text: /*
   *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #ifndef MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_
  #define MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_
  
  #include <jni.h>
  
  #include <memory>
  
  #include "api/sequence_checker.h"
  #include "modules/audio_device/android/audio_manager.h"
  #include "modules/audio_device/audio_device_generic.h"
  #include "modules/audio_device/include/audio_device_defines.h"
  #include "modules/utility/include/helpers_android.h"
  #include "modules/utility/include/jvm_android.h"
  
  namespace webrtc {
  
  // Implements 16-bit mono PCM audio input support for Android using the Java
  // AudioRecord interface. Most of the work is done by its Java counterpart in
  // WebRtcAudioRecord.java. This class is created and lives on a thread in
  // C++-land, but recorded audio buffers are delivered on a high-priority
  // thread managed by the Java class.
  //
  // The Java class makes use of AudioEffect features (mainly AEC) which are
  // first available in Jelly Bean. If it is instantiated running against earlier
  // SDKs, the AEC provided by the APM in WebRTC must be used and enabled
  // separately instead.
  //
  // An instance must be created and destroyed on one and the same thread.
  // All public methods must also be called on the same thread. A thread checker
  // will RTC_DCHECK if any method is called on an invalid thread.
  //
  // This class uses JvmThreadConnector to attach to a Java VM if needed
  // and detach when the object goes out of scope. Additional thread checking
  // guarantees that no other (possibly non attached) thread is used.
  class AudioRecordJni {
   public:
    // Wraps the Java specific parts of the AudioRecordJni into one helper class.
    class JavaAudioRecord {
     public:
      JavaAudioRecord(NativeRegistration* native_registration,
                      std::unique_ptr<GlobalRef> audio_track);
      ~JavaAudioRecord();
  
      int InitRecording(int sample_rate, size_t channels);
      bool StartRecording();
      bool StopRecording();
      bool EnableBuiltInAEC(bool enable);
      bool EnableBuiltInNS(bool enable);
  
     private:
      std::unique_ptr<GlobalRef> audio_record_;
      jmethodID init_recording_;
      jmethodID start_recording_;
      jmethodID stop_recording_;
      jmethodID enable_built_in_aec_;
      jmethodID enable_built_in_ns_;
    };
  
    explicit AudioRecordJni(AudioManager* audio_manager);
    ~AudioRecordJni();
  
    int32_t Init();
    int32_t Terminate();
  
    int32_t InitRecording();
    bool RecordingIsInitialized() const { return initialized_; }
  
    int32_t StartRecording();
    int32_t StopRecording();
    bool Recording() const { return recording_; }
  
    void AttachAudioBuffer(AudioDeviceBuffer* audioBuffer);
  
    int32_t EnableBuiltInAEC(bool enable);
    int32_t EnableBuiltInAGC(bool enable);
    int32_t EnableBuiltInNS(bool enable);
  
   private:
    // Called from Java side so we can cache the address of the Java-manged
    // `byte_buffer` in `direct_buffer_address_`. The size of the buffer
    // is also stored in `direct_buffer_capacity_in_bytes_`.
    // This method will be called by the WebRtcAudioRecord constructor, i.e.,
    // on the same thread that this object is created on.
    static void JNICALL CacheDirectBufferAddress(JNIEnv* env,
                                                 jobject obj,
                                                 jobject byte_buffer,
                                                 jlong nativeAudioRecord);
    void OnCacheDirectBufferAddress(JNIEnv* env, jobject byte_buffer);
  
    // Called periodically by the Java based WebRtcAudioRecord object when
    // recording has started. Each call indicates that there are `length` new
    // bytes recorded in the memory area `direct_buffer_address_` and it is
    // now time to send these to the consumer.
    // This method is called on a high-priority thread from Java. The name of
    // the thread is 'AudioRecordThread'.
    static void JNICALL DataIsRecorded(JNIEnv* env,
                                       jobject obj,
                                       jint length,
                                       jlong nativeAudioRecord);
    void OnDataIsRecorded(int length);
  
    // Stores thread ID in constructor.
    SequenceChecker thread_checker_;
  
    // Stores thread ID in first call to OnDataIsRecorded() from high-priority
    // thread in Java. Detached during construction of this object.
    SequenceChecker thread_checker_java_;
  
    // Calls JavaVM::AttachCurrentThread() if this thread is not attached at
    // construction.
    // Also ensures that DetachCurrentThread() is called at destruction.
    JvmThreadConnector attach_thread_if_needed_;
  
    // Wraps the JNI interface pointer and methods associated with it.
    std::unique_ptr<JNIEnvironment> j_environment_;
  
    // Contains factory method for creating the Java object.
    std::unique_ptr<NativeRegistration> j_native_registration_;
  
    // Wraps the Java specific parts of the AudioRecordJni class.
    std::unique_ptr<AudioRecordJni::JavaAudioRecord> j_audio_record_;
  
    // Raw pointer to the audio manger.
    const AudioManager* audio_manager_;
  
    // Contains audio parameters provided to this class at construction by the
    // AudioManager.
    const AudioParameters audio_parameters_;
  
    // Delay estimate of the total round-trip delay (input + output).
    // Fixed value set once in AttachAudioBuffer() and it can take one out of two
    // possible values. See audio_common.h for details.
    int total_delay_in_milliseconds_;
  
    // Cached copy of address to direct audio buffer owned by `j_audio_record_`.
    void* direct_buffer_address_;
  
    // Number of bytes in the direct audio buffer owned by `j_audio_record_`.
    size_t direct_buffer_capacity_in_bytes_;
  
    // Number audio frames per audio buffer. Each audio frame corresponds to
    // one sample of PCM mono data at 16 bits per sample. Hence, each audio
    // frame contains 2 bytes (given that the Java layer only supports mono).
    // Example: 480 for 48000 Hz or 441 for 44100 Hz.
    size_t frames_per_buffer_;
  
    bool initialized_;
  
    bool recording_;
  
    // Raw pointer handle provided to us in AttachAudioBuffer(). Owned by the
    // AudioDeviceModuleImpl class and called by AudioDeviceModule::Create().
    AudioDeviceBuffer* audio_device_buffer_;
  };
  
  }  // namespace webrtc
  
  #endif  // MODULES_AUDIO_DEVICE_ANDROID_AUDIO_RECORD_JNI_H_
  