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/file_descriptor_posix.h"
   9 #include "base/process.h"
  10 #include "base/sync_socket.h"
  11 #include "base/synchronization/lock.h"
  12 #include "base/time.h"
  13 #include "media/audio/audio_output_controller.h"
  14 #include "media/base/audio_bus.h"
  15
  16 namespace base {
  17 class SharedMemory;
  18 }
  19
  20 namespace content {
  21
  22 // A AudioOutputController::SyncReader implementation using SyncSocket. This
  23 // is used by AudioOutputController to provide a low latency data source for
  24 // transmitting audio packets between the browser process and the renderer
  25 // process.
  26 class AudioSyncReader : public media::AudioOutputController::SyncReader {
  27  public:
  28   AudioSyncReader(base::SharedMemory* shared_memory,
  29                   const media::AudioParameters& params,
  30                   int input_channels);
  31
  32   virtual ~AudioSyncReader();
  33
  34   // media::AudioOutputController::SyncReader implementations.
  35   virtual void UpdatePendingBytes(uint32 bytes) OVERRIDE;
  36   virtual int Read(bool block,
  37                    const media::AudioBus* source,
  38                    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   // Indicates whether the renderer has data available for reading.
  51   bool DataReady();
  52
  53   // Blocks until DataReady() is true or a timeout expires.
  54   void WaitTillDataReady();
  55
  56   base::SharedMemory* shared_memory_;
  57
  58   // Number of input channels for synchronized I/O.
  59   int input_channels_;
  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   // Shared memory wrapper used for transferring audio data from Read() callers.
  72   scoped_ptr<media::AudioBus> input_bus_;
  73
  74   // Maximum amount of audio data which can be transferred in one Read() call.
  75   int packet_size_;
  76
  77   // Track the number of times the renderer missed its real-time deadline and
  78   // report a UMA stat during destruction.
  79   size_t renderer_callback_count_;
  80   size_t renderer_missed_callback_count_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(AudioSyncReader);
  83 };
  84
  85 }  // namespace content
  86
  87 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_SYNC_READER_H_