Bug 1212164: Prevent use of demuxer before it is ready. r=cpearce

dom/media/MediaFormatReader.cpp

@@ -63,9 +63,10 @@ MediaFormatReader::MediaFormatReader(AbstractMediaDecoder* aDecoder,
                                      MediaDataDemuxer* aDemuxer,
                                      TaskQueue* aBorrowedTaskQueue)
   : MediaDecoderReader(aDecoder, aBorrowedTaskQueue)
-  , mDemuxer(aDemuxer)
   , mAudio(this, MediaData::AUDIO_DATA, Preferences::GetUint("media.audio-decode-ahead", 2))
   , mVideo(this, MediaData::VIDEO_DATA, Preferences::GetUint("media.video-decode-ahead", 2))
+  , mDemuxer(aDemuxer)
+  , mDemuxerInitDone(false)
   , mLastReportedNumDecodedFrames(0)
   , mLayersBackendType(layers::LayersBackend::LAYERS_NONE)
   , mInitDone(false)
@@ -272,6 +273,8 @@ MediaFormatReader::OnDemuxerInitDone(nsresult)
   MOZ_ASSERT(OnTaskQueue());
   mDemuxerInitRequest.Complete();
 
+  mDemuxerInitDone = true;
+
   // To decode, we need valid video and a place to put it.
   bool videoActive = !!mDemuxer->GetNumberTracks(TrackInfo::kVideoTrack) &&
     mDecoder->GetImageContainer();
@@ -1593,7 +1596,8 @@ MediaFormatReader::NotifyDemuxer(uint32_t aLength, int64_t aOffset)
   MOZ_ASSERT(OnTaskQueue());
 
   LOGV("aLength=%u, aOffset=%lld", aLength, aOffset);
-  if (mShutdown || !mDemuxer) {
+  if (mShutdown || !mDemuxer ||
+      (!mDemuxerInitDone && !mDemuxerInitRequest.Exists())) {
     return;
   }
 

dom/media/MediaFormatReader.h

@@ -152,7 +152,6 @@ private:
 
   size_t SizeOfQueue(TrackType aTrack);
 
-  nsRefPtr<MediaDataDemuxer> mDemuxer;
   nsRefPtr<PDMFactory> mPlatform;
 
   class DecoderCallback : public MediaDataDecoderCallback {
@@ -355,6 +354,8 @@ private:
   void OnDecoderInitFailed(MediaDataDecoder::DecoderFailureReason aReason);
 
   // Demuxer objects.
+  nsRefPtr<MediaDataDemuxer> mDemuxer;
+  bool mDemuxerInitDone;
   void OnDemuxerInitDone(nsresult);
   void OnDemuxerInitFailed(DemuxerFailureReason aFailure);
   MozPromiseRequestHolder<MediaDataDemuxer::InitPromise> mDemuxerInitRequest;