey(key);
+}
+
+nsresult  nsNewsDatabase::ExpireUpTo(nsMsgKey expireKey)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+nsresult		nsNewsDatabase::ExpireRange(nsMsgKey startRange, nsMsgKey endRange)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+
+NS_IMETHODIMP nsNewsDatabase::GetReadSet(nsMsgKeySet **pSet)
+{
+    if (!pSet) return NS_ERROR_NULL_POINTER;
+    *pSet = m_readSet;
+    return NS_OK;
+}
+
+NS_IMETHODIMP nsNewsDatabase::SetReadSet(nsMsgKeySet *pSet)
+{
+  m_readSet = pSet;
+
+  if (m_readSet)
+  {
+    // compare this read set with the one in the db folder info.
+    // If not equivalent, sync with this one.
+    nsCString dbReadSet;
+    if (m_dbFolderInfo)
+      m_dbFolderInfo->GetCharProperty("readSet", dbReadSet);
+    nsCString newsrcReadSet;
+    m_readSet->Output(getter_Copies(newsrcReadSet));
+    if (!dbReadSet.Equals(newsrcReadSet))
+      SyncWithReadSet();
+  }
+  return NS_OK;
+}
+
+
+bool nsNewsDatabase::SetHdrReadFlag(nsIMsgDBHdr *msgHdr, bool bRead)
+{
+    nsresult rv;
+    bool isRead;
+    rv = IsHeaderRead(msgHdr, &isRead);
+
+    if (isRead == bRead)
+    {
+      // give the base class a chance to update m_flags.
+      nsMsgDatabase::SetHdrReadFlag(msgHdr, bRead);
+      return false;
+    }
+    else {
+      nsMsgKey messageKey;
+
+      // give the base class a chance to update m_flags.
+      nsMsgDatabase::SetHdrReadFlag(msgHdr, bRead);
+      rv = msgHdr->GetMessageKey(&messageKey);
+      if (NS_FAILED(rv)) return false;
+
+      NS_ASSERTION(m_readSet, "m_readSet is null");
+      if (!m_readSet) return false;
+
+      if (!bRead) {
+#ifdef DEBUG_NEWS_DATABASE
+        printf("remove %d from the set\n",messageKey);
+#endif
+
+        m_readSet->Remove(messageKey);
+
+        rv = NotifyReadChanged(nullptr);
+        if (NS_FAILED(rv)) return false;
+      }
+      else {
+#ifdef DEBUG_NEWS_DATABASE
+        printf("add %d to the set\n",messageKey);
+#endif
+
+        if (m_readSet->Add(messageKey) < 0) return false;
+
+        rv = NotifyReadChanged(nullptr);
+        if (NS_FAILED(rv)) return false;
+      }
+    }
+    return true;
+}
+
+NS_IMETHODIMP nsNewsDatabase::MarkAllRead(uint32_t *aNumMarked,
+                                          nsMsgKey **aThoseMarked)
+{
+  nsMsgKey lowWater = nsMsgKey_None, highWater;
+  nsCString knownArts;
+  if (m_dbFolderInfo)
+  {
+    m_dbFolderInfo->GetKnownArtsSet(getter_Copies(knownArts));
+    nsMsgKeySet *knownKeys = nsMsgKeySet::Create(knownArts.get());
+    if (knownKeys)
+      lowWater = knownKeys->GetFirstMember();
+
+    delete knownKeys;
+  }
+  if (lowWater == nsMsgKey_None)
+    GetLowWaterArticleNum(&lowWater);
+  GetHighWaterArticleNum(&highWater);
+  if (lowWater > 2)
+    m_readSet->AddRange(1, lowWater - 1);
+  nsresult err = nsMsgDatabase::MarkAllRead(aNumMarked, aThoseMarked);
+  if (NS_SUCCEEDED(err) && 1 <= highWater)
+    m_readSet->AddRange(1, highWater); // mark everything read in newsrc.
+
+  return err;
+}
+
+nsresult nsNewsDatabase::SyncWithReadSet()
+{
+
+  // The code below attempts to update the underlying nsMsgDatabase's idea
+  // of read/unread flags to match the read set in the .newsrc file. It should
+  // only be called when they don't match, e.g., we crashed after committing the
+  // db but before writing out the .newsrc
+  nsCOMPtr <nsISimpleEnumerator> hdrs;
+  nsresult rv = EnumerateMessages(getter_AddRefs(hdrs));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasMore = false, readInNewsrc, isReadInDB, changed = false;
+  int32_t numMessages = 0, numUnreadMessages = 0;
+  nsMsgKey messageKey;
+  nsCOMPtr <nsIMsgThread> threadHdr;
+
+  // Scan all messages in DB
+  while (NS_SUCCEEDED(rv = hdrs->HasMoreElements(&hasMore)) && hasMore)
+  {
+      nsCOMPtr<nsISupports> supports;
+      rv = hdrs->GetNext(getter_AddRefs(supports));
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      nsCOMPtr <nsIMsgDBHdr> header = do_QueryInterface(supports, &rv);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      rv = nsMsgDatabase::IsHeaderRead(header, &isReadInDB);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      header->GetMessageKey(&messageKey);
+      IsRead(messageKey,&readInNewsrc);
+
+      numMessages++;
+      if (!readInNewsrc)
+        numUnreadMessages++;
+
+      // If DB and readSet disagree on Read/Unread, fix DB
+      if (readInNewsrc!=isReadInDB)
+      {
+        MarkHdrRead(header, readInNewsrc, nullptr);
+        changed = true;
+      }
+  }
+
+  // Update FolderInfo Counters
+  int32_t oldMessages, oldUnreadMessages;
+  rv = m_dbFolderInfo->GetNumMessages(&oldMessages);
+  if (NS_SUCCEEDED(rv) && oldMessages!=numMessages)
+  {
+      changed = true;
+      m_dbFolderInfo->ChangeNumMessages(numMessages-oldMessages);
+  }
+  rv = m_dbFolderInfo->GetNumUnreadMessages(&oldUnreadMessages);
+  if (NS_SUCCEEDED(rv) && oldUnreadMessages!=numUnreadMessages)
+  {
+      changed = true;
+      m_dbFolderInfo->ChangeNumUnreadMessages(numUnreadMessages-oldUnreadMessages);
+  }
+
+  if (changed)
+      Commit(nsMsgDBCommitType::kLargeCommit);
+
+  return rv;
+}
+
+nsresult nsNewsDatabase::AdjustExpungedBytesOnDelete(nsIMsgDBHdr *msgHdr)
+{
+  uint32_t msgFlags;
+  msgHdr->GetFlags(&msgFlags);
+  if (msgFlags & nsMsgMessageFlags::Offline && m_dbFolderInfo)
+  {
+    uint32_t size = 0;
+    (void)msgHdr->GetOfflineMessageSize(&size);
+    return m_dbFolderInfo->ChangeExpungedBytes (size);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultViewFlags(nsMsgViewFlagsTypeValue *aDefaultViewFlags)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultViewFlags);
+  GetIntPref("mailnews.default_news_view_flags", aDefaultViewFlags);
+  if (*aDefaultViewFlags < nsMsgViewFlagsType::kNone ||
+      *aDefaultViewFlags > (nsMsgViewFlagsType::kThreadedDisplay |
+                            nsMsgViewFlagsType::kShowIgnored |
+                            nsMsgViewFlagsType::kUnreadOnly |
+                            nsMsgViewFlagsType::kExpandAll |
+                            nsMsgViewFlagsType::kGroupBySort))
+    *aDefaultViewFlags = nsMsgViewFlagsType::kThreadedDisplay;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultSortType(nsMsgViewSortTypeValue *aDefaultSortType)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultSortType);
+  GetIntPref("mailnews.default_news_sort_type", aDefaultSortType);
+  if (*aDefaultSortType < nsMsgViewSortType::byDate ||
+      *aDefaultSortType > nsMsgViewSortType::byAccount)
+    *aDefaultSortType = nsMsgViewSortType::byThread;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNewsDatabase::GetDefaultSortOrder(nsMsgViewSortOrderValue *aDefaultSortOrder)
+{
+  NS_ENSURE_ARG_POINTER(aDefaultSortOrder);
+  GetIntPref("mailnews.default_news_sort_order", aDefaultSortOrder);
+  if (*aDefaultSortOrder != nsMsgViewSortOrder::descending)
+    *aDefaultSortOrder = nsMsgViewSortOrder::ascending;
+  return NS_OK;
+}