Commit ac8e284b authored by Karl Tomlinson's avatar Karl Tomlinson
Browse files

Bug 1719578 narrow Mutex acquisition in EnumerateAudioDevices() r=padenot 

This removes the possibility of overlooking the MutexAutoUnlock.

Differential Revision: https://phabricator.services.mozilla.com/D134810
parent 7651ddff

dom/media/webrtc/CubebDeviceEnumerator.cpp

+25 −29
Original line number Diff line number Diff line
@@ -219,17 +219,16 @@ static RefPtr<AudioDeviceSet> GetDeviceCollection(Side aSide) { 
RefPtr<const AudioDeviceSet> CubebDeviceEnumerator::EnumerateAudioDevices(

    CubebDeviceEnumerator::Side aSide) {

  MOZ_ASSERT(aSide == Side::INPUT || aSide == Side::OUTPUT);

  MutexAutoLock lock(mMutex);



  RefPtr<AudioDeviceSet> devices;

  RefPtr<const AudioDeviceSet>* devicesCache;

  bool manualInvalidation = true;



  if (aSide == Side::INPUT) {

    devices = std::move(mInputDevices);

    devicesCache = &mInputDevices;

    manualInvalidation = mManualInputInvalidation;

  } else {

    MOZ_ASSERT(aSide == Side::OUTPUT);

    devices = std::move(mOutputDevices);

    devicesCache = &mOutputDevices;

    manualInvalidation = mManualOutputInvalidation;

  }
@@ -237,6 +236,12 @@ RefPtr<const AudioDeviceSet> CubebDeviceEnumerator::EnumerateAudioDevices( 
  if (!context) {

    return new AudioDeviceSet();

  }

  if (!manualInvalidation) {

    MutexAutoLock lock(mMutex);

    if (*devicesCache) {

      return *devicesCache;

    }

  }



#ifdef ANDROID

  cubeb_device_type type = CUBEB_DEVICE_TYPE_UNKNOWN;
@@ -252,13 +257,10 @@ RefPtr<const AudioDeviceSet> CubebDeviceEnumerator::EnumerateAudioDevices( 
    channels = 2;

    name = u"Default audio output device"_ns;

  }



  if (!devices || manualInvalidation) {

    devices = new AudioDeviceSet();

  RefPtr devices = new AudioDeviceSet();

  // Bug 1473346: enumerating devices is not supported on Android in cubeb,

  // simply state that there is a single sink, that it is the default, and has

    // a single channel. All the other values are made up and are not to be

    // used.

  // a single channel. All the other values are made up and are not to be used.

  // Bug 1660391: we can't use fluent here yet to get localized strings, so

  // those are hard-coded en_US strings for now.

  RefPtr<AudioDeviceInfo> info = new AudioDeviceInfo(
@@ -266,19 +268,13 @@ RefPtr<const AudioDeviceSet> CubebDeviceEnumerator::EnumerateAudioDevices( 
      CUBEB_DEVICE_PREF_ALL, CUBEB_DEVICE_FMT_ALL, CUBEB_DEVICE_FMT_S16NE,

      channels, 44100, 44100, 44100, 441, 128);

  devices->AppendElement(std::move(info));

  }

#else

  if (!devices || manualInvalidation) {

    MutexAutoUnlock unlock(mMutex);

    devices = GetDeviceCollection((aSide == Side::INPUT) ? CubebUtils::Input

                                                         : CubebUtils::Output);

  }

  RefPtr devices = GetDeviceCollection(

      (aSide == Side::INPUT) ? CubebUtils::Input : CubebUtils::Output);

#endif



  if (aSide == Side::INPUT) {

    mInputDevices = devices;

  } else {

    mOutputDevices = devices;

  {

    MutexAutoLock lock(mMutex);

    *devicesCache = devices;

  }

  return devices;

}

dom/media/webrtc/CubebDeviceEnumerator.h

+2 −2
Original line number Diff line number Diff line
@@ -70,8 +70,8 @@ class CubebDeviceEnumerator final { 
  RefPtr<const AudioDeviceSet> EnumerateAudioDevices(Side aSide);

  // Synchronize access to mInputDevices and mOutputDevices;

  Mutex mMutex;

  RefPtr<AudioDeviceSet> mInputDevices;

  RefPtr<AudioDeviceSet> mOutputDevices;

  RefPtr<const AudioDeviceSet> mInputDevices;

  RefPtr<const AudioDeviceSet> 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.