refactoring decoder interface

media/base/filters.h

 // Copyright (c) 2010 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.
 
 // Filters are connected in a strongly typed manner, with downstream filters
 // always reading data from upstream filters.  Upstream filters have no clue
 // who is actually reading from them, and return the results via callbacks.
 //
 //                         DemuxerStream(Video) <- VideoDecoder <- VideoRenderer
 // DataSource <- Demuxer <
@@ skipping 247 matching lines @@
     return mime_type::kMajorTypeVideo;
   }
 
   // Initialize a VideoDecoder with the given DemuxerStream, executing the
   // callback upon completion.
   virtual void Initialize(DemuxerStream* stream, FilterCallback* callback) = 0;
 
   // Returns the MediaFormat for this filter.
   virtual const MediaFormat& media_format() = 0;
 
-  // Schedules a read.  Decoder takes ownership of the callback.
-  //
-  // TODO(scherkus): switch Read() callback to scoped_refptr<>.
-  virtual void Read(Callback1<VideoFrame*>::Type* read_callback) = 0;
+  // |set_fill_buffer_done_callback| install permanent callback from downstream
+  // filter (i.e. Renderer). The callback is used to deliver video frames at
+  // runtime to downstream filter
+  typedef Callback1<scoped_refptr<VideoFrame> >::Type FillBufferDoneCallback;
+  void set_fill_buffer_done_callback(FillBufferDoneCallback* callback) {
+    fill_buffer_done_callback_.reset(callback);
+  }
+  FillBufferDoneCallback* fill_buffer_done_callback() {
+    return fill_buffer_done_callback_.get();
+  }
+
+  // Render provides an output buffer for Decoder to write to. These buffers
+  // will be recycled to renderer by fill_buffer_done_callback_;
+  // We could also pass empty pointer here to let decoder provide buffers pool.
+  virtual void FillThisBuffer(scoped_refptr<VideoFrame> frame) = 0;
+
+ private:
+  scoped_ptr<FillBufferDoneCallback> fill_buffer_done_callback_;
 };
 
 
 class AudioDecoder : public MediaFilter {
  public:
   static FilterType filter_type() {
     return FILTER_AUDIO_DECODER;
   }
 
   static const char* major_mime_type() {
     return mime_type::kMajorTypeAudio;
   }
 
   // Initialize a AudioDecoder with the given DemuxerStream, executing the
   // callback upon completion.
   virtual void Initialize(DemuxerStream* stream, FilterCallback* callback) = 0;
 
   // Returns the MediaFormat for this filter.
   virtual const MediaFormat& media_format() = 0;
 
-  // Schedules a read.  Decoder takes ownership of the callback.
-  //
-  // TODO(scherkus): switch Read() callback to scoped_refptr<>.
-  virtual void Read(Callback1<Buffer*>::Type* read_callback) = 0;
+  // |set_fill_buffer_done_callback| install permanent callback from downstream
+  // filter (i.e. Renderer). The callback is used to deliver buffers at
+  // runtime to downstream filter.
+  typedef Callback1<scoped_refptr<Buffer> >::Type FillBufferDoneCallback;
+  void set_fill_buffer_done_callback(FillBufferDoneCallback* callback) {
+    fill_buffer_done_callback_.reset(callback);
+  }
+  FillBufferDoneCallback* fill_buffer_done_callback() {
+     return fill_buffer_done_callback_.get();
+   }
+
+  // Render provides an output buffer for Decoder to write to. These buffers
+  // will be recycled to renderer by fill_buffer_done_callback_;
+  // We could also pass empty pointer here to let decoder provide buffers pool.
+  virtual void FillThisBuffer(scoped_refptr<Buffer> buffer) = 0;
+
+ private:
+  scoped_ptr<FillBufferDoneCallback> fill_buffer_done_callback_;
 };
 
 
 class VideoRenderer : public MediaFilter {
  public:
   static FilterType filter_type() {
     return FILTER_VIDEO_RENDERER;
   }
 
   static const char* major_mime_type() {
@@ skipping 28 matching lines @@
   // buffer.
   virtual bool HasEnded() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FILTERS_H_