Commit f4a986cc authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

mmdevice: simplify thread synchronization

parent a3926236
......@@ -82,18 +82,21 @@ struct aout_sys_t
struct IAudioSessionEvents session_events;
LONG refs;
CRITICAL_SECTION lock; /**< Lock to protect Core Audio API state */
HANDLE device_changed; /**< Event to reset thread */
HANDLE device_ready; /**< Event when thread is reset */
vlc_thread_t thread; /**< Thread for audio session control */
};
/* NOTE: The Core Audio API documentation totally fails to specify the thread
* safety (or lack thereof) of the interfaces. This code is most pessimistic
* and assumes that the API is not thread-safe at all.
* safety (or lack thereof) of the interfaces. This code takes the most
* restrictive assumption, no thread safety: The background thread (MMThread)
* only runs at specified times, namely between the device_ready and
* device_changed events (effectively, a thread barrier but only Windows 8
* provides thread barriers natively).
*
* The audio output owner (i.e. the audio output core) is responsible for
* serializing callbacks. This code only needs to be concerned with
* synchronization between the set of audio output callbacks, the thread
* synchronization between the set of audio output callbacks, MMThread()
* and (trivially) the device and session notifications. */
static int vlc_FromHR(audio_output_t *aout, HRESULT hr)
......@@ -111,9 +114,7 @@ static int TimeGet(audio_output_t *aout, mtime_t *restrict delay)
HRESULT hr;
EnterMTA();
EnterCriticalSection(&sys->lock);
hr = aout_stream_TimeGet(sys->stream, delay);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
return SUCCEEDED(hr) ? 0 : -1;
......@@ -125,9 +126,7 @@ static void Play(audio_output_t *aout, block_t *block)
HRESULT hr;
EnterMTA();
EnterCriticalSection(&sys->lock);
hr = aout_stream_Play(sys->stream, block);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
vlc_FromHR(aout, hr);
......@@ -139,9 +138,7 @@ static void Pause(audio_output_t *aout, bool paused, mtime_t date)
HRESULT hr;
EnterMTA();
EnterCriticalSection(&sys->lock);
hr = aout_stream_Pause(sys->stream, paused);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
vlc_FromHR(aout, hr);
......@@ -151,24 +148,21 @@ static void Pause(audio_output_t *aout, bool paused, mtime_t date)
static void Flush(audio_output_t *aout, bool wait)
{
aout_sys_t *sys = aout->sys;
mtime_t delay = VLC_TS_INVALID;
EnterMTA();
EnterCriticalSection(&sys->lock);
if (wait)
{ /* Loosy drain emulation */
if (FAILED(aout_stream_TimeGet(sys->stream, &delay)))
delay = VLC_TS_INVALID;
mtime_t delay;
if (SUCCEEDED(aout_stream_TimeGet(sys->stream, &delay)))
Sleep((delay / (CLOCK_FREQ / 1000)) + 1);
}
else
aout_stream_Flush(sys->stream);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
if (delay != VLC_TS_INVALID)
Sleep((delay / (CLOCK_FREQ / 1000)) + 1);
}
static ISimpleAudioVolume *GetSimpleVolume(audio_output_t *aout)
......@@ -182,26 +176,21 @@ static ISimpleAudioVolume *GetSimpleVolume(audio_output_t *aout)
if (TryEnterMTA(aout))
return NULL;
EnterCriticalSection(&sys->lock);
hr = IAudioSessionManager_GetSimpleAudioVolume(sys->manager,
&GUID_VLC_AUD_OUT,
FALSE, &volume);
if (FAILED(hr))
{
LeaveCriticalSection(&sys->lock);
LeaveMTA();
msg_Err(aout, "cannot get simple volume (error 0x%lx)", hr);
return NULL;
assert(volume == NULL);
}
return volume;
}
static void PutSimpleVolume(audio_output_t *aout, ISimpleAudioVolume *volume)
static void PutSimpleVolume(ISimpleAudioVolume *volume)
{
aout_sys_t *sys = aout->sys;
ISimpleAudioVolume_Release(volume);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
}
......@@ -214,7 +203,7 @@ static int VolumeSet(audio_output_t *aout, float vol)
HRESULT hr = ISimpleAudioVolume_SetMasterVolume(volume, vol, NULL);
if (FAILED(hr))
msg_Err(aout, "cannot set volume (error 0x%lx)", hr);
PutSimpleVolume(aout, volume);
PutSimpleVolume(volume);
return FAILED(hr) ? -1 : 0;
}
......@@ -228,7 +217,7 @@ static int MuteSet(audio_output_t *aout, bool mute)
HRESULT hr = ISimpleAudioVolume_SetMute(volume, mute ? TRUE : FALSE, NULL);
if (FAILED(hr))
msg_Err(aout, "cannot set volume (error 0x%lx)", hr);
PutSimpleVolume(aout, volume);
PutSimpleVolume(volume);
return FAILED(hr) ? -1 : 0;
}
......@@ -483,7 +472,6 @@ static void MMSession(audio_output_t *aout, aout_sys_t *sys)
HRESULT hr;
/* Register session control */
msg_Err(aout, "HERE: %p", sys->manager);
if (sys->manager != NULL)
{
hr = IAudioSessionManager_GetAudioSessionControl(sys->manager,
......@@ -495,7 +483,6 @@ static void MMSession(audio_output_t *aout, aout_sys_t *sys)
else
control = NULL;
msg_Err(aout, "THERE");
if (control != NULL)
{
wchar_t *ua = var_InheritWide(aout, "user-agent");
......@@ -506,9 +493,8 @@ static void MMSession(audio_output_t *aout, aout_sys_t *sys)
&sys->session_events);
}
LeaveCriticalSection(&sys->lock);
SetEvent(sys->device_ready);
WaitForSingleObject(sys->device_changed, INFINITE);
EnterCriticalSection(&sys->lock);
/* Deregister session control */
if (control != NULL)
......@@ -534,10 +520,8 @@ static void *MMThread(void *data)
aout_sys_t *sys = aout->sys;
EnterMTA();
EnterCriticalSection(&sys->lock);
while (sys->it != NULL)
MMSession(aout, sys);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
return NULL;
}
......@@ -550,7 +534,8 @@ static HRESULT OpenDevice(audio_output_t *aout, const char *devid)
aout_sys_t *sys = aout->sys;
HRESULT hr;
EnterCriticalSection(&sys->lock);
assert(sys->dev == NULL);
if (devid != NULL) /* Device selected explicitly */
{
msg_Dbg(aout, "using selected device %s", devid);
......@@ -584,9 +569,9 @@ static HRESULT OpenDevice(audio_output_t *aout, const char *devid)
else
sys->manager = pv;
}
LeaveCriticalSection(&sys->lock);
SetEvent(sys->device_changed);
WaitForSingleObject(sys->device_ready, INFINITE);
return hr;
}
......@@ -599,7 +584,6 @@ static void CloseDevice(audio_output_t *aout)
assert(sys->dev != NULL);
EnterCriticalSection(&sys->lock);
if (sys->manager != NULL)
{
IAudioSessionManager_Release(sys->manager);
......@@ -608,7 +592,6 @@ static void CloseDevice(audio_output_t *aout)
IMMDevice_Release(sys->dev);
sys->dev = NULL;
LeaveCriticalSection(&sys->lock);
}
static int Start(audio_output_t *aout, audio_sample_format_t *restrict fmt)
......@@ -620,9 +603,7 @@ static int Start(audio_output_t *aout, audio_sample_format_t *restrict fmt)
return -1;
EnterMTA();
EnterCriticalSection(&sys->lock);
sys->stream = aout_stream_Start(aout, fmt, sys->dev, &GUID_VLC_AUD_OUT);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
return (sys->stream != NULL) ? 0 : -1;
......@@ -635,9 +616,7 @@ static void Stop(audio_output_t *aout)
assert (sys->stream != NULL);
EnterMTA();
EnterCriticalSection(&sys->lock);
aout_stream_Stop(sys->stream);
LeaveCriticalSection(&sys->lock);
LeaveMTA();
sys->stream = NULL;
......@@ -661,12 +640,14 @@ static int Open(vlc_object_t *obj)
sys->aout = aout;
sys->stream = NULL;
sys->it = NULL;
sys->dev = NULL;
sys->manager = NULL;
sys->session_events.lpVtbl = &vlc_AudioSessionEvents;
sys->refs = 1;
InitializeCriticalSection(&sys->lock);
sys->device_changed = CreateEvent(NULL, FALSE, FALSE, NULL);
if (unlikely(sys->device_changed == NULL))
sys->device_ready = CreateEvent(NULL, FALSE, FALSE, NULL);
if (unlikely(sys->device_changed == NULL || sys->device_ready == NULL))
goto error;
/* Initialize MMDevice API */
......@@ -686,6 +667,7 @@ static int Open(vlc_object_t *obj)
if (vlc_clone(&sys->thread, MMThread, aout, VLC_THREAD_PRIORITY_LOW))
goto error;
WaitForSingleObject(sys->device_ready, INFINITE);
/* Get a device to start with */
do
......@@ -710,9 +692,10 @@ error:
IMMDeviceEnumerator_Release(sys->it);
LeaveMTA();
}
if (sys->device_ready != NULL)
CloseHandle(sys->device_ready);
if (sys->device_changed != NULL)
CloseHandle(sys->device_changed);
DeleteCriticalSection(&sys->lock);
free(sys);
return VLC_EGENERIC;
}
......@@ -726,20 +709,18 @@ static void Close(vlc_object_t *obj)
var_Destroy (aout, "audio-device");
EnterMTA(); /* enter MTA before thread leaves MTA */
EnterCriticalSection(&sys->lock);
if (sys->dev != NULL)
CloseDevice(aout);
IMMDeviceEnumerator_Release(sys->it);
sys->it = NULL;
LeaveCriticalSection(&sys->lock);
SetEvent(sys->device_changed);
vlc_join(sys->thread, NULL);
LeaveMTA();
CloseHandle(sys->device_ready);
CloseHandle(sys->device_changed);
DeleteCriticalSection(&sys->lock);
free(sys);
}
......
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