Replace AudioDecoder::ProduceAudioSamples/ConsumeAudioSamples with read callbacks.

media/filters/ffmpeg_audio_decoder.h

 // Copyright (c) 2011 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.
 
 #ifndef MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
 #define MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
 
 #include <list>
 
 #include "base/message_loop.h"
 #include "media/base/filters.h"
 
 struct AVCodecContext;
 
 namespace media {
 
 class DataBuffer;
 
 class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
  public:
   explicit FFmpegAudioDecoder(MessageLoop* message_loop);
   virtual ~FFmpegAudioDecoder();
 
   // Filter implementation.
   virtual void Flush(const base::Closure& callback) OVERRIDE;
 
   // AudioDecoder implementation.
   virtual void Initialize(DemuxerStream* stream, const base::Closure& callback,
                           const StatisticsCallback& stats_callback) OVERRIDE;
-  virtual void ProduceAudioSamples(scoped_refptr<Buffer> output) OVERRIDE;
+  virtual void Read(const ReadCB& callback) OVERRIDE;
   virtual int bits_per_channel() OVERRIDE;
   virtual ChannelLayout channel_layout() OVERRIDE;
   virtual int samples_per_second() OVERRIDE;
 
  private:
   // Methods running on decoder thread.
   void DoInitialize(const scoped_refptr<DemuxerStream>& stream,
                     const base::Closure& callback,
                     const StatisticsCallback& stats_callback);
   void DoFlush(const base::Closure& callback);
-  void DoProduceAudioSamples(const scoped_refptr<Buffer>& output);
+  void DoRead(const ReadCB& callback);
   void DoDecodeBuffer(const scoped_refptr<Buffer>& input);
 
   // Reads from the demuxer stream with corresponding callback method.
   void ReadFromDemuxerStream();
   void DecodeBuffer(const scoped_refptr<Buffer>& buffer);
 
   // Updates the output buffer's duration and timestamp based on the input
   // buffer. Will fall back to an estimated timestamp if the input lacks a
   // valid timestamp.
   void UpdateDurationAndTimestamp(const Buffer* input, DataBuffer* output);
 
   // Calculates duration based on size of decoded audio bytes.
   base::TimeDelta CalculateDuration(int size);
 
+  // Delivers decoded samples to |read_cb_| and resets the callback.
+  void DeliverSamples(const scoped_refptr<Buffer>& samples);
+
   MessageLoop* message_loop_;
 
   scoped_refptr<DemuxerStream> demuxer_stream_;
   StatisticsCallback stats_callback_;
   AVCodecContext* codec_context_;
 
   // Decoded audio format.
   int bits_per_channel_;
   ChannelLayout channel_layout_;
   int samples_per_second_;
 
   base::TimeDelta estimated_next_timestamp_;
 
   // Holds decoded audio. As required by FFmpeg, input/output buffers should
   // be allocated with suitable padding and alignment. av_malloc() provides
   // us that guarantee.
   const int decoded_audio_size_;
   uint8* decoded_audio_;  // Allocated via av_malloc().
 
-  // Holds downstream-provided buffers.
-  std::list<scoped_refptr<Buffer> > output_buffers_;
-
-  // Tracks reads issued for compressed data.
-  int pending_reads_;
+  ReadCB read_cb_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FFmpegAudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_