[PATCH v2] xwayland: Fix infinite loop on quick movement through menus

[Tomasz Borowik]

On Wed, 25 Apr 2012 10:34:14 -0400
Kristian Hoegsberg <hoegsberg at gmail.com> wrote:

> On Wed, Apr 25, 2012 at 03:06:57PM +0200, Tomasz Borowik wrote:
> > From 3abf39489deb3eb048174630dc7d41908674408b Mon Sep 17 00:00:00 2001
> > From: timon37 <timon37 at lavabit.com>
> > Date: Wed, 25 Apr 2012 13:28:35 +0200
> > Subject: [PATCH] Fix infinite loop in xwl_screen_post_damage
> > 
> > Happens when first two windows are damaged, then later one is damaged and
> > the other is unrealized. It makes the damaged windows next point to itself.
> 
> Ah, yes, good catch.
> 
> The way we should fix this is that we just
> 
>     xorg_list_init(&xwl_window->damage_link);
> 
> in xwl_screen_post_damage() as we iterate list.  That way we can
> unconditional call xorg_list_del(&xwl_window->link_damage); as we do
> now.  If it's on the list, we take it out, if it's not on the list,
> it's a no-op.
> 

That was my initial thought, but that requires safe iterate (not exactly but I'm not sure if there is a method for cleaning the list in flight), and I came to the conclusion that damage happens way more often than unrealize so it's actually more efficient here.