More media::PipelineImpl cleanup, this time focusing on not taking down the render process.

media/base/pipeline_impl.h

 // Copyright (c) 2008-2009 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.
 
 // Implementation of Pipeline.
 
 #ifndef MEDIA_BASE_PIPELINE_IMPL_H_
 #define MEDIA_BASE_PIPELINE_IMPL_H_
 
 #include <string>
@@ skipping 55 matching lines @@
   // must not be an error.
   bool IsPipelineOk() const;
 
   // Methods called by FilterHostImpl to update pipeline state.
   void SetDuration(base::TimeDelta duration);
   void SetBufferedTime(base::TimeDelta buffered_time);
   void SetTotalBytes(int64 total_bytes);
   void SetBufferedBytes(int64 buffered_bytes);
   void SetVideoSize(size_t width, size_t height);
   void SetTime(base::TimeDelta time);
-  void InternalSetPlaybackRate(float rate);
 
   // Sets the error to the new error code only if the current error state is
   // PIPELINE_OK. Returns true if error set, otherwise leaves current error
   // alone, and returns false.
   bool InternalSetError(PipelineError error);
 
   // Method called by the |pipeline_internal_| to insert a mime type into
   // the |rendered_mime_types_| set.
   void InsertRenderedMimeType(const std::string& major_mime_type);
 
@@ skipping 27 matching lines @@
 
   // Lock used to serialize access for getter/setter methods.
   mutable Lock lock_;
 
   // Video width and height.  Set by a FilterHostImpl object on behalf
   // of a filter.  The video_size_access_lock_ is used to make sure access
   // to the pair of width and height are modified or read in thread safe way.
   size_t video_width_;
   size_t video_height_;
 
-  // Current volume level (from 0.0f to 1.0f).  The volume reflects the last
-  // value the audio filter was called with SetVolume, so there will be a short
-  // period of time between the client calling SetVolume on the pipeline and
-  // this value being updated.  Set by the PipelineInternal just prior to
-  // calling the audio renderer.
+  // Current volume level (from 0.0f to 1.0f).  This value is set immediately
+  // via SetVolume() and a task is dispatched on the message loop to notify the
+  // filters.
   float volume_;
 
-  // Current playback rate (>= 0.0f).  This member reflects the last value
-  // that the filters in the pipeline were called with, so there will be a short
-  // period of time between the client calling SetPlaybackRate and this value
-  // being updated.  Set by the PipelineInternal just prior to calling filters.
+  // Current playback rate (>= 0.0f).  This value is set immediately via
+  // SetPlaybackRate() and a task is dispatched on the message loop to notify
+  // the filters.
   float playback_rate_;
 
   // Current playback time.  Set by a FilterHostImpl object on behalf of the
   // audio renderer filter.
   base::TimeDelta time_;
 
   // Status of the pipeline.  Initialized to PIPELINE_OK which indicates that
   // the pipeline is operating correctly. Any other value indicates that the
   // pipeline is stopped or is stopping.  Clients can call the Stop method to
   // reset the pipeline state, and restore this to PIPELINE_OK.
@@ skipping 35 matching lines @@
   explicit PipelineInternal(PipelineImpl* pipeline, MessageLoop* message_loop);
 
   // After Start() is called, a task of StartTask() is posted on the pipeline
   // thread to perform initialization. See StartTask() to learn more about
   // initialization.
   void Start(FilterFactory* filter_factory,
              const std::string& url_media_source,
              PipelineCallback* start_callback);
   void Stop(PipelineCallback* stop_callback);
   void Seek(base::TimeDelta time, PipelineCallback* seek_callback);
-  void SetPlaybackRate(float rate);
-  void SetVolume(float volume);
+
+  // Notifications that the client has changed the playback rate/volume.

[Alpha Left Google, 2009/07/11 02:05:36]

Notifies?

[scherkus (not reviewing), 2009/07/11 02:39:58]

Done.

+  void PlaybackRateChanged(float playback_rate);
+  void VolumeChanged(float volume);
 
   // Methods called by a FilterHostImpl object.  These methods may be called
   // on any thread, either the pipeline's thread or any other.
 
   // When a filter calls it's FilterHost, the filter host calls back to the
   // pipeline thread.  If the pipeline thread is running a nested message loop
   // then it will be exited.
   void InitializationComplete(FilterHostImpl* host);
 
   // Sets the pipeline time and schedules a task to call back to any filters
@@ skipping 61 matching lines @@
   // StopTask() and ErrorTask() are similar but serve different purposes:
   //   - Both destroy the filter chain.
   //   - Both will execute |start_callback| if the pipeline was initializing.
   //   - StopTask() resets the pipeline to a fresh state, where as ErrorTask()
   //     leaves the pipeline as is for client inspection.
   //   - StopTask() can be scheduled by the client calling Stop(), where as
   //     ErrorTask() is scheduled as a result of a filter calling Error().
   void StopTask(PipelineCallback* stop_callback);
   void ErrorTask(PipelineError error);
 
-  void SetPlaybackRateTask(float rate);
+  // Carries out notifying filters that the playback rate/volume has changed,
+  void PlaybackRateChangedTask(float playback_rate);
+  void VolumeChangedTask(float volume);
+
+  // Carries out notifying filters that we are seeking to a new timestamp.
   void SeekTask(base::TimeDelta time, PipelineCallback* seek_callback);
-  void SetVolumeTask(float volume);
 
   // Internal methods used in the implementation of the pipeline thread.  All
   // of these methods are only called on the pipeline thread.
 
   // The following template functions make use of the fact that media filter
   // derived interfaces are self-describing in the sense that they all contain
   // the static method filter_type() which returns a FilterType enum that
   // uniquely identifies the filter's interface.  In addition, filters that are
   // specific to audio or video also support a static method major_mime_type()
   // which returns a string of "audio/" or "video/".
@@ skipping 87 matching lines @@
 
   typedef std::vector<base::Thread*> FilterThreadVector;
   FilterThreadVector filter_threads_;
 
   DISALLOW_COPY_AND_ASSIGN(PipelineInternal);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_IMPL_H_