Exposes a shlib interface for media/audio path.

chromecast/media/audio/chromecast_device_audio_output_stream.cc

+// Copyright 2015 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 "chromecast/media/audio/chromecast_device_audio_output_stream.h"
+
+#include "base/logging.h"
+
+namespace chromecast {
+namespace media {
+
+ChromecastDeviceAudioOutputStream::ChromecastDeviceAudioOutputStream(
+    CastAudioOutputStream* output_stream,
+    const AudioParameters& params,
+    CastAudioManager* manager)
+    : output_stream_(output_stream),
+      callback_(nullptr),
+      params_(params),
+      audio_manager_(manager) {
+  // Verify validity of parameters.
+  DCHECK(output_stream_);
+  DCHECK(params_.bits_per_sample == 8 || params_.bits_per_sample == 16 ||
+         params_.bits_per_sample == 32);
+}
+
+ChromecastDeviceAudioOutputStream::~ChromecastDeviceAudioOutputStream() {
+}
+
+bool ChromecastDeviceAudioOutputStream::Open() {
+  DCHECK(output_stream_);
+  return output_stream_->Open();
+}
+
+void ChromecastDeviceAudioOutputStream::Start(
+    ::media::AudioOutputStream::AudioSourceCallback* callback) {
+  DCHECK(output_stream_);
+  DCHECK(callback);
+  callback_ = callback;
+  output_stream_->Start(this);
+}
+
+void ChromecastDeviceAudioOutputStream::Stop() {
+  DCHECK(output_stream_);
+  // Note that Stop() may generate AudioSourceCallback events. Ignore these by
+  // setting the callback to NULL before calling stop.
+  callback_ = nullptr;
+  output_stream_->Stop();
+}
+
+void ChromecastDeviceAudioOutputStream::SetVolume(double volume) {
+  DCHECK(output_stream_);
+  output_stream_->SetVolume(volume);
+}
+
+void ChromecastDeviceAudioOutputStream::GetVolume(double* volume) {
+  DCHECK(output_stream_);
+  DCHECK(volume);
+  *volume = output_stream_->GetVolume();
+}
+
+void ChromecastDeviceAudioOutputStream::Close() {
+  DCHECK(output_stream_);
+  DCHECK(audio_manager_);
+
+  // Close the underlying stream.
+  output_stream_->Close();
+  output_stream_ = nullptr;
+
+  // Note: This method must be called to avoid a leak. |this| will be deleted
+  // in this call, so this must be the last line, and this object must not be
+  // used after this function returns. Please see
+  // CastAudioManager::MakeCastOutputStream before changing this behavaior.
+  // TODO(slan): m43 does not have the below API, so commit suicide instead.
+  audio_manager_->ReleaseOutputStream(this);
+}
+
+int ChromecastDeviceAudioOutputStream::GetMoreData(void* dest,
+                                                   uint32_t len,
+                                                   int32_t frames,
+                                                   uint32_t total_bytes_delay) {
+  CHECK(dest);
+  CHECK_GE(frames, 0);
+  uint32_t bytes_needed =
+      frames * params_.channels * params_.bits_per_sample / 8;
+  CHECK_GE(len, bytes_needed);
+
+  // If the stream has been Stop()ped, return no frames filled.
+  if (!callback_)
+    return 0;
+
+  // Pass an empty audio bus of the right size to the source to be filled.
+  scoped_ptr< ::media::AudioBus> bus =
+      ::media::AudioBus::Create(params_.channels, frames);
+  int frames_filled = callback_->OnMoreData(bus.get(), total_bytes_delay);
+  DCHECK_GE(frames_filled, 0);
+  DCHECK_LE(frames_filled, frames);
+
+  // Populate |dest| with interleaved data.
+  bus->ToInterleaved(frames_filled, params_.bits_per_sample / 8, dest);
+  return frames_filled;
+}
+
+void ChromecastDeviceAudioOutputStream::OnError(CastAudioOutputStream* stream) {
+  if (callback_)
+    callback_->OnError(this);
+}
+
+}  // namespace media
+}  // namespace chromecast