& XSLT On Friday 16 June 2006 10:54, Bernd Krause wrote:
>  Hi,
> 
>  I am using the XML::LibXML function $node->nodePath. This is not a
>  documented function but has been discussed on this list.
>  I am observing a memory leak as soon as I use $node->nodePath.
> 
>  Consider the following sample code:
>  =========================================
>  use strict;
>  use XML::LibXML;
> 
>  my $i = 0;
>  my $loop_end = 20000;
>  my $xml_string = '<?xml
>  version="1.0"?><root><aaa><bbb/><ccc/></aaa><ddd><bbb/><eee/></ddd></root>'
> ;
> 
>  my $parser = XML::LibXML->new();
>  my $tree = $parser->parse_string($xml_string) || die;
>  for ($i = 0; $i <= $loop_end; $i++) {
> 
>          my $root = $tree->getDocumentElement;
>          my $dtd = $root->nodeName;
>          my $xpath_string = "//*";
> 
>          foreach my $node ($tree->findnodes("$xpath_string")){
>                  my $xPath = $node->nodePath;    #        <- problem
>          }
>          print $i, "\t", $dtd, "\n";
>  }
>  =========================================
> 
>  If the above code is executed, computer memory consumption increases
>  linearly with $loop_end.
>  However, removing the $node->nodePath instruction immediately resolves the
>  problem: memory consumption remains constant independant of $loop_end.
> 
>  This is not a real problem for single file parsing. The problem occurs
>  because I have to parse a large number of XML files (much larger and more
>  complicated than in the example above). LibXML does a great job on that,
>  it is only the $node->nodePath which eats up all memory and makes my
>  computer stop working.

A totally stupid bug indeed. The definition of nodePath in LibXML.xs misses a 
xmlFree call. It should look like:

nodePath( self )
        xmlNodePtr self
    PREINIT:
        xmlChar * path = NULL;
    CODE:
        path = xmlGetNodePath( self );
        if ( path == NULL ) {
            croak( "cannot calculate path for the given node" );
        }
        RETVAL = nodeC2Sv( path, self );
        xmlFree( path ); /* this line was missing !!! */
    OUTPUT:
        RETVAL

Since axkit was reinstalled I don't have write access to the CVS, so I can't 
fix it permanently ATM. I'll see what I can do about it.

-- Petr

>  My Perl/LibXML environment is:
> 
>  Windows 2000
>  Active State PERL v5.8.3
> 
>  XML::LibXML::LIBXML_DOTTED_VERSION ->  2.6.11
>  XML::LibXML::LIBXML_VERSION ->  20611
>  XML::LibXML::VERSION -> 1.58
> 
>  Is there any way to prevent $node->nodePath from consuming all memory?
>  Thanks in advance for any help,
>  Bernd
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