services/audio/test/fake_loopback_group_member.h

// Copyright 2018 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 SERVICES_AUDIO_TEST_FAKE_LOOPBACK_GROUP_MEMBER_H_
#define SERVICES_AUDIO_TEST_FAKE_LOOPBACK_GROUP_MEMBER_H_

#include <memory>
#include <vector>

#include "base/macros.h"
#include "base/time/time.h"
#include "base/unguessable_token.h"
#include "media/base/audio_parameters.h"
#include "services/audio/loopback_group_member.h"

namespace media {
class AudioBus;
}

namespace audio {

// An implementation of LoopbackGroupMember that can be snooped upon. It
// generates sine wave tones, configurable per channel. Test procedures call
// RenderMoreAudio() to push more data to the Snooper.
//
// This class is not thread-safe. The caller must guarantee method calls are not
// being made simultaneously in multithreaded tests.
class FakeLoopbackGroupMember : public LoopbackGroupMember {
 public:
  explicit FakeLoopbackGroupMember(const media::AudioParameters& params);

  ~FakeLoopbackGroupMember() override;

  // Sets the sine wave |frequency| rendered into channel |ch|. Note that
  // setting the frequency to zero will zero-out the channel signal. For
  // convenience, pass |kSetAllChannels| for |ch| to set all channels to the
  // same frequency.
  void SetChannelTone(int ch, double frequency);

  // Sets the volume of this FakeLoopbackGroupMember. This simulates the current
  // output volume of an audio::OutputStream.
  void SetVolume(double volume);

  // Renders a continuation of the sine wave signal, attaching
  // |output_timestamp| as the timestamp associated with the first frame in the
  // AudioBus being delivered to the Snooper.
  void RenderMoreAudio(base::TimeTicks output_timestamp);

  // LoopbackGroupMember implementation.
  const media::AudioParameters& GetAudioParameters() const override;
  std::string GetDeviceId() const override;
  void StartSnooping(Snooper* snooper) override;
  void StopSnooping(Snooper* snooper) override;
  void StartMuting() override;
  void StopMuting() override;

  static constexpr int kSetAllChannels = -1;

 private:
  const media::AudioParameters params_;
  const std::unique_ptr<media::AudioBus> audio_bus_;

  std::vector<double> frequency_by_channel_;
  double volume_ = 0.0;

  int64_t at_frame_ = 0;

  Snooper* snooper_ = nullptr;

  DISALLOW_COPY_AND_ASSIGN(FakeLoopbackGroupMember);
};

}  // namespace audio

#endif  // SERVICES_AUDIO_TEST_FAKE_LOOPBACK_GROUP_MEMBER_H_