winex11.drv: try work around a crash

[Marcus Meissner]

On Thu, Jan 24, 2008 at 09:00:32AM +0000, Louis. Lenders wrote:
> 
> Hi, basically this is a resend of a patch i sent very long time ago ( http://www.winehq.org/pipermail/wine-patches/2007-April/037733.html )
> 
> It's a fix for bug http://bugs.winehq.org/show_bug.cgi?id=7380#c29
> 
> As explained in comment http://bugs.winehq.org/show_bug.cgi?id=7380#c29
> the cause of these crashes is some buggy mfc-function
> , and as windows is able to work around this, wine should do the same.
> 
> I've put the exception handler only around X11DRV_DIB_SetImageBits_24 , as that's where all the applications crash; if we want to mimic windows behaviour it should be put around all cases i guess, but i'm not sure we want to that and maybe hide other bugs.
> 
> If this patch is rejected could you please comment why, to help fix the bug in a better way

Remembering a different bug with the same issue I think you should not wrap 
DIB_SetImageBits_24 but just check descr->bits in X11DRV_DIB_SetImageBits()

Something along the lines of:

	unsigned long off;
	unsigned char volatile x;

	__TRY {
		for (off=0;off<descr->sizeImage;off+=PAGE_SIZE) {
			x += ((unsigned char*)descr->bits)[off]
		}
	} ...


Ciao, Marcus