Bug 1116925: queue track adds for getUserMedia and cleanup r=roc

dom/media/MediaManager.h

@@ -393,8 +393,6 @@ public:
           NS_ASSERTION(!NS_IsMainThread(), "Never call on main thread");
           nsresult rv;
 
-          source->SetPullEnabled(true);
-
           DOMMediaStream::TrackTypeHints expectedTracks = 0;
           if (mAudioSource) {
             rv = mAudioSource->Start(source, kAudioTrack);
@@ -414,9 +412,14 @@ public:
               return;
             }
           }
+          // Start() queued the tracks to be added synchronously to avoid races
+          source->FinishAddTracks();
 
           mOnTracksAvailableCallback->SetExpectedTracks(expectedTracks);
 
+          source->SetPullEnabled(true);
+          source->AdvanceKnownTracksTime(STREAM_TIME_MAX);
+
           MM_LOG(("started all sources"));
           // Forward mOnTracksAvailableCallback to GetUserMediaNotificationEvent,
           // because mOnTracksAvailableCallback needs to be added to mStream

dom/media/MediaStreamGraph.cpp

@@ -2275,10 +2275,12 @@ SourceMediaStream::SetPullEnabled(bool aEnabled)
 
 void
 SourceMediaStream::AddTrackInternal(TrackID aID, TrackRate aRate, StreamTime aStart,
-                                    MediaSegment* aSegment)
+                                    MediaSegment* aSegment, uint32_t aFlags)
 {
   MutexAutoLock lock(mMutex);
-  TrackData* data = mUpdateTracks.AppendElement();
+  nsTArray<TrackData> *track_data = (aFlags & ADDTRACK_QUEUED) ?
+                                    &mPendingTracks : &mUpdateTracks;
+  TrackData* data = track_data->AppendElement();
   data->mID = aID;
   data->mInputRate = aRate;
   data->mStart = aStart;
@@ -2286,6 +2288,16 @@ SourceMediaStream::AddTrackInternal(TrackID aID, TrackRate aRate, StreamTime aSt
   data->mCommands = TRACK_CREATE;
   data->mData = aSegment;
   data->mHaveEnough = false;
+  if (!(aFlags & ADDTRACK_QUEUED) && GraphImpl()) {
+    GraphImpl()->EnsureNextIteration();
+  }
+}
+
+void
+SourceMediaStream::FinishAddTracks()
+{
+  MutexAutoLock lock(mMutex);
+  mUpdateTracks.MoveElementsFrom(mPendingTracks);
   if (GraphImpl()) {
     GraphImpl()->EnsureNextIteration();
   }
@@ -2515,6 +2527,7 @@ SourceMediaStream::EndAllTrackAndFinish()
     SourceMediaStream::TrackData* data = &mUpdateTracks[i];
     data->mCommands |= TRACK_END;
   }
+  mPendingTracks.Clear();
   FinishWithLockHeld();
   // we will call NotifyEvent() to let GetUserMedia know
 }

dom/media/MediaStreamGraph.h

@@ -720,26 +720,36 @@ public:
   void AddDirectListener(MediaStreamDirectListener* aListener);
   void RemoveDirectListener(MediaStreamDirectListener* aListener);
 
+  enum {
+    ADDTRACK_QUEUED    = 0x01 // Queue track add until FinishAddTracks()
+  };
   /**
    * Add a new track to the stream starting at the given base time (which
    * must be greater than or equal to the last time passed to
    * AdvanceKnownTracksTime). Takes ownership of aSegment. aSegment should
    * contain data starting after aStart.
    */
-  void AddTrack(TrackID aID, StreamTime aStart, MediaSegment* aSegment)
+  void AddTrack(TrackID aID, StreamTime aStart, MediaSegment* aSegment,
+                uint32_t aFlags = 0)
   {
-    AddTrackInternal(aID, GraphRate(), aStart, aSegment);
+    AddTrackInternal(aID, GraphRate(), aStart, aSegment, aFlags);
   }
 
   /**
    * Like AddTrack, but resamples audio from aRate to the graph rate.
    */
   void AddAudioTrack(TrackID aID, TrackRate aRate, StreamTime aStart,
-                     AudioSegment* aSegment)
+                     AudioSegment* aSegment, uint32_t aFlags = 0)
   {
-    AddTrackInternal(aID, aRate, aStart, aSegment);
+    AddTrackInternal(aID, aRate, aStart, aSegment, aFlags);
   }
 
+  /**
+   * Call after a series of AddTrack or AddAudioTrack calls to implement
+   * any pending track adds.
+   */
+  void FinishAddTracks();
+
   /**
    * Append media data to a track. Ownership of aSegment remains with the caller,
    * but aSegment is emptied.
@@ -874,7 +884,8 @@ protected:
   void ResampleAudioToGraphSampleRate(TrackData* aTrackData, MediaSegment* aSegment);
 
   void AddTrackInternal(TrackID aID, TrackRate aRate,
-                        StreamTime aStart, MediaSegment* aSegment);
+                        StreamTime aStart, MediaSegment* aSegment,
+                        uint32_t aFlags);
 
   TrackData* FindDataForTrack(TrackID aID)
   {
@@ -905,6 +916,7 @@ protected:
   // protected by mMutex
   StreamTime mUpdateKnownTracksTime;
   nsTArray<TrackData> mUpdateTracks;
+  nsTArray<TrackData> mPendingTracks;
   nsTArray<nsRefPtr<MediaStreamDirectListener> > mDirectListeners;
   bool mPullEnabled;
   bool mUpdateFinished;

dom/media/webrtc/MediaEngineDefault.cpp

@@ -138,12 +138,11 @@ MediaEngineDefaultVideoSource::Start(SourceMediaStream* aStream, TrackID aID)
     return NS_ERROR_FAILURE;
   }
 
-  aStream->AddTrack(aID, 0, new VideoSegment());
-  aStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
+  aStream->AddTrack(aID, 0, new VideoSegment(), SourceMediaStream::ADDTRACK_QUEUED);
 
   if (mHasFakeTracks) {
     for (int i = 0; i < kFakeVideoTrackCount; ++i) {
-      aStream->AddTrack(kTrackCount + i, 0, new VideoSegment());
+      aStream->AddTrack(kTrackCount + i, 0, new VideoSegment(), SourceMediaStream::ADDTRACK_QUEUED);
     }
   }
 
@@ -389,18 +388,15 @@ MediaEngineDefaultAudioSource::Start(SourceMediaStream* aStream, TrackID aID)
 
   // AddTrack will take ownership of segment
   AudioSegment* segment = new AudioSegment();
-  mSource->AddAudioTrack(aID, AUDIO_RATE, 0, segment);
+  mSource->AddAudioTrack(aID, AUDIO_RATE, 0, segment, SourceMediaStream::ADDTRACK_QUEUED);
 
   if (mHasFakeTracks) {
     for (int i = 0; i < kFakeAudioTrackCount; ++i) {
       mSource->AddAudioTrack(kTrackCount + kFakeVideoTrackCount+i,
-                             AUDIO_RATE, 0, new AudioSegment());
+                             AUDIO_RATE, 0, new AudioSegment(), SourceMediaStream::ADDTRACK_QUEUED);
     }
   }
 
-  // We aren't going to add any more tracks
-  mSource->AdvanceKnownTracksTime(STREAM_TIME_MAX);
-
   // Remember TrackID so we can finish later
   mTrackID = aID;
 

dom/media/webrtc/MediaEngineGonkVideoSource.cpp

@@ -182,7 +182,6 @@ MediaEngineGonkVideoSource::Start(SourceMediaStream* aStream, TrackID aID)
   }
 
   aStream->AddTrack(aID, 0, new VideoSegment());
-  aStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
 
   ReentrantMonitorAutoEnter sync(mCallbackMonitor);
 

dom/media/webrtc/MediaEngineTabVideoSource.cpp

@@ -174,7 +174,6 @@ MediaEngineTabVideoSource::Start(SourceMediaStream* aStream, TrackID aID)
     runnable = new StartRunnable(this);
   NS_DispatchToMainThread(runnable);
   aStream->AddTrack(aID, 0, new VideoSegment());
-  aStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
 
   return NS_OK;
 }

dom/media/webrtc/MediaEngineWebRTCAudio.cpp

@@ -328,8 +328,8 @@ MediaEngineWebRTCAudioSource::Start(SourceMediaStream* aStream, TrackID aID)
   }
 
   AudioSegment* segment = new AudioSegment();
-  aStream->AddAudioTrack(aID, SAMPLE_FREQUENCY, 0, segment);
-  aStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
+  aStream->AddAudioTrack(aID, SAMPLE_FREQUENCY, 0, segment, SourceMediaStream::ADDTRACK_QUEUED);
+
   // XXX Make this based on the pref.
   aStream->RegisterForAudioMixing();
   LOG(("Start audio for stream %p", aStream));

dom/media/webrtc/MediaEngineWebRTCVideo.cpp

@@ -408,8 +408,7 @@ MediaEngineWebRTCVideoSource::Start(SourceMediaStream* aStream, TrackID aID)
     mSources.AppendElement(aStream);
   }
 
-  aStream->AddTrack(aID, 0, new VideoSegment());
-  aStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
+  aStream->AddTrack(aID, 0, new VideoSegment(), SourceMediaStream::ADDTRACK_QUEUED);
 
   if (mState == kStarted) {
     return NS_OK;