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(const media::AudioBus* source,
  39                     media::AudioBus* dest) OVERRIDE;
  40   virtual void Close() OVERRIDE;
  41
  42   bool Init();
  43   bool PrepareForeignSocketHandle(base::ProcessHandle process_handle,
  44 #if defined(OS_WIN)
  45                                   base::SyncSocket::Handle* foreign_handle);
  46 #else
  47                                   base::FileDescriptor* foreign_handle);
  48 #endif
  49
  50  private:
  51   // Blocks until data is ready for reading or a timeout expires.  Returns false
  52   // if an error or timeout occurs.
  53   bool WaitUntilDataIsReady();
  54
  55   const base::SharedMemory* const shared_memory_;
  56
  57   // Mutes all incoming samples. This is used to prevent audible sound
  58   // during automated testing.
  59   const bool mute_audio_;
  60
  61   // Socket for transmitting audio data.
  62   scoped_ptr<base::CancelableSyncSocket> socket_;
  63
  64   // Socket to be used by the renderer. The reference is released after
  65   // PrepareForeignSocketHandle() is called and ran successfully.
  66   scoped_ptr<base::CancelableSyncSocket> foreign_socket_;
  67
  68   // Shared memory wrapper used for transferring audio data to Read() callers.
  69   scoped_ptr<media::AudioBus> output_bus_;
  70
  71   // Maximum amount of audio data which can be transferred in one Read() call.
  72   const int packet_size_;
  73
  74   // Track the number of times the renderer missed its real-time deadline and
  75   // report a UMA stat during destruction.
  76   size_t renderer_callback_count_;
  77   size_t renderer_missed_callback_count_;
  78
  79   // The maximum amount of time to wait for data from the renderer.  Calculated
  80   // from the parameters given at construction.
  81   const base::TimeDelta maximum_wait_time_;
  82
  83   // The index of the audio buffer we're expecting to be sent from the renderer;
  84   // used to block with timeout for audio data.
  85   uint32 buffer_index_;
  86
  87   DISALLOW_COPY_AND_ASSIGN(AudioSyncReader);
  88 };
  89
  90 }  // namespace content
  91
  92 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_