[vlc-devel] [PATCH] vout/macosx: simplify close and make sure all AppKit objects are released on the main thread

[Felix Paul Kühne]

Hi David,

> On 17. Sep 2019, at 23:10, David Fuhrmann <david.fuhrmann at gmail.com> wrote:
> 
> 
>> Am 17.09.2019 um 22:12 schrieb Felix Paul Kühne <fkuehne at videolan.org>:
>> 
>> From: Felix Paul Kühne <felix at feepk.net>
>> 
>> Note that this does _not_ solve #22766.
>> ---
>> modules/video_output/macosx.m | 29 +++++++++++++----------------
>> 1 file changed, 13 insertions(+), 16 deletions(-)
>> 
>> diff --git a/modules/video_output/macosx.m b/modules/video_output/macosx.m
>> index 6290bbf763..5f618a0716 100644
>> --- a/modules/video_output/macosx.m
>> +++ b/modules/video_output/macosx.m
>> @@ -265,21 +265,20 @@ static void Close(vout_display_t *vd)
>>        [sys->glView setVoutDisplay:nil];
>> 
>>        var_Destroy (vd, "drawable-nsobject");
>> -        if ([(id)sys->container respondsToSelector:@selector(removeVoutSubview:)])
>> -        /* This will retain sys->glView */
>> -            [(id)sys->container performSelectorOnMainThread:@selector(removeVoutSubview:)
>> -                                                 withObject:sys->glView
>> -                                              waitUntilDone:NO];
>> -
>> -        /* release on main thread as explained in Open() */
>> -        [(id)sys->container performSelectorOnMainThread:@selector(release)
>> -                                             withObject:nil
>> -                                          waitUntilDone:NO];
>> -        [sys->glView performSelectorOnMainThread:@selector(removeFromSuperview)
>> -                                      withObject:nil
>> -                                   waitUntilDone:NO];
>> -
>>        var_Destroy(vlc_object_parent(vd), "macosx-glcontext");
>> +
>> +        dispatch_sync(dispatch_get_main_queue(), ^{
> 
> As briefly discussed over chat, my fear is that this switch from async to sync deadlocks once closing VLC with a running video.
> 
> In fact, I can easily reproduce this with your patch applied, just try to quit VLC while a video is running:

I don’t oppose using async here. The main issue I want to resolve is that [sys->glView release]; is currently called from a background thread while this AppKit object is created on the main thread, so the release should happen on the main thread, too.

Best regards,

Felix