RE: [XaraXtreme-dev] Abort on arrow keypress

["Phil Martin" <Phil@xxxxxxxx>]

Thanks Gerry, I was was just thinking about looking into that problem
myself (it's a P1 on my list).

The use of StartSpread and CurrentSpread in CompleteTransformation is a
recent change I made to handle dragging across spread boundaries but
obviously I upset non-drag transforms without realising it.

The TransOperation cosntructor has worked for years without initialising
it's other variables so although it really should do so, I don't think
we'll find any new problems because of it.

Phil

> -----Original Message-----
> From: owner-dev@xxxxxxxxxxxxxxxx 
> [mailto:owner-dev@xxxxxxxxxxxxxxxx] On Behalf Of Gerry Iles
> Sent: 28 June 2006 16:19
> To: dev@xxxxxxxxxxxxxx
> Subject: RE: [XaraXtreme-dev] Abort on arrow keypress
> 
> Well, logically, I don't see any reason for the code to call 
> Spread::FindActiveLayer when handling cursor keys as it 
> doesn't do anything to the active layer (the active layer 
> being the layer that newly created objects get put on).
> 
> Looking at the code in CompleteTransformation, it should only 
> be calling FindActiveLayer if the operation is moving the 
> selection from one spread to another.  This shouldn't happen 
> in the text cursor case (until we have flowing text stories 
> that can span multiple spreads :) and I wouldn't have thought 
> the nudge operations would allow it either (though presumably 
> dragging with the mouse would if you actually had more than 
> one spread).
> 
> Looking at the constructor for TransOperation it doesn't 
> actually set all of its member variables sensibly.  I've just 
> committed a fix (r1382) that sets the StartSpread and 
> CurrentSpread to NULL so that in release builds (when memory 
> isn't auto-nulled on allocation) the test in 
> CompleteTransformation works correctly.
> 
> I haven't actually done a release build to test it but this 
> should sort out this specific problem.  There may be other 
> problems caused by the other member variables not being 
> initialised properly and these should really be sorted out too.
> 
> Gerry
> 
> -----Original Message-----
> From: owner-dev@xxxxxxxxxxxxxxxx 
> [mailto:owner-dev@xxxxxxxxxxxxxxxx] On Behalf Of Martin Wuerthner
> Sent: 28 June 2006 15:30
> To: dev@xxxxxxxxxxxxxx
> Subject: [XaraXtreme-dev] Abort on arrow keypress
> 
> When I press an arrow key (either to nudge an object or to 
> move the cursor in a text object) XaraLX aborts with a 
> SIGSEGV. This always happens in release builds, but not in 
> debug builds. The abort happens in Spread::FindActiveLayer at 
> node.h:1137 but also at other places inside this routine. It 
> appears that the this pointer of the FindActiveLayer method 
> call is invalid. The caller is TransOperation::CompleteTransformation.
> 
> Interestingly, in a debug build, Spread::FindActiveLayer is 
> not even called when handling an arrow key, neither when 
> nudging an object nor when moving the cursor.
> 
> So, something is seriously wrong with the program flow 
> earlier on, but only in release builds.
> 
> This is with the current svn version (1381), build on SUSE 
> 10.0 using gcc 4.02.
> 
> Martin
>