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audio: Fix locking in backends that manage their own callback threads.

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Otherwise you might get a race where an app pauses the device, but
the audio callback still manages to run after the pause is in place.
This commit is contained in:
Ryan C. Gordon
2022-05-20 21:07:25 -04:00
parent a95f5a792c
commit dc62fec5e9
6 changed files with 59 additions and 60 deletions
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47
src/audio/nacl/SDL_naclaudio.c
View File

@@ -49,8 +49,8 @@ static void nacl_audio_callback(void* stream, uint32_t buffer_size, PP_TimeDelta
const int len = (int) buffer_size;
SDL_AudioDevice* _this = (SDL_AudioDevice*) data;
SDL_AudioCallback callback = _this->callbackspec.callback;
SDL_LockMutex(private->mutex); /* !!! FIXME: is this mutex necessary? */
SDL_LockMutex(_this->mixer_lock);
/* Only do something if audio is enabled */
if (!SDL_AtomicGet(&_this->enabled) || SDL_AtomicGet(&_this->paused)) {
@@ -58,34 +58,31 @@ static void nacl_audio_callback(void* stream, uint32_t buffer_size, PP_TimeDelta
SDL_AudioStreamClear(_this->stream);
}
SDL_memset(stream, _this->spec.silence, len);
return;
}
} else {
SDL_assert(_this->spec.size == len);
SDL_assert(_this->spec.size == len);
if (_this->stream == NULL) { /* no conversion necessary. */
callback(_this->callbackspec.userdata, stream, len);
} else { /* streaming/converting */
const int stream_len = _this->callbackspec.size;
while (SDL_AudioStreamAvailable(_this->stream) < len) {
callback(_this->callbackspec.userdata, _this->work_buffer, stream_len);
if (SDL_AudioStreamPut(_this->stream, _this->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(_this->stream);
SDL_AtomicSet(&_this->enabled, 0);
break;
}
}
if (_this->stream == NULL) { /* no conversion necessary. */
SDL_LockMutex(_this->mixer_lock);
callback(_this->callbackspec.userdata, stream, len);
SDL_UnlockMutex(_this->mixer_lock);
} else { /* streaming/converting */
const int stream_len = _this->callbackspec.size;
while (SDL_AudioStreamAvailable(_this->stream) < len) {
callback(_this->callbackspec.userdata, _this->work_buffer, stream_len);
if (SDL_AudioStreamPut(_this->stream, _this->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(_this->stream);
SDL_AtomicSet(&_this->enabled, 0);
break;
const int got = SDL_AudioStreamGet(_this->stream, stream, len);
SDL_assert((got < 0) || (got == len));
if (got != len) {
SDL_memset(stream, _this->spec.silence, len);
}
}
const int got = SDL_AudioStreamGet(_this->stream, stream, len);
SDL_assert((got < 0) || (got == len));
if (got != len) {
SDL_memset(stream, _this->spec.silence, len);
}
}
SDL_UnlockMutex(private->mutex);
SDL_UnlockMutex(_this->mixer_lock);
}
static void NACLAUDIO_CloseDevice(SDL_AudioDevice *device) {
@@ -94,7 +91,6 @@ static void NACLAUDIO_CloseDevice(SDL_AudioDevice *device) {
SDL_PrivateAudioData *hidden = (SDL_PrivateAudioData *) device->hidden;
ppb_audio->StopPlayback(hidden->audio);
SDL_DestroyMutex(hidden->mutex);
core->ReleaseResource(hidden->audio);
}
@@ -109,7 +105,6 @@ NACLAUDIO_OpenDevice(_THIS, const char *devname) {
return SDL_OutOfMemory();
}
private->mutex = SDL_CreateMutex();
_this->spec.freq = 44100;
_this->spec.format = AUDIO_S16LSB;
_this->spec.channels = 2;

3
src/audio/nacl/SDL_naclaudio.h
View File

@@ -34,8 +34,7 @@
#define private _this->hidden
typedef struct SDL_PrivateAudioData {
SDL_mutex* mutex;
PP_Resource audio;
PP_Resource audio;
} SDL_PrivateAudioData;
#endif /* SDL_naclaudio_h_ */