content/browser/renderer_host/media/audio_sync_reader.h

   1 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_
   7
   8 #include "base/process/process.h"
   9 #include "base/sync_socket.h"
  10 #include "base/synchronization/lock.h"
  11 #include "base/time/time.h"
  12 #include "media/audio/audio_output_controller.h"
  13 #include "media/base/audio_bus.h"
  14
  15 #if defined(OS_POSIX)
  16 #include "base/file_descriptor_posix.h"
  17 #endif
  18
  19 namespace base {
  20 class SharedMemory;
  21 }
  22
  23 namespace content {
  24
  25 // A AudioOutputController::SyncReader implementation using SyncSocket. This
  26 // is used by AudioOutputController to provide a low latency data source for
  27 // transmitting audio packets between the browser process and the renderer
  28 // process.
  29 class AudioSyncReader : public media::AudioOutputController::SyncReader {
  30  public:
  31   AudioSyncReader(base::SharedMemory* shared_memory,
  32                   const media::AudioParameters& params);
  33
  34   virtual ~AudioSyncReader();
  35
  36   // media::AudioOutputController::SyncReader implementations.
  37   virtual void UpdatePendingBytes(uint32 bytes) OVERRIDE;
  38   virtual void Read(media::AudioBus* dest) OVERRIDE;
  39   virtual void Close() OVERRIDE;
  40
  41   bool Init();
  42   bool PrepareForeignSocketHandle(base::ProcessHandle process_handle,
  43 #if defined(OS_WIN)
  44                                   base::SyncSocket::Handle* foreign_handle);
  45 #else
  46                                   base::FileDescriptor* foreign_handle);
  47 #endif
  48
  49  private:
  50   // Blocks until data is ready for reading or a timeout expires.  Returns false
  51   // if an error or timeout occurs.
  52   bool WaitUntilDataIsReady();
  53
  54   const base::SharedMemory* const shared_memory_;
  55
  56   // Mutes all incoming samples. This is used to prevent audible sound
  57   // during automated testing.
  58   const bool mute_audio_;
  59
  60   // Socket for transmitting audio data.
  61   scoped_ptr<base::CancelableSyncSocket> socket_;
  62
  63   // Socket to be used by the renderer. The reference is released after
  64   // PrepareForeignSocketHandle() is called and ran successfully.
  65   scoped_ptr<base::CancelableSyncSocket> foreign_socket_;
  66
  67   // Shared memory wrapper used for transferring audio data to Read() callers.
  68   scoped_ptr<media::AudioBus> output_bus_;
  69
  70   // Maximum amount of audio data which can be transferred in one Read() call.
  71   const int packet_size_;
  72
  73   // Track the number of times the renderer missed its real-time deadline and
  74   // report a UMA stat during destruction.
  75   size_t renderer_callback_count_;
  76   size_t renderer_missed_callback_count_;
  77
  78   // The maximum amount of time to wait for data from the renderer.  Calculated
  79   // from the parameters given at construction.
  80   const base::TimeDelta maximum_wait_time_;
  81
  82   // The index of the audio buffer we're expecting to be sent from the renderer;
  83   // used to block with timeout for audio data.
  84   uint32 buffer_index_;
  85
  86   DISALLOW_COPY_AND_ASSIGN(AudioSyncReader);
  87 };
  88
  89 }  // namespace content
  90
  91 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_