Bug 1204622 - release codec listener at reader task queue. r=jya

--HG--
extra : rebase_source : adb41147997f51941746af1f8dfe151f784c1771

dom/media/platforms/gonk/GonkMediaDataDecoder.cpp

@@ -61,7 +61,12 @@ GonkMediaDataDecoder::Init()
 nsresult
 GonkMediaDataDecoder::Shutdown()
 {
-  return mManager->Shutdown();
+  nsresult rv = mManager->Shutdown();
+
+  // Because codec allocated runnable and init promise is at reader TaskQueue,
+  // so manager needs to be destroyed at reader TaskQueue to prevent racing.
+  mManager = nullptr;
+  return rv;
 }
 
 // Inserts data into the decoder's pipeline.

dom/media/platforms/gonk/GonkVideoDecoderManager.cpp

@@ -71,6 +71,7 @@ GonkVideoDecoderManager::GonkVideoDecoderManager(
 
 GonkVideoDecoderManager::~GonkVideoDecoderManager()
 {
+  mVideoListener->NotifyManagerRelease();
   MOZ_COUNT_DTOR(GonkVideoDecoderManager);
 }
 
@@ -563,10 +564,25 @@ GonkVideoDecoderManager::VideoResourceListener::~VideoResourceListener()
 void
 GonkVideoDecoderManager::VideoResourceListener::codecReserved()
 {
+  // This class holds VideoResourceListener reference to prevent it's destroyed.
+  class CodecListenerHolder : public nsRunnable {
+  public:
+    CodecListenerHolder(VideoResourceListener* aListener)
+      : mVideoListener(aListener) {}
+
+    NS_IMETHOD Run()
+    {
+      mVideoListener->NotifyCodecReserved();
+      mVideoListener = nullptr;
+      return NS_OK;
+    }
+
+    android::sp<VideoResourceListener> mVideoListener;
+  };
+
   if (mManager) {
-    nsCOMPtr<nsIRunnable> r =
-      NS_NewNonOwningRunnableMethod(mManager, &GonkVideoDecoderManager::codecReserved);
-    mManager->mReaderTaskQueue->Dispatch(r.forget());
+    nsRefPtr<CodecListenerHolder> runner = new CodecListenerHolder(this);
+    mManager->mReaderTaskQueue->Dispatch(runner.forget());
   }
 }
 
@@ -574,12 +590,29 @@ void
 GonkVideoDecoderManager::VideoResourceListener::codecCanceled()
 {
   if (mManager) {
+    MOZ_ASSERT(mManager->mReaderTaskQueue->IsCurrentThreadIn());
     nsCOMPtr<nsIRunnable> r =
       NS_NewNonOwningRunnableMethod(mManager, &GonkVideoDecoderManager::codecCanceled);
     mManager->mReaderTaskQueue->Dispatch(r.forget());
   }
 }
 
+void
+GonkVideoDecoderManager::VideoResourceListener::NotifyManagerRelease()
+{
+  MOZ_ASSERT_IF(mManager, mManager->mReaderTaskQueue->IsCurrentThreadIn());
+  mManager = nullptr;
+}
+
+void
+GonkVideoDecoderManager::VideoResourceListener::NotifyCodecReserved()
+{
+  if (mManager) {
+    MOZ_ASSERT(mManager->mReaderTaskQueue->IsCurrentThreadIn());
+    mManager->codecReserved();
+  }
+}
+
 uint8_t *
 GonkVideoDecoderManager::GetColorConverterBuffer(int32_t aWidth, int32_t aHeight)
 {

dom/media/platforms/gonk/GonkVideoDecoderManager.h

@@ -97,6 +97,9 @@ private:
     void codecReserved() override;
     void codecCanceled() override;
 
+    void NotifyManagerRelease();
+    void NotifyCodecReserved();
+
   private:
     // Forbidden
     VideoResourceListener() = delete;