Bug 1642989 - Use RemoveLastElements instead of RemoveElementsAt where possible. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D78049

accessible/generic/DocAccessible.cpp

@@ -2361,7 +2361,7 @@ void DocAccessible::PutChildrenBack(nsTArray<RefPtr<Accessible>>* aChildren,
     }
   }
 
-  aChildren->RemoveElementsAt(aStartIdx, aChildren->Length() - aStartIdx);
+  aChildren->RemoveLastElements(aChildren->Length() - aStartIdx);
 }
 
 bool DocAccessible::MoveChild(Accessible* aChild, Accessible* aNewParent,

accessible/generic/HyperTextAccessible.cpp

@@ -1806,18 +1806,20 @@ void HyperTextAccessible::Shutdown() {
 }
 
 bool HyperTextAccessible::RemoveChild(Accessible* aAccessible) {
-  int32_t childIndex = aAccessible->IndexInParent();
-  int32_t count = mOffsets.Length() - childIndex;
-  if (count > 0) mOffsets.RemoveElementsAt(childIndex, count);
+  const int32_t childIndex = aAccessible->IndexInParent();
+  if (childIndex < static_cast<int64_t>(mOffsets.Length())) {
+    mOffsets.RemoveLastElements(mOffsets.Length() -
+                                aAccessible->IndexInParent());
+  }
 
   return AccessibleWrap::RemoveChild(aAccessible);
 }
 
 bool HyperTextAccessible::InsertChildAt(uint32_t aIndex, Accessible* aChild) {
-  int32_t count = mOffsets.Length() - aIndex;
-  if (count > 0) {
-    mOffsets.RemoveElementsAt(aIndex, count);
+  if (aIndex < mOffsets.Length()) {
+    mOffsets.RemoveLastElements(mOffsets.Length() - aIndex);
   }
+
   return AccessibleWrap::InsertChildAt(aIndex, aChild);
 }
 

dom/html/HTMLMediaElement.cpp

@@ -3536,7 +3536,8 @@ void HTMLMediaElement::UpdateOutputTrackSources() {
   }
 
   // Then work out the differences.
-  mediaTracksToAdd.RemoveElementsAt(
+  mediaTracksToAdd.RemoveLastElements(
+      mediaTracksToAdd.end() -
       std::remove_if(mediaTracksToAdd.begin(), mediaTracksToAdd.end(),
                      [this, &trackSourcesToRemove](const auto& track) {
                        const bool remove =
@@ -3545,8 +3546,7 @@ void HTMLMediaElement::UpdateOutputTrackSources() {
                          trackSourcesToRemove.RemoveElement(track->GetId());
                        }
                        return remove;
-                     }),
-      mediaTracksToAdd.end());
+                     }));
 
   // First remove stale track sources.
   for (const auto& id : trackSourcesToRemove) {

dom/indexedDB/ActorsParent.cpp

@@ -12752,12 +12752,12 @@ void ConnectionPool::NoteClosedDatabase(DatabaseInfo* aDatabaseInfo) {
 
   // See if we need to fire any complete callbacks now that the database is
   // finished.
-  mCompleteCallbacks.RemoveElementsAt(
+  mCompleteCallbacks.RemoveLastElements(
+      mCompleteCallbacks.end() -
       std::remove_if(mCompleteCallbacks.begin(), mCompleteCallbacks.end(),
                      [&me = *this](const auto& completeCallback) {
                        return me.MaybeFireCallback(completeCallback.get());
-                     }),
-      mCompleteCallbacks.end());
+                     }));
 
   // If that was the last database and we're supposed to be shutting down then
   // we are finished.
@@ -20826,14 +20826,14 @@ nsresult FactoryOp::SendVersionChangeMessages(
 
   // We don't want to wait forever if we were not able to send the
   // message.
-  mMaybeBlockedDatabases.RemoveElementsAt(
+  mMaybeBlockedDatabases.RemoveLastElements(
+      mMaybeBlockedDatabases.end() -
       std::remove_if(mMaybeBlockedDatabases.begin(),
                      mMaybeBlockedDatabases.end(),
                      [aOldVersion, &aNewVersion](auto& maybeBlockedDatabase) {
                        return !maybeBlockedDatabase->SendVersionChange(
                            aOldVersion, aNewVersion);
-                     }),
-      mMaybeBlockedDatabases.end());
+                     }));
 
   return NS_OK;
 }  // namespace indexedDB

dom/indexedDB/IDBTransaction.cpp

@@ -646,13 +646,13 @@ void IDBTransaction::AbortInternal(const nsresult aAbortCode,
             return static_cast<uint64_t>(objectStoreId);
           });
 
-      mObjectStores.RemoveElementsAt(
+      mObjectStores.RemoveLastElements(
+          mObjectStores.end() -
           std::remove_if(mObjectStores.begin(), mObjectStores.end(),
                          [&validIds](const auto& objectStore) {
                            return !validIds.Contains(
                                uint64_t(objectStore->Id()));
-                         }),
-          mObjectStores.end());
+                         }));
 
       std::copy_if(std::make_move_iterator(mDeletedObjectStores.begin()),
                    std::make_move_iterator(mDeletedObjectStores.end()),

dom/media/MediaRecorder.cpp

@@ -1442,10 +1442,9 @@ void MediaRecorder::Start(const Optional<uint32_t>& aTimeslice,
   if (mStream) {
     mStream->GetTracks(tracks);
   }
-  tracks.RemoveElementsAt(
-      std::remove_if(tracks.begin(), tracks.end(),
-                     [](const auto& t) { return t->Ended(); }),
-      tracks.end());
+  tracks.RemoveLastElements(
+      tracks.end() - std::remove_if(tracks.begin(), tracks.end(),
+                                    [](const auto& t) { return t->Ended(); }));
 
   // 5. If the value of recorder’s state attribute is not inactive, throw an
   //    InvalidStateError DOMException and abort these steps.

dom/media/MediaSegment.h

@@ -479,7 +479,7 @@ class MediaSegmentBase : public MediaSegment {
     }
     // At this point `i` is already advanced due to last check in the loop.
     if (i < mChunks.Length()) {
-      mChunks.RemoveElementsAt(i, mChunks.Length() - i);
+      mChunks.RemoveLastElements(mChunks.Length() - i);
     }
     MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
                "Capacity must be retained after removing chunks");

dom/media/VideoOutput.h

@@ -165,7 +165,7 @@ class VideoOutput : public DirectMediaTrackListener {
     // there might be old frames lingering. We'll find the current one and
     // re-send that.
     DropPastFrames();
-    mFrames.RemoveElementsAt(1, mFrames.Length() - 1);
+    mFrames.RemoveLastElements(mFrames.Length() - 1);
     SendFrames();
     mFrames.ClearAndRetainStorage();
   }

dom/media/ogg/OggCodecState.cpp

@@ -1177,7 +1177,7 @@ bool OpusState::ReconstructOpusGranulepos(void) {
             // Encoders SHOULD NOT produce streams like this, but we'll handle
             // it for them anyway.
             gp = last_gp;
-            mUnstamped.RemoveElementsAt(i + 1, mUnstamped.Length() - (i + 1));
+            mUnstamped.RemoveLastElements(mUnstamped.Length() - (i + 1));
             packet->e_o_s = 1;
           }
         }

dom/media/webaudio/AudioNodeTrack.cpp

@@ -480,8 +480,8 @@ void AudioNodeTrack::UpMixDownMixChunk(const AudioBlock* aChunk,
       }
     } else {
       // Drop the remaining aOutputChannels
-      aOutputChannels.RemoveElementsAt(
-          aOutputChannelCount, aOutputChannels.Length() - aOutputChannelCount);
+      aOutputChannels.RemoveLastElements(aOutputChannels.Length() -
+                                         aOutputChannelCount);
     }
   }
 }

dom/media/webspeech/synth/SpeechSynthesis.cpp

@@ -162,7 +162,7 @@ void SpeechSynthesis::Cancel() {
   if (!mSpeechQueue.IsEmpty() && HasSpeakingTask()) {
     // Remove all queued utterances except for current one, we will remove it
     // in OnEnd
-    mSpeechQueue.RemoveElementsAt(1, mSpeechQueue.Length() - 1);
+    mSpeechQueue.RemoveLastElements(mSpeechQueue.Length() - 1);
   } else {
     mSpeechQueue.Clear();
   }

gfx/gl/GLTextureImage.cpp

@@ -407,8 +407,7 @@ void TiledTextureImage::Resize(const gfx::IntSize& aSize) {
   }
 
   // Prune any unused tiles at the end of the store.
-  unsigned int length = mImages.Length();
-  for (; i < length; i++) mImages.RemoveLastElement();
+  mImages.RemoveLastElements(mImages.Length() - i);
 
   // Reset tile-store properties.
   mRows = rows;

image/SourceBuffer.cpp

@@ -250,7 +250,7 @@ nsresult SourceBuffer::Compact() {
              "Compacted chunk has slack space");
 
   // Remove the redundant chunks.
-  mChunks.RemoveElementsAt(1, mChunks.Length() - 1);
+  mChunks.RemoveLastElements(mChunks.Length() - 1);
   mChunks.Compact();
 
   return NS_OK;

layout/painting/nsCSSRenderingGradients.cpp

@@ -519,7 +519,7 @@ static void ClampColorStops(nsTArray<ColorStop>& aStops) {
           InterpolateColorStop(aStops[i - 1], aStops[i],
                                /* aPosition = */ 1, aStops[i - 1].mColor);
       // Remove all the elements whose position is greater than 1.
-      aStops.RemoveElementsAt(i + 1, aStops.Length() - (i + 1));
+      aStops.RemoveLastElements(aStops.Length() - (i + 1));
     }
     if (aStops[i - 1].mPosition <= 0 && aStops[i].mPosition > 0) {
       // Add a point to position 0.

xpcom/base/CycleCollectedJSContext.cpp

@@ -412,7 +412,8 @@ void CycleCollectedJSContext::CleanupIDBTransactions(uint32_t aRecursionDepth) {
   nsTArray<PendingIDBTransactionData> localQueue =
       std::move(mPendingIDBTransactions);
 
-  localQueue.RemoveElementsAt(
+  localQueue.RemoveLastElements(
+      localQueue.end() -
       std::remove_if(localQueue.begin(), localQueue.end(),
                      [aRecursionDepth](PendingIDBTransactionData& data) {
                        if (data.mRecursionDepth != aRecursionDepth) {
@@ -426,8 +427,7 @@ void CycleCollectedJSContext::CleanupIDBTransactions(uint32_t aRecursionDepth) {
                        }
 
                        return true;
-                     }),
-      localQueue.end());
+                     }));
 
   // If mPendingIDBTransactions has events in it now, they were added from
   // something we called, so they belong at the end of the queue.

xpcom/threads/TimerThread.cpp

@@ -674,11 +674,8 @@ void TimerThread::RemoveLeadingCanceledTimersInternal() {
   }
 
   // Finally, remove the canceled timers from the back of the
-  // nsTArray.  Note, since std::pop_heap() uses iterators
-  // we must convert to nsTArray indices and number of
-  // elements here.
-  mTimers.RemoveElementsAt(sortedEnd - mTimers.begin(),
-                           mTimers.end() - sortedEnd);
+  // nsTArray.
+  mTimers.RemoveLastElements(mTimers.end() - sortedEnd);
 }
 
 void TimerThread::RemoveFirstTimerInternal() {