fixed bug in wl_list

Iskren Chernev iskren.chernev at gmail.com
Sat Mar 12 12:54:36 PST 2011


In my opinion the problem is this:
The code to remove the element from the list is called every time, and the
code to insert it is called only when 'surface'. So in case surface is NULL
the item won't be added, but will be removed next time the function is
entered. Isn't that the case?

I don't have a detailed understanding of this exact code, but isn't the
explanation as simple as that?
Should I add some debugging info to see if this is indeed the case, or you
are sure that the problem lies somewhere else?

About the 'tagging' -- are you proposing to add a boolean flag to the
listener to explicitly mark it as 'in a list' or 'out of a list'?

Regards,
Iskren

On Sat, Mar 12, 2011 at 9:48 PM, Marty Jack <martyj19 at comcast.net> wrote:

>
>
> On 03/12/2011 02:20 PM, Bill Spitzak wrote:
> > On 03/12/2011 04:28 AM, Marty Jack wrote:
> >> I have never encountered a system where it was believed to be desirable
> to allow something to be removed twice.  It is important to keep data
> structures clean.  If anything you would be more likely to see a debugging
> mode where the lists were fully checked after every insert or remove to make
> sure they are internally consistent, especially if they are important to
> keeping the system running.  It's not that much different from memory
> allocation.  A block is allocated, or it is free, and a double free is a
> bug.
> >
> > Making it crash at the moment the second remove is attempted is better
> than it leaving the data corrupted and crashing later. It makes it a lot
> easier to find out why it went wrong.
> >
> > I think that is what the newest version of the patch is doing, right?
> > _______________________________________________
> > wayland-devel mailing list
> > wayland-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/wayland-devel
> >
>
> Oh and no, the second version of the patch makes the second remove a no-op.
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> wayland-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/wayland-devel
>
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