[ quesa-Bugs-1032785 ] DrawContext mask image initialisation

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Bugs item #1032785, was opened at 2004-09-22 09:44
Message generated for change (Comment added) made by jwwalker
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=442052&aid=1032785&group_id=45158

Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: bork3d (bork3d)
Assigned to: Nobody/Anonymous (nobody)
Summary: DrawContext mask image initialisation

Initial Comment:
A "malloc debug: double free" occurs in 
Q3Bitmap_Empty. 
The pointer to be freed is garbage due to an uninitialised 
field in a TQ3MacDrawContextData structure declared on 
the stack. This can be fixed where the DrawingContext is 
initialized in e3drawcontext_mac_new().

/* E3MacDrawContext_New is being called without the 
mask image field explicitly set, causing problems in 
Q3Bitmap_Empty.
 * Callers _do_ however set maskState to kQ3False, 
so respect a valid mask image if maskState is kQ3True
 */
if (instanceData-
>data.macData.theData.drawContextData.maskState == 
kQ3False)
  instanceData-
>data.macData.theData.drawContextData.mask.image = 
NULL;

Similar fixes should be applied to other platform specific 
DrawingContext initialisation routines, such as 
e3drawcontext_windc_new() etc


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>Comment By: James W. Walker (jwwalker)
Date: 2004-09-22 10:27

Message:
Logged In: YES 
user_id=433183

I don't understand this.  If some client code calls 
Q3MacDrawContext_New 
without setting all the fields of the TQ3MacDrawContextData structure, 
that's their bug, not Quesa's.  Furthermore, e3drawcontext_mac_delete 
does check the maskState field before calling Q3Bitmap_Empty.

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