/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright  1999-2004 The Apache Software Foundation.

 *

 *  Licensed under the Apache License, Version 2.0 (the "License");

 *  you may not use this file except in compliance with the License.

 *  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 *  Unless required by applicable law or agreed to in writing, software

 *  distributed under the License is distributed on an "AS IS" BASIS,

 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 *  See the License for the specific language governing permissions and

 *  limitations under the License.

 *

 */

package com.sun.org.apache.xml.internal.security.transforms.implementations;

import javax.xml.transform.TransformerException;

import com.sun.org.apache.xml.internal.dtm.DTM;

import com.sun.org.apache.xml.internal.security.utils.I18n;

import com.sun.org.apache.xml.internal.security.utils.XMLUtils;

import com.sun.org.apache.xpath.internal.NodeSetDTM;

import com.sun.org.apache.xpath.internal.XPathContext;

import com.sun.org.apache.xpath.internal.functions.Function;

import com.sun.org.apache.xpath.internal.objects.XNodeSet;

import com.sun.org.apache.xpath.internal.objects.XObject;

import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;

import org.w3c.dom.Document;

import org.w3c.dom.Node;

/**

 * The 'here()' function returns a node-set containing the attribute or

 * processing instruction node or the parent element of the text node

 * that directly bears the XPath expression.  This expression results

 * in an error if the containing XPath expression does not appear in the

 * same XML document against which the XPath expression is being evaluated.

 *

 * Mainpart is stolen from FuncId.java

 *

 * This does crash under Xalan2.2.D7 and works under Xalan2.2.D9

 *

 * To get this baby to work, a special trick has to be used. The function needs

 * access to the Node where the XPath expression has been defined. This is done

 * by constructing a {@link FuncHere} which has this Node as 'owner'.

 *

 * @see "http://www.w3.org/Signature/Drafts/xmldsig-core/Overview.html#function-here"

 */

public class FuncHere extends Function {

   /**

         *

         */

        private static final long serialVersionUID = 1L;

   /**

    * The here function returns a node-set containing the attribute or

    * processing instruction node or the parent element of the text node

    * that directly bears the XPath expression.  This expression results

    * in an error if the containing XPath expression does not appear in the

    * same XML document against which the XPath expression is being evaluated.

    *

    * @param xctxt

    * @return the xobject

    * @throws javax.xml.transform.TransformerException

    */

   public XObject execute(XPathContext xctxt)

           throws javax.xml.transform.TransformerException {

      Node xpathOwnerNode = (Node) xctxt.getOwnerObject();

      if (xpathOwnerNode == null) {

         return null;

      }

      int xpathOwnerNodeDTM = xctxt.getDTMHandleFromNode(xpathOwnerNode);

      int currentNode = xctxt.getCurrentNode();

      DTM dtm = xctxt.getDTM(currentNode);

      int docContext = dtm.getDocument();

      if (DTM.NULL == docContext) {

         error(xctxt, XPATHErrorResources.ER_CONTEXT_HAS_NO_OWNERDOC, null);

      }

      {

         // check whether currentNode and the node containing the XPath expression

         // are in the same document

         Document currentDoc =

            XMLUtils.getOwnerDocument(dtm.getNode(currentNode));

         Document xpathOwnerDoc = XMLUtils.getOwnerDocument(xpathOwnerNode);

         if (currentDoc != xpathOwnerDoc) {

            throw new TransformerException(I18n

               .translate("xpath.funcHere.documentsDiffer"));

         }

      }

      XNodeSet nodes = new XNodeSet(xctxt.getDTMManager());

      NodeSetDTM nodeSet = nodes.mutableNodeset();

      {

         int hereNode = DTM.NULL;

         switch (dtm.getNodeType(xpathOwnerNodeDTM)) {

         case Node.ATTRIBUTE_NODE : {

            // returns a node-set containing the attribute

            hereNode = xpathOwnerNodeDTM;

            nodeSet.addNode(hereNode);

            break;

         }

         case Node.PROCESSING_INSTRUCTION_NODE : {

            // returns a node-set containing the processing instruction node

            hereNode = xpathOwnerNodeDTM;

            nodeSet.addNode(hereNode);

            break;

         }

         case Node.TEXT_NODE : {

            // returns a node-set containing the parent element of the

            // text node that directly bears the XPath expression

            hereNode = dtm.getParent(xpathOwnerNodeDTM);

            nodeSet.addNode(hereNode);

            break;

         }

         default :

            break;

         }

      }

      /** $todo$ Do I have to do this detach() call? */

      nodeSet.detach();

      return nodes;

   }

   /**

    * No arguments to process, so this does nothing.

    * @param vars

    * @param globalsSize

    */

   public void fixupVariables(java.util.Vector vars, int globalsSize) {

      // do nothing

   }

}