/*

 * 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.

 */

/*

 * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved.

 */

package org.jcp.xml.dsig.internal.dom;

import org.w3c.dom.Attr;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import com.sun.org.apache.xml.internal.security.Init;

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

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolver;

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverContext;

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

import javax.xml.crypto.*;

import javax.xml.crypto.dom.*;

/**

 * DOM-based implementation of URIDereferencer.

 *

 */

public final class DOMURIDereferencer implements URIDereferencer {

    static final URIDereferencer INSTANCE = new DOMURIDereferencer();

    private DOMURIDereferencer() {

        // need to call com.sun.org.apache.xml.internal.security.Init.init()

        // before calling any apache security code

        Init.init();

    }

    public Data dereference(URIReference uriRef, XMLCryptoContext context)

        throws URIReferenceException {

        if (uriRef == null) {

            throw new NullPointerException("uriRef cannot be null");

        }

        if (context == null) {

            throw new NullPointerException("context cannot be null");

        }

        DOMURIReference domRef = (DOMURIReference) uriRef;

        Attr uriAttr = (Attr) domRef.getHere();

        String uri = uriRef.getURI();

        DOMCryptoContext dcc = (DOMCryptoContext) context;

        String baseURI = context.getBaseURI();

        boolean secVal = Utils.secureValidation(context);

        if (secVal && Policy.restrictReferenceUriScheme(uri)) {

            throw new URIReferenceException(

                "Uri " + uri + " is forbidden when secure validation is enabled");

        }

        // Check if same-document URI and already registered on the context

        if (uri != null && uri.length() != 0 && uri.charAt(0) == '#') {

            String id = uri.substring(1);

            if (id.startsWith("xpointer(id(")) {

                int i1 = id.indexOf('\'');

                int i2 = id.indexOf('\'', i1+1);

                id = id.substring(i1+1, i2);

            }

            // check if element is registered by Id

            Node referencedElem = uriAttr.getOwnerDocument().getElementById(id);

            if (referencedElem == null) {

               // see if element is registered in DOMCryptoContext

               referencedElem = dcc.getElementById(id);

            }

            if (referencedElem != null) {

                if (secVal && Policy.restrictDuplicateIds()) {

                    Element start = referencedElem.getOwnerDocument().getDocumentElement();

                    if (!XMLUtils.protectAgainstWrappingAttack(start, (Element)referencedElem, id)) {

                        String error = "Multiple Elements with the same ID "

                            + id + " detected when secure validation"

                            + " is enabled";

                        throw new URIReferenceException(error);

                    }

                }

                XMLSignatureInput result = new XMLSignatureInput(referencedElem);

                result.setSecureValidation(secVal);

                if (!uri.substring(1).startsWith("xpointer(id(")) {

                    result.setExcludeComments(true);

                }

                result.setMIMEType("text/xml");

                if (baseURI != null && baseURI.length() > 0) {

                    result.setSourceURI(baseURI.concat(uriAttr.getNodeValue()));

                } else {

                    result.setSourceURI(uriAttr.getNodeValue());

                }

                return new ApacheNodeSetData(result);

            }

        }

        try {

            ResourceResolverContext resContext = new ResourceResolverContext(uriAttr, baseURI, false);

            XMLSignatureInput in = ResourceResolver.resolve(resContext);

            if (in.isOctetStream()) {

                return new ApacheOctetStreamData(in);

            } else {

                return new ApacheNodeSetData(in);

            }

        } catch (Exception e) {

            throw new URIReferenceException(e);

        }

    }

}