Refactor PipelineImpl to use CompositeFilter to manage Filter state transitions.

media/base/pipeline_impl.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.
 
 // Implementation of Pipeline.
 
 #ifndef MEDIA_BASE_PIPELINE_IMPL_H_
 #define MEDIA_BASE_PIPELINE_IMPL_H_
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 #include "base/threading/thread.h"
 #include "base/time.h"
 #include "media/base/clock.h"
+#include "media/base/composite_filter.h"
 #include "media/base/filter_host.h"
 #include "media/base/pipeline.h"
 
 namespace media {
 
 
 // PipelineImpl runs the media pipeline.  Filters are created and called on the
 // message loop injected into this object. PipelineImpl works like a state
 // machine to perform asynchronous initialization, pausing, seeking and playing.
 //
@@ skipping 81 matching lines @@
     kStopped,
     kError,
   };
 
   virtual ~PipelineImpl();
 
   // Reset the state of the pipeline object to the initial state.  This method
   // is used by the constructor, and the Stop() method.
   void ResetState();
 
+  // Updates |state_|. All state transitions should use this call.
+  void set_state(State next_state);
+
   // Simple method used to make sure the pipeline is running normally.
   bool IsPipelineOk();
 
   // Helper method to tell whether we are in the state of initializing.
   bool IsPipelineInitializing();
 
   // Helper method to tell whether we are stopped or in error.
   bool IsPipelineStopped();
 
   // Helper method to tell whether we are in transition to stop state.
@@ skipping 214 matching lines @@
   // Vector of major mime types that have been rendered by this pipeline.
   typedef std::set<std::string> RenderedMimeTypesSet;
   RenderedMimeTypesSet rendered_mime_types_;
 
   // The following data members are only accessed by tasks posted to
   // |message_loop_|.
 
   // Member that tracks the current state.
   State state_;
 
-  // For kPausing, kSeeking and kStarting, we need to track how many filters
-  // have completed transitioning to the destination state.  When
-  // |remaining_transitions_| reaches 0 the pipeline can transition out
-  // of the current state.
-  size_t remaining_transitions_;
-
   // For kSeeking we need to remember where we're seeking between filter
   // replies.
   base::TimeDelta seek_timestamp_;
 
   // For GetCurrentBytes()/SetCurrentBytes() we need to know what byte we are
   // currently reading.
   int64 current_bytes_;
 
   // Set to true in DisableAudioRendererTask().
   bool audio_disabled_;
 
   // Keep track of the maximum buffered position so the buffering appears
   // smooth.
   // TODO(vrk): This is a hack.
   base::TimeDelta max_buffered_time_;
 
   // Filter collection as passed in by Start().
   scoped_ptr<FilterCollection> filter_collection_;
 
   // URL for the data source as passed in by Start().
   std::string url_;
 
   // Callbacks for various pipeline operations.
   scoped_ptr<PipelineCallback> seek_callback_;
   scoped_ptr<PipelineCallback> stop_callback_;
   scoped_ptr<PipelineCallback> ended_callback_;
   scoped_ptr<PipelineCallback> error_callback_;
   scoped_ptr<PipelineCallback> network_callback_;
 
-  // Vector of our filters and map maintaining the relationship between the
-  // FilterType and the filter itself.
-  typedef std::vector<scoped_refptr<Filter> > FilterVector;
-  FilterVector filters_;
+  // Reference to the filter(s) that constitute the pipeline.
+  scoped_refptr<Filter> pipeline_filter_;
 
   // Renderer references used for setting the volume and determining
   // when playback has finished.
   scoped_refptr<AudioRenderer> audio_renderer_;
   scoped_refptr<VideoRenderer> video_renderer_;
 
-  // Vector of threads owned by the pipeline and being used by filters.
-  typedef std::vector<base::Thread*> FilterThreadVector;
-  FilterThreadVector filter_threads_;
-
   // Helper class that stores filter references during pipeline
   // initialization.
   class PipelineInitState;
   scoped_ptr<PipelineInitState> pipeline_init_state_;
 
   FRIEND_TEST_ALL_PREFIXES(PipelineImplTest, GetBufferedTime);
   FRIEND_TEST_ALL_PREFIXES(PipelineImplTest, AudioStreamShorterThanVideo);
 
   DISALLOW_COPY_AND_ASSIGN(PipelineImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_IMPL_H_