Add m-esr52 at 52.6.0

1 files changed, 901 insertions, 0 deletions

diff --git a/modules/libpref/nsPrefBranch.cpp b/modules/libpref/nsPrefBranch.cpp
new file mode 100644
index 000000000..2fd4992c8
--- /dev/null
+++ b/modules/libpref/nsPrefBranch.cpp
@@ -0,0 +1,901 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "mozilla/dom/ContentChild.h"
+#include "nsXULAppAPI.h"
+
+#include "nsPrefBranch.h"
+#include "nsILocalFile.h" // nsILocalFile used for backwards compatibility
+#include "nsIObserverService.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIDirectoryService.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsXPIDLString.h"
+#include "nsPrintfCString.h"
+#include "nsIStringBundle.h"
+#include "prefapi.h"
+#include "PLDHashTable.h"
+
+#include "nsCRT.h"
+#include "mozilla/Services.h"
+
+#include "prefapi_private_data.h"
+
+#ifdef MOZ_CRASHREPORTER
+#include "nsICrashReporter.h"
+#endif
+
+#include "nsIConsoleService.h"
+
+#ifdef DEBUG
+#define ENSURE_MAIN_PROCESS(message, pref) do {                                \
+  if (GetContentChild()) {                                                     \
+    nsPrintfCString msg("ENSURE_MAIN_PROCESS failed. %s %s", message, pref);   \
+    NS_ERROR(msg.get());                                                       \
+    return NS_ERROR_NOT_AVAILABLE;                                             \
+  }                                                                            \
+} while (0);
+#else
+#define ENSURE_MAIN_PROCESS(message, pref)                                     \
+  if (GetContentChild()) {                                                     \
+    return NS_ERROR_NOT_AVAILABLE;                                             \
+  }
+#endif
+
+using mozilla::dom::ContentChild;
+
+static ContentChild*
+GetContentChild()
+{
+  if (XRE_IsContentProcess()) {
+    ContentChild* cpc = ContentChild::GetSingleton();
+    if (!cpc) {
+      NS_RUNTIMEABORT("Content Protocol is NULL!  We're going to crash!");
+    }
+    return cpc;
+  }
+  return nullptr;
+}
+
+/*
+ * Constructor/Destructor
+ */
+
+nsPrefBranch::nsPrefBranch(const char *aPrefRoot, bool aDefaultBranch)
+{
+  mPrefRoot = aPrefRoot;
+  mPrefRootLength = mPrefRoot.Length();
+  mIsDefault = aDefaultBranch;
+  mFreeingObserverList = false;
+
+  nsCOMPtr<nsIObserverService> observerService =
+    mozilla::services::GetObserverService();
+  if (observerService) {
+    ++mRefCnt;    // Our refcnt must be > 0 when we call this, or we'll get deleted!
+    // add weak so we don't have to clean up at shutdown
+    observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, true);
+    --mRefCnt;
+  }
+}
+
+nsPrefBranch::~nsPrefBranch()
+{
+  freeObserverList();
+
+  nsCOMPtr<nsIObserverService> observerService =
+    mozilla::services::GetObserverService();
+  if (observerService)
+    observerService->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
+}
+
+
+/*
+ * nsISupports Implementation
+ */
+
+NS_IMPL_ADDREF(nsPrefBranch)
+NS_IMPL_RELEASE(nsPrefBranch)
+
+NS_INTERFACE_MAP_BEGIN(nsPrefBranch)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrefBranch)
+  NS_INTERFACE_MAP_ENTRY(nsIPrefBranch)
+  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIPrefBranch2, !mIsDefault)
+  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIPrefBranchInternal, !mIsDefault)
+  NS_INTERFACE_MAP_ENTRY(nsIObserver)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+NS_INTERFACE_MAP_END
+
+
+/*
+ * nsIPrefBranch Implementation
+ */
+
+NS_IMETHODIMP nsPrefBranch::GetRoot(char **aRoot)
+{
+  NS_ENSURE_ARG_POINTER(aRoot);
+  mPrefRoot.Truncate(mPrefRootLength);
+  *aRoot = ToNewCString(mPrefRoot);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::GetPrefType(const char *aPrefName, int32_t *_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  switch (PREF_GetPrefType(pref)) {
+    case PrefType::String:
+      *_retval = PREF_STRING;
+      break;
+    case PrefType::Int:
+      *_retval = PREF_INT;
+      break;
+    case PrefType::Bool:
+      *_retval = PREF_BOOL;
+        break;
+    case PrefType::Invalid:
+    default:
+      *_retval = PREF_INVALID;
+      break;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::GetBoolPref(const char *aPrefName, bool *_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_GetBoolPref(pref, _retval, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::SetBoolPref(const char *aPrefName, bool aValue)
+{
+  ENSURE_MAIN_PROCESS("Cannot SetBoolPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_SetBoolPref(pref, aValue, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::GetFloatPref(const char *aPrefName, float *_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  nsAutoCString stringVal;
+  nsresult rv = GetCharPref(pref, getter_Copies(stringVal));
+  if (NS_SUCCEEDED(rv)) {
+    *_retval = stringVal.ToFloat(&rv);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsPrefBranch::GetCharPref(const char *aPrefName, char **_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_CopyCharPref(pref, _retval, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::SetCharPref(const char *aPrefName, const char *aValue)
+{
+  nsresult rv = CheckSanityOfStringLength(aPrefName, aValue);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return SetCharPrefInternal(aPrefName, aValue);
+}
+
+nsresult nsPrefBranch::SetCharPrefInternal(const char *aPrefName, const char *aValue)
+
+{
+  ENSURE_MAIN_PROCESS("Cannot SetCharPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  NS_ENSURE_ARG(aValue);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_SetCharPref(pref, aValue, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::GetIntPref(const char *aPrefName, int32_t *_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_GetIntPref(pref, _retval, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::SetIntPref(const char *aPrefName, int32_t aValue)
+{
+  ENSURE_MAIN_PROCESS("Cannot SetIntPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_SetIntPref(pref, aValue, mIsDefault);
+}
+
+NS_IMETHODIMP nsPrefBranch::GetComplexValue(const char *aPrefName, const nsIID & aType, void **_retval)
+{
+  NS_ENSURE_ARG(aPrefName);
+
+  nsresult       rv;
+  nsXPIDLCString utf8String;
+
+  // we have to do this one first because it's different than all the rest
+  if (aType.Equals(NS_GET_IID(nsIPrefLocalizedString))) {
+    nsCOMPtr<nsIPrefLocalizedString> theString(do_CreateInstance(NS_PREFLOCALIZEDSTRING_CONTRACTID, &rv));
+    if (NS_FAILED(rv)) return rv;
+
+    const char *pref = getPrefName(aPrefName);
+    bool    bNeedDefault = false;
+
+    if (mIsDefault) {
+      bNeedDefault = true;
+    } else {
+      // if there is no user (or locked) value
+      if (!PREF_HasUserPref(pref) && !PREF_PrefIsLocked(pref)) {
+        bNeedDefault = true;
+      }
+    }
+
+    // if we need to fetch the default value, do that instead, otherwise use the
+    // value we pulled in at the top of this function
+    if (bNeedDefault) {
+      nsXPIDLString utf16String;
+      rv = GetDefaultFromPropertiesFile(pref, getter_Copies(utf16String));
+      if (NS_SUCCEEDED(rv)) {
+        theString->SetData(utf16String.get());
+      }
+    } else {
+      rv = GetCharPref(aPrefName, getter_Copies(utf8String));
+      if (NS_SUCCEEDED(rv)) {
+        theString->SetData(NS_ConvertUTF8toUTF16(utf8String).get());
+      }
+    }
+
+    if (NS_SUCCEEDED(rv)) {
+      theString.forget(reinterpret_cast<nsIPrefLocalizedString**>(_retval));
+    }
+
+    return rv;
+  }
+
+  // if we can't get the pref, there's no point in being here
+  rv = GetCharPref(aPrefName, getter_Copies(utf8String));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // also check nsILocalFile, for backwards compatibility
+  if (aType.Equals(NS_GET_IID(nsIFile)) || aType.Equals(NS_GET_IID(nsILocalFile))) {
+    if (GetContentChild()) {
+      NS_ERROR("cannot get nsIFile pref from content process");
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+
+    nsCOMPtr<nsIFile> file(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+
+    if (NS_SUCCEEDED(rv)) {
+      rv = file->SetPersistentDescriptor(utf8String);
+      if (NS_SUCCEEDED(rv)) {
+        file.forget(reinterpret_cast<nsIFile**>(_retval));
+        return NS_OK;
+      }
+    }
+    return rv;
+  }
+
+  if (aType.Equals(NS_GET_IID(nsIRelativeFilePref))) {
+    if (GetContentChild()) {
+      NS_ERROR("cannot get nsIRelativeFilePref from content process");
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+
+    nsACString::const_iterator keyBegin, strEnd;
+    utf8String.BeginReading(keyBegin);
+    utf8String.EndReading(strEnd);    
+
+    // The pref has the format: [fromKey]a/b/c
+    if (*keyBegin++ != '[')        
+      return NS_ERROR_FAILURE;
+    nsACString::const_iterator keyEnd(keyBegin);
+    if (!FindCharInReadable(']', keyEnd, strEnd))
+      return NS_ERROR_FAILURE;
+    nsAutoCString key(Substring(keyBegin, keyEnd));
+    
+    nsCOMPtr<nsIFile> fromFile;
+    nsCOMPtr<nsIProperties> directoryService(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv));
+    if (NS_FAILED(rv))
+      return rv;
+    rv = directoryService->Get(key.get(), NS_GET_IID(nsIFile), getter_AddRefs(fromFile));
+    if (NS_FAILED(rv))
+      return rv;
+    
+    nsCOMPtr<nsIFile> theFile;
+    rv = NS_NewNativeLocalFile(EmptyCString(), true, getter_AddRefs(theFile));
+    if (NS_FAILED(rv))
+      return rv;
+    rv = theFile->SetRelativeDescriptor(fromFile, Substring(++keyEnd, strEnd));
+    if (NS_FAILED(rv))
+      return rv;
+    nsCOMPtr<nsIRelativeFilePref> relativePref;
+    rv = NS_NewRelativeFilePref(theFile, key, getter_AddRefs(relativePref));
+    if (NS_FAILED(rv))
+      return rv;
+
+    relativePref.forget(reinterpret_cast<nsIRelativeFilePref**>(_retval));
+    return NS_OK;
+  }
+
+  if (aType.Equals(NS_GET_IID(nsISupportsString))) {
+    nsCOMPtr<nsISupportsString> theString(do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID, &rv));
+
+    if (NS_SUCCEEDED(rv)) {
+      // Debugging to see why we end up with very long strings here with
+      // some addons, see bug 836263.
+      nsAutoString wdata;
+      if (!AppendUTF8toUTF16(utf8String, wdata, mozilla::fallible)) {
+#ifdef MOZ_CRASHREPORTER
+        nsCOMPtr<nsICrashReporter> cr =
+          do_GetService("@mozilla.org/toolkit/crash-reporter;1");
+        if (cr) {
+          cr->AnnotateCrashReport(NS_LITERAL_CSTRING("bug836263-size"),
+                                  nsPrintfCString("%x", utf8String.Length()));
+          cr->RegisterAppMemory(uint64_t(utf8String.BeginReading()),
+                                std::min(0x1000U, utf8String.Length()));
+        }
+#endif
+        NS_RUNTIMEABORT("bug836263");
+      }
+      theString->SetData(wdata);
+      theString.forget(reinterpret_cast<nsISupportsString**>(_retval));
+    }
+    return rv;
+  }
+
+  NS_WARNING("nsPrefBranch::GetComplexValue - Unsupported interface type");
+  return NS_NOINTERFACE;
+}
+
+nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, const char* aValue) {
+  if (!aValue) {
+    return NS_OK;
+  }
+  return CheckSanityOfStringLength(aPrefName, strlen(aValue));
+}
+
+nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, const nsAString& aValue) {
+  return CheckSanityOfStringLength(aPrefName, aValue.Length());
+}
+
+nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, const uint32_t aLength) {
+  if (aLength > MAX_PREF_LENGTH) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  if (aLength <= MAX_ADVISABLE_PREF_LENGTH) {
+    return NS_OK;
+  }
+  nsresult rv;
+  nsCOMPtr<nsIConsoleService> console = do_GetService("@mozilla.org/consoleservice;1", &rv);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  nsAutoCString message(nsPrintfCString("Warning: attempting to write %d bytes to preference %s. This is bad "
+                                        "for general performance and memory usage. Such an amount of data "
+                                        "should rather be written to an external file. This preference will "
+                                        "not be sent to any content processes.",
+                                        aLength,
+                                        getPrefName(aPrefName)));
+  rv = console->LogStringMessage(NS_ConvertUTF8toUTF16(message).get());
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return NS_OK;
+}
+
+/*static*/
+void nsPrefBranch::ReportToConsole(const nsAString& aMessage)
+{
+  nsresult rv;
+  nsCOMPtr<nsIConsoleService> console = do_GetService("@mozilla.org/consoleservice;1", &rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+  nsAutoString message(aMessage);
+  console->LogStringMessage(message.get());
+}
+
+NS_IMETHODIMP nsPrefBranch::SetComplexValue(const char *aPrefName, const nsIID & aType, nsISupports *aValue)
+{
+  ENSURE_MAIN_PROCESS("Cannot SetComplexValue from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+
+  nsresult   rv = NS_NOINTERFACE;
+
+  // also check nsILocalFile, for backwards compatibility
+  if (aType.Equals(NS_GET_IID(nsIFile)) || aType.Equals(NS_GET_IID(nsILocalFile))) {
+    nsCOMPtr<nsIFile> file = do_QueryInterface(aValue);
+    if (!file)
+      return NS_NOINTERFACE;
+    nsAutoCString descriptorString;
+
+    rv = file->GetPersistentDescriptor(descriptorString);
+    if (NS_SUCCEEDED(rv)) {
+      rv = SetCharPrefInternal(aPrefName, descriptorString.get());
+    }
+    return rv;
+  }
+
+  if (aType.Equals(NS_GET_IID(nsIRelativeFilePref))) {
+    nsCOMPtr<nsIRelativeFilePref> relFilePref = do_QueryInterface(aValue);
+    if (!relFilePref)
+      return NS_NOINTERFACE;
+
+    nsCOMPtr<nsIFile> file;
+    relFilePref->GetFile(getter_AddRefs(file));
+    if (!file)
+      return NS_NOINTERFACE;
+    nsAutoCString relativeToKey;
+    (void) relFilePref->GetRelativeToKey(relativeToKey);
+
+    nsCOMPtr<nsIFile> relativeToFile;
+    nsCOMPtr<nsIProperties> directoryService(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv));
+    if (NS_FAILED(rv))
+      return rv;
+    rv = directoryService->Get(relativeToKey.get(), NS_GET_IID(nsIFile), getter_AddRefs(relativeToFile));
+    if (NS_FAILED(rv))
+      return rv;
+
+    nsAutoCString relDescriptor;
+    rv = file->GetRelativeDescriptor(relativeToFile, relDescriptor);
+    if (NS_FAILED(rv))
+      return rv;
+
+    nsAutoCString descriptorString;
+    descriptorString.Append('[');
+    descriptorString.Append(relativeToKey);
+    descriptorString.Append(']');
+    descriptorString.Append(relDescriptor);
+    return SetCharPrefInternal(aPrefName, descriptorString.get());
+  }
+
+  if (aType.Equals(NS_GET_IID(nsISupportsString))) {
+    nsCOMPtr<nsISupportsString> theString = do_QueryInterface(aValue);
+
+    if (theString) {
+      nsString wideString;
+
+      rv = theString->GetData(wideString);
+      if (NS_SUCCEEDED(rv)) {
+        // Check sanity of string length before any lengthy conversion
+        rv = CheckSanityOfStringLength(aPrefName, wideString);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+        rv = SetCharPrefInternal(aPrefName, NS_ConvertUTF16toUTF8(wideString).get());
+      }
+    }
+    return rv;
+  }
+
+  if (aType.Equals(NS_GET_IID(nsIPrefLocalizedString))) {
+    nsCOMPtr<nsIPrefLocalizedString> theString = do_QueryInterface(aValue);
+
+    if (theString) {
+      nsXPIDLString wideString;
+
+      rv = theString->GetData(getter_Copies(wideString));
+      if (NS_SUCCEEDED(rv)) {
+        // Check sanity of string length before any lengthy conversion
+        rv = CheckSanityOfStringLength(aPrefName, wideString);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+        rv = SetCharPrefInternal(aPrefName, NS_ConvertUTF16toUTF8(wideString).get());
+      }
+    }
+    return rv;
+  }
+
+  NS_WARNING("nsPrefBranch::SetComplexValue - Unsupported interface type");
+  return NS_NOINTERFACE;
+}
+
+NS_IMETHODIMP nsPrefBranch::ClearUserPref(const char *aPrefName)
+{
+  ENSURE_MAIN_PROCESS("Cannot ClearUserPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_ClearUserPref(pref);
+}
+
+NS_IMETHODIMP nsPrefBranch::PrefHasUserValue(const char *aPrefName, bool *_retval)
+{
+  NS_ENSURE_ARG_POINTER(_retval);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  *_retval = PREF_HasUserPref(pref);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::LockPref(const char *aPrefName)
+{
+  ENSURE_MAIN_PROCESS("Cannot LockPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_LockPref(pref, true);
+}
+
+NS_IMETHODIMP nsPrefBranch::PrefIsLocked(const char *aPrefName, bool *_retval)
+{
+  ENSURE_MAIN_PROCESS("Cannot check PrefIsLocked from content process:", aPrefName);
+  NS_ENSURE_ARG_POINTER(_retval);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  *_retval = PREF_PrefIsLocked(pref);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::UnlockPref(const char *aPrefName)
+{
+  ENSURE_MAIN_PROCESS("Cannot UnlockPref from content process:", aPrefName);
+  NS_ENSURE_ARG(aPrefName);
+  const char *pref = getPrefName(aPrefName);
+  return PREF_LockPref(pref, false);
+}
+
+NS_IMETHODIMP nsPrefBranch::ResetBranch(const char *aStartingAt)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP nsPrefBranch::DeleteBranch(const char *aStartingAt)
+{
+  ENSURE_MAIN_PROCESS("Cannot DeleteBranch from content process:", aStartingAt);
+  NS_ENSURE_ARG(aStartingAt);
+  const char *pref = getPrefName(aStartingAt);
+  return PREF_DeleteBranch(pref);
+}
+
+NS_IMETHODIMP nsPrefBranch::GetChildList(const char *aStartingAt, uint32_t *aCount, char ***aChildArray)
+{
+  char            **outArray;
+  int32_t         numPrefs;
+  int32_t         dwIndex;
+  AutoTArray<nsCString, 32> prefArray;
+
+  NS_ENSURE_ARG(aStartingAt);
+  NS_ENSURE_ARG_POINTER(aCount);
+  NS_ENSURE_ARG_POINTER(aChildArray);
+
+  *aChildArray = nullptr;
+  *aCount = 0;
+
+  // this will contain a list of all the pref name strings
+  // allocate on the stack for speed
+
+  const char* parent = getPrefName(aStartingAt);
+  size_t parentLen = strlen(parent);
+  for (auto iter = gHashTable->Iter(); !iter.Done(); iter.Next()) {
+    auto entry = static_cast<PrefHashEntry*>(iter.Get());
+    if (strncmp(entry->key, parent, parentLen) == 0) {
+      prefArray.AppendElement(entry->key);
+    }
+  }
+
+  // now that we've built up the list, run the callback on
+  // all the matching elements
+  numPrefs = prefArray.Length();
+
+  if (numPrefs) {
+    outArray = (char **)moz_xmalloc(numPrefs * sizeof(char *));
+    if (!outArray)
+      return NS_ERROR_OUT_OF_MEMORY;
+
+    for (dwIndex = 0; dwIndex < numPrefs; ++dwIndex) {
+      // we need to lop off mPrefRoot in case the user is planning to pass this
+      // back to us because if they do we are going to add mPrefRoot again.
+      const nsCString& element = prefArray[dwIndex];
+      outArray[dwIndex] = (char *)nsMemory::Clone(
+        element.get() + mPrefRootLength, element.Length() - mPrefRootLength + 1);
+
+      if (!outArray[dwIndex]) {
+        // we ran out of memory... this is annoying
+        NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(dwIndex, outArray);
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+    }
+    *aChildArray = outArray;
+  }
+  *aCount = numPrefs;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::AddObserver(const char *aDomain, nsIObserver *aObserver, bool aHoldWeak)
+{
+  PrefCallback *pCallback;
+  const char *pref;
+
+  NS_ENSURE_ARG(aDomain);
+  NS_ENSURE_ARG(aObserver);
+
+  // hold a weak reference to the observer if so requested
+  if (aHoldWeak) {
+    nsCOMPtr<nsISupportsWeakReference> weakRefFactory = do_QueryInterface(aObserver);
+    if (!weakRefFactory) {
+      // the caller didn't give us a object that supports weak reference... tell them
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    // Construct a PrefCallback with a weak reference to the observer.
+    pCallback = new PrefCallback(aDomain, weakRefFactory, this);
+
+  } else {
+    // Construct a PrefCallback with a strong reference to the observer.
+    pCallback = new PrefCallback(aDomain, aObserver, this);
+  }
+
+  if (mObservers.Get(pCallback)) {
+    NS_WARNING("Ignoring duplicate observer.");
+    delete pCallback;
+    return NS_OK;
+  }
+
+  mObservers.Put(pCallback, pCallback);
+
+  // We must pass a fully qualified preference name to the callback
+  // aDomain == nullptr is the only possible failure, and we trapped it with
+  // NS_ENSURE_ARG above.
+  pref = getPrefName(aDomain);
+  PREF_RegisterCallback(pref, NotifyObserver, pCallback);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrefBranch::RemoveObserver(const char *aDomain, nsIObserver *aObserver)
+{
+  NS_ENSURE_ARG(aDomain);
+  NS_ENSURE_ARG(aObserver);
+
+  nsresult rv = NS_OK;
+
+  // If we're in the middle of a call to freeObserverList, don't process this
+  // RemoveObserver call -- the observer in question will be removed soon, if
+  // it hasn't been already.
+  //
+  // It's important that we don't touch mObservers in any way -- even a Get()
+  // which returns null might cause the hashtable to resize itself, which will
+  // break the iteration in freeObserverList.
+  if (mFreeingObserverList)
+    return NS_OK;
+
+  // Remove the relevant PrefCallback from mObservers and get an owning
+  // pointer to it.  Unregister the callback first, and then let the owning
+  // pointer go out of scope and destroy the callback.
+  PrefCallback key(aDomain, aObserver, this);
+  nsAutoPtr<PrefCallback> pCallback;
+  mObservers.RemoveAndForget(&key, pCallback);
+  if (pCallback) {
+    // aDomain == nullptr is the only possible failure, trapped above
+    const char *pref = getPrefName(aDomain);
+    rv = PREF_UnregisterCallback(pref, NotifyObserver, pCallback);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsPrefBranch::Observe(nsISupports *aSubject, const char *aTopic, const char16_t *someData)
+{
+  // watch for xpcom shutdown and free our observers to eliminate any cyclic references
+  if (!nsCRT::strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    freeObserverList();
+  }
+  return NS_OK;
+}
+
+/* static */
+void nsPrefBranch::NotifyObserver(const char *newpref, void *data)
+{
+  PrefCallback *pCallback = (PrefCallback *)data;
+
+  nsCOMPtr<nsIObserver> observer = pCallback->GetObserver();
+  if (!observer) {
+    // The observer has expired.  Let's remove this callback.
+    pCallback->GetPrefBranch()->RemoveExpiredCallback(pCallback);
+    return;
+  }
+
+  // remove any root this string may contain so as to not confuse the observer
+  // by passing them something other than what they passed us as a topic
+  uint32_t len = pCallback->GetPrefBranch()->GetRootLength();
+  nsAutoCString suffix(newpref + len);
+
+  observer->Observe(static_cast<nsIPrefBranch *>(pCallback->GetPrefBranch()),
+                    NS_PREFBRANCH_PREFCHANGE_TOPIC_ID,
+                    NS_ConvertASCIItoUTF16(suffix).get());
+}
+
+size_t
+nsPrefBranch::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
+{
+  size_t n = aMallocSizeOf(this);
+  n += mPrefRoot.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+  n += mObservers.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  return n;
+}
+
+void nsPrefBranch::freeObserverList(void)
+{
+  // We need to prevent anyone from modifying mObservers while we're iterating
+  // over it. In particular, some clients will call RemoveObserver() when
+  // they're removed and destructed via the iterator; we set
+  // mFreeingObserverList to keep those calls from touching mObservers.
+  mFreeingObserverList = true;
+  for (auto iter = mObservers.Iter(); !iter.Done(); iter.Next()) {
+    nsAutoPtr<PrefCallback>& callback = iter.Data();
+    nsPrefBranch *prefBranch = callback->GetPrefBranch();
+    const char *pref = prefBranch->getPrefName(callback->GetDomain().get());
+    PREF_UnregisterCallback(pref, nsPrefBranch::NotifyObserver, callback);
+    iter.Remove();
+  }
+  mFreeingObserverList = false;
+}
+
+void
+nsPrefBranch::RemoveExpiredCallback(PrefCallback *aCallback)
+{
+  NS_PRECONDITION(aCallback->IsExpired(), "Callback should be expired.");
+  mObservers.Remove(aCallback);
+}
+
+nsresult nsPrefBranch::GetDefaultFromPropertiesFile(const char *aPrefName, char16_t **return_buf)
+{
+  nsresult rv;
+
+  // the default value contains a URL to a .properties file
+    
+  nsXPIDLCString propertyFileURL;
+  rv = PREF_CopyCharPref(aPrefName, getter_Copies(propertyFileURL), true);
+  if (NS_FAILED(rv))
+    return rv;
+
+  nsCOMPtr<nsIStringBundleService> bundleService =
+    mozilla::services::GetStringBundleService();
+  if (!bundleService)
+    return NS_ERROR_FAILURE;
+
+  nsCOMPtr<nsIStringBundle> bundle;
+  rv = bundleService->CreateBundle(propertyFileURL,
+                                   getter_AddRefs(bundle));
+  if (NS_FAILED(rv))
+    return rv;
+
+  // string names are in unicode
+  nsAutoString stringId;
+  stringId.AssignASCII(aPrefName);
+
+  return bundle->GetStringFromName(stringId.get(), return_buf);
+}
+
+const char *nsPrefBranch::getPrefName(const char *aPrefName)
+{
+  NS_ASSERTION(aPrefName, "null pref name!");
+
+  // for speed, avoid strcpy if we can:
+  if (mPrefRoot.IsEmpty())
+    return aPrefName;
+
+  // isn't there a better way to do this? this is really kind of gross.
+  mPrefRoot.Truncate(mPrefRootLength);
+  mPrefRoot.Append(aPrefName);
+  return mPrefRoot.get();
+}
+
+//----------------------------------------------------------------------------
+// nsPrefLocalizedString
+//----------------------------------------------------------------------------
+
+nsPrefLocalizedString::nsPrefLocalizedString()
+{
+}
+
+nsPrefLocalizedString::~nsPrefLocalizedString()
+{
+}
+
+
+/*
+ * nsISupports Implementation
+ */
+
+NS_IMPL_ADDREF(nsPrefLocalizedString)
+NS_IMPL_RELEASE(nsPrefLocalizedString)
+
+NS_INTERFACE_MAP_BEGIN(nsPrefLocalizedString)
+    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrefLocalizedString)
+    NS_INTERFACE_MAP_ENTRY(nsIPrefLocalizedString)
+    NS_INTERFACE_MAP_ENTRY(nsISupportsString)
+NS_INTERFACE_MAP_END
+
+nsresult nsPrefLocalizedString::Init()
+{
+  nsresult rv;
+  mUnicodeString = do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID, &rv);
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsPrefLocalizedString::GetData(char16_t **_retval)
+{
+  nsAutoString data;
+
+  nsresult rv = GetData(data);
+  if (NS_FAILED(rv))
+    return rv;
+  
+  *_retval = ToNewUnicode(data);
+  if (!*_retval)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrefLocalizedString::SetData(const char16_t *aData)
+{
+  if (!aData)
+    return SetData(EmptyString());
+  return SetData(nsDependentString(aData));
+}
+
+NS_IMETHODIMP
+nsPrefLocalizedString::SetDataWithLength(uint32_t aLength,
+                                         const char16_t *aData)
+{
+  if (!aData)
+    return SetData(EmptyString());
+  return SetData(Substring(aData, aLength));
+}
+
+//----------------------------------------------------------------------------
+// nsRelativeFilePref
+//----------------------------------------------------------------------------
+
+NS_IMPL_ISUPPORTS(nsRelativeFilePref, nsIRelativeFilePref)
+
+nsRelativeFilePref::nsRelativeFilePref()
+{
+}
+
+nsRelativeFilePref::~nsRelativeFilePref()
+{
+}
+
+NS_IMETHODIMP nsRelativeFilePref::GetFile(nsIFile **aFile)
+{
+  NS_ENSURE_ARG_POINTER(aFile);
+  *aFile = mFile;
+  NS_IF_ADDREF(*aFile);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsRelativeFilePref::SetFile(nsIFile *aFile)
+{
+  mFile = aFile;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsRelativeFilePref::GetRelativeToKey(nsACString& aRelativeToKey)
+{
+  aRelativeToKey.Assign(mRelativeToKey);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsRelativeFilePref::SetRelativeToKey(const nsACString& aRelativeToKey)
+{
+  mRelativeToKey.Assign(aRelativeToKey);
+  return NS_OK;
+}
+
+#undef ENSURE_MAIN_PROCESS