Re^4: copyCurrentNode in XML::LibXML::Reader will add xmlns attribute ( setNamespaceDeclURI )

I don't get it. I experimented with $node->setNamespace(undef, undef, 1) which seems to be the simplest namespace handling fucntion, but I couldn't get it work.

XML::LibXML defines setNamespace in the following way:

sub setNamespace {
    my $self = shift;
    my $n = $self->nodeName;
    if ( $self->_setNamespace(@_) ){
        if ( scalar @_ < 3 || $_[2] == 1 ){
            $self->setNodeName( $n );
        }
        return 1;
    }
    return 0;
}
[download]

where _setNamespace comes from its XS component, the important part (I guess) is the following:

       if ( nsPrefix == NULL && nsURI == NULL ) {
            /* special case: empty namespace */
            if ( (ns = xmlSearchNs(node->doc, node, NULL)) &&
                 ( ns->href && xmlStrlen( ns->href ) != 0 ) ) {
                /* won't take it */
                RETVAL = 0;
            } else if ( flag ) {
                /* no namespace */
                xmlSetNs(node, NULL);
                RETVAL = 1;
            } else {
                RETVAL = 0;
            }
        }
[download]

setNamespace returns 1, so I guess it goes the "else if" branch, but the namespace isn't removed from the node. xmlSetNs comes from libxml2 and is defined as (debugging ifdefs removed)

void
xmlSetNs(xmlNodePtr node, xmlNsPtr ns) {
    if (node == NULL) {
    return;
    }
    if ((node->type == XML_ELEMENT_NODE) ||
        (node->type == XML_ATTRIBUTE_NODE))
    node->ns = ns;
}
[download]

Anyone can explain why the namespace isn't changed?

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

Comment on Re^4: copyCurrentNode in XML::LibXML::Reader will add xmlns attribute ( setNamespaceDeclURI ) Select or Download Code

Replies are listed 'Best First'.
Re^5: copyCurrentNode in XML::LibXML::Reader will add xmlns attribute ( setNamespaceDeclURI ) by beech (Parson) on Sep 20, 2017 at 18:18 UTC
Anyone can explain why the namespace isn't changed? Hi, Its some kind of bug, if I were setup to compile libxml2 I'd narrow it down with this addition to LibXML.xs `int _setNamespaceNULL(self ) SV * self PREINIT: xmlNodePtr node = PmmSvNode(self); INIT: if ( node == NULL ) { croak( "lost node" ); } CODE: xmlSetNs(node, NULL); RETVAL = 1; OUTPUT: RETVAL` [download]	[reply] [d/l]
Re^6: copyCurrentNode in XML::LibXML::Reader will add xmlns attribute ( setNamespaceDeclURI ) by choroba (Cardinal) on Sep 30, 2017 at 09:59 UTC
My knowledge of C is less than basic (yes, I used Basic a lot as a child). But, I was able to compile the following and verify that libxml2 is able to clear the namespace, so the problem must lie in the XS land: #include <stdio.h> #include <libxml/tree.h> #include <libxml/parser.h> #include <libxml/xpath.h> #include <libxml/xpathInternals.h> int main (int argc, char *argv) { xmlInitParser(); xmlDoc document; document = xmlParseDoc("<r xmlns:p='http://p.p'><p:a>HERE</p:a></r>" +); xmlXPathContext xpc; xpc = xmlXPathNewContext(document); xmlXPathRegisterNs(xpc, "p", "http://p.p"); xmlXPathObject xp; xp = xmlXPathEvalExpression("/r/p:a", xpc); if (xp == NULL) return(1); xmlNodeSet nodes; nodes = xp->nodesetval; xmlNode node; node = nodes->nodeTab[0]; xmlSetNs(node, NULL); xmlChar s; int size; xmlDocDumpMemory(document, &s, &size); char string; string = (char )s; printf("%s", string); return(0); } [download] Outputs: `<?xml version="1.0"?> <r xmlns:p="http://p.p"><a>HERE</a></r>` [download] ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7*2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re^6: copyCurrentNode in XML::LibXML::Reader will add xmlns attribute ( setNamespaceDeclURI ) by choroba (Cardinal) on Oct 01, 2017 at 20:09 UTC
Should work now. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l]


No such thing as a small change
	PerlMonks