audio_handler.h

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/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
 
#include <memory>
#include <mutex>
#include <thread>
#include <vector>
 
#include "cuttlefish/host/frontend/webrtc/libcommon/audio_source.h"
#include "cuttlefish/host/frontend/webrtc/libdevice/audio_sink.h"
#include "cuttlefish/host/libs/audio_connector/server.h"
 
namespace cuttlefish {
class AudioHandler : public AudioServerExecutor {
  // TODO(jemoreira): This can probably be avoided if playback goes through the
  // audio device instead.
  struct HoldingBuffer {
    std::vector<uint8_t> buffer;
    size_t count;
 
    void Reset(size_t size);
    size_t Add(const volatile uint8_t* data, size_t max_len);
    size_t Take(uint8_t* dst, size_t len);
    bool empty() const;
    bool full() const;
    size_t freeCapacity() const;
    uint8_t* data();
    uint8_t* end();
  };
  struct StreamDesc {
    std::mutex mtx;
    int bits_per_sample = -1;
    int sample_rate = -1;
    int channels = -1;
    bool active = false;
    HoldingBuffer buffer;
  };
 
 public:
  AudioHandler(
      std::unique_ptr<AudioServer> audio_server,
      std::vector<std::shared_ptr<webrtc_streaming::AudioSink>> audio_sinks,
      std::shared_ptr<webrtc_streaming::AudioSource> audio_source);
  ~AudioHandler() override = default;
 
  void Start();
 
  // AudioServerExecutor implementation
  void StreamsInfo(StreamInfoCommand& cmd) override;
  void SetStreamParameters(StreamSetParamsCommand& cmd) override;
  void PrepareStream(StreamControlCommand& cmd) override;
  void ReleaseStream(StreamControlCommand& cmd) override;
  void StartStream(StreamControlCommand& cmd) override;
  void StopStream(StreamControlCommand& cmd) override;
  void ChmapsInfo(ChmapInfoCommand& cmd) override;
  void JacksInfo(JackInfoCommand& cmd) override;
 
  void OnPlaybackBuffer(TxBuffer buffer) override;
  void OnCaptureBuffer(RxBuffer buffer) override;
 
 private:
  [[noreturn]] void Loop();
  bool IsCapture(uint32_t stream_id) const;
 
  std::vector<std::shared_ptr<webrtc_streaming::AudioSink>> audio_sinks_;
  std::unique_ptr<AudioServer> audio_server_;
  std::thread server_thread_;
  std::vector<StreamDesc> stream_descs_ = {};
  std::shared_ptr<webrtc_streaming::AudioSource> audio_source_;
  std::vector<virtio_snd_pcm_info> streams_;
};
}  // namespace cuttlefish