media/audio/audio_logging.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_AUDIO_AUDIO_LOGGING_H_
   6 #define MEDIA_AUDIO_AUDIO_LOGGING_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11
  12 namespace media {
  13 class AudioParameters;
  14
  15 // AudioLog logs state information about an active audio component.  Each method
  16 // takes a |component_id| along with method specific information.  Its methods
  17 // are safe to call from any thread.
  18 class AudioLog {
  19  public:
  20   virtual ~AudioLog() {}
  21
  22   // Called when an audio component is created.  |params| are the parameters of
  23   // the created stream.  |device_id| is the id of the audio device opened by
  24   // the created stream.
  25   virtual void OnCreated(int component_id,
  26                          const media::AudioParameters& params,
  27                          const std::string& device_id) = 0;
  28
  29   // Called when an audio component is started, generally this is synonymous
  30   // with "playing."
  31   virtual void OnStarted(int component_id) = 0;
  32
  33   // Called when an audio component is stopped, generally this is synonymous
  34   // with "paused."
  35   virtual void OnStopped(int component_id) = 0;
  36
  37   // Called when an audio component is closed, generally this is synonymous
  38   // with "deleted."
  39   virtual void OnClosed(int component_id) = 0;
  40
  41   // Called when an audio component encounters an error.
  42   virtual void OnError(int component_id) = 0;
  43
  44   // Called when an audio component changes volume.  |volume| is the new volume.
  45   virtual void OnSetVolume(int component_id, double volume) = 0;
  46 };
  47
  48 // AudioLogFactory dispenses AudioLog instances to owning classes for tracking
  49 // AudioComponent behavior.  All AudioComponents have the concept of an owning
  50 // class:
  51 //
  52 //    - AudioInputRendererHost for AudioInputController
  53 //    - AudioRendererHost for AudioOutputController
  54 //    - AudioOutputDispatcherImpl for AudioOutputStream
  55 //
  56 // Each of these owning classes may own multiple instances of each component, as
  57 // such each AudioLog supports logging for multiple instances.
  58 class AudioLogFactory {
  59  public:
  60   enum AudioComponent {
  61     // Input controllers have a 1:1 mapping with streams, so there's no need to
  62     // track both controllers and streams.
  63     AUDIO_INPUT_CONTROLLER,
  64     // Output controllers may or may not be backed by an active stream, so we
  65     // need to track both controllers and streams.
  66     AUDIO_OUTPUT_CONTROLLER,
  67     AUDIO_OUTPUT_STREAM,
  68     AUDIO_COMPONENT_MAX
  69   };
  70
  71   // Create a new AudioLog object for tracking the behavior for one or more
  72   // instances of the given component.  Each instance of an "owning" class must
  73   // create its own AudioLog.
  74   virtual scoped_ptr<AudioLog> CreateAudioLog(AudioComponent component) = 0;
  75
  76  protected:
  77   virtual ~AudioLogFactory() {}
  78 };
  79
  80 }  // namespace media
  81
  82 #endif  // MEDIA_AUDIO_AUDIO_LOGGING_H_