Add the copresence DirectiveHandler.

components/copresence/mediums/audio/audio_recorder.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_recorder.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/logging.h"
+#include "base/run_loop.h"
+#include "base/synchronization/waitable_event.h"
+#include "components/copresence/common/copresence_constants.h"
+#include "content/public/browser/browser_thread.h"
+#include "media/audio/audio_manager.h"
+#include "media/audio/audio_manager_base.h"
+#include "media/base/audio_bus.h"
+
+namespace {
+
+const float kProcessIntervalMs = 500.0;  // milliseconds.

[xiyuan, 2014/07/25 21:02:10]

nit: 500.0f

[rkc, 2014/07/28 21:02:03]

Done.

+
+void AudioBusToString(scoped_ptr<media::AudioBus> source, std::string* buffer) {

[Daniel Erat, 2014/07/28 21:18:18]

std::string seems strange to use for passing audio data around. can this just be
a std::vector<float> instead?

[rkc, 2014/07/29 00:33:36]

We'd have to end up converting this to a string anyway, since that is the form
we pass ArrayBuffer's to JS from an extension. The original code passed around a
std::vector<float> which involved about 1-2 extra copies of the entire data.
This is much more efficient.

+  buffer->resize(source->frames() * source->channels() * sizeof(float));
+  float* buffer_view = reinterpret_cast<float*>(string_as_array(buffer));
+
+  const int channels = source->channels();
+  for (int ch = 0; ch < channels; ++ch) {
+    for (int si = 0, di = ch; si < source->frames(); ++si, di += channels)
+      buffer_view[di] = source->channel(ch)[si];
+  }
+}
+
+// Called every kProcessIntervalMs to process the recorded audio. This
+// converts our samples to the required sample rate, interleaves the samples
+// and sends them to the whispernet decoder to process.
+void ProcessSamples(
+    scoped_ptr<media::AudioBus> bus,
+    const copresence::AudioRecorder::DecodeSamplesCallback& callback) {
+  std::string samples;
+  AudioBusToString(bus.Pass(), &samples);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE, base::Bind(callback, samples));
+}
+
+}  // namespace
+
+namespace copresence {
+
+// Public methods.
+
+AudioRecorder::AudioRecorder(const DecodeSamplesCallback& decode_callback)
+    : stream_(NULL),
+      is_recording_(false),
+      decode_callback_(decode_callback),
+      total_buffer_frames_(0),
+      buffer_frame_index_(0),
+      input_stream_for_testing_(NULL) {
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::InitializeOnAudioThread,
+                 base::Unretained(this)));
+}
+
+AudioRecorder::AudioRecorder(
+    const DecodeSamplesCallback& decode_callback,
+    media::AudioInputStream* input_stream_for_testing,
+    scoped_ptr<media::AudioParameters> params_for_testing)
+    : stream_(NULL),
+      is_recording_(false),
+      decode_callback_(decode_callback),
+      total_buffer_frames_(0),
+      buffer_frame_index_(0),
+      input_stream_for_testing_(input_stream_for_testing),
+      params_for_testing_(params_for_testing.Pass()) {
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::InitializeOnAudioThread,
+                 base::Unretained(this)));
+}
+
+AudioRecorder::~AudioRecorder() {
+}
+
+void AudioRecorder::Record() {
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::RecordOnAudioThread, base::Unretained(this)));
+}
+
+void AudioRecorder::Stop() {
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::StopOnAudioThread, base::Unretained(this)));
+}
+
+void AudioRecorder::Finalize() {
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::FinalizeOnAudioThread,
+                 base::Unretained(this)));
+}
+
+// Private methods.
+
+void AudioRecorder::InitializeOnAudioThread() {
+  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  media::AudioParameters params =

[Daniel Erat, 2014/07/28 21:18:18]

just do:

  media::AudioParameters params = params_for_testing_ ?
      *params_for_testing_ :
      media::AudioManager::Get()->GetInputStreamParameters(...);

?

[rkc, 2014/07/29 00:33:36]

Doing that for the stream already, missed this one.

Done.

+      media::AudioManager::Get()->GetInputStreamParameters(
+          media::AudioManagerBase::kDefaultDeviceId);
+
+  if (params_for_testing_.get())
+    params = *params_for_testing_;
+
+  const media::AudioParameters dest_params(params.format(),
+                                           kDefaultChannelLayout,
+                                           kDefaultChannels,
+                                           params.input_channels(),
+                                           kDefaultSampleRate,
+                                           kDefaultBitsPerSample,
+                                           params.frames_per_buffer(),
+                                           media::AudioParameters::NO_EFFECTS);
+
+  converter_.reset(new media::AudioConverter(
+      params, dest_params, params.sample_rate() == dest_params.sample_rate()));
+  converter_->AddInput(this);
+
+  total_buffer_frames_ = kProcessIntervalMs * dest_params.sample_rate() / 1000;
+  buffer_ =
+      media::AudioBus::Create(dest_params.channels(), total_buffer_frames_);
+  buffer_frame_index_ = 0;
+
+  stream_ = input_stream_for_testing_ ? input_stream_for_testing_ : stream_ =
+                media::AudioManager::Get()->MakeAudioInputStream(
+                    params, media::AudioManagerBase::kDefaultDeviceId);
+
+  if (!stream_ || !stream_->Open()) {
+    LOG(ERROR) << "Failed to open an input stream.";
+    if (stream_) {
+      stream_->Close();
+      stream_ = NULL;
+    }
+    return;
+  }
+  stream_->SetVolume(stream_->GetMaxVolume());
+}
+
+void AudioRecorder::RecordOnAudioThread() {
+  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  if (!stream_ || is_recording_)
+    return;
+
+  DVLOG(2) << "Recording Audio.";
+  converter_->Reset();
+  stream_->Start(this);
+  is_recording_ = true;
+}
+
+void AudioRecorder::StopOnAudioThread() {
+  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  if (!stream_)
+    return;
+
+  stream_->Stop();
+  is_recording_ = false;
+}
+
+void AudioRecorder::StopAndCloseOnAudioThread() {
+  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  if (!stream_)
+    return;
+
+  if (is_recording_)
+    stream_->Stop();
+  stream_->Close();
+  stream_ = NULL;
+
+  is_recording_ = false;
+}
+
+void AudioRecorder::FinalizeOnAudioThread() {
+  DCHECK(media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread());
+  StopAndCloseOnAudioThread();
+  delete this;
+}
+
+void AudioRecorder::OnData(media::AudioInputStream* stream,
+                           const media::AudioBus* source,
+                           uint32 /* hardware_delay_bytes */,
+                           double /* volume */) {

[Daniel Erat, 2014/07/28 21:18:18]

DCHECK which thread this is running on

[rkc, 2014/07/29 00:33:35]

This isn't necessarily going to be called on the default AudioThread, but can be
called from a special thread optimized for performance.

+  temp_conversion_buffer_ = source;
+  while (temp_conversion_buffer_) {
+    // source->frames() == source_params.frames_per_buffer(), so we only have
+    // one chunk of data in the source; correspondingly set the destination
+    // size to one chunk.
+    // TODO(rkc): Optimize this to directly write into buffer_ so we can avoid
+    // the copy into this buffer and then the copy back into buffer_.
+    scoped_ptr<media::AudioBus> converted_source =
+        media::AudioBus::Create(kDefaultChannels, converter_->ChunkSize());
+    // Convert accumulated samples into converted_source. Note: One call may not
+    // be enough to consume the samples from |source|.  The converter may have
+    // accumulated samples over time due to a fractional input:output sample
+    // rate ratio.  Since |source| is ephemeral, Convert() must be called until
+    // |source| is at least buffered into the converter.  Once |source| is
+    // consumed during ProvideInput(), |temp_conversion_buffer_| will be set to
+    // NULL, which will break the conversion loop.
+    converter_->Convert(converted_source.get());
+
+    int remaining_buffer_frames = buffer_->frames() - buffer_frame_index_;
+    int frames_to_copy =
+        std::min(remaining_buffer_frames, converted_source->frames());
+    converted_source->CopyPartialFramesTo(
+        0, frames_to_copy, buffer_frame_index_, buffer_.get());
+    buffer_frame_index_ += frames_to_copy;
+
+    // Buffer full, send it for processing.
+    if (buffer_->frames() == buffer_frame_index_) {
+      ProcessSamples(buffer_.Pass(), decode_callback_);
+      buffer_ = media::AudioBus::Create(kDefaultChannels, total_buffer_frames_);
+      buffer_frame_index_ = 0;
+
+      // Copy any remaining frames in the source to our buffer.
+      int remaining_source_frames = converted_source->frames() - frames_to_copy;
+      converted_source->CopyPartialFramesTo(frames_to_copy,
+                                            remaining_source_frames,
+                                            buffer_frame_index_,
+                                            buffer_.get());
+      buffer_frame_index_ += remaining_source_frames;
+    }
+  }
+}
+
+void AudioRecorder::OnError(media::AudioInputStream* /* stream */) {
+  LOG(ERROR) << "Error during sound recording.";
+  media::AudioManager::Get()->GetTaskRunner()->PostTask(
+      FROM_HERE,
+      base::Bind(&AudioRecorder::StopAndCloseOnAudioThread,
+                 base::Unretained(this)));
+}
+
+double AudioRecorder::ProvideInput(media::AudioBus* dest,
+                                   base::TimeDelta /* buffer_delay */) {
+  DCHECK(temp_conversion_buffer_);
+  DCHECK_LE(temp_conversion_buffer_->frames(), dest->frames());
+  temp_conversion_buffer_->CopyTo(dest);
+  temp_conversion_buffer_ = NULL;
+  return 1.0;
+}
+
+bool AudioRecorder::IsRecording() {
+  if (media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread())

[DaleCurtis, 2014/07/25 20:41:29]

Ditto.

[rkc, 2014/07/28 21:02:03]

Done.

+    return false;
+
+  // All this does is flush the tasks on the audio thread.
+  base::RunLoop rl;
+  media::AudioManager::Get()->GetTaskRunner()->PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(base::IgnoreResult(&AudioRecorder::IsRecording),
+                 base::Unretained(this)),
+      rl.QuitClosure());
+  rl.Run();
+
+  return is_recording_;
+}
+
+}  // namespace copresence