Adding pulseaudio input support to chrome

media/audio/pulse/pulse_util.cc

+// Copyright (c) 2012 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/pulse_util.h"
+
+#include "base/logging.h"
+#include "media/audio/audio_manager_base.h"
+
+namespace media {
+
+namespace {
+
+pa_channel_position ChromiumToPAChannelPosition(Channels channel) {
+  switch (channel) {
+    // PulseAudio does not differentiate between left/right and
+    // stereo-left/stereo-right, both translate to front-left/front-right.
+    case LEFT:
+      return PA_CHANNEL_POSITION_FRONT_LEFT;
+    case RIGHT:
+      return PA_CHANNEL_POSITION_FRONT_RIGHT;
+    case CENTER:
+      return PA_CHANNEL_POSITION_FRONT_CENTER;
+    case LFE:
+      return PA_CHANNEL_POSITION_LFE;
+    case BACK_LEFT:
+      return PA_CHANNEL_POSITION_REAR_LEFT;
+    case BACK_RIGHT:
+      return PA_CHANNEL_POSITION_REAR_RIGHT;
+    case LEFT_OF_CENTER:
+      return PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER;
+    case RIGHT_OF_CENTER:
+      return PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER;
+    case BACK_CENTER:
+      return PA_CHANNEL_POSITION_REAR_CENTER;
+    case SIDE_LEFT:
+      return PA_CHANNEL_POSITION_SIDE_LEFT;
+    case SIDE_RIGHT:
+      return PA_CHANNEL_POSITION_SIDE_RIGHT;
+    case CHANNELS_MAX:
+      return PA_CHANNEL_POSITION_INVALID;
+    default:
+      NOTREACHED() << "Invalid channel: " << channel;
+      return PA_CHANNEL_POSITION_INVALID;
+  }
+}
+
+}  // namespace
+
+PulseInputObject::PulseInputObject()
+    : pa_mainloop_(NULL),
+      pa_context_(NULL),
+      devices(NULL),
+      sample_rate_(0),
+      initialized_(false) {
+  Initialize();
+}
+
+PulseInputObject::~PulseInputObject() {
+  Terminate();
+}
+
+void PulseInputObject::GetInputDevices(AudioDeviceNames* device_names) {
+  DCHECK(pa_mainloop_);
+  DCHECK(pa_context_);
+  devices = device_names;
+  AutoPulseLock auto_lock(pa_mainloop_);
+  pa_operation* operation = pa_context_get_source_info_list(
+      pa_context_, DevicesInfoCallback, this);
+  WaitForOperationCompletion(pa_mainloop_, operation);
+
+  if (!device_names->empty()) {
+    device_names->push_front(
+        AudioDeviceName(AudioManagerBase::kDefaultDeviceName,
+                        AudioManagerBase::kDefaultDeviceId));
+  }
+}
+
+int PulseInputObject::GetNativeSampleRate() {
+  DCHECK(pa_mainloop_);
+  DCHECK(pa_context_);
+  AutoPulseLock auto_lock(pa_mainloop_);
+  pa_operation* operation = pa_context_get_server_info(
+      pa_context_, SamplerateInfoCallback, this);
+  WaitForOperationCompletion(pa_mainloop_, operation);
+
+  return sample_rate_;
+}
+
+void PulseInputObject::Initialize() {
+  DCHECK(!initialized_);
+  DCHECK(!pa_mainloop_);
+
+  // Create a mainloop API and connect to the default server.
+  // The mainloop is the internal asynchronous API event loop.
+  pa_mainloop_ = pa_threaded_mainloop_new();
+  if (!pa_mainloop_)
+    return;
+
+  // Start the threaded mainloop.
+  if (pa_threaded_mainloop_start(pa_mainloop_)) {
+    Terminate();
+    return;
+  }
+
+  // Lock the event loop object, effectively blocking the event loop thread
+  // from processing events. This is necessary.
+  AutoPulseLock auto_lock(pa_mainloop_);
+
+  pa_mainloop_api* pa_mainloop_api = pa_threaded_mainloop_get_api(pa_mainloop_);
+  pa_context_ = pa_context_new(pa_mainloop_api, "Chrome input");
+  DCHECK(pa_context_) << "Failed to create PA context";
+  if (!pa_context_) {
+    return;
+  }
+
+  pa_context_set_state_callback(pa_context_, &ContextStateCallback, this);
+  if (pa_context_connect(pa_context_, NULL, PA_CONTEXT_NOAUTOSPAWN, NULL)) {
+    DLOG(ERROR) << "Failed to connect to the context";
+    return;
+  }
+
+  // Wait until |pa_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(pa_context_);
+    if (!PA_CONTEXT_IS_GOOD(context_state)) {
+      return;
+    }
+    if (context_state == PA_CONTEXT_READY)
+      break;
+    pa_threaded_mainloop_wait(pa_mainloop_);
+  }
+
+  initialized_ = true;
+}
+
+void PulseInputObject::Terminate() {
+  if (!pa_mainloop_) {
+    DCHECK(!pa_context_);
+    return;
+  }
+
+  {
+    AutoPulseLock auto_lock(pa_mainloop_);
+    if (pa_context_) {
+      // Clear our state callback.
+      pa_context_set_state_callback(pa_context_, NULL, NULL);
+      pa_context_disconnect(pa_context_);
+      pa_context_unref(pa_context_);
+      pa_context_ = NULL;
+    }
+  }
+
+  pa_threaded_mainloop_stop(pa_mainloop_);
+  pa_threaded_mainloop_free(pa_mainloop_);
+  pa_mainloop_ = NULL;
+  initialized_ = false;
+}
+
+void PulseInputObject::ContextStateCallback(pa_context* context,
+                                            void* user_data) {
+  PulseInputObject* pulse = reinterpret_cast<PulseInputObject*>(user_data);
+  pa_threaded_mainloop_signal(pulse->mainloop(), 0);
+}
+
+void PulseInputObject::DevicesInfoCallback(pa_context* context,
+                                           const pa_source_info* info,
+                                           int error, void *user_data) {
+  PulseInputObject* pulse = reinterpret_cast<PulseInputObject*>(user_data);
+
+  if (error) {
+    // Signal the pulse object that it is done.
+    pa_threaded_mainloop_signal(pulse->mainloop(), 0);
+    return;
+  }
+
+  // Exclude the output devices.
+  if (info->monitor_of_sink == PA_INVALID_INDEX) {
+    pulse->devices->push_back(media::AudioDeviceName(info->description,
+                                                     info->name));
+  }
+}
+
+void PulseInputObject::SamplerateInfoCallback(pa_context* context,
+                                              const pa_server_info* info,
+                                              void* user_data) {
+  PulseInputObject* pulse = reinterpret_cast<PulseInputObject*>(user_data);
+
+  pulse->sample_rate_ = info->sample_spec.rate;
+  pa_threaded_mainloop_signal(pulse->mainloop(), 0);
+}
+
+pa_sample_format_t BitsToPASampleFormat(int bits_per_sample) {
+  switch (bits_per_sample) {
+    case 8:
+      return PA_SAMPLE_U8;
+    case 16:
+      return PA_SAMPLE_S16LE;
+    case 24:
+      return PA_SAMPLE_S24LE;
+    case 32:
+      return PA_SAMPLE_S32LE;
+    default:
+      NOTREACHED() << "Invalid bits per sample: " << bits_per_sample;
+      return PA_SAMPLE_INVALID;
+  }
+}
+
+// pa_stream_success_cb_t
+void StreamSuccessCallback(pa_stream* s, int error, void* mainloop) {
+  pa_threaded_mainloop* pa_mainloop =
+      static_cast<pa_threaded_mainloop*>(mainloop);
+  pa_threaded_mainloop_signal(pa_mainloop, 0);
+}
+
+pa_channel_map ChannelLayoutToPAChannelMap(ChannelLayout channel_layout) {
+  pa_channel_map channel_map;
+  pa_channel_map_init(&channel_map);
+
+  channel_map.channels = ChannelLayoutToChannelCount(channel_layout);
+  for (Channels ch = LEFT; ch < CHANNELS_MAX;
+      ch = static_cast<Channels>(ch + 1)) {
+    int channel_index = ChannelOrder(channel_layout, ch);
+    if (channel_index < 0)
+      continue;
+
+    channel_map.map[channel_index] = ChromiumToPAChannelPosition(ch);
+  }
+
+  return channel_map;
+}
+
+void WaitForOperationCompletion(pa_threaded_mainloop* pa_mainloop,
+                                pa_operation* operation) {
+  if (!operation) {
+    DLOG(WARNING) << "Operation is NULL";
+    return;
+  }
+
+  while (pa_operation_get_state(operation) == PA_OPERATION_RUNNING)
+    pa_threaded_mainloop_wait(pa_mainloop);
+
+  pa_operation_unref(operation);
+}
+
+}  // namespace media