XQilla: empty string passed to XMLScanner::setExternalSchemaLocation

[J Napoli]

Hi,

While testing XQilla with Xerces-C 2.8.0  I was getting XML parse 
exceptions trying to run the basic examples.  Looking into the code I 
noticed that XQilla by default passes an empty string (where val != NULL 
&& XMLString::stringLen(val) == 0) to 
XMLScanner::setExternalSchemaLocation and 
setExternalNoNamespaceSchemaLocation.  This seems to trick the scanner 
into thinking there is an external schema to parse. 
SGMLScanner::resolveSchemaGrammar then throws a parse exception because 
it tries to parse a URL constructed by concatenating the current working 
directory with the empty string.

Is this an XQilla or Xerces problem?  Should Xerces ignore 0-length 
strings here?

Modifying XMLScanner::setExternalSchemaLocation to ignore 0-length 
strings seems to fix the problem (same issue with 
setExternalNoNamespaceSchemaLocation):

----

inline void XMLScanner::setExternalSchemaLocation(const XMLCh* const 
schemaLocation)
{
   if (fExternalSchemaLocation) {
       fMemoryManager->deallocate(fExternalSchemaLocation);
       fExternalSchemaLocation = NULL;
   }

   // Only set if we're passed a non-trivial string
   if (schemaLocation && XMLString::stringLen (schemaLocation))
       fExternalSchemaLocation = XMLString::replicate(schemaLocation, 
fMemoryManager);
}

Thanks,
Jerry