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Posted to c-dev@xerces.apache.org by radada <pa...@yahoo.fr> on 2009/05/15 16:16:49 UTC

Core Dump while releasing Parser ressources...

Hi there : )

I think I'm going nuts : (
Thanks to Alberto, I've got a code which is approximatively good. As told in
a previous post, I implemented a functional layer over the xerces library so
that we can use it in our software at work.
In order to control as much as possible the memory leaks, I created a
singleton which can (and only it can) create DOMDocument and
XercesDOMParser. It is reponsible too for the releasing of the objets.

So for the parser, I've got a release method : 

void XMLFactory::releaseParser(ParserXML* p_poParser)
{  
   #ifdef AFF
      cout << "XMLFactory::releaseParser()" << endl;
   #endif


   // suppression en se basant sur les adresses des objets
   for (int i=0; i<m_oListeParserXML.entries(); i++)
   {
      ParserXML* ptr = NULL;
      ptr = m_oListeParserXML.at(i);
      if (ptr == p_poParser)
         m_oListeParserXML.removeAt(i);
   }
      
   // on delete l'objet (on test avant s'il n'est pas NULL avec le
ThrowIfNullWithMsg)
   DeleteIfObject(p_poParser);
}

In the destructor of the Parser, I've got this : 

ParserXML::~ParserXML()
{   
   #ifdef AFF
      cout << "Destructeur de ParserXML" << endl;
   #endif
   
   if (m_poDocument != NULL)
   {
      m_poDocument->release();
   }
   m_poDOMParser->reset();

   DeleteIfObject(m_poDOMParser);
   DeleteIfObject(m_poErrorHandler);
   DeleteIfObject(m_poDOMDocument);
   DeleteIfObject(m_poElementXML);
}

Some strange things happen, especially when I compare my code to the DOM
Programming Guide Chapter "Constructing a XercesDOMParser"
(http://xerces.apache.org/xerces-c/program-dom-3.html). It seems that, to
delete a parser and its ressources, one only have to delete the parser.
If I do that, I get a core Dump while deleting the DOMDocument.
So I added a m_poDOMParser->resetDocumentPool(), but it had the same effect.
Then I tried with m_poDOMParser->reset() and it did work! Well, not that
much. Sometimes it does, sometimes it doesn't. I still get a core Dump
sometimes, always when deleting the parser...

Just for the record, here is the parsing method : 

 ElementXML* ParserXML::parse(const char* p_pcBuffer)
{
   #ifdef AFF
      cout << "ParserXML::parse()" << endl;
   #endif
      
   // Si aucun buffer n'est passé, on renvoie NULL
   if (p_pcBuffer == NULL)
   {
      return NULL;
   }
   
   // si le parser n'a pas libéré les ressources du précédent parse   
   if (m_bDocumentParsed)
   {
      if (m_poDocument != NULL)
      {
         m_poDocument->release();
      }
      m_poDOMParser->reset();
      m_bDocumentParsed = false;
   }
   
   char* l_pcMessage;
   // on crée un objet pour le parsing
   MemBufInputSource l_oInputSource((const XMLByte*)p_pcBuffer,
                                    strlen(p_pcBuffer),
                                    (const XMLCh*)  "ParserXML");
   try
   {
      // on parse
      m_poDOMParser->parse(l_oInputSource);
      
      // on récupère le DOMDocument parsé
      m_poDocument = m_poDOMParser->getDocument();
      
      // on libère la mémoire si besoin
      DeleteIfObject(m_poElementXML);
      //on crée un nouveau ElementXML avec les données du DOMDocument
      m_poElementXML = new ElementXML(m_poDocument->getDocumentElement());
      // on indique que le Document a été correctement parsé
      m_bDocumentParsed = true;
      // on retourne l'ElementXML ainsi créé
      return m_poElementXML;
   }
   catch(XMLException& XMLEx)
   {
      l_pcMessage = XMLString::transcode(XMLEx.getMessage());
      ExceptMessage ex("T00500", "XML Exception", l_pcMessage);
      XMLString::release(&l_pcMessage);
      ex.doThrow();
   }
   catch(DOMException& DOMEx)
   {
      l_pcMessage = XMLString::transcode(DOMEx.msg);
      ExceptMessage ex("T00501", "XML Exception", l_pcMessage);
      XMLString::release(&l_pcMessage);
      ex.doThrow();
   }
   catch(SAXParseException& SaxParseEx)
   {
      l_pcMessage = XMLString::transcode(SaxParseEx.getMessage());
      ExceptMessage ex("T00502", "SAXParse Exception", l_pcMessage);
      XMLString::release(&l_pcMessage);
      ex.doThrow();
   }
   catch(SAXException& SaxEx)
   {
      l_pcMessage = XMLString::transcode(SaxEx.getMessage());
      ExceptMessage ex("T00502", "SAX Exception", l_pcMessage);
      XMLString::release(&l_pcMessage);
      ex.doThrow();
   }
   catch(...)
   {
      ExceptMessage ex("T00450", " ", "Erreur inconnue");
      ex.doThrow();
   }
}

You just can't imagine how happy will I be when I won't have to code into
this libraby :D
Anyway, as always, if you find something weird, or even the tinniest clue,
please, post here.

Thanks a lot.

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