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

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

View File

@@ -49,39 +49,40 @@ FillSound(void *device, void *stream, size_t len,
SDL_AudioDevice *audio = (SDL_AudioDevice *) device;
SDL_AudioCallback callback = audio->callbackspec.callback;
SDL_LockMutex(audio->mixer_lock);
/* Only do something if audio is enabled */
if (!SDL_AtomicGet(&audio->enabled) || SDL_AtomicGet(&audio->paused)) {
if (audio->stream) {
SDL_AudioStreamClear(audio->stream);
}
SDL_memset(stream, audio->spec.silence, len);
return;
}
} else {
SDL_assert(audio->spec.size == len);
SDL_assert(audio->spec.size == len);
if (audio->stream == NULL) { /* no conversion necessary. */
callback(audio->callbackspec.userdata, (Uint8 *) stream, len);
} else { /* streaming/converting */
const int stream_len = audio->callbackspec.size;
const int ilen = (int) len;
while (SDL_AudioStreamAvailable(audio->stream) < ilen) {
callback(audio->callbackspec.userdata, audio->work_buffer, stream_len);
if (SDL_AudioStreamPut(audio->stream, audio->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(audio->stream);
SDL_AtomicSet(&audio->enabled, 0);
break;
}
}
if (audio->stream == NULL) { /* no conversion necessary. */
SDL_LockMutex(audio->mixer_lock);
callback(audio->callbackspec.userdata, (Uint8 *) stream, len);
SDL_UnlockMutex(audio->mixer_lock);
} else { /* streaming/converting */
const int stream_len = audio->callbackspec.size;
const int ilen = (int) len;
while (SDL_AudioStreamAvailable(audio->stream) < ilen) {
callback(audio->callbackspec.userdata, audio->work_buffer, stream_len);
if (SDL_AudioStreamPut(audio->stream, audio->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(audio->stream);
SDL_AtomicSet(&audio->enabled, 0);
break;
const int got = SDL_AudioStreamGet(audio->stream, stream, ilen);
SDL_assert((got < 0) || (got == ilen));
if (got != ilen) {
SDL_memset(stream, audio->spec.silence, len);
}
}
const int got = SDL_AudioStreamGet(audio->stream, stream, ilen);
SDL_assert((got < 0) || (got == ilen));
if (got != ilen) {
SDL_memset(stream, audio->spec.silence, len);
}
}
SDL_UnlockMutex(audio->mixer_lock);
}
static void