Privitize WaitTillDataReady() and DataReady().

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/atomic_ref_count.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
 #include "base/timer.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"
 
 // An AudioOutputController controls an AudioOutputStream and provides data
 // to this output stream. It has an important function that it executes
 // audio operations like play, pause, stop, etc. on a separate thread,
 // namely the audio manager thread.
 //
 // All the public methods of AudioOutputController are non-blocking.
 // The actual operations are performed on the audio manager thread.
 //
 // Here is a state transition diagram for the AudioOutputController:
 //
-//   *[ Empty ]  -->  [ Created ]  -->  [ Starting ]  -->  [ Playing ]  --.
-//        |                |               |    ^               |         |
-//        |                |               |    |               |         |
-//        |                |               |    |               v         |
-//        |                |               |    `---------  [ Paused ]    |
-//        |                |               |                    |         |
-//        |                v               v                    |         |
-//        `----------->  [      Closed       ]  <-------------------------'
+//   *[ Empty ]  -->  [ Created ]  -->  [ Playing ]  -------.
+//        |                |               |    ^           |
+//        |                |               |    |           |
+//        |                |               |    |           v
+//        |                |               |    `-----  [ Paused ]
+//        |                |               |                |
+//        |                v               v                |
+//        `----------->  [      Closed       ]  <-----------'
 //
 // * Initial state
 //
 // At any time after reaching the Created state but before Closed, the
 // AudioOutputController may be notified of a device change via
 // OnDeviceChange().  As the OnDeviceChange() is processed, state transitions
 // will occur, ultimately ending up in an equivalent pre-call state.  E.g., if
 // the state was Paused, the new state will be Created, since these states are
 // all functionally equivalent and require a Play() call to continue to the next
 // state.
 //
 // The AudioOutputStream can request data from the AudioOutputController via the
 // AudioSourceCallback interface. AudioOutputController uses the SyncReader
 // passed to it via construction to synchronously fulfill this read request.
 //
-// Since AudioOutputController uses AudioManager's message loop the controller
-// uses WeakPtr to allow safe cancellation of pending tasks.
-//
 
 namespace media {
 
 class AudioSilenceDetector;
 
 class MEDIA_EXPORT AudioOutputController
     : public base::RefCountedThreadSafe<AudioOutputController>,
       public AudioOutputStream::AudioSourceCallback,
       public AudioSourceDiverter,
       NON_EXPORTED_BASE(public AudioManager::AudioDeviceListener)  {
@@ skipping 19 matching lines @@
   // now that it can handle synchronized I/O.
   class SyncReader {
    public:
     virtual ~SyncReader() {}
 
     // Notify the synchronous reader the number of bytes in the
     // AudioOutputController not yet played. This is used by SyncReader to
     // prepare more data and perform synchronization.
     virtual void UpdatePendingBytes(uint32 bytes) = 0;
 
-    // Attempt to completely fill |dest|, return the actual number of
-    // frames that could be read.
-    // |source| may optionally be provided for input data.
-    virtual int Read(AudioBus* source, AudioBus* dest) = 0;
+    // Attempt to completely fill |dest|, return the actual number of frames
+    // that could be read.  |source| may optionally be provided for input data.
+    // If |block| is specified, the Read() will block until data is available
+    // or a timeout is reached.
+    virtual int Read(bool block, const AudioBus* source, AudioBus* dest) = 0;
 
     // Close this synchronous reader.
     virtual void Close() = 0;
-
-    // Check if data is ready.
-    virtual bool DataReady() = 0;
   };
 
   // Factory method for creating an AudioOutputController.
   // This also creates and opens an AudioOutputStream on the audio manager
   // thread, and if this is successful, the |event_handler| will receive an
   // OnCreated() call from the same audio manager thread.  |audio_manager| must
   // outlive AudioOutputController.
   static scoped_refptr<AudioOutputController> Create(
       AudioManager* audio_manager, EventHandler* event_handler,
       const AudioParameters& params, SyncReader* sync_reader);
@@ skipping 18 matching lines @@
   // Sets the volume of the audio output stream.
   void SetVolume(double volume);
 
   // AudioSourceCallback implementation.
   virtual int OnMoreData(AudioBus* dest,
                          AudioBuffersState buffers_state) OVERRIDE;
   virtual int OnMoreIOData(AudioBus* source,
                            AudioBus* dest,
                            AudioBuffersState buffers_state) OVERRIDE;
   virtual void OnError(AudioOutputStream* stream) OVERRIDE;
-  // Deprecated: Currently only used for starting audio playback and for audio
-  // mirroring.
-  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.
   enum State {
     kEmpty,
     kCreated,
-    kStarting,
     kPlaying,
     kPaused,
     kClosed,
     kError,
   };
 
   friend class base::RefCountedThreadSafe<AudioOutputController>;
   virtual ~AudioOutputController();
 
  private:
   // We are polling sync reader if data became available.
   static const int kPollNumAttempts;
   static const int kPollPauseInMilliseconds;
 
   AudioOutputController(AudioManager* audio_manager, EventHandler* handler,
                         const AudioParameters& params, SyncReader* sync_reader);
 
   // The following methods are executed on the audio manager thread.
   void DoCreate(bool is_for_device_change);
   void DoPlay();
-  void PollAndStartIfDataReady();
   void DoPause();
   void DoClose();
   void DoSetVolume(double volume);
   void DoReportError();
   void DoStartDiverting(AudioOutputStream* to_stream);
   void DoStopDiverting();
 
   // Called at regular intervals during playback to check for a change in
   // silence and call EventHandler::OnAudible() when state changes occur.
   void MaybeInvokeAudibleCallback();
 
-  // Helper methods that start/stop physical stream.
-  void StartStream();
+  // Helper method that stops the physical stream.
   void StopStream();
 
   // Helper method that stops, closes, and NULLs |*stream_|.
   void DoStopCloseAndClearStream();
 
   // Sanity-check that entry/exit to OnMoreIOData() by the hardware audio thread
   // happens only between AudioOutputStream::Start() and Stop().
   void AllowEntryToOnMoreIOData();
   void DisallowEntryToOnMoreIOData();
 
   AudioManager* const audio_manager_;
   const AudioParameters params_;
   EventHandler* const 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
@@ skipping 10 matching lines @@
   // SyncReader is used only in low latency mode for synchronous reading.
   SyncReader* const sync_reader_;
 
   // The message loop of audio manager thread that this object runs on.
   const 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_;
 
-  // Used to auto-cancel the delayed tasks that are created to poll for data
-  // (when starting-up a stream).
-  base::WeakPtrFactory<AudioOutputController> weak_this_;
-
   // Scans audio samples from OnMoreIOData() as input and causes
   // EventHandler::OnAudbile() to be called whenever a transition to a period of
   // silence or non-silence is detected.
   scoped_ptr<AudioSilenceDetector> silence_detector_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioOutputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_OUTPUT_CONTROLLER_H_