Tab Audio Capture: Browser-side connect/disconnect functionality.

media/audio/audio_output_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "media/audio/audio_buffers_state.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager.h"
+#include "media/audio/audio_source_diverter.h"
 #include "media/audio/simple_sources.h"
 #include "media/base/media_export.h"
 
 namespace base {
 class WaitableEvent;
 }  // namespace base
 
 class MessageLoop;
 
 // An AudioOutputController controls an AudioOutputStream and provides data
@@ skipping 34 matching lines @@
 //
 // Since AudioOutputController uses AudioManager's message loop the controller
 // uses WeakPtr to allow safe cancellation of pending tasks.
 //
 
 namespace media {
 
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback,
+      public AudioSourceDiverter,
       NON_EXPORTED_BASE(public AudioManager::AudioDeviceListener)  {
  public:
   // An event handler that receives events from the AudioOutputController. The
   // following methods are called on the audio manager thread.
   class MEDIA_EXPORT EventHandler {
    public:
     virtual void OnCreated(AudioOutputController* controller) = 0;
     virtual void OnPlaying(AudioOutputController* controller) = 0;
     virtual void OnPaused(AudioOutputController* controller) = 0;
     virtual void OnError(AudioOutputController* controller, int error_code) = 0;
@@ skipping 68 matching lines @@
                            AudioBuffersState buffers_state) OVERRIDE;
   virtual void OnError(AudioOutputStream* stream, int code) OVERRIDE;
   virtual void WaitTillDataReady() OVERRIDE;
 
   // AudioDeviceListener implementation.  When called AudioOutputController will
   // shutdown the existing |stream_|, transition to the kRecreating state,
   // create a new stream, and then transition back to an equivalent state prior
   // to being called.
   virtual void OnDeviceChange() OVERRIDE;
 
+  // AudioSourceDiverter implementation.
+  virtual const AudioParameters& GetAudioParameters() OVERRIDE;
+  virtual void StartDiverting(AudioOutputStream* to_stream) OVERRIDE;
+  virtual void StopDiverting() OVERRIDE;
+
  protected:
-    // Internal state of the source.
+  // Internal state of the source.
   enum State {
     kEmpty,
     kCreated,
     kPlaying,
     kStarting,
     kPausedWhenStarting,
     kPaused,
     kClosed,
     kError,
     kRecreating,
@@ skipping 12 matching lines @@
 
   // The following methods are executed on the audio manager thread.
   void DoCreate();
   void DoPlay();
   void PollAndStartIfDataReady();
   void DoPause();
   void DoFlush();
   void DoClose();
   void DoSetVolume(double volume);
   void DoReportError(int code);
+  void DoStartDiverting(AudioOutputStream* to_stream);
+  void DoStopDiverting();
 
   // Helper method that starts physical stream.
   void StartStream();
 
   // Helper method that stops, closes, and NULLs |*stream_|.
   // Signals event when done if it is not NULL.
   void DoStopCloseAndClearStream(base::WaitableEvent *done);
 
   AudioManager* const audio_manager_;
+  const AudioParameters params_;
 
   // |handler_| may be called only if |state_| is not kClosed.
   EventHandler* handler_;
 
   // Note: It's important to invalidate the weak pointers whenever stream_ is
   // changed.  See comment for weak_this_.
   AudioOutputStream* stream_;
 
+  // When non-NULL, audio is being diverted to this stream.
+  AudioOutputStream* diverting_to_stream_;
+
   // The current volume of the audio stream.
   double volume_;
 
   // |state_| is written on the audio manager thread and is read on the
   // hardware audio thread. These operations need to be locked. But lock
   // is not required for reading on the audio manager thread.
   State state_;
 
   // The |lock_| must be acquired whenever we access |state_| from a thread
   // other than the audio manager thread.
   base::Lock lock_;
 
   // SyncReader is used only in low latency mode for synchronous reading.
   SyncReader* sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // When starting stream we wait for data to become available.
   // Number of times left.
   int number_polling_attempts_left_;
 
-  AudioParameters params_;
-
   // Used to auto-cancel the delayed tasks that are created to poll for data
   // (when starting-up a stream).
   base::WeakPtrFactory<AudioOutputController> weak_this_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_