[cairo] Returning cached erroneous patterns

[Behdad Esfahbod]

On Thu, 2007-03-29 at 00:16 +0100, Chris Wilson wrote:
> Behdad Esfahbod (behdad at behdad.org) said: 
> > On Thu, 2007-03-22 at 14:12 -0400, Baz wrote:
> > > All of this comes from patterns being mutable, for adding color stops,
> > > and setting user data. Should those operations should even be possible
> > > on patterns with more than one reference?
> > 
> > Ok, thanks for raising the issue.  The problem is that solid patterns
> > are not immutable as we expected.  Giving away the same mutable object
> > multiple times is definitely wrong.
> 
> Hmm, solid-patterns were not the only objects to be subjectable to this
> unrecoverable error condition. A similar happenstance also occurs with
> scaled fonts. :-(

Except that the user cannot put a scaled-font into an error state.  It
just happens on real errors like out-of-memory.  That's not a problem
IMO.

> For the time being I'm using this patch to continue testing malloc
> failures.

The patch looks like the right approach to me.

-- 
behdad
http://behdad.org/

"Those who would give up Essential Liberty to purchase a little
 Temporary Safety, deserve neither Liberty nor Safety."
        -- Benjamin Franklin, 1759