Bug 1208373 - Introduce a new blocking mode to MediaInputPort. r=jesup

This lets us notify about a created TrackUnionStream track (and since it was
created, we can notify when it ends), even though it has been blocked from main
thread.

MozReview-Commit-ID: HyopzISBfbb

--HG--
extra : rebase_source : a18be6b0fcb194c016ae06c62eb5cebbf86eb8d5
extra : intermediate-source : 38e3e48c8dd011a0503f1241c7b21a630738c6c0
extra : source : 690904309e169aa74f95163f0d796493ef882972

dom/media/DOMMediaStream.cpp

@@ -98,10 +98,10 @@ DOMMediaStream::TrackPort::GetSourceTrackId() const
 }
 
 already_AddRefed<Pledge<bool>>
-DOMMediaStream::TrackPort::BlockSourceTrackId(TrackID aTrackId)
+DOMMediaStream::TrackPort::BlockSourceTrackId(TrackID aTrackId, BlockingMode aBlockingMode)
 {
   if (mInputPort) {
-    return mInputPort->BlockSourceTrackId(aTrackId);
+    return mInputPort->BlockSourceTrackId(aTrackId, aBlockingMode);
   }
   RefPtr<Pledge<bool>> rejected = new Pledge<bool>();
   rejected->Reject(NS_ERROR_FAILURE);
@@ -1040,8 +1040,10 @@ DOMMediaStream::CloneDOMTrack(MediaStreamTrack& aTrack,
   if (aTrack.Ended()) {
     // For extra suspenders, make sure that we don't forward data by mistake
     // to the clone when the original has already ended.
+    // We only block END_EXISTING to allow any pending clones to end.
     RefPtr<Pledge<bool, nsresult>> blockingPledge =
-      inputPort->BlockSourceTrackId(inputTrackID);
+      inputPort->BlockSourceTrackId(inputTrackID,
+                                    BlockingMode::END_EXISTING);
     Unused << blockingPledge;
   }
 
@@ -1249,7 +1251,9 @@ DOMMediaStream::BlockPlaybackTrack(TrackPort* aTrack)
 {
   MOZ_ASSERT(aTrack);
   ++mTracksPendingRemoval;
-  RefPtr<Pledge<bool>> p = aTrack->BlockSourceTrackId(aTrack->GetTrack()->mTrackID);
+  RefPtr<Pledge<bool>> p =
+    aTrack->BlockSourceTrackId(aTrack->GetTrack()->mTrackID,
+                               BlockingMode::CREATION);
   RefPtr<DOMMediaStream> self = this;
   p->Then([self] (const bool& aIgnore) { self->NotifyPlaybackTrackBlocked(); },
           [] (const nsresult& aIgnore) { NS_ERROR("Could not remove track from MSG"); }

dom/media/DOMMediaStream.h

@@ -34,6 +34,8 @@ class MediaStreamDirectListener;
 class MediaStreamGraph;
 class ProcessedMediaStream;
 
+enum class BlockingMode;
+
 namespace dom {
 class AudioNode;
 class HTMLCanvasElement;
@@ -304,7 +306,8 @@ public:
      * destroyed. Returns a pledge that gets resolved when the MediaStreamGraph
      * has applied the block in the playback stream.
      */
-    already_AddRefed<media::Pledge<bool, nsresult>> BlockSourceTrackId(TrackID aTrackId);
+    already_AddRefed<media::Pledge<bool, nsresult>>
+    BlockSourceTrackId(TrackID aTrackId, BlockingMode aBlockingMode);
 
   private:
     RefPtr<MediaInputPort> mInputPort;

dom/media/MediaStreamGraph.cpp

@@ -3147,24 +3147,26 @@ MediaInputPort::SetGraphImpl(MediaStreamGraphImpl* aGraph)
 }
 
 void
-MediaInputPort::BlockSourceTrackIdImpl(TrackID aTrackId)
+MediaInputPort::BlockSourceTrackIdImpl(TrackID aTrackId, BlockingMode aBlockingMode)
 {
-  mBlockedTracks.AppendElement(aTrackId);
+  mBlockedTracks.AppendElement(Pair<TrackID, BlockingMode>(aTrackId, aBlockingMode));
 }
 
 already_AddRefed<Pledge<bool>>
-MediaInputPort::BlockSourceTrackId(TrackID aTrackId)
+MediaInputPort::BlockSourceTrackId(TrackID aTrackId, BlockingMode aBlockingMode)
 {
   class Message : public ControlMessage {
   public:
     explicit Message(MediaInputPort* aPort,
                      TrackID aTrackId,
+                     BlockingMode aBlockingMode,
                      already_AddRefed<nsIRunnable> aRunnable)
       : ControlMessage(aPort->GetDestination()),
-        mPort(aPort), mTrackId(aTrackId), mRunnable(aRunnable) {}
+        mPort(aPort), mTrackId(aTrackId), mBlockingMode(aBlockingMode),
+        mRunnable(aRunnable) {}
     void Run() override
     {
-      mPort->BlockSourceTrackIdImpl(mTrackId);
+      mPort->BlockSourceTrackIdImpl(mTrackId, mBlockingMode);
       if (mRunnable) {
         mStream->Graph()->DispatchToMainThreadAfterStreamStateUpdate(mRunnable.forget());
       }
@@ -3175,6 +3177,7 @@ MediaInputPort::BlockSourceTrackId(TrackID aTrackId)
     }
     RefPtr<MediaInputPort> mPort;
     TrackID mTrackId;
+    BlockingMode mBlockingMode;
     nsCOMPtr<nsIRunnable> mRunnable;
   };
 
@@ -3187,7 +3190,7 @@ MediaInputPort::BlockSourceTrackId(TrackID aTrackId)
     pledge->Resolve(true);
     return NS_OK;
   });
-  GraphImpl()->AppendMessage(MakeUnique<Message>(this, aTrackId, runnable.forget()));
+  GraphImpl()->AppendMessage(MakeUnique<Message>(this, aTrackId, aBlockingMode, runnable.forget()));
   return pledge.forget();
 }
 
@@ -3230,7 +3233,7 @@ ProcessedMediaStream::AllocateInputPort(MediaStream* aStream, TrackID aTrackID,
                        aInputNumber, aOutputNumber);
   if (aBlockedTracks) {
     for (TrackID trackID : *aBlockedTracks) {
-      port->BlockSourceTrackIdImpl(trackID);
+      port->BlockSourceTrackIdImpl(trackID, BlockingMode::CREATION);
     }
   }
   port->SetGraphImpl(GraphImpl());

dom/media/MediaStreamGraph.h

@@ -1184,6 +1184,23 @@ protected:
   bool mNeedsMixing;
 };
 
+/**
+ * The blocking mode decides how a track should be blocked in a MediaInputPort.
+ */
+enum class BlockingMode
+{
+  /**
+   * BlockingMode CREATION blocks the source track from being created
+   * in the destination. It'll end if it already exists.
+   */
+  CREATION,
+  /**
+   * BlockingMode END_EXISTING allows a track to be created in the destination
+   * but will end it before any data has been passed through.
+   */
+  END_EXISTING,
+};
+
 /**
  * Represents a connection between a ProcessedMediaStream and one of its
  * input streams.
@@ -1265,16 +1282,39 @@ public:
    * Returns a pledge that resolves on the main thread after the track block has
    * been applied by the MSG.
    */
-  already_AddRefed<media::Pledge<bool, nsresult>> BlockSourceTrackId(TrackID aTrackId);
+  already_AddRefed<media::Pledge<bool, nsresult>> BlockSourceTrackId(TrackID aTrackId,
+                                                                     BlockingMode aBlockingMode);
 private:
-  void BlockSourceTrackIdImpl(TrackID aTrackId);
+  void BlockSourceTrackIdImpl(TrackID aTrackId, BlockingMode aBlockingMode);
 
 public:
-  // Returns true if aTrackId has not been blocked and this port has not
-  // been locked to another track.
+  // Returns true if aTrackId has not been blocked for any reason and this port
+  // has not been locked to another track.
   bool PassTrackThrough(TrackID aTrackId) {
-    return !mBlockedTracks.Contains(aTrackId) &&
-           (mSourceTrack == TRACK_ANY || mSourceTrack == aTrackId);
+    bool blocked = false;
+    for (auto pair : mBlockedTracks) {
+      if (pair.first() == aTrackId &&
+          (pair.second() == BlockingMode::CREATION ||
+           pair.second() == BlockingMode::END_EXISTING)) {
+        blocked = true;
+        break;
+      }
+    }
+    return !blocked && (mSourceTrack == TRACK_ANY || mSourceTrack == aTrackId);
+  }
+
+  // Returns true if aTrackId has not been blocked for track creation and this
+  // port has not been locked to another track.
+  bool AllowCreationOf(TrackID aTrackId) {
+    bool blocked = false;
+    for (auto pair : mBlockedTracks) {
+      if (pair.first() == aTrackId &&
+          pair.second() == BlockingMode::CREATION) {
+        blocked = true;
+        break;
+      }
+    }
+    return !blocked && (mSourceTrack == TRACK_ANY || mSourceTrack == aTrackId);
   }
 
   uint16_t InputNumber() const { return mInputNumber; }
@@ -1329,7 +1369,9 @@ private:
   // Web Audio.
   const uint16_t mInputNumber;
   const uint16_t mOutputNumber;
-  nsTArray<TrackID> mBlockedTracks;
+
+  typedef Pair<TrackID, BlockingMode> BlockedTrack;
+  nsTArray<BlockedTrack> mBlockedTracks;
 
   // Our media stream graph
   MediaStreamGraphImpl* mGraph;

dom/media/MediaStreamTrack.cpp

@@ -237,7 +237,7 @@ MediaStreamTrack::Stop()
   MOZ_ASSERT(mOwningStream, "Every MediaStreamTrack needs an owning DOMMediaStream");
   DOMMediaStream::TrackPort* port = mOwningStream->FindOwnedTrackPort(*this);
   MOZ_ASSERT(port, "A MediaStreamTrack must exist in its owning DOMMediaStream");
-  RefPtr<Pledge<bool>> p = port->BlockSourceTrackId(mInputTrackID);
+  RefPtr<Pledge<bool>> p = port->BlockSourceTrackId(mInputTrackID, BlockingMode::CREATION);
   Unused << p;
 
   mReadyState = MediaStreamTrackState::Ended;

dom/media/TrackUnionStream.cpp

@@ -107,7 +107,7 @@ TrackUnionStream::TrackUnionStream(DOMMediaStream* aWrapper) :
             break;
           }
         }
-        if (!found && mInputs[i]->PassTrackThrough(tracks->GetID())) {
+        if (!found && mInputs[i]->AllowCreationOf(tracks->GetID())) {
           bool trackFinished = false;
           trackAdded = true;
           uint32_t mapIndex = AddTrack(mInputs[i], tracks.get(), aFrom);