/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/**

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements. See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership. The ASF licenses this file

 * to you 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 java.io.OutputStream;

import javax.xml.transform.TransformerException;

import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityRuntimeException;

import com.sun.org.apache.xml.internal.security.signature.NodeFilter;

import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;

import com.sun.org.apache.xml.internal.security.transforms.Transform;

import com.sun.org.apache.xml.internal.security.transforms.TransformSpi;

import com.sun.org.apache.xml.internal.security.transforms.TransformationException;

import com.sun.org.apache.xml.internal.security.transforms.Transforms;

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

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

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

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

import org.w3c.dom.DOMException;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

/**

 * Class TransformXPath

 *

 * Implements the {@code http://www.w3.org/TR/1999/REC-xpath-19991116}

 * transform.

 *

 * @see <a href="http://www.w3.org/TR/1999/REC-xpath-19991116">XPath</a>

 *

 */

public class TransformXPath extends TransformSpi {

    /** Field implementedTransformURI */

    public static final String implementedTransformURI = Transforms.TRANSFORM_XPATH;

    /**

     * Method engineGetURI

     *

     * {@inheritDoc}

     */

    protected String engineGetURI() {

        return implementedTransformURI;

    }

    /**

     * Method enginePerformTransform

     * {@inheritDoc}

     * @param input

     *

     * @throws TransformationException

     */

    protected XMLSignatureInput enginePerformTransform(

        XMLSignatureInput input, OutputStream os, Transform transformObject

    ) throws TransformationException {

        try {

            /**

             * If the actual input is an octet stream, then the application MUST

             * convert the octet stream to an XPath node-set suitable for use by

             * Canonical XML with Comments. (A subsequent application of the

             * REQUIRED Canonical XML algorithm would strip away these comments.)

             *

             * ...

             *

             * The evaluation of this expression includes all of the document's nodes

             * (including comments) in the node-set representing the octet stream.

             */

            Element xpathElement =

                XMLUtils.selectDsNode(

                    transformObject.getElement().getFirstChild(), Constants._TAG_XPATH, 0);

            if (xpathElement == null) {

                Object exArgs[] = { "ds:XPath", "Transform" };

                throw new TransformationException("xml.WrongContent", exArgs);

            }

            Node xpathnode = xpathElement.getFirstChild();

            if (xpathnode == null) {

                throw new DOMException(

                    DOMException.HIERARCHY_REQUEST_ERR, "Text must be in ds:Xpath"

                );

            }

            String str = XMLUtils.getStrFromNode(xpathnode);

            input.setNeedsToBeExpanded(needsCircumvent(str));

            XPathFactory xpathFactory = XPathFactory.newInstance();

            XPathAPI xpathAPIInstance = xpathFactory.newXPathAPI();

            input.addNodeFilter(new XPathNodeFilter(xpathElement, xpathnode, str, xpathAPIInstance));

            input.setNodeSet(true);

            return input;

        } catch (DOMException ex) {

            throw new TransformationException(ex);

        }

    }

    /**

     * @param str

     * @return true if needs to be circumvent for bug.

     */

    private boolean needsCircumvent(String str) {

        return str.indexOf("namespace") != -1 || str.indexOf("name()") != -1;

    }

    static class XPathNodeFilter implements NodeFilter {

        XPathAPI xPathAPI;

        Node xpathnode;

        Element xpathElement;

        String str;

        XPathNodeFilter(Element xpathElement, Node xpathnode, String str, XPathAPI xPathAPI) {

            this.xpathnode = xpathnode;

            this.str = str;

            this.xpathElement = xpathElement;

            this.xPathAPI = xPathAPI;

        }

        /**

         * @see com.sun.org.apache.xml.internal.security.signature.NodeFilter#isNodeInclude(org.w3c.dom.Node)

         */

        public int isNodeInclude(Node currentNode) {

            try {

                boolean include = xPathAPI.evaluate(currentNode, xpathnode, str, xpathElement);

                if (include) {

                    return 1;

                }

                return 0;

            } catch (TransformerException e) {

                Object[] eArgs = {currentNode};

                throw new XMLSecurityRuntimeException("signature.Transform.node", eArgs, e);

            } catch (Exception e) {

                Object[] eArgs = {currentNode, currentNode.getNodeType()};

                throw new XMLSecurityRuntimeException("signature.Transform.nodeAndType",eArgs, e);

            }

        }

        public int isNodeIncludeDO(Node n, int level) {

            return isNodeInclude(n);

        }

    }

}