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 * 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.
 *
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package com.sun.org.apache.xml.internal.security.utils.resolver.implementations;



import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;
import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException;
import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverSpi;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;


Handles barename XPointer Reference URIs.


To retain comments while selecting an element by an identifier ID,
use the following full XPointer: URI='#xpointer(id('ID'))'.


To retain comments while selecting the entire document,
use the following full XPointer: URI='#xpointer(/)'.
This XPointer contains a simple XPath expression that includes
the root node, which the second to last step above replaces with all
nodes of the parse tree (all descendants, plus all attributes,
plus all namespaces nodes).
Author:
$Author: mullan $/**
 * Handles barename XPointer Reference URIs.
 * <BR />
 * To retain comments while selecting an element by an identifier ID,
 * use the following full XPointer: URI='#xpointer(id('ID'))'.
 * <BR />
 * To retain comments while selecting the entire document,
 * use the following full XPointer: URI='#xpointer(/)'.
 * This XPointer contains a simple XPath expression that includes
 * the root node, which the second to last step above replaces with all
 * nodes of the parse tree (all descendants, plus all attributes,
 * plus all namespaces nodes).
 *
 * @author $Author: mullan $
 */
public class ResolverXPointer extends ResourceResolverSpi {

   
logging logging facility /** {@link java.util.logging} logging facility */
    static java.util.logging.Logger log =
        java.util.logging.Logger.getLogger(
                            ResolverXPointer.class.getName());

    public boolean engineIsThreadSafe() {
        return true;
    }

    
@inheritDoc
/**
     * @inheritDoc
     */
    public XMLSignatureInput engineResolve(Attr uri, String baseURI)
           throws ResourceResolverException {

        Node resultNode = null;
        Document doc = uri.getOwnerElement().getOwnerDocument();

        String uriStr = uri.getNodeValue();
        if (isXPointerSlash(uriStr)) {
            resultNode = doc;

        } else if (isXPointerId(uriStr)) {
            String id = getXPointerId(uriStr);
            resultNode = doc.getElementById(id);

            if (secureValidation) {
                Element start = uri.getOwnerDocument().getDocumentElement();
                if (!XMLUtils.protectAgainstWrappingAttack(start, id)) {
                    Object exArgs[] = { id };
                    throw new ResourceResolverException(
                        "signature.Verification.MultipleIDs", exArgs,
                        uri, baseURI);
                }
            }

            if (resultNode == null) {
               Object exArgs[] = { id };

               throw new ResourceResolverException(
                  "signature.Verification.MissingID", exArgs, uri, baseURI);
            }
        }

        XMLSignatureInput result = new XMLSignatureInput(resultNode);

        result.setMIMEType("text/xml");
        if (baseURI != null && baseURI.length() > 0) {
            result.setSourceURI(baseURI.concat(uri.getNodeValue()));
        } else {
            result.setSourceURI(uri.getNodeValue());
        }

        return result;
    }

   
@inheritDoc
/**
    * @inheritDoc
    */
   public boolean engineCanResolve(Attr uri, String BaseURI) {

      if (uri == null) {
         return false;
      }
          String uriStr =uri.getNodeValue();
      if (isXPointerSlash(uriStr) || isXPointerId(uriStr)) {
         return true;
      }

      return false;
   }

   
Method isXPointerSlash
Params:
uri – 
Returns:
true if begins with xpointer/**
    * Method isXPointerSlash
    *
    * @param uri
    * @return true if begins with xpointer
    */
   private static boolean isXPointerSlash(String uri) {

      if (uri.equals("#xpointer(/)")) {
         return true;
      }

      return false;
   }


   private static final String XP="#xpointer(id(";
   private static final int XP_LENGTH=XP.length();
   
Method isXPointerId
Params:
uri – 
Returns:
it it has an xpointer id/**
    * Method isXPointerId
    *
    * @param uri
    * @return it it has an xpointer id
    *
    */
   private static boolean isXPointerId(String uri) {


      if (uri.startsWith(XP)
              && uri.endsWith("))")) {
         String idPlusDelim = uri.substring(XP_LENGTH,
                                                     uri.length()
                                                     - 2);

         // log.log(java.util.logging.Level.FINE, "idPlusDelim=" + idPlusDelim);
                 int idLen=idPlusDelim.length() -1;
         if (((idPlusDelim.charAt(0) == '"') && (idPlusDelim
                 .charAt(idLen) == '"')) || ((idPlusDelim
                 .charAt(0) == '\'') && (idPlusDelim
                 .charAt(idLen) == '\''))) {
            if (log.isLoggable(java.util.logging.Level.FINE))
                log.log(java.util.logging.Level.FINE, "Id="
                      + idPlusDelim.substring(1, idLen));

            return true;
         }
      }

      return false;
   }

   
Method getXPointerId
Params:
uri – 
Returns:
xpointerId to search./**
    * Method getXPointerId
    *
    * @param uri
    * @return xpointerId to search.
    */
   private static String getXPointerId(String uri) {


      if (uri.startsWith(XP)
              && uri.endsWith("))")) {
         String idPlusDelim = uri.substring(XP_LENGTH,uri.length()
                                                     - 2);
                 int idLen=idPlusDelim.length() -1;
         if (((idPlusDelim.charAt(0) == '"') && (idPlusDelim
                 .charAt(idLen) == '"')) || ((idPlusDelim
                 .charAt(0) == '\'') && (idPlusDelim
                 .charAt(idLen) == '\''))) {
            return idPlusDelim.substring(1, idLen);
         }
      }

      return null;
   }
}