Bug 1185407. Part 1 - have AudioSink::Init() return a promise. r=kinetik.

dom/media/AudioSink.cpp

@@ -38,26 +38,27 @@ AudioSink::AudioSink(MediaDecoderStateMachine* aStateMachine,
 {
 }
 
-nsresult
+nsRefPtr<GenericPromise>
 AudioSink::Init()
 {
+  nsRefPtr<GenericPromise> p = mEndPromise.Ensure(__func__);
   nsresult rv = NS_NewNamedThread("Media Audio",
                                   getter_AddRefs(mThread),
                                   nullptr,
                                   MEDIA_THREAD_STACK_SIZE);
   if (NS_FAILED(rv)) {
-    mStateMachine->OnAudioSinkError();
-    return rv;
+    mEndPromise.Reject(rv, __func__);
+    return p;
   }
 
   nsCOMPtr<nsIRunnable> event = NS_NewRunnableMethod(this, &AudioSink::AudioLoop);
   rv =  mThread->Dispatch(event, NS_DISPATCH_NORMAL);
   if (NS_FAILED(rv)) {
-    mStateMachine->OnAudioSinkError();
-    return rv;
+    mEndPromise.Reject(rv, __func__);
+    return p;
   }
 
-  return NS_OK;
+  return p;
 }
 
 int64_t
@@ -142,9 +143,10 @@ AudioSink::AudioLoop()
   AssertOnAudioThread();
   SINK_LOG("AudioLoop started");
 
-  if (NS_FAILED(InitializeAudioStream())) {
+  nsresult rv = InitializeAudioStream();
+  if (NS_FAILED(rv)) {
     NS_WARNING("Initializing AudioStream failed.");
-    mStateMachine->DispatchOnAudioSinkError();
+    mEndPromise.Reject(rv, __func__);
     return;
   }
 
@@ -235,11 +237,7 @@ AudioSink::Cleanup()
   AssertCurrentThreadInMonitor();
   nsRefPtr<AudioStream> audioStream;
   audioStream.swap(mAudioStream);
-  // Suppress the callback when the stop is requested by MediaDecoderStateMachine.
-  // See Bug 115334.
-  if (!mStopAudioThread) {
-    mStateMachine->DispatchOnAudioSinkComplete();
-  }
+  mEndPromise.Resolve(true, __func__);
 
   ReentrantMonitorAutoExit exit(GetReentrantMonitor());
   audioStream->Shutdown();

dom/media/AudioSink.h

@@ -10,6 +10,7 @@
 #include "MediaDecoderReader.h"
 #include "mozilla/dom/AudioChannelBinding.h"
 #include "mozilla/Atomics.h"
+#include "mozilla/MozPromise.h"
 
 namespace mozilla {
 
@@ -23,7 +24,9 @@ public:
   AudioSink(MediaDecoderStateMachine* aStateMachine,
             int64_t aStartTime, AudioInfo aInfo, dom::AudioChannel aChannel);
 
-  nsresult Init();
+  // Return a promise which will be resolved when AudioSink finishes playing,
+  // or rejected if any error.
+  nsRefPtr<GenericPromise> Init();
 
   int64_t GetPosition();
 
@@ -140,6 +143,8 @@ private:
   bool mSetPreservesPitch;
 
   bool mPlaying;
+
+  MozPromiseHolder<GenericPromise> mEndPromise;
 };
 
 } // namespace mozilla

dom/media/MediaDecoderStateMachine.cpp

@@ -1086,8 +1086,7 @@ void MediaDecoderStateMachine::MaybeStartPlayback()
   SetPlayStartTime(TimeStamp::Now());
   MOZ_ASSERT(IsPlaying());
 
-  nsresult rv = StartAudioThread();
-  NS_ENSURE_SUCCESS_VOID(rv);
+  StartAudioThread();
 
   // Tell DecodedStream to start playback with specified start time and media
   // info. This is consistent with how we create AudioSink in StartAudioThread().
@@ -1481,6 +1480,7 @@ void MediaDecoderStateMachine::StopAudioThread()
     }
     mAudioSink = nullptr;
   }
+  mAudioSinkPromise.DisconnectIfExists();
 }
 
 nsresult
@@ -1783,31 +1783,31 @@ MediaDecoderStateMachine::RequestVideoData()
   }
 }
 
-nsresult
+void
 MediaDecoderStateMachine::StartAudioThread()
 {
   MOZ_ASSERT(OnTaskQueue());
   AssertCurrentThreadInMonitor();
   if (mAudioCaptured) {
     MOZ_ASSERT(!mAudioSink);
-    return NS_OK;
+    return;
   }
 
   if (HasAudio() && !mAudioSink) {
-    auto audioStartTime = GetMediaTime();
     mAudioCompleted = false;
-    mAudioSink = new AudioSink(this, audioStartTime,
+    mAudioSink = new AudioSink(this, GetMediaTime(),
                                mInfo.mAudio, mDecoder->GetAudioChannel());
-    // OnAudioSinkError() will be called before Init() returns if an error
-    // occurs during initialization.
-    nsresult rv = mAudioSink->Init();
-    NS_ENSURE_SUCCESS(rv, rv);
+
+    mAudioSinkPromise.Begin(
+      mAudioSink->Init()->Then(
+        OwnerThread(), __func__, this,
+        &MediaDecoderStateMachine::OnAudioSinkComplete,
+        &MediaDecoderStateMachine::OnAudioSinkError));
 
     mAudioSink->SetVolume(mVolume);
     mAudioSink->SetPlaybackRate(mPlaybackRate);
     mAudioSink->SetPreservesPitch(mPreservesPitch);
   }
-  return NS_OK;
 }
 
 int64_t MediaDecoderStateMachine::AudioDecodedUsecs()
@@ -3122,11 +3122,12 @@ void MediaDecoderStateMachine::OnAudioSinkComplete()
 {
   MOZ_ASSERT(OnTaskQueue());
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
-  if (mAudioCaptured) {
-    return;
-  }
+  MOZ_ASSERT(!mAudioCaptured, "Should be disconnected when capturing audio.");
+
+  mAudioSinkPromise.Complete();
   ResyncAudioClock();
   mAudioCompleted = true;
+
   // Kick the decode thread; it may be sleeping waiting for this to finish.
   mDecoder->GetReentrantMonitor().NotifyAll();
 }
@@ -3135,11 +3136,9 @@ void MediaDecoderStateMachine::OnAudioSinkError()
 {
   MOZ_ASSERT(OnTaskQueue());
   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
-  // AudioSink not used with captured streams, so ignore errors in this case.
-  if (mAudioCaptured) {
-    return;
-  }
+  MOZ_ASSERT(!mAudioCaptured, "Should be disconnected when capturing audio.");
 
+  mAudioSinkPromise.Complete();
   ResyncAudioClock();
   mAudioCompleted = true;
 

dom/media/MediaDecoderStateMachine.h

@@ -517,7 +517,7 @@ protected:
 
   // Starts the audio thread. The decoder monitor must be held with exactly
   // one lock count. Called on the state machine thread.
-  nsresult StartAudioThread();
+  void StartAudioThread();
 
   // Notification method invoked when mPlayState changes.
   void PlayStateChanged();
@@ -1317,6 +1317,8 @@ private:
   // Media data resource from the decoder.
   nsRefPtr<MediaResource> mResource;
 
+  MozPromiseRequestHolder<GenericPromise> mAudioSinkPromise;
+
 private:
   // The buffered range. Mirrored from the decoder thread.
   Mirror<media::TimeIntervals> mBuffered;