Bug 1557501. Stop using [array] in nsIPrefBranch. r=njn

Differential Revision: https://phabricator.services.mozilla.com/D34032

--HG--
extra : moz-landing-system : lando

gfx/thebes/gfxFcPlatformFontList.cpp

@@ -2376,12 +2376,11 @@ bool gfxFcPlatformFontList::PrefFontListsUseOnlyGenerics() {
   static const char kFontNamePrefix[] = "font.name.";
 
   bool prefFontsUseOnlyGenerics = true;
-  uint32_t count;
-  char** names;
-  nsresult rv = Preferences::GetRootBranch()->GetChildList(kFontNamePrefix,
-                                                           &count, &names);
-  if (NS_SUCCEEDED(rv) && count) {
-    for (size_t i = 0; i < count; i++) {
+  nsTArray<nsCString> names;
+  nsresult rv =
+      Preferences::GetRootBranch()->GetChildList(kFontNamePrefix, names);
+  if (NS_SUCCEEDED(rv)) {
+    for (auto& name : names) {
       // Check whether all font.name prefs map to generic keywords
       // and that the pref name and keyword match.
       //   Ex: font.name.serif.ar ==> "serif" (ok)
@@ -2393,12 +2392,13 @@ bool gfxFcPlatformFontList::PrefFontListsUseOnlyGenerics() {
       //       font.name-list.serif.ar ==> "Something, serif"
       //                                           (return false)
 
-      nsDependentCString prefName(names[i] + ArrayLength(kFontNamePrefix) - 1);
+      nsDependentCSubstring prefName =
+          Substring(name, ArrayLength(kFontNamePrefix) - 1);
       nsCCharSeparatedTokenizer tokenizer(prefName, '.');
       const nsDependentCSubstring& generic = tokenizer.nextToken();
       const nsDependentCSubstring& langGroup = tokenizer.nextToken();
       nsAutoCString fontPrefValue;
-      Preferences::GetCString(names[i], fontPrefValue);
+      Preferences::GetCString(name.get(), fontPrefValue);
       if (fontPrefValue.IsEmpty()) {
         // The font name list may have two or more family names as comma
         // separated list.  In such case, not matching with generic font
@@ -2414,7 +2414,6 @@ bool gfxFcPlatformFontList::PrefFontListsUseOnlyGenerics() {
         break;
       }
     }
-    NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(count, names);
   }
   return prefFontsUseOnlyGenerics;
 }

intl/hyphenation/glue/nsHyphenationManager.cpp

@@ -278,16 +278,15 @@ void nsHyphenationManager::LoadAliases() {
   if (!prefRootBranch) {
     return;
   }
-  uint32_t prefCount;
-  char** prefNames;
-  nsresult rv = prefRootBranch->GetChildList(kIntlHyphenationAliasPrefix,
-                                             &prefCount, &prefNames);
-  if (NS_SUCCEEDED(rv) && prefCount > 0) {
-    for (uint32_t i = 0; i < prefCount; ++i) {
+  nsTArray<nsCString> prefNames;
+  nsresult rv =
+      prefRootBranch->GetChildList(kIntlHyphenationAliasPrefix, prefNames);
+  if (NS_SUCCEEDED(rv)) {
+    for (auto& prefName : prefNames) {
       nsAutoCString value;
-      rv = Preferences::GetCString(prefNames[i], value);
+      rv = Preferences::GetCString(prefName.get(), value);
       if (NS_SUCCEEDED(rv)) {
-        nsAutoCString alias(prefNames[i]);
+        nsAutoCString alias(prefName);
         alias.Cut(0, sizeof(kIntlHyphenationAliasPrefix) - 1);
         ToLowerCase(alias);
         ToLowerCase(value);
@@ -296,6 +295,5 @@ void nsHyphenationManager::LoadAliases() {
         mHyphAliases.Put(aliasAtom, valueAtom);
       }
     }
-    NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(prefCount, prefNames);
   }
 }

modules/libpref/Preferences.cpp

@@ -2575,24 +2575,15 @@ nsPrefBranch::DeleteBranch(const char* aStartingAt) {
 }
 
 NS_IMETHODIMP
-nsPrefBranch::GetChildList(const char* aStartingAt, uint32_t* aCount,
-                           char*** aChildArray) {
-  char** outArray;
-  int32_t numPrefs;
-  int32_t dwIndex;
-  AutoTArray<nsCString, 32> prefArray;
-
+nsPrefBranch::GetChildList(const char* aStartingAt,
+                           nsTArray<nsCString>& aChildArray) {
   NS_ENSURE_ARG(aStartingAt);
-  NS_ENSURE_ARG_POINTER(aCount);
-  NS_ENSURE_ARG_POINTER(aChildArray);
 
   MOZ_ASSERT(NS_IsMainThread());
 
-  *aChildArray = nullptr;
-  *aCount = 0;
-
   // This will contain a list of all the pref name strings. Allocated on the
   // stack for speed.
+  AutoTArray<nsCString, 32> prefArray;
 
   const PrefName& parent = GetPrefName(aStartingAt);
   size_t parentLen = parent.Length();
@@ -2604,22 +2595,12 @@ nsPrefBranch::GetChildList(const char* aStartingAt, uint32_t* aCount,
 
   // 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*));
-
-    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*)moz_xmemdup(element.get() + mPrefRoot.Length(),
-                             element.Length() - mPrefRoot.Length() + 1);
-    }
-    *aChildArray = outArray;
+  aChildArray.SetCapacity(prefArray.Length());
+  for (auto& element : prefArray) {
+    // 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.
+    aChildArray.AppendElement(Substring(element, mPrefRoot.Length()));
   }
-  *aCount = numPrefs;
 
   return NS_OK;
 }

modules/libpref/nsIPrefBranch.idl

@@ -336,8 +336,7 @@ interface nsIPrefBranch : nsISupports
    * @param aStartingAt The point on the branch at which to start enumerating
    *                    the child preferences. Pass in "" to enumerate all
    *                    preferences referenced by this branch.
-   * @param aCount      Receives the number of elements in the array.
-   * @param aChildArray Receives the array of child preferences.
+   * @return            The array of child preferences.
    *
    * @note
    * This method can be called on either a default or user branch but, in
@@ -345,9 +344,7 @@ interface nsIPrefBranch : nsISupports
    *
    * @throws Error The preference(s) do not exist or an error occurred.
    */
-  void getChildList(in string aStartingAt,
-                    [optional] out unsigned long aCount,
-                    [array, size_is(aCount), retval] out string aChildArray);
+  Array<ACString> getChildList(in string aStartingAt);
 
   /**
    * Called to reset all of the preferences referenced by this branch to their

toolkit/components/url-classifier/nsUrlClassifierUtils.cpp

@@ -828,15 +828,13 @@ nsresult nsUrlClassifierUtils::ReadProvidersFromPrefs(ProviderDictType& aDict) {
 
   // We've got a pref branch for "browser.safebrowsing.provider.".
   // Enumerate all children prefs and parse providers.
-  uint32_t childCount;
-  char** childArray;
-  rv = prefBranch->GetChildList("", &childCount, &childArray);
+  nsTArray<nsCString> childArray;
+  rv = prefBranch->GetChildList("", childArray);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Collect providers from childArray.
   nsTHashtable<nsCStringHashKey> providers;
-  for (uint32_t i = 0; i < childCount; i++) {
-    nsCString child(childArray[i]);
+  for (auto& child : childArray) {
     auto dotPos = child.FindChar('.');
     if (dotPos < 0) {
       continue;
@@ -846,7 +844,6 @@ nsresult nsUrlClassifierUtils::ReadProvidersFromPrefs(ProviderDictType& aDict) {
 
     providers.PutEntry(provider);
   }
-  NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(childCount, childArray);
 
   // Now we have all providers. Check which one owns |aTableName|.
   // e.g. The owning lists of provider "google" is defined in

toolkit/components/url-classifier/tests/mochitest/test_safebrowsing_bug1272239.html

@@ -32,7 +32,7 @@ const prefs = [
 var providers = {};
 
 var branch = SpecialPowers.Services.prefs.getBranch("browser.safebrowsing.provider.");
-var children = branch.getChildList("", {});
+var children = branch.getChildList("");
 
 for (var child of children) {
   var prefComponents =  child.split(".");

xpcom/base/LogModulePrefWatcher.cpp

@@ -35,16 +35,14 @@ NS_IMPL_ISUPPORTS(LogModulePrefWatcher, nsIObserver)
  * pref to false, or use the MOZ_LOG_FILE and MOZ_LOG_MODULES env vars.
  */
 static void ResetExistingPrefs() {
-  uint32_t count;
-  char** names;
-  nsresult rv = Preferences::GetRootBranch()->GetChildList(kLoggingPrefPrefix,
-                                                           &count, &names);
-  if (NS_SUCCEEDED(rv) && count) {
-    for (size_t i = 0; i < count; i++) {
+  nsTArray<nsCString> names;
+  nsresult rv =
+      Preferences::GetRootBranch()->GetChildList(kLoggingPrefPrefix, names);
+  if (NS_SUCCEEDED(rv)) {
+    for (auto& name : names) {
       // Clearing the pref will cause it to reload, thus resetting the log level
-      Preferences::ClearUser(names[i]);
+      Preferences::ClearUser(name.get());
     }
-    NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(count, names);
   }
 }
 
@@ -112,14 +110,12 @@ static void LoadExistingPrefs() {
     return;
   }
 
-  uint32_t count;
-  char** names;
-  nsresult rv = root->GetChildList(kLoggingPrefPrefix, &count, &names);
-  if (NS_SUCCEEDED(rv) && count) {
-    for (size_t i = 0; i < count; i++) {
-      LoadPrefValue(names[i]);
+  nsTArray<nsCString> names;
+  nsresult rv = root->GetChildList(kLoggingPrefPrefix, names);
+  if (NS_SUCCEEDED(rv)) {
+    for (auto& name : names) {
+      LoadPrefValue(name.get());
     }
-    NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(count, names);
   }
 }