Bug 1423253 - Change CanvasCaptureMediaStream's driver to push instead of pull. r=padenot

Differential Revision: https://phabricator.services.mozilla.com/D22900

--HG--
extra : moz-landing-system : lando

dom/media/CanvasCaptureMediaStream.cpp

@@ -8,7 +8,6 @@
 #include "DOMMediaStream.h"
 #include "ImageContainer.h"
 #include "MediaStreamGraph.h"
-#include "MediaStreamListener.h"
 #include "gfxPlatform.h"
 #include "mozilla/Atomics.h"
 #include "mozilla/dom/CanvasCaptureMediaStreamBinding.h"
@@ -22,100 +21,17 @@ using namespace mozilla::gfx;
 namespace mozilla {
 namespace dom {
 
-class OutputStreamDriver::TrackListener : public MediaStreamTrackListener {
- public:
-  TrackListener(TrackID aTrackId, const PrincipalHandle& aPrincipalHandle,
-                SourceMediaStream* aSourceStream)
-      : mEnded(false),
-        mSourceStream(aSourceStream),
-        mTrackId(aTrackId),
-        mPrincipalHandle(aPrincipalHandle),
-        mMutex("CanvasCaptureMediaStream OutputStreamDriver::StreamListener") {
-    MOZ_ASSERT(mSourceStream);
-  }
-
-  void Forget() {
-    EndTrack();
-    mSourceStream->EndTrack(mTrackId);
-
-    MutexAutoLock lock(mMutex);
-    mImage = nullptr;
-  }
-
-  void EndTrack() { mEnded = true; }
-
-  void SetImage(const RefPtr<layers::Image>& aImage, const TimeStamp& aTime) {
-    MutexAutoLock lock(mMutex);
-    mImage = aImage;
-    mImageTime = aTime;
-  }
-
-  void NotifyPull(MediaStreamGraph* aGraph, StreamTime aEndOfAppendedData,
-                  StreamTime aDesiredTime) override {
-    // Called on the MediaStreamGraph thread.
-    TRACE_AUDIO_CALLBACK_COMMENT("SourceMediaStream %p track %i",
-                                 mSourceStream.get(), mTrackId);
-    MOZ_ASSERT(mSourceStream);
-    StreamTime delta = aDesiredTime - aEndOfAppendedData;
-    MOZ_ASSERT(delta > 0);
-
-    MutexAutoLock lock(mMutex);
-
-    RefPtr<Image> image = mImage;
-    IntSize size = image ? image->GetSize() : IntSize(0, 0);
-    VideoSegment segment;
-    segment.AppendFrame(image.forget(), delta, size, mPrincipalHandle, false,
-                        mImageTime);
-
-    mSourceStream->AppendToTrack(mTrackId, &segment);
-
-    if (mEnded) {
-      mSourceStream->EndTrack(mTrackId);
-    }
-  }
-
-  void NotifyEnded() override {
-    Forget();
-
-    mSourceStream->Graph()->DispatchToMainThreadStableState(
-        NS_NewRunnableFunction(
-            "OutputStreamDriver::TrackListener::RemoveTrackListener",
-            [self = RefPtr<TrackListener>(this), this]() {
-              if (!mSourceStream->IsDestroyed()) {
-                mSourceStream->RemoveTrackListener(this, mTrackId);
-              }
-            }));
-  }
-
-  void NotifyRemoved() override { Forget(); }
-
- protected:
-  ~TrackListener() = default;
-
- private:
-  Atomic<bool> mEnded;
-  const RefPtr<SourceMediaStream> mSourceStream;
-  const TrackID mTrackId;
-  const PrincipalHandle mPrincipalHandle;
-
-  Mutex mMutex;
-  // The below members are protected by mMutex.
-  RefPtr<layers::Image> mImage;
-  TimeStamp mImageTime;
-};
-
 OutputStreamDriver::OutputStreamDriver(SourceMediaStream* aSourceStream,
                                        const TrackID& aTrackId,
                                        const PrincipalHandle& aPrincipalHandle)
     : FrameCaptureListener(),
+      mTrackId(aTrackId),
       mSourceStream(aSourceStream),
-      mTrackListener(
-          new TrackListener(aTrackId, aPrincipalHandle, aSourceStream)) {
+      mPrincipalHandle(aPrincipalHandle) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(mSourceStream);
+  MOZ_ASSERT(IsTrackIDExplicit(mTrackId));
   mSourceStream->AddTrack(aTrackId, new VideoSegment());
-  mSourceStream->AddTrackListener(mTrackListener, aTrackId);
-  mSourceStream->SetPullingEnabled(aTrackId, true);
 
   // All CanvasCaptureMediaStreams shall at least get one frame.
   mFrameCaptureRequested = true;
@@ -123,16 +39,24 @@ OutputStreamDriver::OutputStreamDriver(SourceMediaStream* aSourceStream,
 
 OutputStreamDriver::~OutputStreamDriver() {
   MOZ_ASSERT(NS_IsMainThread());
-  // MediaStreamGraph will keep the listener alive until it can end the track in
-  // the graph on the next NotifyPull().
-  mTrackListener->EndTrack();
+  EndTrack();
 }
 
-void OutputStreamDriver::EndTrack() { mTrackListener->EndTrack(); }
+void OutputStreamDriver::EndTrack() {
+  MOZ_ASSERT(NS_IsMainThread());
+  mSourceStream->EndTrack(mTrackId);
+}
 
 void OutputStreamDriver::SetImage(const RefPtr<layers::Image>& aImage,
                                   const TimeStamp& aTime) {
-  mTrackListener->SetImage(aImage, aTime);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  TRACE_COMMENT("SourceMediaStream %p track %i", mSourceStream.get(), mTrackId);
+
+  VideoSegment segment;
+  segment.AppendFrame(do_AddRef(aImage), 1, aImage->GetSize(), mPrincipalHandle,
+                      false, aTime);
+  mSourceStream->AppendToTrack(mTrackId, &segment);
 }
 
 // ----------------------------------------------------------------------

dom/media/CanvasCaptureMediaStream.h

@@ -14,7 +14,6 @@ class nsIPrincipal;
 
 namespace mozilla {
 class DOMMediaStream;
-class MediaStreamListener;
 class SourceMediaStream;
 
 namespace layers {
@@ -44,16 +43,10 @@ class OutputStreamFrameListener;
  * | Canvas |  SetFrameCapture()        | (FrameCaptureListener) |
  * |________| ------------------------> |________________________|
  *                                                  |
- *                                                  | SetImage()
+ *                                                  | SetImage() -
+ *                                                  | AppendToTrack()
+ *                                                  |
  *                                                  v
- *                                         ____________________
- *                                        |Stream/TrackListener|
- * ---------------------------------------| (All image access  |---------------
- *     === MediaStreamGraph Thread ===    |   Mutex Guarded)   |
- *                                        |____________________|
- *                                              ^       |
- *                                 NotifyPull() |       | AppendToTrack()
- *                                              |       v
  *                                      ___________________________
  *                                     |                           |
  *                                     |  MSG / SourceMediaStream  |
@@ -93,12 +86,11 @@ class OutputStreamDriver : public FrameCaptureListener {
 
  protected:
   virtual ~OutputStreamDriver();
-  class StreamListener;
-  class TrackListener;
 
  private:
+  const TrackID mTrackId;
   const RefPtr<SourceMediaStream> mSourceStream;
-  const RefPtr<TrackListener> mTrackListener;
+  const PrincipalHandle mPrincipalHandle;
 };
 
 class CanvasCaptureMediaStream : public DOMMediaStream {