1 files changed, 439 insertions, 0 deletions
diff --git a/storage/mozStorageConnection.h b/storage/mozStorageConnection.h
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index 000000000..979ac6436
--- /dev/null
+++ b/storage/mozStorageConnection.h
@@ -0,0 +1,439 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * 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 mozilla_storage_Connection_h
+#define mozilla_storage_Connection_h
+
+#include "nsAutoPtr.h"
+#include "nsCOMPtr.h"
+#include "mozilla/Mutex.h"
+#include "nsProxyRelease.h"
+#include "nsThreadUtils.h"
+#include "nsIInterfaceRequestor.h"
+
+#include "nsDataHashtable.h"
+#include "mozIStorageProgressHandler.h"
+#include "SQLiteMutex.h"
+#include "mozIStorageConnection.h"
+#include "mozStorageService.h"
+#include "mozIStorageAsyncConnection.h"
+#include "mozIStorageCompletionCallback.h"
+
+#include "nsIMutableArray.h"
+#include "mozilla/Attributes.h"
+
+#include "sqlite3.h"
+
+class nsIFile;
+class nsIFileURL;
+class nsIEventTarget;
+class nsIThread;
+
+namespace mozilla {
+namespace storage {
+
+class Connection final : public mozIStorageConnection
+                       , public nsIInterfaceRequestor
+{
+public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEASYNCCONNECTION
+  NS_DECL_MOZISTORAGECONNECTION
+  NS_DECL_NSIINTERFACEREQUESTOR
+
+  /**
+   * Structure used to describe user functions on the database connection.
+   */
+  struct FunctionInfo {
+    enum FunctionType {
+      SIMPLE,
+      AGGREGATE
+    };
+
+    nsCOMPtr<nsISupports> function;
+    FunctionType type;
+    int32_t numArgs;
+  };
+
+  /**
+   * @param aService
+   *        Pointer to the storage service.  Held onto for the lifetime of the
+   *        connection.
+   * @param aFlags
+   *        The flags to pass to sqlite3_open_v2.
+   * @param aAsyncOnly
+   *        If |true|, the Connection only implements asynchronous interface:
+   *        - |mozIStorageAsyncConnection|;
+   *        If |false|, the result also implements synchronous interface:
+   *        - |mozIStorageConnection|.
+   * @param aIgnoreLockingMode
+   *        If |true|, ignore locks in force on the file. Only usable with
+   *        read-only connections. Defaults to false.
+   *        Use with extreme caution. If sqlite ignores locks, reads may fail
+   *        indicating database corruption (the database won't actually be
+   *        corrupt) or produce wrong results without any indication that has
+   *        happened.
+   */
+  Connection(Service *aService, int aFlags, bool aAsyncOnly,
+             bool aIgnoreLockingMode = false);
+
+  /**
+   * Creates the connection to an in-memory database.
+   */
+  nsresult initialize();
+
+  /**
+   * Creates the connection to the database.
+   *
+   * @param aDatabaseFile
+   *        The nsIFile of the location of the database to open, or create if it
+   *        does not exist.
+   */
+  nsresult initialize(nsIFile *aDatabaseFile);
+
+  /**
+   * Creates the connection to the database.
+   *
+   * @param aFileURL
+   *        The nsIFileURL of the location of the database to open, or create if it
+   *        does not exist.
+   */
+  nsresult initialize(nsIFileURL *aFileURL);
+
+  /**
+   * Fetches runtime status information for this connection.
+   *
+   * @param aStatusOption One of the SQLITE_DBSTATUS options defined at
+   *        http://www.sqlite.org/c3ref/c_dbstatus_options.html
+   * @param [optional] aMaxValue if provided, will be set to the highest
+   *        istantaneous value.
+   * @return the current value for the specified option.
+   */
+  int32_t getSqliteRuntimeStatus(int32_t aStatusOption,
+                                 int32_t* aMaxValue=nullptr);
+  /**
+   * Registers/unregisters a commit hook callback.
+   *
+   * @param aCallbackFn a callback function to be invoked on transactions
+   *        commit.  Pass nullptr to unregister the current callback.
+   * @param [optional] aData if provided, will be passed to the callback.
+   * @see http://sqlite.org/c3ref/commit_hook.html
+   */
+  void setCommitHook(int (*aCallbackFn)(void *) , void *aData=nullptr) {
+    MOZ_ASSERT(mDBConn, "A connection must exist at this point");
+    ::sqlite3_commit_hook(mDBConn, aCallbackFn, aData);
+  };
+
+  /**
+   * Gets autocommit status.
+   */
+  bool getAutocommit() {
+    return mDBConn && static_cast<bool>(::sqlite3_get_autocommit(mDBConn));
+  };
+
+  /**
+   * Lazily creates and returns a background execution thread.  In the future,
+   * the thread may be re-claimed if left idle, so you should call this
+   * method just before you dispatch and not save the reference.
+   *
+   * @returns an event target suitable for asynchronous statement execution.
+   */
+  nsIEventTarget *getAsyncExecutionTarget();
+
+  /**
+   * Mutex used by asynchronous statements to protect state.  The mutex is
+   * declared on the connection object because there is no contention between
+   * asynchronous statements (they are serialized on mAsyncExecutionThread).
+   * Currently protects:
+   *  - Connection.mAsyncExecutionThreadShuttingDown
+   *  - Connection.mAsyncExecutionThread
+   *  - Connection.mConnectionClosed
+   *  - AsyncExecuteStatements.mCancelRequested
+   */
+  Mutex sharedAsyncExecutionMutex;
+
+  /**
+   * Wraps the mutex that SQLite gives us from sqlite3_db_mutex.  This is public
+   * because we already expose the sqlite3* native connection and proper
+   * operation of the deadlock detector requires everyone to use the same single
+   * SQLiteMutex instance for correctness.
+   */
+  SQLiteMutex sharedDBMutex;
+
+  /**
+   * References the thread this database was opened on.  This MUST be thread it is
+   * closed on.
+   */
+  const nsCOMPtr<nsIThread> threadOpenedOn;
+
+  /**
+   * Closes the SQLite database, and warns about any non-finalized statements.
+   */
+  nsresult internalClose(sqlite3 *aDBConn);
+
+  /**
+   * Shuts down the passed-in async thread.
+   */
+  void shutdownAsyncThread(nsIThread *aAsyncThread);
+
+  /**
+   * Obtains the filename of the connection.  Useful for logging.
+   */
+  nsCString getFilename();
+
+  /**
+   * Creates an sqlite3 prepared statement object from an SQL string.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to prepare the statement with.
+   * @param aSQL
+   *        The SQL statement string to compile.
+   * @param _stmt
+   *        New sqlite3_stmt object.
+   * @return the result from sqlite3_prepare_v2.
+   */
+  int prepareStatement(sqlite3* aNativeConnection,
+                       const nsCString &aSQL, sqlite3_stmt **_stmt);
+
+  /**
+   * Performs a sqlite3_step on aStatement, while properly handling SQLITE_LOCKED
+   * when not on the main thread by waiting until we are notified.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to step the statement with.
+   * @param aStatement
+   *        A pointer to a sqlite3_stmt object.
+   * @return the result from sqlite3_step.
+   */
+  int stepStatement(sqlite3* aNativeConnection, sqlite3_stmt* aStatement);
+
+  /**
+   * Raw connection transaction management.
+   *
+   * @see BeginTransactionAs, CommitTransaction, RollbackTransaction.
+   */
+  nsresult beginTransactionInternal(sqlite3 *aNativeConnection,
+                                    int32_t aTransactionType=TRANSACTION_DEFERRED);
+  nsresult commitTransactionInternal(sqlite3 *aNativeConnection);
+  nsresult rollbackTransactionInternal(sqlite3 *aNativeConnection);
+
+  bool connectionReady();
+
+  /**
+   * True if this connection is shutting down but not yet closed.
+   */
+  bool isClosing();
+
+  /**
+   * True if the underlying connection is closed.
+   * Any sqlite resources may be lost when this returns true, so nothing should
+   * try to use them.
+   */
+  bool isClosed();
+
+  nsresult initializeClone(Connection *aClone, bool aReadOnly);
+
+private:
+  ~Connection();
+  nsresult initializeInternal();
+
+  /**
+   * Sets the database into a closed state so no further actions can be
+   * performed.
+   *
+   * @note mDBConn is set to nullptr in this method.
+   */
+  nsresult setClosedState();
+
+  /**
+   * Helper for calls to sqlite3_exec. Reports long delays to Telemetry.
+   *
+   * @param aNativeConnection
+   *        The underlying Sqlite connection to execute the query with.
+   * @param aSqlString
+   *        SQL string to execute
+   * @return the result from sqlite3_exec.
+   */
+  int executeSql(sqlite3 *aNativeConnection, const char *aSqlString);
+
+  /**
+   * Describes a certain primitive type in the database.
+   *
+   * Possible Values Are:
+   *  INDEX - To check for the existence of an index
+   *  TABLE - To check for the existence of a table
+   */
+  enum DatabaseElementType {
+    INDEX,
+    TABLE
+  };
+
+  /**
+   * Determines if the specified primitive exists.
+   *
+   * @param aElementType
+   *        The type of element to check the existence of
+   * @param aElementName
+   *        The name of the element to check for
+   * @returns true if element exists, false otherwise
+   */
+  nsresult databaseElementExists(enum DatabaseElementType aElementType,
+                                 const nsACString& aElementName,
+                                 bool *_exists);
+
+  bool findFunctionByInstance(nsISupports *aInstance);
+
+  static int sProgressHelper(void *aArg);
+  // Generic progress handler
+  // Dispatch call to registered progress handler,
+  // if there is one. Do nothing in other cases.
+  int progressHandler();
+
+  sqlite3 *mDBConn;
+  nsCOMPtr<nsIFileURL> mFileURL;
+  nsCOMPtr<nsIFile> mDatabaseFile;
+
+  /**
+   * The filename that will be reported to telemetry for this connection. By
+   * default this will be the leaf of the path to the database file.
+  */
+  nsCString mTelemetryFilename;
+
+  /**
+   * Lazily created thread for asynchronous statement execution.  Consumers
+   * should use getAsyncExecutionTarget rather than directly accessing this
+   * field.
+   */
+  nsCOMPtr<nsIThread> mAsyncExecutionThread;
+
+  /**
+   * Set to true by Close() or AsyncClose() prior to shutdown.
+   *
+   * If false, we guarantee both that the underlying sqlite3 database
+   * connection is still open and that getAsyncExecutionTarget() can
+   * return a thread. Once true, either the sqlite3 database
+   * connection is being shutdown or it has been
+   * shutdown. Additionally, once true, getAsyncExecutionTarget()
+   * returns null.
+   *
+   * This variable should be accessed while holding the
+   * sharedAsyncExecutionMutex.
+   */
+  bool mAsyncExecutionThreadShuttingDown;
+
+  /**
+   * Tracks whether the async thread has been initialized and Shutdown() has
+   * not yet been invoked on it.
+   */
+#ifdef DEBUG
+  bool mAsyncExecutionThreadIsAlive;
+#endif
+
+  /**
+   * Set to true just prior to calling sqlite3_close on the
+   * connection.
+   *
+   * This variable should be accessed while holding the
+   * sharedAsyncExecutionMutex.
+   */
+  bool mConnectionClosed;
+
+  /**
+   * Tracks if we have a transaction in progress or not.  Access protected by
+   * sharedDBMutex.
+   */
+  bool mTransactionInProgress;
+
+  /**
+   * Stores the mapping of a given function by name to its instance.  Access is
+   * protected by sharedDBMutex.
+   */
+  nsDataHashtable<nsCStringHashKey, FunctionInfo> mFunctions;
+
+  /**
+   * Stores the registered progress handler for the database connection.  Access
+   * is protected by sharedDBMutex.
+   */
+  nsCOMPtr<mozIStorageProgressHandler> mProgressHandler;
+
+  /**
+   * Stores the flags we passed to sqlite3_open_v2.
+   */
+  const int mFlags;
+
+  /**
+   * Stores whether we should ask sqlite3_open_v2 to ignore locking.
+   */
+  const bool mIgnoreLockingMode;
+
+  // This is here for two reasons: 1) It's used to make sure that the
+  // connections do not outlive the service.  2) Our custom collating functions
+  // call its localeCompareStrings() method.
+  RefPtr<Service> mStorageService;
+
+  /**
+   * If |false|, this instance supports synchronous operations
+   * and it can be cast to |mozIStorageConnection|.
+   */
+  const bool mAsyncOnly;
+};
+
+
+/**
+ * A Runnable designed to call a mozIStorageCompletionCallback on
+ * the appropriate thread.
+ */
+class CallbackComplete final : public Runnable
+{
+public:
+  /**
+   * @param aValue The result to pass to the callback. It must
+   *               already be owned by the main thread.
+   * @param aCallback The callback. It must already be owned by the
+   *                  main thread.
+   */
+  CallbackComplete(nsresult aStatus,
+                   nsISupports* aValue,
+                   already_AddRefed<mozIStorageCompletionCallback> aCallback)
+    : mStatus(aStatus)
+    , mValue(aValue)
+    , mCallback(aCallback)
+  {
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread());
+    nsresult rv = mCallback->Complete(mStatus, mValue);
+
+    // Ensure that we release on the main thread
+    mValue = nullptr;
+    mCallback = nullptr;
+    return rv;
+  }
+
+private:
+  nsresult mStatus;
+  nsCOMPtr<nsISupports> mValue;
+  // This is a RefPtr<T> and not a nsCOMPtr<T> because
+  // nsCOMP<T> would cause an off-main thread QI, which
+  // is not a good idea (and crashes XPConnect).
+  RefPtr<mozIStorageCompletionCallback> mCallback;
+};
+
+} // namespace storage
+} // namespace mozilla
+
+/**
+ * Casting Connection to nsISupports is ambiguous.
+ * This method handles that.
+ */
+inline nsISupports*
+ToSupports(mozilla::storage::Connection* p)
+{
+  return NS_ISUPPORTS_CAST(mozIStorageAsyncConnection*, p);
+}
+
+#endif // mozilla_storage_Connection_h