chromeos/audio/cras_audio

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
IsSameAudioDevice
OnOutputVolumeChanged
OnInputGainChanged
OnOutputMuteChanged
OnInputMuteChanged
OnAudioNodesChanged
OnActiveOutputNodeChanged
OnActiveInputNodeChanged
Initialize
InitializeForTesting
Shutdown
IsInitialized
Get
AddAudioObserver
RemoveAudioObserver
IsOutputMuted
IsOutputMutedForDevice
IsOutputVolumeBelowDefaultMuteLvel
IsInputMuted
IsInputMutedForDevice
GetOutputDefaultVolumeMuteThreshold
GetOutputVolumePercent
GetOutputVolumePercentForDevice
GetInputGainPercent
GetInputGainPercentForDevice
GetActiveOutputNode
GetActiveInputNode
GetAudioDevices
GetActiveOutputDevice
has_alternative_input
has_alternative_output
SetOutputVolumePercent
SetInputGainPercent
AdjustOutputVolumeByPercent
SetOutputMute
AdjustOutputVolumeToAudibleLevel
SetInputMute
SetActiveOutputNode
SetActiveInputNode
SetVolumeGainPercentForDevice
SetMuteForDevice
LogErrors
log_errors_
AudioClientRestarted
NodesChanged
ActiveOutputNodeChanged
ActiveInputNodeChanged
OnAudioPolicyPrefChanged
EmitLoginPromptVisibleCalled
GetDeviceFromId
SetupAudioInputState
SetupAudioOutputState
InitializeAudioState
ApplyAudioPolicy
SetOutputNodeVolume
SetOutputMuteInternal
SetInputNodeGain
SetInputMuteInternal
GetNodes
ChangeActiveDevice
NonActiveDeviceUnplugged
SwitchToDevice
HasDeviceChange
FoundNewDevice
GetSanitizedAudioDevice
UpdateDevicesAndSwitchActive
HandleGetNodes
HandleGetNodesError
// Copyright (c) 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 "chromeos/audio/cras_audio_handler.h"

#include <algorithm>
#include <cmath>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "chromeos/audio/audio_devices_pref_handler.h"
#include "chromeos/audio/audio_devices_pref_handler_stub.h"
#include "chromeos/dbus/dbus_thread_manager.h"

using std::max;
using std::min;

namespace chromeos {

namespace {

// Default value for unmuting, as a percent in the range [0, 100].
// Used when sound is unmuted, but volume was less than kMuteThresholdPercent.
const int kDefaultUnmuteVolumePercent = 4;

// Volume value which should be considered as muted in range [0, 100].
const int kMuteThresholdPercent = 1;

static CrasAudioHandler* g_cras_audio_handler = NULL;

bool IsSameAudioDevice(const AudioDevice& a, const AudioDevice& b) {
  return a.id == b.id && a.is_input == b.is_input && a.type == b.type
      && a.device_name == b.device_name;
}

}  // namespace

CrasAudioHandler::AudioObserver::AudioObserver() {
}

CrasAudioHandler::AudioObserver::~AudioObserver() {
}

void CrasAudioHandler::AudioObserver::OnOutputVolumeChanged() {
}

void CrasAudioHandler::AudioObserver::OnInputGainChanged() {
}

void CrasAudioHandler::AudioObserver::OnOutputMuteChanged() {
}

void CrasAudioHandler::AudioObserver::OnInputMuteChanged() {
}

void CrasAudioHandler::AudioObserver::OnAudioNodesChanged() {
}

void CrasAudioHandler::AudioObserver::OnActiveOutputNodeChanged() {
}

void CrasAudioHandler::AudioObserver::OnActiveInputNodeChanged() {
}

// static
void CrasAudioHandler::Initialize(
    scoped_refptr<AudioDevicesPrefHandler> audio_pref_handler) {
  CHECK(!g_cras_audio_handler);
  g_cras_audio_handler = new CrasAudioHandler(audio_pref_handler);
}

// static
void CrasAudioHandler::InitializeForTesting() {
  CHECK(!g_cras_audio_handler);
  CrasAudioHandler::Initialize(new AudioDevicesPrefHandlerStub());
}

// static
void CrasAudioHandler::Shutdown() {
  CHECK(g_cras_audio_handler);
  delete g_cras_audio_handler;
  g_cras_audio_handler = NULL;
}

// static
bool CrasAudioHandler::IsInitialized() {
  return g_cras_audio_handler != NULL;
}

// static
CrasAudioHandler* CrasAudioHandler::Get() {
  CHECK(g_cras_audio_handler)
      << "CrasAudioHandler::Get() called before Initialize().";
  return g_cras_audio_handler;
}

void CrasAudioHandler::AddAudioObserver(AudioObserver* observer) {
  observers_.AddObserver(observer);
}

void CrasAudioHandler::RemoveAudioObserver(AudioObserver* observer) {
  observers_.RemoveObserver(observer);
}

bool CrasAudioHandler::IsOutputMuted() {
  return output_mute_on_;
}

bool CrasAudioHandler::IsOutputMutedForDevice(uint64 device_id) {
  const AudioDevice* device = GetDeviceFromId(device_id);
  if (!device)
    return false;
  return audio_pref_handler_->GetMuteValue(*device);
}

bool CrasAudioHandler::IsOutputVolumeBelowDefaultMuteLvel() {
  return output_volume_ <= kMuteThresholdPercent;
}

bool CrasAudioHandler::IsInputMuted() {
  return input_mute_on_;
}

bool CrasAudioHandler::IsInputMutedForDevice(uint64 device_id) {
  const AudioDevice* device = GetDeviceFromId(device_id);
  if (!device)
    return false;
  return audio_pref_handler_->GetMuteValue(*device);
}

int CrasAudioHandler::GetOutputDefaultVolumeMuteThreshold() {
  return kMuteThresholdPercent;
}

int CrasAudioHandler::GetOutputVolumePercent() {
  return output_volume_;
}

int CrasAudioHandler::GetOutputVolumePercentForDevice(uint64 device_id) {
  if (device_id == active_output_node_id_) {
    return output_volume_;
  } else {
    const AudioDevice* device = GetDeviceFromId(device_id);
    return static_cast<int>(audio_pref_handler_->GetOutputVolumeValue(device));
  }
}

int CrasAudioHandler::GetInputGainPercent() {
  return input_gain_;
}

int CrasAudioHandler::GetInputGainPercentForDevice(uint64 device_id) {
  if (device_id == active_input_node_id_) {
    return input_gain_;
  } else {
    const AudioDevice* device = GetDeviceFromId(device_id);
    return static_cast<int>(audio_pref_handler_->GetInputGainValue(device));
  }
}

uint64 CrasAudioHandler::GetActiveOutputNode() const {
  return active_output_node_id_;
}

uint64 CrasAudioHandler::GetActiveInputNode() const {
  return active_input_node_id_;
}

void CrasAudioHandler::GetAudioDevices(AudioDeviceList* device_list) const {
  device_list->clear();
  for (AudioDeviceMap::const_iterator it = audio_devices_.begin();
       it != audio_devices_.end(); ++it)
    device_list->push_back(it->second);
}

bool CrasAudioHandler::GetActiveOutputDevice(AudioDevice* device) const {
  const AudioDevice* active_device = GetDeviceFromId(active_output_node_id_);
  if (!active_device || !device)
    return false;
  *device = *active_device;
  return true;
}

bool CrasAudioHandler::has_alternative_input() const {
  return has_alternative_input_;
}

bool CrasAudioHandler::has_alternative_output() const {
  return has_alternative_output_;
}

void CrasAudioHandler::SetOutputVolumePercent(int volume_percent) {
  volume_percent = min(max(volume_percent, 0), 100);
  if (volume_percent <= kMuteThresholdPercent)
    volume_percent = 0;
  output_volume_ = volume_percent;

  if (const AudioDevice* device = GetDeviceFromId(active_output_node_id_))
    audio_pref_handler_->SetVolumeGainValue(*device, output_volume_);

  SetOutputNodeVolume(active_output_node_id_, output_volume_);
  FOR_EACH_OBSERVER(AudioObserver, observers_, OnOutputVolumeChanged());
}

// TODO: Rename the 'Percent' to something more meaningful.
void CrasAudioHandler::SetInputGainPercent(int gain_percent) {
  // NOTE: We do not sanitize input gain values since the range is completely
  // dependent on the device.
  input_gain_ = gain_percent;

  if (const AudioDevice* device = GetDeviceFromId(active_input_node_id_))
    audio_pref_handler_->SetVolumeGainValue(*device, input_gain_);

  SetInputNodeGain(active_input_node_id_, input_gain_);
  FOR_EACH_OBSERVER(AudioObserver, observers_, OnInputGainChanged());
}

void CrasAudioHandler::AdjustOutputVolumeByPercent(int adjust_by_percent) {
  SetOutputVolumePercent(output_volume_ + adjust_by_percent);
}

void CrasAudioHandler::SetOutputMute(bool mute_on) {
  if (!SetOutputMuteInternal(mute_on))
    return;

  if (const AudioDevice* device = GetDeviceFromId(active_output_node_id_))
    audio_pref_handler_->SetMuteValue(*device, output_mute_on_);

  FOR_EACH_OBSERVER(AudioObserver, observers_, OnOutputMuteChanged());
}

void CrasAudioHandler::AdjustOutputVolumeToAudibleLevel() {
  if (output_volume_ <= kMuteThresholdPercent) {
    // Avoid the situation when sound has been unmuted, but the volume
    // is set to a very low value, so user still can't hear any sound.
    SetOutputVolumePercent(kDefaultUnmuteVolumePercent);
  }
}

void CrasAudioHandler::SetInputMute(bool mute_on) {
  if (!SetInputMuteInternal(mute_on))
    return;

  AudioDevice device;
  if (const AudioDevice* device = GetDeviceFromId(active_input_node_id_))
    audio_pref_handler_->SetMuteValue(*device, input_mute_on_);


  FOR_EACH_OBSERVER(AudioObserver, observers_, OnInputMuteChanged());
}

void CrasAudioHandler::SetActiveOutputNode(uint64 node_id) {
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetActiveOutputNode(node_id);
  FOR_EACH_OBSERVER(AudioObserver, observers_, OnActiveOutputNodeChanged());
}

void CrasAudioHandler::SetActiveInputNode(uint64 node_id) {
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetActiveInputNode(node_id);
  FOR_EACH_OBSERVER(AudioObserver, observers_, OnActiveInputNodeChanged());
}

void CrasAudioHandler::SetVolumeGainPercentForDevice(uint64 device_id,
                                                     int value) {
  if (device_id == active_output_node_id_) {
    SetOutputVolumePercent(value);
    return;
  } else if (device_id == active_input_node_id_) {
    SetInputGainPercent(value);
    return;
  }

  if (const AudioDevice* device = GetDeviceFromId(device_id)) {
    if (!device->is_input) {
      value = min(max(value, 0), 100);
      if (value <= kMuteThresholdPercent)
        value = 0;
    }
    audio_pref_handler_->SetVolumeGainValue(*device, value);
  }
}

void CrasAudioHandler::SetMuteForDevice(uint64 device_id, bool mute_on) {
  if (device_id == active_output_node_id_) {
    SetOutputMute(mute_on);
    return;
  } else if (device_id == active_input_node_id_) {
    SetInputMute(mute_on);
    return;
  }

  AudioDevice device;
  if (const AudioDevice* device = GetDeviceFromId(device_id))
    audio_pref_handler_->SetMuteValue(*device, mute_on);
}

void CrasAudioHandler::LogErrors() {
  log_errors_ = true;
}

CrasAudioHandler::CrasAudioHandler(
    scoped_refptr<AudioDevicesPrefHandler> audio_pref_handler)
    : audio_pref_handler_(audio_pref_handler),
      weak_ptr_factory_(this),
      output_mute_on_(false),
      input_mute_on_(false),
      output_volume_(0),
      input_gain_(0),
      active_output_node_id_(0),
      active_input_node_id_(0),
      has_alternative_input_(false),
      has_alternative_output_(false),
      output_mute_locked_(false),
      input_mute_locked_(false),
      log_errors_(false) {
  if (!audio_pref_handler.get())
    return;
  // If the DBusThreadManager or the CrasAudioClient aren't available, there
  // isn't much we can do. This should only happen when running tests.
  if (!chromeos::DBusThreadManager::IsInitialized() ||
      !chromeos::DBusThreadManager::Get() ||
      !chromeos::DBusThreadManager::Get()->GetCrasAudioClient())
    return;
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->AddObserver(this);
  audio_pref_handler_->AddAudioPrefObserver(this);
  if (chromeos::DBusThreadManager::Get()->GetSessionManagerClient()) {
    chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
        AddObserver(this);
  }
  InitializeAudioState();
}

CrasAudioHandler::~CrasAudioHandler() {
  if (!chromeos::DBusThreadManager::IsInitialized() ||
      !chromeos::DBusThreadManager::Get() ||
      !chromeos::DBusThreadManager::Get()->GetCrasAudioClient())
    return;
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      RemoveObserver(this);
  chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
      RemoveObserver(this);
  if (audio_pref_handler_.get())
    audio_pref_handler_->RemoveAudioPrefObserver(this);
  audio_pref_handler_ = NULL;
}

void CrasAudioHandler::AudioClientRestarted() {
  // Make sure the logging is enabled in case cras server
  // restarts after crashing.
  LogErrors();
  InitializeAudioState();
}

void CrasAudioHandler::NodesChanged() {
  // Refresh audio nodes data.
  GetNodes();
}

void CrasAudioHandler::ActiveOutputNodeChanged(uint64 node_id) {
  if (active_output_node_id_ == node_id)
    return;

  // Active audio output device should always be changed by chrome.
  // During system boot, cras may change active input to unknown device 0x1,
  // we don't need to log it, since it is not an valid device.
  if (GetDeviceFromId(node_id)) {
    LOG_IF(WARNING, log_errors_)
        << "Active output node changed unexpectedly by system node_id="
        << "0x" << std::hex << node_id;
  }
}

void CrasAudioHandler::ActiveInputNodeChanged(uint64 node_id) {
  if (active_input_node_id_ == node_id)
    return;

  // Active audio input device should always be changed by chrome.
  // During system boot, cras may change active input to unknown device 0x2,
  // we don't need to log it, since it is not an valid device.
  if (GetDeviceFromId(node_id)) {
    LOG_IF(WARNING, log_errors_)
        << "Active input node changed unexpectedly by system node_id="
        << "0x" << std::hex << node_id;
  }
}

void CrasAudioHandler::OnAudioPolicyPrefChanged() {
  ApplyAudioPolicy();
}

void CrasAudioHandler::EmitLoginPromptVisibleCalled() {
  // Enable logging after cras server is started, which will be after
  // EmitLoginPromptVisible.
  LogErrors();
}

const AudioDevice* CrasAudioHandler::GetDeviceFromId(uint64 device_id) const {
  AudioDeviceMap::const_iterator it = audio_devices_.find(device_id);
  if (it == audio_devices_.end())
    return NULL;

  return &(it->second);
}

void CrasAudioHandler::SetupAudioInputState() {
  // Set the initial audio state to the ones read from audio prefs.
  const AudioDevice* device = GetDeviceFromId(active_input_node_id_);
  if (!device) {
    LOG_IF(ERROR, log_errors_)
        << "Can't set up audio state for unknown input device id ="
        << "0x" << std::hex << active_input_node_id_;
    return;
  }
  input_mute_on_ = audio_pref_handler_->GetMuteValue(*device);
  input_gain_ = audio_pref_handler_->GetInputGainValue(device);
  SetInputMuteInternal(input_mute_on_);
  // TODO(rkc,jennyz): Set input gain once we decide on how to store
  // the gain values since the range and step are both device specific.
}

void CrasAudioHandler::SetupAudioOutputState() {
  const AudioDevice* device = GetDeviceFromId(active_output_node_id_);
  if (!device) {
    LOG_IF(ERROR, log_errors_)
        << "Can't set up audio state for unknown output device id ="
        << "0x" << std::hex << active_output_node_id_;
    return;
  }
  output_mute_on_ = audio_pref_handler_->GetMuteValue(*device);
  output_volume_ = audio_pref_handler_->GetOutputVolumeValue(device);

  SetOutputMuteInternal(output_mute_on_);
  SetOutputNodeVolume(active_output_node_id_, output_volume_);
}

void CrasAudioHandler::InitializeAudioState() {
  ApplyAudioPolicy();
  GetNodes();
}

void CrasAudioHandler::ApplyAudioPolicy() {
  output_mute_locked_ = false;
  if (!audio_pref_handler_->GetAudioOutputAllowedValue()) {
    // Mute the device, but do not update the preference.
    SetOutputMuteInternal(true);
    output_mute_locked_ = true;
  } else {
    // Restore the mute state.
    const AudioDevice* device = GetDeviceFromId(active_output_node_id_);
    if (device)
      SetOutputMuteInternal(audio_pref_handler_->GetMuteValue(*device));
  }

  input_mute_locked_ = false;
  if (audio_pref_handler_->GetAudioCaptureAllowedValue()) {
    // Set input mute if we have discovered active input device.
    const AudioDevice* device = GetDeviceFromId(active_input_node_id_);
    if (device)
      SetInputMuteInternal(false);
  } else {
    SetInputMute(true);
    input_mute_locked_ = true;
  }
}

void CrasAudioHandler::SetOutputNodeVolume(uint64 node_id, int volume) {
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetOutputNodeVolume(node_id, volume);
}

bool  CrasAudioHandler::SetOutputMuteInternal(bool mute_on) {
  if (output_mute_locked_)
    return false;

  output_mute_on_ = mute_on;
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetOutputUserMute(mute_on);
  return true;
}

void CrasAudioHandler::SetInputNodeGain(uint64 node_id, int gain) {
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetInputNodeGain(node_id, gain);
}

bool CrasAudioHandler::SetInputMuteInternal(bool mute_on) {
  if (input_mute_locked_)
    return false;

  input_mute_on_ = mute_on;
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->
      SetInputMute(mute_on);
  return true;
}

void CrasAudioHandler::GetNodes() {
  chromeos::DBusThreadManager::Get()->GetCrasAudioClient()->GetNodes(
      base::Bind(&CrasAudioHandler::HandleGetNodes,
                 weak_ptr_factory_.GetWeakPtr()),
      base::Bind(&CrasAudioHandler::HandleGetNodesError,
                 weak_ptr_factory_.GetWeakPtr()));
}

bool CrasAudioHandler::ChangeActiveDevice(const AudioDevice& new_active_device,
                                          uint64* current_active_node_id) {
  // If the device we want to switch to is already the current active device,
  // do nothing.
  if (new_active_device.active &&
      new_active_device.id == *current_active_node_id) {
    return false;
  }

  // Reset all other input or output devices' active status. The active audio
  // device from the previous user session can be remembered by cras, but not
  // in chrome. see crbug.com/273271.
  for (AudioDeviceMap::iterator it = audio_devices_.begin();
       it != audio_devices_.end(); ++it) {
    if (it->second.is_input == new_active_device.is_input &&
        it->second.id != new_active_device.id)
      it->second.active = false;
  }

  // Set the current active input/output device to the new_active_device.
  *current_active_node_id = new_active_device.id;
  audio_devices_[*current_active_node_id].active = true;
  return true;
}

bool CrasAudioHandler::NonActiveDeviceUnplugged(
    size_t old_devices_size,
    size_t new_devices_size,
    uint64 current_active_node) {
  return (new_devices_size < old_devices_size &&
          GetDeviceFromId(current_active_node));
}

void CrasAudioHandler::SwitchToDevice(const AudioDevice& device) {
  if (device.is_input) {
    if (!ChangeActiveDevice(device, &active_input_node_id_))
      return;
    SetupAudioInputState();
    SetActiveInputNode(active_input_node_id_);
  } else {
    if (!ChangeActiveDevice(device, &active_output_node_id_))
      return;
    SetupAudioOutputState();
    SetActiveOutputNode(active_output_node_id_);
  }
}

bool CrasAudioHandler::HasDeviceChange(const AudioNodeList& new_nodes,
                                       bool is_input) {
  size_t num_old_devices = 0;
  size_t num_new_devices = 0;
  for (AudioDeviceMap::const_iterator it = audio_devices_.begin();
       it != audio_devices_.end(); ++it) {
    if (is_input == it->second.is_input)
      ++num_old_devices;
  }

  for (AudioNodeList::const_iterator it = new_nodes.begin();
       it != new_nodes.end(); ++it) {
    if (is_input == it->is_input) {
      ++num_new_devices;
      // Look to see if the new device not in the old device list.
      AudioDevice device(*it);
      if (FoundNewDevice(device))
        return true;
    }
  }
  return num_old_devices != num_new_devices;
}

bool CrasAudioHandler::FoundNewDevice(const AudioDevice& device) {
  const AudioDevice* device_found = GetDeviceFromId(device.id);
  if (!device_found)
    return true;

  if (!IsSameAudioDevice(device, *device_found)) {
    LOG(WARNING) << "Different Audio devices with same id:"
        << " new device: " << device.ToString()
        << " old device: " << device_found->ToString();
    return true;
  }
  return false;
}

// Sanitize the audio node data. When a device is plugged in or unplugged, there
// should be only one NodesChanged signal from cras. However, we've observed
// the case that multiple NodesChanged signals being sent from cras. After the
// first NodesChanged being processed, chrome sets the active node properly.
// However, the NodesChanged received after the first one, can return stale
// nodes data in GetNodes call, the staled nodes data does not reflect the
// latest active node state. Since active audio node should only be set by
// chrome, the inconsistent data from cras could be the result of stale data
// described above and sanitized.
AudioDevice CrasAudioHandler::GetSanitizedAudioDevice(const AudioNode& node) {
  AudioDevice device(node);
  if (device.is_input) {
    if (device.active && device.id != active_input_node_id_) {
      LOG(WARNING) << "Stale audio device data, should not be active: "
          << " device = " << device.ToString()
          << " current active input node id = 0x" << std::hex
          << active_input_node_id_;
      device.active = false;
    } else if (device.id == active_input_node_id_ && !device.active) {
      LOG(WARNING) << "Stale audio device data, should be active:"
          << " device = " << device.ToString()
          << " current active input node id = 0x" << std::hex
          << active_input_node_id_;
      device.active = true;
    }
  } else {
    if (device.active && device.id != active_output_node_id_) {
      LOG(WARNING) << "Stale audio device data, should not be active: "
          << " device = " << device.ToString()
          << " current active output node id = 0x" << std::hex
          << active_output_node_id_;
      device.active = false;
    } else if (device.id == active_output_node_id_ && !device.active) {
      LOG(WARNING) << "Stale audio device data, should be active:"
          << " device = " << device.ToString()
          << " current active output node id = 0x" << std::hex
          << active_output_node_id_;
      device.active = true;
    }
  }
  return device;
}

void CrasAudioHandler::UpdateDevicesAndSwitchActive(
    const AudioNodeList& nodes) {
  size_t old_audio_devices_size = audio_devices_.size();
  bool output_devices_changed = HasDeviceChange(nodes, false);
  bool input_devices_changed = HasDeviceChange(nodes, true);
  audio_devices_.clear();
  has_alternative_input_ = false;
  has_alternative_output_ = false;

  while (!input_devices_pq_.empty())
    input_devices_pq_.pop();
  while (!output_devices_pq_.empty())
    output_devices_pq_.pop();

  for (size_t i = 0; i < nodes.size(); ++i) {
    AudioDevice device = GetSanitizedAudioDevice(nodes[i]);
    audio_devices_[device.id] = device;

    if (!has_alternative_input_ &&
        device.is_input &&
        device.type != AUDIO_TYPE_INTERNAL_MIC) {
      has_alternative_input_ = true;
    } else if (!has_alternative_output_ &&
               !device.is_input &&
               device.type != AUDIO_TYPE_INTERNAL_SPEAKER) {
      has_alternative_output_ = true;
    }

    if (device.is_input)
      input_devices_pq_.push(device);
    else
      output_devices_pq_.push(device);
  }

  // If audio nodes change is caused by unplugging some non-active audio
  // devices, the previously set active audio device will stay active.
  // Otherwise, switch to a new active audio device according to their priority.
  if (input_devices_changed &&
      !NonActiveDeviceUnplugged(old_audio_devices_size,
                                audio_devices_.size(),
                                active_input_node_id_) &&
      !input_devices_pq_.empty())
    SwitchToDevice(input_devices_pq_.top());
  if (output_devices_changed &&
      !NonActiveDeviceUnplugged(old_audio_devices_size,
                                audio_devices_.size(),
                                active_output_node_id_) &&
      !output_devices_pq_.empty()) {
    SwitchToDevice(output_devices_pq_.top());
  }
}

void CrasAudioHandler::HandleGetNodes(const chromeos::AudioNodeList& node_list,
                                      bool success) {
  if (!success) {
    LOG_IF(ERROR, log_errors_) << "Failed to retrieve audio nodes data";
    return;
  }

  UpdateDevicesAndSwitchActive(node_list);
  FOR_EACH_OBSERVER(AudioObserver, observers_, OnAudioNodesChanged());
}

void CrasAudioHandler::HandleGetNodesError(const std::string& error_name,
                                           const std::string& error_msg) {
  LOG_IF(ERROR, log_errors_) << "Failed to call GetNodes: "
      << error_name  << ": " << error_msg;
}
}  // namespace chromeos
/* [<][>][^][v][top][bottom][index][help] */
root/chromeos/audio/cras_audio_handler.cc

DEFINITIONS
