Created attachment 322446 [details] [review]
wayland: Don't unset surface->buffer when wl_buffer destroyed

Don't unset the surface->buffer if the associated wl_buffer object is
destroyed. The MetaWaylandBuffer doesn't really only represent a
wl_buffer object, but also the data (texture) created from the given
wl_buffer. Thus, for example destroying a released SHM wl_buffer should
not destroy the MetaWaylandBuffer instance, because the texture may
still be used.

This commit also fixes a race where calc_showing would hide a window
because, at the time of calculation whether it should be showing, the
surface's buffer had been destroyed as described above.

Review of attachment 322446 [details] [review]:

Looks good, just a couple minor comments below

::: src/wayland/meta-wayland-buffer.c
@@ +181,3 @@
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = meta_wayland_buffer_dispose;

nit: could be finalize instead of dispose

::: src/wayland/meta-wayland-surface.c
@@ +438,2 @@
   state->buffer = NULL;
+  wl_list_remove (&state->buffer_destroy_listener.link);

This isn't strictly necessary, right ? It's the right thing to do, and should have been here already, but unrelated to the rest of the patch. Perhaps do it a separate commit ?

(In reply to Rui Matos from comment #2)
> Review of attachment 322446 [details] [review] [review]:
> 
> Looks good, just a couple minor comments below
> 
> ::: src/wayland/meta-wayland-buffer.c
> @@ +181,3 @@
> +  GObjectClass *object_class = G_OBJECT_CLASS (klass);
> +
> +  object_class->dispose = meta_wayland_buffer_dispose;
> 
> nit: could be finalize instead of dispose

Sure.

> 
> ::: src/wayland/meta-wayland-surface.c
> @@ +438,2 @@
>    state->buffer = NULL;
> +  wl_list_remove (&state->buffer_destroy_listener.link);
> 
> This isn't strictly necessary, right ? It's the right thing to do, and
> should have been here already, but unrelated to the rest of the patch.
> Perhaps do it a separate commit ?

No. I'll remove that call. I intend to get rid of the wl_signal as well so I won't bother with it now.

Attachment 322446 [details] pushed as d340c3a - wayland: Don't unset surface->buffer when wl_buffer destroyed