I am using Xerces C++ 2.3 on HPUX. My application uses a thread pool with each thread owning an instance of a parser. XML documents arrive in a queue and are processed by one of the available parsers from the thread pool. Under certain circumstances when I return from a parse my heap is trashed. It all seems to start with a parser exception caused by an invalid XML document. The exception is handled and reported and all seems fine until another valid document is processed. It may be the very next document or it may be several documents later but very soon after the bad document is parsed the parsing of a subsequent good document causes the corruption.
Here is a snippet of code that shows how each thread in the pool handles the parsing…
// Instantiate the DOM parser.
static const XMLCh gLS[] = {chLatin_L, chLatin_S, chNull};
DOMImplementation* impl = DOMImplementationRegistry::getDOMImplementation(gLS);
parser = ((DOMImplementationLS*)impl)->createDOMBuilder(DOMImplementationLS::MODE_SYNCHRONOUS, 0);
parser->setFeature(XMLUni::fgDOMNamespaces, true);
parser->setFeature(XMLUni::fgXercesSchema, true);
parser->setFeature(XMLUni::fgXercesSchemaFullChecking, true);
parser->setFeature(XMLUni::fgDOMValidation, true);
parser->setFeature(XMLUni::fgDOMDatatypeNormalization, true);
// Create error handler and install it
parser->setErrorHandler(&errorHandler);
// Create entity resolver and install it
parser->setEntityResolver(&entityResolver);
//reset error count
errorHandler.resetErrors();
for (;;)
{
// get xml document from queue
xmlParser.resetDocumentPool();
std::auto_ptr<MemBufInputSource> mem(new MemBufInputSource(reinterpret_cast<const XMLByte*>(xml->buffer), xml->size, xmlBufferID, false));
std::auto_ptr<Wrapper4InputSource> src(new Wrapper4InputSource(mem.get(), false));
DOMDocument* doc = 0;
errorHandler.resetErrors();
try
{
checkHeap(); // All is fine here
doc = parser->parse(*src);
checkHeap(); // Heap is trashed
}
catch (const XMLException& exception)
{
oss << "XML Exception: " << StrX(exception.getMessage());
throw ValidationException(oss.str());
}
catch (const DOMException& exception)
{
oss << "DOM Exception: " << exception.code;
throw ValidationException(oss.str());
}
// other processing
}
I’ve been looking at this for several days now and am at a loss. Has anyone seen anything like this? Any thoughts, comments, suggestions, or ideas will be greatly appreciated.
Steve
