Bug 1208373 - Implement MediaStreamTrack.readyState. r=smaug,jib

MozReview-Commit-ID: EoMaG0R3Dpp

--HG--
extra : rebase_source : 47d0fedfc4701d2e629ba43b30b0a7fb95322660
extra : intermediate-source : 8cffa26910a860fafe49fd2c43e86ab4020e6cea
extra : source : eb945c96027405effd2138a069eabd68f192f15c

dom/media/DOMMediaStream.cpp

@@ -1035,6 +1035,15 @@ DOMMediaStream::CloneDOMTrack(MediaStreamTrack& aTrack,
   NotifyTrackAdded(newTrack);
 
   newTrack->SetEnabled(aTrack.Enabled());
+  newTrack->SetReadyState(aTrack.ReadyState());
+
+  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.
+    RefPtr<Pledge<bool, nsresult>> blockingPledge =
+      inputPort->BlockSourceTrackId(inputTrackID);
+    Unused << blockingPledge;
+  }
 
   return newTrack.forget();
 }

dom/media/MediaStreamTrack.cpp

@@ -115,7 +115,8 @@ MediaStreamTrack::MediaStreamTrack(DOMMediaStream* aStream, TrackID aTrackID,
   : mOwningStream(aStream), mTrackID(aTrackID),
     mInputTrackID(aInputTrackID), mSource(aSource),
     mPrincipal(aSource->GetPrincipal()),
-    mEnded(false), mEnabled(true), mRemote(aSource->IsRemote()), mStopped(false)
+    mReadyState(MediaStreamTrackState::Live),
+    mEnabled(true), mRemote(aSource->IsRemote())
 {
 
   if (!gMediaStreamTrackLog) {
@@ -216,8 +217,8 @@ MediaStreamTrack::Stop()
 {
   LOG(LogLevel::Info, ("MediaStreamTrack %p Stop()", this));
 
-  if (mStopped) {
-    LOG(LogLevel::Warning, ("MediaStreamTrack %p Already stopped", this));
+  if (Ended()) {
+    LOG(LogLevel::Warning, ("MediaStreamTrack %p Already ended", this));
     return;
   }
 
@@ -239,7 +240,7 @@ MediaStreamTrack::Stop()
   RefPtr<Pledge<bool>> p = port->BlockSourceTrackId(mInputTrackID);
   Unused << p;
 
-  mStopped = true;
+  mReadyState = MediaStreamTrackState::Ended;
 }
 
 already_AddRefed<Promise>
@@ -355,13 +356,13 @@ MediaStreamTrack::NotifyEnded()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  if (mEnded) {
+  if (Ended()) {
     return;
   }
 
   LOG(LogLevel::Info, ("MediaStreamTrack %p ended", this));
 
-  mEnded = true;
+  mReadyState = MediaStreamTrackState::Ended;
 
   DispatchTrustedEvent(NS_LITERAL_STRING("ended"));
 }

dom/media/MediaStreamTrack.h

@@ -266,10 +266,20 @@ public:
   already_AddRefed<Promise>
   ApplyConstraints(const dom::MediaTrackConstraints& aConstraints, ErrorResult &aRv);
   already_AddRefed<MediaStreamTrack> Clone();
+  MediaStreamTrackState ReadyState() { return mReadyState; }
 
   IMPL_EVENT_HANDLER(ended)
 
-  bool Ended() const { return mEnded; }
+  /**
+   * Convenience (and legacy) method for when ready state is "ended".
+   */
+  bool Ended() const { return mReadyState == MediaStreamTrackState::Ended; }
+
+  /**
+   * Forces the ready state to a particular value, for instance when we're
+   * cloning an already ended track.
+   */
+  void SetReadyState(MediaStreamTrackState aState) { mReadyState = aState; }
 
   /**
    * Notified by the MediaStreamGraph, through our owning MediaStream on the
@@ -407,10 +417,9 @@ protected:
   nsCOMPtr<nsIPrincipal> mPendingPrincipal;
   RefPtr<PrincipalHandleListener> mPrincipalHandleListener;
   nsString mID;
-  bool mEnded;
+  MediaStreamTrackState mReadyState;
   bool mEnabled;
   const bool mRemote;
-  bool mStopped;
 };
 
 } // namespace dom

dom/webidl/MediaStreamTrack.webidl

@@ -63,6 +63,11 @@ dictionary MediaTrackConstraints : MediaTrackConstraintSet {
     sequence<MediaTrackConstraintSet> advanced;
 };
 
+enum MediaStreamTrackState {
+    "live",
+    "ended"
+};
+
 [Exposed=Window]
 interface MediaStreamTrack : EventTarget {
     readonly    attribute DOMString             kind;
@@ -74,7 +79,7 @@ interface MediaStreamTrack : EventTarget {
 //              attribute EventHandler          onunmute;
 //  readonly    attribute boolean               _readonly;
 //  readonly    attribute boolean               remote;
-//  readonly    attribute MediaStreamTrackState readyState;
+    readonly    attribute MediaStreamTrackState readyState;
                 attribute EventHandler          onended;
     MediaStreamTrack       clone ();
     void                   stop ();