Replace trampolining in FFmpegDemuxer with explicit thread calling convention checks.

media/filters/ffmpeg_demuxer.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Implements the Demuxer interface using FFmpeg's libavformat.  At this time
 // will support demuxing any audio/video format thrown at it.  The streams
 // output mime types audio/x-ffmpeg and video/x-ffmpeg and include an integer
 // key FFmpegCodecID which contains the CodecID enumeration value.  The CodecIDs
 // can be used to create and initialize the corresponding FFmpeg decoder.
 //
 // FFmpegDemuxer sets the duration of pipeline during initialization by using
 // the duration of the longest audio/video stream.
 //
 // NOTE: since FFmpegDemuxer reads packets sequentially without seeking, media
 // files with very large drift between audio/video streams may result in
 // excessive memory consumption.
 //
 // When stopped, FFmpegDemuxer and FFmpegDemuxerStream release all callbacks
 // and buffered packets.  Reads from a stopped FFmpegDemuxerStream will not be
 // replied to.
 
 #ifndef MEDIA_FILTERS_FFMPEG_DEMUXER_H_
 #define MEDIA_FILTERS_FFMPEG_DEMUXER_H_
 
-#include <deque>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/threading/thread.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/decoder_buffer_queue.h"
 #include "media/base/demuxer.h"
 #include "media/base/pipeline.h"
@@ skipping 53 matching lines @@
 
   // Returns true if this stream has capacity for additional data.
   bool HasAvailableCapacity();
 
  protected:
   virtual ~FFmpegDemuxerStream();
 
  private:
   friend class FFmpegDemuxerTest;
 
-  // Runs callbacks in |read_queue_| for each available |buffer_queue_|, calling
-  // NotifyHasPendingRead() if there are still pending items in |read_queue_|.
-  void SatisfyPendingReads();
+  // Runs |read_cb_| if present with the front of |buffer_queue_|, calling
+  // NotifyCapacityAvailable() if capacity is still available.
+  void SatisfyPendingRead();
 
   // Converts an FFmpeg stream timestamp into a base::TimeDelta.
   static base::TimeDelta ConvertStreamTimestamp(const AVRational& time_base,
                                                 int64 timestamp);
 
   FFmpegDemuxer* demuxer_;
   scoped_refptr<base::MessageLoopProxy> message_loop_;
   AVStream* stream_;
   AudioDecoderConfig audio_config_;
   VideoDecoderConfig video_config_;
   Type type_;
   base::TimeDelta duration_;
   bool stopped_;
   bool end_of_stream_;
   base::TimeDelta last_packet_timestamp_;
   Ranges<base::TimeDelta> buffered_ranges_;
 
   DecoderBufferQueue buffer_queue_;
-
-  typedef std::deque<ReadCB> ReadQueue;
-  ReadQueue read_queue_;
+  ReadCB read_cb_;
 
   scoped_ptr<FFmpegH264ToAnnexBBitstreamConverter> bitstream_converter_;
   bool bitstream_converter_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxerStream);
 };
 
 class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
  public:
   FFmpegDemuxer(const scoped_refptr<base::MessageLoopProxy>& message_loop,
@@ skipping 14 matching lines @@
   // about capacity and what buffered data is available.
   void NotifyCapacityAvailable();
   void NotifyBufferingChanged();
 
  private:
   // To allow tests access to privates.
   friend class FFmpegDemuxerTest;
 
   virtual ~FFmpegDemuxer();
 
-  // Carries out initialization on the demuxer thread.
-  void InitializeTask(DemuxerHost* host, const PipelineStatusCB& status_cb);
+  // FFmpeg callbacks during initialization.
   void OnOpenContextDone(const PipelineStatusCB& status_cb, bool result);
   void OnFindStreamInfoDone(const PipelineStatusCB& status_cb, int result);
 
-  // Carries out a seek on the demuxer thread.
-  void SeekTask(base::TimeDelta time, const PipelineStatusCB& cb);
+  // FFmpeg callbacks during seeking.
   void OnSeekFrameDone(const PipelineStatusCB& cb, int result);
 
-  // Carries out demuxing and satisfying stream reads on the demuxer thread.
-  void DemuxTask();
+  // FFmpeg callbacks during reading + helper method to initiate reads.
+  void ReadFrameIfNeeded();
   void OnReadFrameDone(ScopedAVPacket packet, int result);
 
-  // Carries out stopping the demuxer streams on the demuxer thread.
-  void StopTask(const base::Closure& callback);
+  // DataSource callbacks during stopping.
   void OnDataSourceStopped(const base::Closure& callback);
 
-  // Carries out disabling the audio stream on the demuxer thread.
-  void DisableAudioStreamTask();
-
   // Returns true iff any stream has additional capacity. Note that streams can
   // go over capacity depending on how the file is muxed.
   bool StreamsHaveAvailableCapacity();
 
   // Signal all FFmpegDemuxerStreams that the stream has ended.
   void StreamHasEnded();
 
   // Called by |url_protocol_| whenever |data_source_| returns a read error.
   void OnDataSourceError();
 
@@ skipping 54 matching lines @@
   // FFmpegURLProtocol implementation and corresponding glue bits.
   BlockingUrlProtocol url_protocol_;
   scoped_ptr<FFmpegGlue> glue_;
 
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_DEMUXER_H_