Re: XalanSimplePrefixResolver and XPath

Paul Lalonde wrote:
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> Hi.  I'm tring to use Xalan's XPath support to run queries on some 
> Collada documents I have.  I've run into the issue that the documents 
> all declare themselves in an anonymous namespace:
>     <?xml version="1.0" encoding="utf-8"?>
>     <COLLADA xmlns="http://www.collada.org/2005/11/COLLADASchema"; 
> version="1.4.0">
>         <asset>
>         ...
>         </asset>
>     </COLLADA>
>     
> So I want my XPath expressions to refer through that namespace.  I 
> thought I'd try using the XalanSimplePrefixResolver doing something like 
> this:
>         XalanSimplePrefixResolver thePrefixResolver(
>                                   XalanDOMString("c"),
>                                   
> XalanDOMString("http://www.collada.org/2005/11/COLLADASchema";),
>                                   
> XalanDOMString("http://www.collada.org/2005/11/COLLADASchema";)
>                                   );
XalanSimplePrefixResolver holds references to existing XalanDOMString 
instances, and you are passing in temporaries that are destroyed after the 
constructor is called.  As a result, the instance contains references to 
three XalanDOMString instances that have already been destroyed.  When the 
XPath compiler attempts to use the PrefixResolver, it contains garbage data.
Declare the XalanDOMString instances on the stack, not as temporaries, and 
your code will work.
Dave