Adding pulseaudio input support to chrome

media/audio/pulse/audio_manager_pulse.cc

+// Copyright 2013 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 "media/audio/pulse/audio_manager_pulse.h"
+
+#include "base/command_line.h"
+#include "base/environment.h"
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "base/nix/xdg_util.h"
+#include "base/process_util.h"
+#include "base/stl_util.h"
+#include "media/audio/audio_util.h"
+#include "media/audio/linux/audio_manager_linux.h"
+#include "media/audio/pulse/pulse_input.h"
+#include "media/audio/pulse/pulse_output.h"
+#include "media/audio/pulse/pulse_stubs.h"
+#include "media/audio/pulse/pulse_util.h"
+
+using media_audio_pulse::kModulePulse;
+using media_audio_pulse::InitializeStubs;
+using media_audio_pulse::StubPathMap;
+
+namespace media {
+
+using pulse::AutoPulseLock;
+using pulse::WaitForOperationCompletion;
+
+// Maximum number of output streams that can be open simultaneously.
+static const int kMaxOutputStreams = 50;
+
+static const base::FilePath::CharType kPulseLib[] =
+    FILE_PATH_LITERAL("libpulse.so.0");
+
+// static
+AudioManager* AudioManagerPulse::Create() {
+  scoped_ptr<AudioManagerPulse> ret(new AudioManagerPulse());
+  if (ret->Init())
+    return ret.release();
+
+  DVLOG(1) << "PulseAudio is not available on the OS";
+  return NULL;
+}
+
+AudioManagerPulse::AudioManagerPulse()
+    : input_mainloop_(NULL),
+      input_context_(NULL),
+      devices_(NULL),
+      native_input_sample_rate_(0) {
+  SetMaxOutputStreamsAllowed(kMaxOutputStreams);
+}
+
+AudioManagerPulse::~AudioManagerPulse() {
+  DestroyPulse();
+  Shutdown();
+}
+
+// Implementation of AudioManager.
+bool AudioManagerPulse::HasAudioOutputDevices() {
+  // TODO(xians): implement this function.
+  return true;
+}
+
+bool AudioManagerPulse::HasAudioInputDevices() {
+  // TODO(xians): implement this function.
+  return true;
+}
+
+void AudioManagerPulse::ShowAudioInputSettings() {
+  AudioManagerLinux::ShowLinuxAudioInputSettings();
+}
+
+void AudioManagerPulse::GetAudioInputDeviceNames(
+    media::AudioDeviceNames* device_names) {
+  DCHECK(device_names->empty());
+  DCHECK(input_mainloop_);
+  DCHECK(input_context_);
+  devices_ = device_names;
+  AutoPulseLock auto_lock(input_mainloop_);
+  pa_operation* operation = pa_context_get_source_info_list(
+      input_context_, DevicesInfoCallback, this);
+  WaitForOperationCompletion(input_mainloop_, operation);
+
+  // Append the default device on the top of the list if the list is not empty.
+  if (!device_names->empty()) {
+    device_names->push_front(
+        AudioDeviceName(AudioManagerBase::kDefaultDeviceName,
+                        AudioManagerBase::kDefaultDeviceId));
+  }
+}
+
+AudioOutputStream* AudioManagerPulse::MakeLinearOutputStream(
+    const AudioParameters& params) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
+  return MakeOutputStream(params);
+}
+
+AudioOutputStream* AudioManagerPulse::MakeLowLatencyOutputStream(
+    const AudioParameters& params) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
+  return MakeOutputStream(params);
+}
+
+AudioInputStream* AudioManagerPulse::MakeLinearInputStream(
+    const AudioParameters& params, const std::string& device_id) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
+  return MakeInputStream(params, device_id);
+}
+
+AudioInputStream* AudioManagerPulse::MakeLowLatencyInputStream(
+    const AudioParameters& params, const std::string& device_id) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
+  return MakeInputStream(params, device_id);
+}
+
+AudioOutputStream* AudioManagerPulse::MakeOutputStream(
+    const AudioParameters& params) {
+  return new PulseAudioOutputStream(params, this);
+}
+
+AudioInputStream* AudioManagerPulse::MakeInputStream(
+    const AudioParameters& params, const std::string& device_id) {
+  return new PulseAudioInputStream(this, device_id, params,
+                                   input_mainloop_, input_context_);
+}
+
+AudioParameters AudioManagerPulse::GetPreferredLowLatencyOutputStreamParameters(
+    const AudioParameters& input_params) {
+  // TODO(xians): figure out the optimized buffer size for the Pulse IO.
+  int buffer_size = GetAudioHardwareBufferSize();
+  if (input_params.frames_per_buffer() < buffer_size)
+    buffer_size = input_params.frames_per_buffer();
+
+  // TODO(dalecurtis): This should include bits per channel and channel layout
+  // eventually.
+  return AudioParameters(
+      AudioParameters::AUDIO_PCM_LOW_LATENCY, input_params.channel_layout(),
+      input_params.sample_rate(), 16, buffer_size);
+}
+
+int AudioManagerPulse::GetNativeSampleRate() {
+  DCHECK(input_mainloop_);
+  DCHECK(input_context_);
+  AutoPulseLock auto_lock(input_mainloop_);
+  pa_operation* operation = pa_context_get_server_info(
+      input_context_, SampleRateInfoCallback, this);
+  WaitForOperationCompletion(input_mainloop_, operation);
+
+  return native_input_sample_rate_;
+}
+
+bool AudioManagerPulse::Init() {
+  DCHECK(!input_mainloop_);
+
+  StubPathMap paths;
+
+  // Check if the pulse library is avialbale.
+  paths[kModulePulse].push_back(kPulseLib);
+  if (!InitializeStubs(paths)) {
+    DLOG(WARNING) << "Failed on loading the Pulse library and symbols";
+    return false;
+  }
+
+  // Create a mainloop API and connect to the default server.
+  // The mainloop is the internal asynchronous API event loop.
+  input_mainloop_ = pa_threaded_mainloop_new();
+  if (!input_mainloop_)
+    return false;
+
+  // Start the threaded mainloop.
+  if (pa_threaded_mainloop_start(input_mainloop_)) {
+    DestroyPulse();
+    return false;
+  }
+
+  // Lock the event loop object, effectively blocking the event loop thread
+  // from processing events. This is necessary.
+  AutoPulseLock auto_lock(input_mainloop_);
+
+  pa_mainloop_api* pa_mainloop_api =
+      pa_threaded_mainloop_get_api(input_mainloop_);
+  input_context_ = pa_context_new(pa_mainloop_api, "Chrome input");
+  DCHECK(input_context_) << "Failed to create PA context";
+  if (!input_context_) {
+    return false;
+  }
+
+  pa_context_set_state_callback(input_context_, &pulse::ContextStateCallback,
+                                input_mainloop_);
+  if (pa_context_connect(input_context_, NULL, PA_CONTEXT_NOAUTOSPAWN, NULL)) {
+    DLOG(ERROR) << "Failed to connect to the context";
+    return false;
+  }
+
+  // Wait until |input_context_| is ready.  pa_threaded_mainloop_wait() must be
+  // called after pa_context_get_state() in case the context is already ready,
+  // otherwise pa_threaded_mainloop_wait() will hang indefinitely.
+  while (true) {
+    pa_context_state_t context_state = pa_context_get_state(input_context_);
+    if (!PA_CONTEXT_IS_GOOD(context_state)) {
+      return false;
+    }
+    if (context_state == PA_CONTEXT_READY)
+      break;
+    pa_threaded_mainloop_wait(input_mainloop_);
+  }
+
+  return true;
+}
+
+void AudioManagerPulse::DestroyPulse() {
+  if (!input_mainloop_) {
+    DCHECK(!input_context_);
+    return;
+  }
+
+  {
+    AutoPulseLock auto_lock(input_mainloop_);
+    if (input_context_) {
+      // Clear our state callback.
+      pa_context_set_state_callback(input_context_, NULL, NULL);
+      pa_context_disconnect(input_context_);
+      pa_context_unref(input_context_);
+      input_context_ = NULL;
+    }
+  }
+
+  pa_threaded_mainloop_stop(input_mainloop_);
+  pa_threaded_mainloop_free(input_mainloop_);
+  input_mainloop_ = NULL;
+}
+
+void AudioManagerPulse::DevicesInfoCallback(pa_context* context,
+                                            const pa_source_info* info,
+                                            int error, void *user_data) {
+  AudioManagerPulse* manager = reinterpret_cast<AudioManagerPulse*>(user_data);
+
+  if (error) {
+    // Signal the pulse object that it is done.
+    pa_threaded_mainloop_signal(manager->input_mainloop_, 0);
+    return;
+  }
+
+  // Exclude the output devices.
+  if (info->monitor_of_sink == PA_INVALID_INDEX) {
+    manager->devices_->push_back(media::AudioDeviceName(info->description,
+                                                        info->name));
+  }
+}
+
+void AudioManagerPulse::SampleRateInfoCallback(pa_context* context,
+                                               const pa_server_info* info,
+                                               void* user_data) {
+  AudioManagerPulse* manager = reinterpret_cast<AudioManagerPulse*>(user_data);
+
+  manager->native_input_sample_rate_ = info->sample_spec.rate;
+  pa_threaded_mainloop_signal(manager->input_mainloop_, 0);
+}
+
+}  // namespace media