Bug 1195939 - Flush decode queue on Reset() in gmp-clearkey - r=cpearce

media/gmp-clearkey/0.1/VideoDecoder.cpp

@@ -33,6 +33,7 @@ VideoDecoder::VideoDecoder(GMPVideoHost *aHostAPI)
   , mMutex(nullptr)
   , mNumInputTasks(0)
   , mSentExtraData(false)
+  , mIsFlushing(false)
   , mHasShutdown(false)
 {
   // We drop the ref in DecodingComplete().
@@ -140,6 +141,11 @@ VideoDecoder::DecodeTask(GMPVideoEncodedFrame* aInput)
   AutoReleaseVideoFrame ensureFrameReleased(aInput);
   HRESULT hr;
 
+  if (mIsFlushing) {
+    CK_LOGD("VideoDecoder::DecodeTask rejecting frame: flushing.");
+    return;
+  }
+
   {
     AutoLock lock(mMutex);
     mNumInputTasks--;
@@ -343,15 +349,29 @@ VideoDecoder::SampleToVideoFrame(IMFSample* aSample,
   return S_OK;
 }
 
+void
+VideoDecoder::ResetCompleteTask()
+{
+  mIsFlushing = false;
+  if (mCallback) {
+    MaybeRunOnMainThread(WrapTask(mCallback,
+                                  &GMPVideoDecoderCallback::ResetComplete));
+  }
+}
+
 void
 VideoDecoder::Reset()
 {
+  mIsFlushing = true;
   if (mDecoder) {
     mDecoder->Reset();
   }
-  if (mCallback) {
-    mCallback->ResetComplete();
-  }
+
+  // Schedule ResetComplete callback to run after existing frames have been
+  // flushed out of the task queue.
+  EnsureWorker();
+  mWorkerThread->Post(WrapTaskRefCounted(this,
+                                         &VideoDecoder::ResetCompleteTask));
 }
 
 void

media/gmp-clearkey/0.1/VideoDecoder.h

@@ -60,6 +60,8 @@ private:
 
   void DecodeTask(GMPVideoEncodedFrame* aInputFrame);
 
+  void ResetCompleteTask();
+
   void ReturnOutput(IMFSample* aSample,
                     int32_t aWidth,
                     int32_t aHeight,
@@ -85,6 +87,8 @@ private:
   int32_t mNumInputTasks;
   bool mSentExtraData;
 
+  std::atomic<bool> mIsFlushing;
+
   bool mHasShutdown;
 };