[PATCH] wayland-client: Initialize newly created wl_proxys to zero.

[Pekka Paalanen]

On Sun, 10 Aug 2014 15:59:08 +0200
"Nils Chr. Brause" <nilschrbrause at gmail.com> wrote:

> On Sat, Aug 9, 2014 at 3:14 PM, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> 
> > But I do wonder, if it ever makes sense to check user data for
> > NULL, and set if it is NULL. If user_data is NULL, how can you
> > ever be sure, that the wl_proxy was created by your code, and not
> > by some library you use?
> >
> > Even when user_data is not NULL, you should have some explicit way
> > of checking whether the pointer is yours or not.
> >
> 
> If I would use any external libraries (like Qt or something), I agree that I
> could not possibly trust the value of user_data, since I don't know, what
> the library is doing there.
> 
> But I'm not using any external libraries, just libwayland-client. I thought
> that all proxies that are created by marshal_constructor or come from
> events with new_id type arguments are created by either of these two
> functions and therefore would have a NULL user_data if they got
> initialised there. If this is wrong, please tell me. :)

No, I do not think that is wrong, but are you not writing language
bindings or a wrapper library, which means you do not know how your code
will be used?

I still do not understand why you would ever really need to check if
user_data is set on a proxy or not. When you create a wl_proxy by
sending a request, I would suggest to always set user_data, so it will
never be unset by you. For events, you know, that a new_id in an event
will always be a new wl_proxy and the user_data is unset, so you can
unconditionally set it. Again, never unset by you. Would that also help?


Thanks,
pq