[cairo] segment fault when rendering text with space charactors onto glitz surface.

[sunmoon1997]

Vladimir Vukicevic wrote:

>On 8/9/05, David Reveman <davidr at novell.com> wrote:
>  
>
>>On Tue, 2005-08-09 at 09:51 -0700, Vladimir Vukicevic wrote:
>>    
>>
>>>Here's an updated patch for this issue, as well as not initializing
>>>the memory entry member (I sent both patches separately earlier, this
>>>is both combined and updated to latest CVS).  Carl/David, let me know
>>>if it's ok to commit this..
>>>      
>>>
>>It's OK commit it.
>>
>>I'm not sure the:
>>(area == &_empty_area)
>>check is necessary as the code should never try top move in areas with
>>width == 0 or height == 0 but I might be wrong so it's OK to commit it
>>as it is, I'll change it later if it turns out not necessary.
>>    
>>
>
>Hmm, so applying this patch to current CVS (with my patch checked in)
>still caused a slightly different crash with 0-space characters.  The
>attached patch fixes it, but at this point I'm just playing
>whack-a-mole without a full understanding of the glitz glyph caching
>implementation... in any case I'd like to check the patch in, since
>text seems to render with it, but I have no idea about the correctness
>-- specifically, I'm not sure why we ever have an image_entry->image
>for a space character.  The move_in check isn't needed with this...
>
>    - Vlad
>  
>
>------------------------------------------------------------------------
>
>Index: cairo-glitz-surface.c
>===================================================================
>RCS file: /cvs/cairo/cairo/src/cairo-glitz-surface.c,v
>retrieving revision 1.57
>diff -u -8 -p -r1.57 cairo-glitz-surface.c
>--- cairo-glitz-surface.c	9 Aug 2005 20:42:54 -0000	1.57
>+++ cairo-glitz-surface.c	9 Aug 2005 21:25:11 -0000
>@@ -1261,19 +1261,16 @@ struct _cairo_glitz_root_area {
>     cairo_glitz_area_t		   *area;
>     const cairo_glitz_area_funcs_t *funcs;
> };
> 
> static cairo_status_t
> _cairo_glitz_area_move_in (cairo_glitz_area_t *area,
> 			   void		      *closure)
> {
>-    if (area == &_empty_area)
>-	return CAIRO_STATUS_SUCCESS;
>-
>     area->closure = closure;
>     area->state   = CAIRO_GLITZ_AREA_OCCUPIED;
>     
>     return (*area->root->funcs->move_in) (area, area->closure);
> }
> 
> static void
> _cairo_glitz_area_move_out (cairo_glitz_area_t *area)
>@@ -1780,17 +1777,18 @@ _cairo_glitz_cache_glyph (cairo_glitz_gl
>     int			 am, rm, gm, bm;
> 
>     entry->size = image_entry->size;
>     
>     if (entry->size.width  > GLYPH_CACHE_MAX_WIDTH ||
> 	entry->size.height > GLYPH_CACHE_MAX_HEIGHT)
> 	return CAIRO_STATUS_SUCCESS;
> 
>-    if (!image_entry->image)
>+    if ((entry->size.width  == 0 && entry->size.height == 0) ||
>+        !image_entry->image)
>     {
> 	entry->area = &_empty_area;
> 	return CAIRO_STATUS_SUCCESS;
>     }
>     
>     format = pixman_image_get_format (image_entry->image->pixman_image);
>     if (!format)
> 	return CAIRO_STATUS_NO_MEMORY;
>  
>
>------------------------------------------------------------------------
>
>_______________________________________________
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>cairo at cairographics.org
>http://lists.freedesktop.org/mailman/listinfo/cairo
>  
>
Hi,
    This patch doesn't fix the problem completely. My test program still 
get segment fault. I attach a  small patch to complete the fix.

Many thanks.
Jinghua Luo

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