Creating the audio_modem component

components/copresence/mediums/audio/audio_player_impl.cc

-// Copyright 2014 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.
-
-#include "components/copresence/mediums/audio/audio_player_impl.h"
-
-#include <algorithm>
-#include <string>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/logging.h"
-#include "base/run_loop.h"
-#include "components/copresence/public/copresence_constants.h"
-#include "content/public/browser/browser_thread.h"
-#include "media/audio/audio_manager.h"
-#include "media/audio/audio_parameters.h"
-#include "media/base/audio_bus.h"
-
-namespace {
-
-const int kDefaultFrameCount = 1024;
-const double kOutputVolumePercent = 1.0f;
-
-}  // namespace
-
-namespace copresence {
-
-// Public methods.
-
-AudioPlayerImpl::AudioPlayerImpl()
-    : is_playing_(false), stream_(nullptr), frame_index_(0) {
-}
-
-AudioPlayerImpl::~AudioPlayerImpl() {
-}
-
-void AudioPlayerImpl::Initialize() {
-  media::AudioManager::Get()->GetTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&AudioPlayerImpl::InitializeOnAudioThread,
-                 base::Unretained(this)));
-}
-
-void AudioPlayerImpl::Play(
-    const scoped_refptr<media::AudioBusRefCounted>& samples) {
-  media::AudioManager::Get()->GetTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&AudioPlayerImpl::PlayOnAudioThread,
-                 base::Unretained(this),
-                 samples));
-}
-
-void AudioPlayerImpl::Stop() {
-  media::AudioManager::Get()->GetTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&AudioPlayerImpl::StopOnAudioThread, base::Unretained(this)));
-}
-
-void AudioPlayerImpl::Finalize() {
-  media::AudioManager::Get()->GetTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&AudioPlayerImpl::FinalizeOnAudioThread,
-                 base::Unretained(this)));
-}
-
-// Private methods.
-
-void AudioPlayerImpl::InitializeOnAudioThread() {
-  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
-  stream_ = output_stream_for_testing_
-                ? output_stream_for_testing_.get()
-                : media::AudioManager::Get()->MakeAudioOutputStreamProxy(
-                      media::AudioParameters(
-                          media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
-                          media::CHANNEL_LAYOUT_MONO,
-                          kDefaultSampleRate,
-                          kDefaultBitsPerSample,
-                          kDefaultFrameCount),
-                      std::string());
-
-  if (!stream_ || !stream_->Open()) {
-    LOG(ERROR) << "Failed to open an output stream.";
-    if (stream_) {
-      stream_->Close();
-      stream_ = nullptr;
-    }
-    return;
-  }
-  stream_->SetVolume(kOutputVolumePercent);
-}
-
-void AudioPlayerImpl::PlayOnAudioThread(
-    const scoped_refptr<media::AudioBusRefCounted>& samples) {
-  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
-  if (!stream_ || is_playing_)
-    return;
-
-  {
-    base::AutoLock al(state_lock_);
-    samples_ = samples;
-    frame_index_ = 0;
-  }
-
-  VLOG(3) << "Starting playback.";
-  is_playing_ = true;
-  stream_->Start(this);
-}
-
-void AudioPlayerImpl::StopOnAudioThread() {
-  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
-  if (!stream_ || !is_playing_)
-    return;
-
-  VLOG(3) << "Stopping playback.";
-  stream_->Stop();
-  is_playing_ = false;
-}
-
-void AudioPlayerImpl::StopAndCloseOnAudioThread() {
-  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
-  if (!stream_)
-    return;
-
-  StopOnAudioThread();
-  stream_->Close();
-  stream_ = nullptr;
-}
-
-void AudioPlayerImpl::FinalizeOnAudioThread() {
-  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
-  StopAndCloseOnAudioThread();
-  delete this;
-}
-
-int AudioPlayerImpl::OnMoreData(media::AudioBus* dest,
-                                uint32 /* total_bytes_delay */) {
-  base::AutoLock al(state_lock_);
-  // Continuously play our samples till explicitly told to stop.
-  const int leftover_frames = samples_->frames() - frame_index_;
-  const int frames_to_copy = std::min(dest->frames(), leftover_frames);
-
-  samples_->CopyPartialFramesTo(frame_index_, frames_to_copy, 0, dest);
-  frame_index_ += frames_to_copy;
-
-  // If we didn't fill the destination audio bus, wrap around and fill the rest.
-  if (leftover_frames <= dest->frames()) {
-    samples_->CopyPartialFramesTo(
-        0, dest->frames() - frames_to_copy, frames_to_copy, dest);
-    frame_index_ = dest->frames() - frames_to_copy;
-  }
-
-  return dest->frames();
-}
-
-void AudioPlayerImpl::OnError(media::AudioOutputStream* /* stream */) {
-  LOG(ERROR) << "Error during system sound reproduction.";
-  media::AudioManager::Get()->GetTaskRunner()->PostTask(
-      FROM_HERE,
-      base::Bind(&AudioPlayerImpl::StopAndCloseOnAudioThread,
-                 base::Unretained(this)));
-}
-
-void AudioPlayerImpl::FlushAudioLoopForTesting() {
-  if (media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread())
-    return;
-
-  // Queue task on the audio thread, when it is executed, that means we've
-  // successfully executed all the tasks before us.
-  base::RunLoop rl;
-  media::AudioManager::Get()->GetTaskRunner()->PostTaskAndReply(
-      FROM_HERE,
-      base::Bind(base::IgnoreResult(&AudioPlayerImpl::FlushAudioLoopForTesting),
-                 base::Unretained(this)),
-      rl.QuitClosure());
-  rl.Run();
-}
-
-}  // namespace copresence