Removing DataSource from Filter hierarchy

media/base/demuxer.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_BASE_DEMUXER_H_
 #define MEDIA_BASE_DEMUXER_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/time.h"
+#include "media/base/data_source.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/media_export.h"
-
-// TODO(acolwell): Remove include once DataSource & Preload are moved
-// out of "media/base/filters.h" and Stop() is converted to use new callbacks.
-#include "media/base/filters.h"
 #include "media/base/pipeline_status.h"
+#include "media/base/preload.h"
 
 namespace media {
 
-class FilterHost;
+class MEDIA_EXPORT DemuxerHost : public DataSourceHost {
+ public:
+  virtual ~DemuxerHost();
+
+  // Get the duration of the media in microseconds.  If the duration has not
+  // been determined yet, then returns 0.
+  virtual void SetDuration(base::TimeDelta duration) = 0;
+
+  // Set the approximate amount of playable data buffered so far in micro-
+  // seconds.
+  virtual void SetBufferedTime(base::TimeDelta buffered_time) = 0;
+
+  // Sets the byte offset at which the client is requesting the video.
+  virtual void SetCurrentReadPosition(int64 offset) = 0;
+
+  // Stops execution of the pipeline due to a fatal error.  Do not call this
+  // method with PIPELINE_OK.
+  virtual void OnDemuxerError(PipelineStatus error) = 0;
+};
 
 class MEDIA_EXPORT Demuxer
     : public base::RefCountedThreadSafe<Demuxer> {
  public:
+  Demuxer();
+
   // Sets the private member |host_|. This is the first method called by
-  // the FilterHost after a demuxer is created.  The host holds a strong
+  // the DemuxerHost after a demuxer is created.  The host holds a strong
   // reference to the demuxer.  The reference held by the host is guaranteed
   // to be released before the host object is destroyed by the pipeline.
-  //
-  // TODO(acolwell): Change this to a narrow DemuxerHost interface.
-  virtual void set_host(FilterHost* host);
+  virtual void set_host(DemuxerHost* host);
 
   // The pipeline playback rate has been changed.  Demuxers may implement this
   // method if they need to respond to this call.
   virtual void SetPlaybackRate(float playback_rate);
 
   // Carry out any actions required to seek to the given time, executing the
   // callback upon completion.
   virtual void Seek(base::TimeDelta time, const PipelineStatusCB& callback);
 
   // The pipeline is being stopped either as a result of an error or because
@@ skipping 21 matching lines @@
   virtual int GetBitrate() = 0;
 
   // Returns true if the source is from a local file or stream (such as a
   // webcam stream), false otherwise.
   virtual bool IsLocalSource() = 0;
 
   // Returns true if seeking is possible; false otherwise.
   virtual bool IsSeekable() = 0;
 
  protected:
-  Demuxer();
-  FilterHost* host() { return host_; }
+  // Only allow derived objects access to the DemuxerHost. This is
+  // kept out of the public interface because demuxers need to be
+  // aware of all calls made to the host object so they can insure
+  // the state presented to the host is always consistent with its own
+  // state.
+  DemuxerHost* host() { return host_; }
 
   friend class base::RefCountedThreadSafe<Demuxer>;
   virtual ~Demuxer();
 
  private:
-  FilterHost* host_;
+  DemuxerHost* host_;
 
   DISALLOW_COPY_AND_ASSIGN(Demuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DEMUXER_H_