Add callback in VideoDecoder and AudioDecoder to return decoded frames.

media/filters/decoder_stream.cc

Index: media/filters/decoder_stream.cc
diff --git a/media/filters/decoder_stream.cc b/media/filters/decoder_stream.cc
index 4f712be2f2227883e37710fd9ae5a1b6b9bd9751..cedba00f43ba8fd420c22b1d71975d9911556a49 100644
--- a/media/filters/decoder_stream.cc
+++ b/media/filters/decoder_stream.cc
@@ -80,6 +80,8 @@ void DecoderStream<StreamType>::Initialize(DemuxerStream* stream,
   decoder_selector_->SelectDecoder(
       stream, low_delay,
       base::Bind(&DecoderStream<StreamType>::OnDecoderSelected,
+                 weak_factory_.GetWeakPtr()),
+      base::Bind(&DecoderStream<StreamType>::OnDecodeOutputReady,
                  weak_factory_.GetWeakPtr()));
 }
 
@@ -113,19 +115,7 @@ void DecoderStream<StreamType>::Read(const ReadCB& read_cb) {
     ready_outputs_.pop_front();
   }
 
-  // Decoder may be in reinitializing state as result of the previous Read().
-  if (state_ == STATE_REINITIALIZING_DECODER)
-    return;
-
-  if (!CanDecodeMore())
-    return;
-
-  if (state_ == STATE_FLUSHING_DECODER) {
-    FlushDecoder();
-    return;
-  }
-
-  if (state_ != STATE_PENDING_DEMUXER_READ)
+  if (state_ == STATE_NORMAL && CanDecodeMore())
     ReadFromDemuxerStream();
 }
 
@@ -216,7 +206,7 @@ void DecoderStream<StreamType>::Stop(const base::Closure& closure) {
 template <DemuxerStream::Type StreamType>
 bool DecoderStream<StreamType>::CanReadWithoutStalling() const {
   DCHECK(task_runner_->BelongsToCurrentThread());
-  return decoder_->CanReadWithoutStalling();
+  return !ready_outputs_.empty() || decoder_->CanReadWithoutStalling();
 }
 
 template <>
@@ -226,6 +216,16 @@ bool DecoderStream<DemuxerStream::AUDIO>::CanReadWithoutStalling() const {
 }
 
 template <DemuxerStream::Type StreamType>
+int DecoderStream<StreamType>::GetMaxDecodeRequests() const {
+  return decoder_->GetMaxDecodeRequests();
+}
+
+template <>
+int DecoderStream<DemuxerStream::AUDIO>::GetMaxDecodeRequests() const {
+  return 1;
+}
+
+template <DemuxerStream::Type StreamType>
 bool DecoderStream<StreamType>::CanDecodeMore() const {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
@@ -234,13 +234,7 @@ bool DecoderStream<StreamType>::CanDecodeMore() const {
   // empty.
   int num_decodes =
       static_cast<int>(ready_outputs_.size()) + pending_decode_requests_;
-  return num_decodes < decoder_->GetMaxDecodeRequests();
-}
-
-template <>
-bool DecoderStream<DemuxerStream::AUDIO>::CanDecodeMore() const {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  return !pending_decode_requests_ && ready_outputs_.empty();
+  return num_decodes < GetMaxDecodeRequests();
 }
 
 template <DemuxerStream::Type StreamType>
@@ -290,7 +284,7 @@ void DecoderStream<StreamType>::Decode(
     const scoped_refptr<DecoderBuffer>& buffer) {
   FUNCTION_DVLOG(2);
   DCHECK(state_ == STATE_NORMAL || state_ == STATE_FLUSHING_DECODER) << state_;
-  DCHECK(CanDecodeMore());
+  DCHECK_LT(pending_decode_requests_, GetMaxDecodeRequests());
   DCHECK(reset_cb_.is_null());
   DCHECK(stop_cb_.is_null());
   DCHECK(buffer);
@@ -300,28 +294,26 @@ void DecoderStream<StreamType>::Decode(
   TRACE_EVENT_ASYNC_BEGIN0("media", GetTraceString<StreamType>(), this);
   ++pending_decode_requests_;
   decoder_->Decode(buffer,
-                   base::Bind(&DecoderStream<StreamType>::OnDecodeOutputReady,
+                   base::Bind(&DecoderStream<StreamType>::OnDecodeDone,
                               weak_factory_.GetWeakPtr(),
-                              buffer_size));
+                              buffer_size,
+                              buffer->end_of_stream()));
 }
 
 template <DemuxerStream::Type StreamType>
 void DecoderStream<StreamType>::FlushDecoder() {
-  if (pending_decode_requests_ == 0)
-    Decode(DecoderBuffer::CreateEOSBuffer());
+  Decode(DecoderBuffer::CreateEOSBuffer());
 }
 
 template <DemuxerStream::Type StreamType>
-void DecoderStream<StreamType>::OnDecodeOutputReady(
-    int buffer_size,
-    typename Decoder::Status status,
-    const scoped_refptr<Output>& output) {
-  FUNCTION_DVLOG(2) << status << " " << output;
+void DecoderStream<StreamType>::OnDecodeDone(int buffer_size,
+                                             bool end_of_stream,
+                                             typename Decoder::Status status) {
+  FUNCTION_DVLOG(2) << status;
   DCHECK(state_ == STATE_NORMAL || state_ == STATE_FLUSHING_DECODER ||
          state_ == STATE_PENDING_DEMUXER_READ || state_ == STATE_ERROR)
       << state_;
   DCHECK(stop_cb_.is_null());
-  DCHECK_EQ(status == Decoder::kOk, output != NULL);
   DCHECK_GT(pending_decode_requests_, 0);
 
   --pending_decode_requests_;
@@ -333,31 +325,54 @@ void DecoderStream<StreamType>::OnDecodeOutputReady(
     return;
   }
 
-  if (status == Decoder::kDecodeError) {
-    state_ = STATE_ERROR;
-    ready_outputs_.clear();
-    if (!read_cb_.is_null())
-      SatisfyRead(DECODE_ERROR, NULL);
+  // Drop decoding result if Reset() was called during decoding.
+  // The resetting process will be handled when the decoder is reset.
+  if (!reset_cb_.is_null())
     return;
-  }
 
-  if (status == Decoder::kDecryptError) {
-    state_ = STATE_ERROR;
-    ready_outputs_.clear();
-    if (!read_cb_.is_null())
-      SatisfyRead(DECRYPT_ERROR, NULL);
-    return;
+  switch (status) {
+    case Decoder::kDecodeError:
+    case Decoder::kDecryptError:
+      state_ = STATE_ERROR;
+      ready_outputs_.clear();
+      if (!read_cb_.is_null())
+        SatisfyRead(DECODE_ERROR, NULL);
+      break;
+
+    case Decoder::kAborted:
+      // Decoder can return kAborted only when Reset is pending.
+      NOTREACHED();
+      break;
+
+    case Decoder::kOk:
+      // Any successful decode counts!
+      if (buffer_size > 0) {
+        StreamTraits::ReportStatistics(statistics_cb_, buffer_size);
+      }
+
+      if (state_ == STATE_NORMAL) {
+        if (CanDecodeMore() && !end_of_stream)
+          ReadFromDemuxerStream();
+      } else if (state_ == STATE_FLUSHING_DECODER) {
+        if (!pending_decode_requests_)
+          ReinitializeDecoder();
+      }
+      break;
   }
+}
 
-  if (status == Decoder::kAborted) {
-    if (!read_cb_.is_null())
-      SatisfyRead(ABORTED, NULL);
-    return;
-  }
+template <DemuxerStream::Type StreamType>
+void DecoderStream<StreamType>::OnDecodeOutputReady(
+    const scoped_refptr<Output>& output) {
+  FUNCTION_DVLOG(2) << output;
+  DCHECK(output);
+  DCHECK(state_ == STATE_NORMAL || state_ == STATE_FLUSHING_DECODER ||
+         state_ == STATE_PENDING_DEMUXER_READ || state_ == STATE_ERROR)
+      << state_;
 
-  // Any successful decode counts!
-  if (buffer_size > 0) {
-    StreamTraits::ReportStatistics(statistics_cb_, buffer_size);
+  if (state_ == STATE_ERROR) {
+    DCHECK(read_cb_.is_null());
+    return;
   }
 
   // Drop decoding result if Reset() was called during decoding.
@@ -365,29 +380,13 @@ void DecoderStream<StreamType>::OnDecodeOutputReady(
   if (!reset_cb_.is_null())
     return;
 
-  // Decoder flushed. Reinitialize the decoder.
-  if (state_ == STATE_FLUSHING_DECODER &&
-      status == Decoder::kOk && output->end_of_stream()) {
-    ReinitializeDecoder();
-    return;
-  }
-
-  if (status == Decoder::kNotEnoughData) {
-    if (state_ == STATE_NORMAL)
-      ReadFromDemuxerStream();
-    else if (state_ == STATE_FLUSHING_DECODER)
-      FlushDecoder();
+  if (state_ == STATE_FLUSHING_DECODER && output->end_of_stream()) {
+    // ReinitializeDecoder() will be called from OnDecodeDone().
     return;
   }
 
-  DCHECK(output);
-
   // Store decoded output.
   ready_outputs_.push_back(output);
-  scoped_refptr<Output> extra_output;
-  while ((extra_output = decoder_->GetDecodeOutput()) != NULL) {
-    ready_outputs_.push_back(extra_output);
-  }
 
   // Satisfy outstanding read request, if any.
   if (!read_cb_.is_null()) {
@@ -460,7 +459,8 @@ void DecoderStream<StreamType>::OnBufferReady(
   }
 
   if (status == DemuxerStream::kAborted) {
-    SatisfyRead(DEMUXER_READ_ABORTED, NULL);
+    if (!read_cb_.is_null())
+      SatisfyRead(DEMUXER_READ_ABORTED, NULL);
     return;
   }
 
@@ -494,6 +494,8 @@ void DecoderStream<StreamType>::ReinitializeDecoder() {
       StreamTraits::GetDecoderConfig(*stream_),
       low_delay_,
       base::Bind(&DecoderStream<StreamType>::OnDecoderReinitialized,
+                 weak_factory_.GetWeakPtr()),
+      base::Bind(&DecoderStream<StreamType>::OnDecodeOutputReady,
                  weak_factory_.GetWeakPtr()));
 }