Bug 753852. Don't try to notify the graph to perform its next iteration if this stream has been removed from the graph. r=jesup

content/media/MediaStreamGraph.cpp

@@ -1794,35 +1794,45 @@ MediaStream::RemoveListener(MediaStreamListener* aListener)
 }
 
 void
-SourceMediaStream::AddTrack(TrackID aID, TrackRate aRate, TrackTicks aStart,
-                            MediaSegment* aSegment)
+SourceMediaStream::DestroyImpl()
 {
   {
     MutexAutoLock lock(mMutex);
-    TrackData* data = mUpdateTracks.AppendElement();
-    data->mID = aID;
-    data->mRate = aRate;
-    data->mStart = aStart;
-    data->mCommands = TRACK_CREATE;
-    data->mData = aSegment;
-    data->mHaveEnough = false;
+    mDestroyed = true;
+  }
+  MediaStream::DestroyImpl();
+}
+
+void
+SourceMediaStream::AddTrack(TrackID aID, TrackRate aRate, TrackTicks aStart,
+                            MediaSegment* aSegment)
+{
+  MutexAutoLock lock(mMutex);
+  TrackData* data = mUpdateTracks.AppendElement();
+  data->mID = aID;
+  data->mRate = aRate;
+  data->mStart = aStart;
+  data->mCommands = TRACK_CREATE;
+  data->mData = aSegment;
+  data->mHaveEnough = false;
+  if (!mDestroyed) {
+    GraphImpl()->EnsureNextIteration();
   }
-  GraphImpl()->EnsureNextIteration();
 }
 
 void
 SourceMediaStream::AppendToTrack(TrackID aID, MediaSegment* aSegment)
 {
-  {
-    MutexAutoLock lock(mMutex);
-    TrackData *track = FindDataForTrack(aID);
-    if (track) {
-      track->mData->AppendFrom(aSegment);
-    } else {
-      NS_ERROR("Append to non-existant track!");
-    }
+  MutexAutoLock lock(mMutex);
+  TrackData *track = FindDataForTrack(aID);
+  if (track) {
+    track->mData->AppendFrom(aSegment);
+  } else {
+    NS_ERROR("Append to non-existent track!");
+  }
+  if (!mDestroyed) {
+    GraphImpl()->EnsureNextIteration();
   }
-  GraphImpl()->EnsureNextIteration();
 }
 
 bool
@@ -1858,36 +1868,36 @@ SourceMediaStream::DispatchWhenNotEnoughBuffered(TrackID aID,
 void
 SourceMediaStream::EndTrack(TrackID aID)
 {
-  {
-    MutexAutoLock lock(mMutex);
-    TrackData *track = FindDataForTrack(aID);
-    if (track) {
-      track->mCommands |= TRACK_END;
-    } else {
-      NS_ERROR("End of non-existant track");
-    }
+  MutexAutoLock lock(mMutex);
+  TrackData *track = FindDataForTrack(aID);
+  if (track) {
+    track->mCommands |= TRACK_END;
+  } else {
+    NS_ERROR("End of non-existant track");
+  }
+  if (!mDestroyed) {
+    GraphImpl()->EnsureNextIteration();
   }
-  GraphImpl()->EnsureNextIteration();
 }
 
 void
 SourceMediaStream::AdvanceKnownTracksTime(StreamTime aKnownTime)
 {
-  {
-    MutexAutoLock lock(mMutex);
-    mUpdateKnownTracksTime = aKnownTime;
+  MutexAutoLock lock(mMutex);
+  mUpdateKnownTracksTime = aKnownTime;
+  if (!mDestroyed) {
+    GraphImpl()->EnsureNextIteration();
   }
-  GraphImpl()->EnsureNextIteration();
 }
 
 void
 SourceMediaStream::Finish()
 {
-  {
-    MutexAutoLock lock(mMutex);
-    mUpdateFinished = true;
+  MutexAutoLock lock(mMutex);
+  mUpdateFinished = true;
+  if (!mDestroyed) {
+    GraphImpl()->EnsureNextIteration();
   }
-  GraphImpl()->EnsureNextIteration();
 }
 
 static const PRUint32 kThreadLimit = 4;

content/media/MediaStreamGraph.h

@@ -371,11 +371,14 @@ class SourceMediaStream : public MediaStream {
 public:
   SourceMediaStream(nsDOMMediaStream* aWrapper) :
     MediaStream(aWrapper), mMutex("mozilla::media::SourceMediaStream"),
-    mUpdateKnownTracksTime(0), mUpdateFinished(false)
+    mUpdateKnownTracksTime(0), mUpdateFinished(false), mDestroyed(false)
   {}
 
   virtual SourceMediaStream* AsSourceStream() { return this; }
 
+  // Media graph thread only
+  virtual void DestroyImpl();
+
   // Call these on any thread.
   /**
    * Add a new track to the stream starting at the given base time (which
@@ -467,11 +470,14 @@ protected:
     return nsnull;
   }
 
+  // This must be acquired *before* MediaStreamGraphImpl's lock, if they are
+  // held together.
   Mutex mMutex;
   // protected by mMutex
   StreamTime mUpdateKnownTracksTime;
   nsTArray<TrackData> mUpdateTracks;
   bool mUpdateFinished;
+  bool mDestroyed;
 };
 
 /**