[vlc-devel] [vlc-commits] skins2: ensure playlist gets stopped before terminating vlc.

Rémi Denis-Courmont remi at remlab.net
Tue Dec 3 21:27:33 CET 2019

Le tiistaina 3. joulukuuta 2019, 21.25.31 EET Alexandre Janniaux a écrit :
> > Sure - it can be argued that there is a hierarchy. In fact, that's how it
> > works in LibVLC apps.
> Indeed.
> > But then, that implies that the "main" interface is started before the
> > playlist, so that it can register the callback to allocate the video
> > window
> > early enough.
> Why would the implementation need that ?
> > And that means the "main" interface must be started and stopped
> > in two phases, one before and one after the playlist is respectively
> > started or stopped.
> I agree that we cannot do that, been there.

I don't think it's infeasible. It needs core and main interface plugin changes 
to separate the with and without playlist phases of initialization. In any 
case, if it were not feasible, then the hierarchical model is not feasible so 
it sounds like you are contradicting your own self here.

The video window is needed when the playlist starts. No matter how you put it, 
that means the video window provider must be registered before the playlist 
starts. The main interface can only register its video window provider if it 
has started.

Treating the main interface the same way as the secondary control interface is 
all a big lie anyway as the MacOS interface hijacks the main thread - which is 
essentially only possible for one interface out of all of them.

> > And it can also be argued that there is no hierarchy. The original window
> > embedding system relied on reparenting to move the video into and out of
> > the interface when the interface was created and destroyed (though the
> > implementation was riddled with races and highly prone to crashes).
> I don't see how reparenting widgets at the Qt level change
> anything to a hierarchy of lifetime. I don't think it is
> a releveant example even if I agree with the hacks being
> done with a stable widget to workaround xid changes.

It was of course reparenting the underlying window, not the Qt widget. The Qt 
interface did not even exist at that time. C.f. the old code.

Rémi Denis-Courmont

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