Bug 1189506. Convert ChangeExplicitBlockerCount to MediaStream::Suspend/Resume. r=padenot

--HG--
extra : commitid : EAfe35GbRPL
extra : rebase_source : f6da37f3a9e8eefbdcf3e6787ec7edcc99e53859

dom/camera/CameraPreviewMediaStream.cpp

@@ -91,11 +91,6 @@ CameraPreviewMediaStream::RemoveVideoOutput(VideoFrameContainer* aContainer)
   }
 }
 
-void
-CameraPreviewMediaStream::ChangeExplicitBlockerCount(int32_t aDelta)
-{
-}
-
 void
 CameraPreviewMediaStream::AddListener(MediaStreamListener* aListener)
 {

dom/camera/CameraPreviewMediaStream.h

@@ -48,7 +48,8 @@ public:
   virtual void RemoveAudioOutput(void* aKey) override;
   virtual void AddVideoOutput(VideoFrameContainer* aContainer) override;
   virtual void RemoveVideoOutput(VideoFrameContainer* aContainer) override;
-  virtual void ChangeExplicitBlockerCount(int32_t aDelta) override;
+  virtual void Suspend() override {}
+  virtual void Resume() override {}
   virtual void AddListener(MediaStreamListener* aListener) override;
   virtual void RemoveListener(MediaStreamListener* aListener) override;
   virtual void Destroy() override;

dom/media/MediaRecorder.cpp

@@ -407,7 +407,7 @@ public:
     MOZ_ASSERT(NS_IsMainThread());
 
     NS_ENSURE_TRUE(mTrackUnionStream, NS_ERROR_FAILURE);
-    mTrackUnionStream->ChangeExplicitBlockerCount(1);
+    mTrackUnionStream->Suspend();
 
     return NS_OK;
   }
@@ -418,7 +418,7 @@ public:
     MOZ_ASSERT(NS_IsMainThread());
 
     NS_ENSURE_TRUE(mTrackUnionStream, NS_ERROR_FAILURE);
-    mTrackUnionStream->ChangeExplicitBlockerCount(-1);
+    mTrackUnionStream->Resume();
 
     return NS_OK;
   }

dom/media/MediaStreamGraph.cpp

@@ -2144,18 +2144,16 @@ MediaStream::RemoveVideoOutput(VideoFrameContainer* aContainer)
 }
 
 void
-MediaStream::ChangeExplicitBlockerCount(int32_t aDelta)
+MediaStream::Suspend()
 {
   class Message : public ControlMessage {
   public:
-    Message(MediaStream* aStream, int32_t aDelta) :
-      ControlMessage(aStream), mDelta(aDelta) {}
+    explicit Message(MediaStream* aStream) :
+      ControlMessage(aStream) {}
     virtual void Run()
     {
-      mStream->ChangeExplicitBlockerCountImpl(
-          mStream->GraphImpl()->mStateComputedTime, mDelta);
+      mStream->GraphImpl()->IncrementSuspendCount(mStream);
     }
-    int32_t mDelta;
   };
 
   // This can happen if this method has been called asynchronously, and the
@@ -2163,7 +2161,28 @@ MediaStream::ChangeExplicitBlockerCount(int32_t aDelta)
   if (mMainThreadDestroyed) {
     return;
   }
-  GraphImpl()->AppendMessage(new Message(this, aDelta));
+  GraphImpl()->AppendMessage(new Message(this));
+}
+
+void
+MediaStream::Resume()
+{
+  class Message : public ControlMessage {
+  public:
+    explicit Message(MediaStream* aStream) :
+      ControlMessage(aStream) {}
+    virtual void Run()
+    {
+      mStream->GraphImpl()->DecrementSuspendCount(mStream);
+    }
+  };
+
+  // This can happen if this method has been called asynchronously, and the
+  // stream has been destroyed since then.
+  if (mMainThreadDestroyed) {
+    return;
+  }
+  GraphImpl()->AppendMessage(new Message(this));
 }
 
 void

dom/media/MediaStreamGraph.h

@@ -362,9 +362,13 @@ public:
   // Only the first enabled video track is played.
   virtual void AddVideoOutput(VideoFrameContainer* aContainer);
   virtual void RemoveVideoOutput(VideoFrameContainer* aContainer);
-  // Explicitly block. Useful for example if a media element is pausing
-  // and we need to stop its stream emitting its buffered data.
-  virtual void ChangeExplicitBlockerCount(int32_t aDelta);
+  // Explicitly suspend. Useful for example if a media element is pausing
+  // and we need to stop its stream emitting its buffered data. As soon as the
+  // Suspend message reaches the graph, the stream stops processing. It
+  // ignores its inputs and produces silence/no video until Resumed. Its
+  // current time does not advance.
+  virtual void Suspend();
+  virtual void Resume();
   void BlockStreamIfNeeded();
   void UnblockStreamIfNeeded();
   // Events will be dispatched by calling methods of aListener.

dom/media/mediasink/DecodedStream.cpp

@@ -86,14 +86,21 @@ private:
 };
 
 static void
-UpdateStreamBlocking(MediaStream* aStream, bool aBlocking)
+UpdateStreamSuspended(MediaStream* aStream, bool aBlocking)
 {
-  int32_t delta = aBlocking ? 1 : -1;
   if (NS_IsMainThread()) {
-    aStream->ChangeExplicitBlockerCount(delta);
+    if (aBlocking) {
+      aStream->Suspend();
+    } else {
+      aStream->Resume();
+    }
   } else {
-    nsCOMPtr<nsIRunnable> r = NS_NewRunnableMethodWithArg<int32_t>(
-      aStream, &MediaStream::ChangeExplicitBlockerCount, delta);
+    nsCOMPtr<nsIRunnable> r;
+    if (aBlocking) {
+      r = NS_NewRunnableMethod(aStream, &MediaStream::Suspend);
+    } else {
+      r = NS_NewRunnableMethod(aStream, &MediaStream::Resume);
+    }
     AbstractThread::MainThread()->Dispatch(r.forget());
   }
 }
@@ -189,7 +196,7 @@ DecodedStreamData::SetPlaying(bool aPlaying)
 {
   if (mPlaying != aPlaying) {
     mPlaying = aPlaying;
-    UpdateStreamBlocking(mStream, !mPlaying);
+    UpdateStreamSuspended(mStream, !mPlaying);
   }
 }
 

dom/media/webaudio/AudioDestinationNode.cpp

@@ -680,7 +680,7 @@ AudioDestinationNode::SetIsOnlyNodeForContext(bool aIsOnlyNode)
   }
 
   if (aIsOnlyNode) {
-    mStream->ChangeExplicitBlockerCount(1);
+    mStream->Suspend();
     mStartedBlockingDueToBeingOnlyNode = TimeStamp::Now();
     // Don't do an update of mExtraCurrentTimeSinceLastStartedBlocking until the next stable state.
     mExtraCurrentTimeUpdatedSinceLastStableState = true;
@@ -690,7 +690,7 @@ AudioDestinationNode::SetIsOnlyNodeForContext(bool aIsOnlyNode)
     ExtraCurrentTime();
     mExtraCurrentTime += mExtraCurrentTimeSinceLastStartedBlocking;
     mExtraCurrentTimeSinceLastStartedBlocking = 0;
-    mStream->ChangeExplicitBlockerCount(-1);
+    mStream->Resume();
     mStartedBlockingDueToBeingOnlyNode = TimeStamp();
   }
 }

dom/media/webspeech/synth/nsSpeechTask.cpp

@@ -563,7 +563,7 @@ nsSpeechTask::Pause()
   }
 
   if (mStream) {
-    mStream->ChangeExplicitBlockerCount(1);
+    mStream->Suspend();
   }
 
   if (!mInited) {
@@ -586,7 +586,7 @@ nsSpeechTask::Resume()
   }
 
   if (mStream) {
-    mStream->ChangeExplicitBlockerCount(-1);
+    mStream->Resume();
   }
 
   if (mPrePaused) {
@@ -612,7 +612,7 @@ nsSpeechTask::Cancel()
   }
 
   if (mStream) {
-    mStream->ChangeExplicitBlockerCount(1);
+    mStream->Suspend();
   }
 
   if (!mInited) {
@@ -628,7 +628,7 @@ void
 nsSpeechTask::ForceEnd()
 {
   if (mStream) {
-    mStream->ChangeExplicitBlockerCount(1);
+    mStream->Suspend();
   }
 
   if (!mInited) {