text: // 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_ANDROID_OPENSLES_INPUT_H_
  #define MEDIA_AUDIO_ANDROID_OPENSLES_INPUT_H_
  
  #include <SLES/OpenSLES.h>
  #include <SLES/OpenSLES_Android.h>
  #include <stdint.h>
  
  #include "base/compiler_specific.h"
  #include "base/macros.h"
  #include "base/synchronization/lock.h"
  #include "base/threading/thread_checker.h"
  #include "media/audio/android/opensles_util.h"
  #include "media/audio/audio_io.h"
  #include "media/audio/audio_parameters.h"
  
  namespace media {
  
  class AudioBus;
  class AudioManagerAndroid;
  
  // Implements PCM audio input support for Android using the OpenSLES API.
  // This class is created and lives on the Audio Manager thread but recorded
  // audio buffers are delivered on an internal OpenSLES audio thread. All public
  // methods should be called on the Audio Manager thread.
  class OpenSLESInputStream : public AudioInputStream {
   public:
    static const int kMaxNumOfBuffersInQueue = 2;
  
    OpenSLESInputStream(AudioManagerAndroid* manager,
                        const AudioParameters& params);
  
    ~OpenSLESInputStream() override;
  
    // Implementation of AudioInputStream.
    bool Open() override;
    void Start(AudioInputCallback* callback) override;
    void Stop() override;
    void Close() override;
    double GetMaxVolume() override;
    void SetVolume(double volume) override;
    double GetVolume() override;
    bool SetAutomaticGainControl(bool enabled) override;
    bool GetAutomaticGainControl() override;
    bool IsMuted() override;
  
   private:
    bool CreateRecorder();
  
    // Called from OpenSLES specific audio worker thread.
    static void SimpleBufferQueueCallback(
        SLAndroidSimpleBufferQueueItf buffer_queue,
        void* instance);
  
    // Called from OpenSLES specific audio worker thread.
    void ReadBufferQueue();
  
    // Called in Open();
    void SetupAudioBuffer();
  
    // Called in Close();
    void ReleaseAudioBuffer();
  
    // If OpenSLES reports an error this function handles it and passes it to
    // the attached AudioInputCallback::OnError().
    void HandleError(SLresult error);
  
    base::ThreadChecker thread_checker_;
  
    // Protects |callback_|, |active_buffer_index_|, |audio_data_|,
    // |buffer_size_bytes_| and |simple_buffer_queue_|.
    base::Lock lock_;
  
    AudioManagerAndroid* audio_manager_;
  
    AudioInputCallback* callback_;
  
    // Shared engine interfaces for the app.
    media::ScopedSLObjectItf recorder_object_;
    media::ScopedSLObjectItf engine_object_;
  
    SLRecordItf recorder_;
  
    // Buffer queue recorder interface.
    SLAndroidSimpleBufferQueueItf simple_buffer_queue_;
  
    SLDataFormat_PCM format_;
  
    // Audio buffers that are allocated in the constructor based on
    // info from audio parameters.
    uint8_t* audio_data_[kMaxNumOfBuffersInQueue];
  
    int active_buffer_index_;
    int buffer_size_bytes_;
  
    bool started_;
  
    scoped_ptr<media::AudioBus> audio_bus_;
  
    DISALLOW_COPY_AND_ASSIGN(OpenSLESInputStream);
  };
  
  }  // namespace media
  
  #endif  // MEDIA_AUDIO_ANDROID_OPENSLES_INPUT_H_
  