[libxml++] proposed function to xmlpp::Node

[Julius Mittenzwei <julius muenchen-sued de>]

Hi all,

i would propose to add the attached function to xmlpp::Node.
This function tests whether the node or any subnode match with the  
given xpath-expression.
( NodeSet find(const Glib::ustring& xpath); is not suitable for that  
purpose, because some expressions don't return an NodeSet).

I would ask you to add this code snippet to the cvs-repository.

Best regards
/Julius

-----------------------------
libxml++/nodes/node.h:
-----------------------------

  /** Test nodes with XPath expression
   * @param xpath The XPath of the nodes.
   * @return True if any node matches the XPath expression, false  
otherwise.
   */
   bool test(const Glib::ustring& xpath) const;

  /** Test nodes with XPath expression
   * @param xpath The XPath of the nodes.
   * @param namespaces A map of namespace prefixes to namespace URIs  
to be used while finding.
   * @return True if any node matches the XPath expression, false  
otherwise.
   */
  bool test(const Glib::ustring& xpath, const PrefixNsMap&  
namespaces) const;

-----------------------------
libxml++/nodes/node.cc:
-----------------------------

static bool test_impl(xmlXPathContext* ctxt, const Glib::ustring& xpath)
{
  bool ret;
  xmlXPathObject* result = xmlXPathEval((const xmlChar*)xpath.c_str 
(), ctxt);

  if(!result)
  {
    xmlXPathFreeContext(ctxt);
    throw exception("Invalid XPath: " + xpath);
  }

  ret = xmlXPathCastToBoolean(result);

  xmlXPathFreeObject(result);
  xmlXPathFreeContext(ctxt);

  return ret;
}

bool Node::test(const Glib::ustring& xpath) const
{
  xmlXPathContext* ctxt = xmlXPathNewContext(impl_->doc);
  ctxt->node = impl_;

  return test_impl(ctxt, xpath);
}

bool Node::test(const Glib::ustring& xpath,
                   const PrefixNsMap& namespaces) const
{
  xmlXPathContext* ctxt = xmlXPathNewContext(impl_->doc);
  ctxt->node = impl_;

  for (PrefixNsMap::const_iterator it=namespaces.begin();
       it != namespaces.end(); it++)
    xmlXPathRegisterNs(ctxt,
                       reinterpret_cast<const xmlChar*>(it- 
>first.c_str()),
                       reinterpret_cast<const xmlChar*>(it- 
>second.c_str()));

  return test_impl(ctxt, xpath);
}

-----------------------------



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