| // 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_DEVICE_THREAD_H_ |
| #define MEDIA_AUDIO_AUDIO_DEVICE_THREAD_H_ |
| |
| #include <stdint.h> |
| |
| #include "base/macros.h" |
| #include "base/sync_socket.h" |
| #include "base/threading/platform_thread.h" |
| #include "base/threading/thread_checker.h" |
| #include "media/base/audio_parameters.h" |
| #include "media/base/media_export.h" |
| |
| namespace media { |
| |
| // Data transfer between browser and render process uses a combination |
| // of sync sockets and shared memory. To read from the socket and render |
| // data, we use a worker thread, a.k.a. the AudioDeviceThread, which reads |
| // data from the browser via the socket and fills the shared memory from the |
| // audio thread via the AudioDeviceThread::Callback interface/class. |
| class MEDIA_EXPORT AudioDeviceThread : public base::PlatformThread::Delegate { |
| public: |
| // This is the callback interface/base class that Audio[Output|Input]Device |
| // implements to render input/output data. The callbacks run on the |
| // thread owned by AudioDeviceThread. |
| class Callback { |
| public: |
| Callback(const AudioParameters& audio_parameters, |
| uint32_t segment_length, |
| uint32_t total_segments); |
| |
| // One time initialization for the callback object on the audio thread. |
| void InitializeOnAudioThread(); |
| |
| // Derived implementations must map shared memory appropriately before |
| // Process can be called. |
| virtual void MapSharedMemory() = 0; |
| |
| // Called whenever we receive notifications about pending input data. |
| virtual void Process(uint32_t pending_data) = 0; |
| |
| base::TimeDelta buffer_duration() const { |
| return audio_parameters_.GetBufferDuration(); |
| } |
| |
| protected: |
| virtual ~Callback(); |
| |
| // Protected so that derived classes can access directly. |
| // The variables are 'const' since values are calculated/set in the |
| // constructor and must never change. |
| const AudioParameters audio_parameters_; |
| |
| const uint32_t memory_length_; |
| const uint32_t total_segments_; |
| const uint32_t segment_length_; |
| |
| // Detached in constructor and attached in InitializeOnAudioThread() which |
| // is called on the audio device thread. Sub-classes can then use it for |
| // various thread checking purposes. |
| base::ThreadChecker thread_checker_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(Callback); |
| }; |
| |
| // Creates and automatically starts the audio thread. |
| AudioDeviceThread(Callback* callback, |
| base::SyncSocket::ScopedHandle socket, |
| const char* thread_name, |
| base::ThreadPriority thread_priority); |
| |
| // This tells the audio thread to stop and clean up the data; this is a |
| // synchronous process and the thread will stop before the method returns. |
| // Blocking call, see base/threading/thread_restrictions.h. |
| ~AudioDeviceThread() override; |
| |
| private: |
| base::TimeDelta GetRealtimePeriod() final; |
| void ThreadMain() final; |
| |
| Callback* const callback_; |
| const char* thread_name_; |
| base::CancelableSyncSocket socket_; |
| base::PlatformThreadHandle thread_handle_; |
| |
| DISALLOW_COPY_AND_ASSIGN(AudioDeviceThread); |
| }; |
| |
| } // namespace media. |
| |
| #endif // MEDIA_AUDIO_AUDIO_DEVICE_THREAD_H_ |