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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#include "AudioDeviceInfo.h"
#include "CubebUtils.h"
#include "cubeb/cubeb.h"
#include "MediaEventSource.h"
#include "mozilla/Mutex.h"
#include "nsTArray.h"
namespace mozilla {
// This class implements a cache for accessing the audio device list.
// It can be accessed on any thread.
class CubebDeviceEnumerator final {
static CubebDeviceEnumerator* GetInstance();
static void Shutdown();
// This method returns a list of all the input audio devices
// (sources) available on this machine.
// This method is safe to call from all threads.
void EnumerateAudioInputDevices(
nsTArray<RefPtr<AudioDeviceInfo>>& aOutDevices);
// Similar for the audio audio devices (sinks). Also thread safe.
void EnumerateAudioOutputDevices(
nsTArray<RefPtr<AudioDeviceInfo>>& aOutDevices);
// From a cubeb device id, return the info for this device, if it's still a
// valid id, or nullptr otherwise.
// This method is safe to call from any thread.
already_AddRefed<AudioDeviceInfo> DeviceInfoFromID(
CubebUtils::AudioDeviceID aID);
// From a device name, return the info for this device, if it's a valid name,
// or nullptr otherwise.
// This method is safe to call from any thread.
already_AddRefed<AudioDeviceInfo> DeviceInfoFromName(const nsString& aName);
enum class Side {
already_AddRefed<AudioDeviceInfo> DeviceInfoFromName(const nsString& aName,
Side aSide);
// Event source to listen for changes to the audio input device list on.
MediaEventSource<void>& OnAudioInputDeviceListChange() {
return mOnInputDeviceListChange;
// Event source to listen for changes to the audio output device list on.
MediaEventSource<void>& OnAudioOutputDeviceListChange() {
return mOnOutputDeviceListChange;
// Return the default device for a particular side.
RefPtr<AudioDeviceInfo> DefaultDevice(Side aSide);
// Static functions called by cubeb when the audio device list changes
// (i.e. when a new device is made available, or non-available). This
// simply calls `AudioDeviceListChanged` below.
static void InputAudioDeviceListChanged_s(cubeb* aContext, void* aUser);
static void OutputAudioDeviceListChanged_s(cubeb* aContext, void* aUser);
// Invalidates the cached audio input device list, can be called on any
// thread.
void AudioDeviceListChanged(Side aSide);
void EnumerateAudioDevices(Side aSide);
// Synchronize access to mInputDevices and mOutputDevices;
Mutex mMutex;
nsTArray<RefPtr<AudioDeviceInfo>> mInputDevices;
nsTArray<RefPtr<AudioDeviceInfo>> mOutputDevices;
// If mManual*Invalidation is true, then it is necessary to query the device
// list each time instead of relying on automatic invalidation of the cache by
// cubeb itself. Set in the constructor and then can be access on any thread.
bool mManualInputInvalidation;
bool mManualOutputInvalidation;
MediaEventProducer<void> mOnInputDeviceListChange;
MediaEventProducer<void> mOnOutputDeviceListChange;
typedef CubebDeviceEnumerator Enumerator;
typedef CubebDeviceEnumerator::Side EnumeratorSide;
} // namespace mozilla