content/browser/renderer_host/media/audio_mirroring_manager.h

   1 // Copyright (c) 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 // AudioMirroringManager is a singleton object that maintains a set of active
   6 // audio mirroring destinations and auto-connects/disconnects audio streams
   7 // to/from those destinations.  It is meant to be used exclusively on the IO
   8 // BrowserThread.
   9 //
  10 // How it works:
  11 //
  12 //   1. AudioRendererHost gets a CreateStream message from the render process
  13 //      and, among other things, creates an AudioOutputController to control the
  14 //      audio data flow between the render and browser processes.
  15 //   2. At some point, AudioRendererHost receives an "associate with render
  16 //      view" message.  Among other actions, it registers the
  17 //      AudioOutputController with AudioMirroringManager (as a Diverter).
  18 //   3. A user request to mirror all the audio for a single RenderView is made.
  19 //      A MirroringDestination is created, and StartMirroring() is called to
  20 //      begin the mirroring session.  This causes AudioMirroringManager to
  21 //      instruct any matching Diverters to divert their audio data to the
  22 //      MirroringDestination.
  23 //
  24 // #2 and #3 above may occur in any order, as it is the job of
  25 // AudioMirroringManager to realize when the players can be "matched up."
  26
  27 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_MIRRORING_MANAGER_H_
  28 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_MIRRORING_MANAGER_H_
  29
  30 #include <map>
  31 #include <utility>
  32
  33 #include "base/basictypes.h"
  34 #include "content/common/content_export.h"
  35 #include "media/audio/audio_source_diverter.h"
  36
  37 namespace media {
  38 class AudioOutputStream;
  39 }
  40
  41 namespace content {
  42
  43 class CONTENT_EXPORT AudioMirroringManager {
  44  public:
  45   // Interface for diverting audio data to an alternative AudioOutputStream.
  46   typedef media::AudioSourceDiverter Diverter;
  47
  48   // Interface to be implemented by audio mirroring destinations.  See comments
  49   // for StartMirroring() and StopMirroring() below.
  50   class MirroringDestination {
  51    public:
  52     // Create a consumer of audio data in the format specified by |params|, and
  53     // connect it as an input to mirroring.  When Close() is called on the
  54     // returned AudioOutputStream, the input is disconnected and the object
  55     // becomes invalid.
  56     virtual media::AudioOutputStream* AddInput(
  57         const media::AudioParameters& params) = 0;
  58
  59    protected:
  60     virtual ~MirroringDestination() {}
  61   };
  62
  63   AudioMirroringManager();
  64
  65   virtual ~AudioMirroringManager();
  66
  67   // Add/Remove a diverter for an audio stream with a known RenderView target
  68   // (represented by |render_process_id| + |render_view_id|).  Multiple
  69   // diverters may be added for the same target.  |diverter| must live until
  70   // after RemoveDiverter() is called.
  71   //
  72   // Re-entrancy warning: These methods should not be called by a Diverter
  73   // during a Start/StopDiverting() invocation.
  74   virtual void AddDiverter(int render_process_id, int render_view_id,
  75                            Diverter* diverter);
  76   virtual void RemoveDiverter(int render_process_id, int render_view_id,
  77                               Diverter* diverter);
  78
  79   // Start/stop mirroring all audio output streams associated with a RenderView
  80   // target (represented by |render_process_id| + |render_view_id|) to
  81   // |destination|.  |destination| must live until after StopMirroring() is
  82   // called.
  83   virtual void StartMirroring(int render_process_id, int render_view_id,
  84                               MirroringDestination* destination);
  85   virtual void StopMirroring(int render_process_id, int render_view_id,
  86                              MirroringDestination* destination);
  87
  88  private:
  89   // A mirroring target is a RenderView identified by a
  90   // <render_process_id, render_view_id> pair.
  91   typedef std::pair<int, int> Target;
  92
  93   // Note: Objects in these maps are not owned.
  94   typedef std::multimap<Target, Diverter*> DiverterMap;
  95   typedef std::map<Target, MirroringDestination*> SessionMap;
  96
  97   // Currently-active divertable audio streams.
  98   DiverterMap diverters_;
  99
 100   // Currently-active mirroring sessions.
 101   SessionMap sessions_;
 102
 103   DISALLOW_COPY_AND_ASSIGN(AudioMirroringManager);
 104 };
 105
 106 }  // namespace content
 107
 108 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_MIRRORING_MANAGER_H_