Bug 1156472 - Part 7 - Allow to un-capture an HTMLMediaElement. r=pehrsons,jwwang

dom/html/HTMLMediaElement.cpp

@@ -4708,7 +4708,23 @@ NS_IMETHODIMP HTMLMediaElement::WindowAudioCaptureChanged()
         mCaptureStreamPort = msg->ConnectToCaptureStream(id, mPlaybackStream->GetStream());
       }
     } else {
-      // TODO: uncapture
+      mAudioCapturedByWindow = false;
+      if (mDecoder) {
+        ProcessedMediaStream* ps =
+          mCaptureStreamPort->GetSource()->AsProcessedStream();
+        MOZ_ASSERT(ps);
+
+        for (uint32_t i = 0; i < mOutputStreams.Length(); i++) {
+          if (mOutputStreams[i].mStream->GetStream() == ps) {
+            mOutputStreams.RemoveElementAt(i);
+            break;
+          }
+        }
+
+        mDecoder->RemoveOutputStream(ps);
+      }
+      mCaptureStreamPort->Destroy();
+      mCaptureStreamPort = nullptr;
     }
   }
 

dom/media/DecodedStream.cpp

@@ -289,6 +289,14 @@ DecodedStream::OutputStreams()
   return mOutputStreams;
 }
 
+bool
+DecodedStream::HasConsumers() const
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  ReentrantMonitorAutoEnter mon(GetReentrantMonitor());
+  return mOutputStreams.IsEmpty();
+}
+
 ReentrantMonitor&
 DecodedStream::GetReentrantMonitor() const
 {

dom/media/DecodedStream.h

@@ -114,6 +114,7 @@ public:
   int64_t AudioEndTime() const;
   int64_t GetPosition() const;
   bool IsFinished() const;
+  bool HasConsumers() const;
 
   // Return true if stream is finished.
   bool SendData(double aVolume, bool aIsSameOrigin);

dom/media/MediaDecoder.cpp

@@ -326,6 +326,13 @@ void MediaDecoder::AddOutputStream(ProcessedMediaStream* aStream,
   mDecoderStateMachine->AddOutputStream(aStream, aFinishWhenEnded);
 }
 
+void MediaDecoder::RemoveOutputStream(MediaStream* aStream)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mDecoderStateMachine, "Must be called after Load().");
+  mDecoderStateMachine->RemoveOutputStream(aStream);
+}
+
 double MediaDecoder::GetDuration()
 {
   MOZ_ASSERT(NS_IsMainThread());

dom/media/MediaDecoder.h

@@ -399,6 +399,8 @@ public:
   // The stream is initially blocked. The decoder is responsible for unblocking
   // it while it is playing back.
   virtual void AddOutputStream(ProcessedMediaStream* aStream, bool aFinishWhenEnded);
+  // Remove an output stream added with AddOutputStream.
+  virtual void RemoveOutputStream(MediaStream* aStream);
 
   // Return the duration of the video in seconds.
   virtual double GetDuration();

dom/media/MediaDecoderStateMachine.cpp

@@ -3140,6 +3140,25 @@ void MediaDecoderStateMachine::DispatchAudioCaptured()
   OwnerThread()->Dispatch(r.forget());
 }
 
+void MediaDecoderStateMachine::DispatchAudioUncaptured()
+{
+  nsRefPtr<MediaDecoderStateMachine> self = this;
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction([self] () -> void
+  {
+    MOZ_ASSERT(self->OnTaskQueue());
+    ReentrantMonitorAutoEnter mon(self->mDecoder->GetReentrantMonitor());
+    if (self->mAudioCaptured) {
+      // Start again the audio sink
+      self->mAudioCaptured = false;
+      if (self->IsPlaying()) {
+        self->StartAudioThread();
+      }
+      self->ScheduleStateMachine();
+    }
+  });
+  OwnerThread()->Dispatch(r.forget());
+}
+
 void MediaDecoderStateMachine::AddOutputStream(ProcessedMediaStream* aStream,
                                                bool aFinishWhenEnded)
 {
@@ -3149,6 +3168,16 @@ void MediaDecoderStateMachine::AddOutputStream(ProcessedMediaStream* aStream,
   DispatchAudioCaptured();
 }
 
+void MediaDecoderStateMachine::RemoveOutputStream(MediaStream* aStream)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  DECODER_LOG("RemoveOutputStream=%p!", aStream);
+  mDecodedStream->Remove(aStream);
+  if (!mDecodedStream->HasConsumers()) {
+    DispatchAudioUncaptured();
+  }
+}
+
 } // namespace mozilla
 
 // avoid redefined macro in unified build

dom/media/MediaDecoderStateMachine.h

@@ -148,6 +148,8 @@ public:
   };
 
   void AddOutputStream(ProcessedMediaStream* aStream, bool aFinishWhenEnded);
+  // Remove an output stream added with AddOutputStream.
+  void RemoveOutputStream(MediaStream* aStream);
 
   // Set/Unset dormant state.
   void SetDormant(bool aDormant);
@@ -159,6 +161,7 @@ private:
   void InitializationTask();
 
   void DispatchAudioCaptured();
+  void DispatchAudioUncaptured();
 
   void Shutdown();
 public: