1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /**
6 * Licensed to the Apache Software Foundation (ASF) under one
7 * or more contributor license agreements. See the NOTICE file
8 * distributed with this work for additional information
9 * regarding copyright ownership. The ASF licenses this file
10 * to you under the Apache License, Version 2.0 (the
11 * "License"); you may not use this file except in compliance
12 * with the License. You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing,
17 * software distributed under the License is distributed on an
18 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
19 * KIND, either express or implied. See the License for the
20 * specific language governing permissions and limitations
21 * under the License.
22 */
23 /*
24 * Copyright (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved.
25 */
26 /*
27 * $Id$
28 */
29 package com.sun.org.apache.xml.internal.security.signature.reference;
30
31 import java.util.ArrayList;
32 import java.util.Iterator;
33 import java.util.List;
34 import java.util.ListIterator;
35 import java.util.NoSuchElementException;
36 import org.w3c.dom.NamedNodeMap;
37 import org.w3c.dom.Node;
38
39 /**
40 * A representation of a <code>ReferenceNodeSetData</code> type containing a node-set.
41 * This is a subtype of NodeSetData that represents a dereferenced
42 * same-document URI as the root of a subdocument. The main reason is
43 * for efficiency and performance, as some transforms can operate
44 * directly on the subdocument and there is no need to convert it
45 * first to an XPath node-set.
46 */
47 public class ReferenceSubTreeData implements ReferenceNodeSetData {
48
49 private boolean excludeComments;
50 private Node root;
51
52 public ReferenceSubTreeData(Node root, boolean excludeComments) {
53 this.root = root;
54 this.excludeComments = excludeComments;
55 }
56
57 public Iterator<Node> iterator() {
58 return new DelayedNodeIterator(root, excludeComments);
59 }
60
61 public Node getRoot() {
62 return root;
63 }
64
65 public boolean excludeComments() {
66 return excludeComments;
67 }
68
69 /**
70 * This is an Iterator that contains a backing node-set that is
71 * not populated until the caller first attempts to advance the iterator.
72 */
73 static class DelayedNodeIterator implements Iterator<Node> {
74 private Node root;
75 private List<Node> nodeSet;
76 private ListIterator<Node> li;
77 private boolean withComments;
78
79 DelayedNodeIterator(Node root, boolean excludeComments) {
80 this.root = root;
81 this.withComments = !excludeComments;
82 }
83
84 public boolean hasNext() {
85 if (nodeSet == null) {
86 nodeSet = dereferenceSameDocumentURI(root);
87 li = nodeSet.listIterator();
88 }
89 return li.hasNext();
90 }
91
92 public Node next() {
93 if (nodeSet == null) {
94 nodeSet = dereferenceSameDocumentURI(root);
95 li = nodeSet.listIterator();
96 }
97 if (li.hasNext()) {
98 return li.next();
99 } else {
100 throw new NoSuchElementException();
101 }
102 }
103
104 public void remove() {
105 throw new UnsupportedOperationException();
106 }
107
108 /**
109 * Dereferences a same-document URI fragment.
110 *
111 * @param node the node (document or element) referenced by the
112 * URI fragment. If null, returns an empty set.
113 * @return a set of nodes (minus any comment nodes)
114 */
115 private List<Node> dereferenceSameDocumentURI(Node node) {
116 List<Node> nodeSet = new ArrayList<Node>();
117 if (node != null) {
118 nodeSetMinusCommentNodes(node, nodeSet, null);
119 }
120 return nodeSet;
121 }
122
123 /**
124 * Recursively traverses the subtree, and returns an XPath-equivalent
125 * node-set of all nodes traversed, excluding any comment nodes,
126 * if specified.
127 *
128 * @param node the node to traverse
129 * @param nodeSet the set of nodes traversed so far
130 * @param the previous sibling node
131 */
132 @SuppressWarnings("fallthrough")
133 private void nodeSetMinusCommentNodes(Node node, List<Node> nodeSet,
134 Node prevSibling)
135 {
136 switch (node.getNodeType()) {
137 case Node.ELEMENT_NODE :
138 nodeSet.add(node);
139 NamedNodeMap attrs = node.getAttributes();
140 if (attrs != null) {
141 for (int i = 0, len = attrs.getLength(); i < len; i++) {
142 nodeSet.add(attrs.item(i));
143 }
144 }
145 Node pSibling = null;
146 for (Node child = node.getFirstChild(); child != null;
147 child = child.getNextSibling()) {
148 nodeSetMinusCommentNodes(child, nodeSet, pSibling);
149 pSibling = child;
150 }
151 break;
152 case Node.DOCUMENT_NODE :
153 pSibling = null;
154 for (Node child = node.getFirstChild(); child != null;
155 child = child.getNextSibling()) {
156 nodeSetMinusCommentNodes(child, nodeSet, pSibling);
157 pSibling = child;
158 }
159 break;
160 case Node.TEXT_NODE :
161 case Node.CDATA_SECTION_NODE:
162 // emulate XPath which only returns the first node in
163 // contiguous text/cdata nodes
164 if (prevSibling != null &&
165 (prevSibling.getNodeType() == Node.TEXT_NODE ||
166 prevSibling.getNodeType() == Node.CDATA_SECTION_NODE)) {
167 return;
168 }
169 nodeSet.add(node);
170 break;
171 case Node.PROCESSING_INSTRUCTION_NODE :
172 nodeSet.add(node);
173 break;
174 case Node.COMMENT_NODE:
175 if (withComments) {
176 nodeSet.add(node);
177 }
178 }
179 }
180 }
181 }