Implementation of Pipeline and FilterHost interfaces. This is a large change...

media/base/pipeline.h

 // Copyright (c) 2006-2009 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.
 
 // The pipeline is the public API clients use for playing back media.  Clients
 // provide a filter factory containing the filters they want the pipeline to
 // use to render media.
 
 #ifndef MEDIA_BASE_PIPELINE_H_
 #define MEDIA_BASE_PIPELINE_H_
 
 #include <string>
 
 #include "base/task.h"
+#include "base/time.h"
 #include "media/base/factory.h"
 
 namespace media {
 
 // Error definitions for pipeline.
 enum PipelineError {
   PIPELINE_OK,
   PIPELINE_ERROR_NETWORK,
   PIPELINE_ERROR_DECODE,
   PIPELINE_ERROR_ABORT,
   PIPELINE_ERROR_INITIALIZATION_FAILED,
   PIPELINE_STOPPING
 };
 
 // Base class for Pipeline class which allows for read-only access to members.
 // Filters are allowed to access the PipelineStatus interface but are not given
 // access to the client Pipeline methods.
 class PipelineStatus {
  public:
   // Returns the current initialization state of the pipeline.  Clients can
   // examine this to determine if it is acceptable to call SetRate/SetVolume/
   // Seek after calling Start on the pipeline.  Note that this will be
   // set to true prior to a call to the client's |init_complete_callback| if
   // initialization is successful.
   virtual bool IsInitialized() const = 0;
 
   // Get the duration of the media in microseconds.  If the duration has not
   // been determined yet, then returns 0.
-  virtual int64 GetDuration() const = 0;
+  virtual base::TimeDelta GetDuration() const = 0;
 
   // Get the approximate amount of playable data buffered so far in micro-
   // seconds.
-  virtual int64 GetBufferedTime() const = 0;
+  virtual base::TimeDelta GetBufferedTime() const = 0;
 
   // Get the total size of the media file.  If the size has not yet been
   // determined or can not be determined, this value is 0.
   virtual int64 GetTotalBytes() const = 0;
 
   // Get the total number of bytes that are buffered on the client and ready to
   // be played.
   virtual int64 GetBufferedBytes() const = 0;
 
   // Gets the size of the video output in pixel units.  If there is no video
   // or the video has not been rendered yet, the width and height will be 0.
   virtual void GetVideoSize(size_t* width_out, size_t* height_out) const = 0;
 
   // Gets the current volume setting being used by the audio renderer.  When
   // the pipeline is started, this value will be 1.0f.  Valid values range
   // from 0.0f to 1.0f.
   virtual float GetVolume() const = 0;
 
   // Gets the current playback rate of the pipeline.  When the pipeline is
   // started, the playback rate will be 0.0f.  A rate of 1.0f indicates
   // that the pipeline is rendering the media at the standard rate.  Valid
   // values for playback rate are >= 0.0f.
   virtual float GetPlaybackRate() const = 0;
 
   // Gets the current pipeline time in microseconds.  For a pipeline "time"
   // progresses from 0 to the end of the media.
-  virtual int64 GetTime() const = 0;
+  virtual base::TimeDelta GetTime() const = 0;
 
   // Gets the current error status for the pipeline.  If the pipeline is
   // operating correctly, this will return OK.
   virtual PipelineError GetError() const = 0;
 
  protected:
-  virtual ~PipelineStatus() = 0;
+  virtual ~PipelineStatus() {}
 };
 
 
 class Pipeline : public PipelineStatus {
  public:
   // Build a pipeline to render the given URI using the given filter factory to
   // construct a filter chain.  Returns true if successful, false otherwise
   // (i.e., pipeline already started).  Note that a return value of true
   // only indicates that the initialization process has started successfully.
   // Pipeline initializaion is an inherently asynchronous process.  Clients
@@ skipping 17 matching lines @@
   // called the Start method.
   virtual bool Start(FilterFactory* filter_factory,
                      const std::string& uri,
                      Callback1<bool>::Type* init_complete_callback) = 0;
 
   // Stops the pipeline and resets to an uninitialized state.  This method
   // will block the calling thread until the pipeline has been completely
   // torn down and reset to an uninitialized state.  After calling Stop, it
   // is acceptable to call Start again since Stop leaves the pipeline
   // in a state identical to a newly created pipeline.
+  // Calling this method is not strictly required because the pipeline
+  // destructor will stop it pipeline if it has not been stopped already.
   virtual void Stop() = 0;
 
-  // Attempt to adjust the playback rate.  Returns true if successful,
-  // false otherwise.  Setting a playback rate of 0.0f pauses all rendering
-  // of the media.  A rate of 1.0f indicates a normal playback rate.  Values
-  // for the playback rate must be greater than or equal to 0.0f.
+  // Attempt to adjust the playback rate. Setting a playback rate of 0.0f pauses
+  // all rendering of the media.  A rate of 1.0f indicates a normal playback
+  // rate.  Values for the playback rate must be greater than or equal to 0.0f.
   // TODO(ralphl) What about maximum rate?  Does HTML5 specify a max?
   //
   // This method must be called only after initialization has completed.
-  virtual bool SetPlaybackRate(float playback_rate) = 0;
+  virtual void SetPlaybackRate(float playback_rate) = 0;
 
-  // Attempt to seek to the position in microseconds.  Returns true if
-  // successful, false otherwise.  Playback is paused after the seek completes.
+  // Attempt to seek to the position in microseconds.
   //
   // This method must be called only after initialization has completed.
-  virtual bool Seek(int64 time) = 0;
+  virtual void Seek(base::TimeDelta time) = 0;
 
   // Attempt to set the volume of the audio renderer.  Valid values for volume
   // range from 0.0f (muted) to 1.0f (full volume).  This value affects all
   // channels proportionately for multi-channel audio streams.
   //
   // This method must be called only after initialization has completed.
-  virtual bool SetVolume(float volume) = 0;
+  virtual void SetVolume(float volume) = 0;
+
+ protected:
+  virtual ~Pipeline() {}
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_H_