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 package com.sun.org.apache.xml.internal.security.utils;
24
25 import java.lang.reflect.Constructor;
26 import java.lang.reflect.Method;
27 import java.lang.reflect.Modifier;
28
29 import javax.xml.transform.ErrorListener;
30 import javax.xml.transform.SourceLocator;
31 import javax.xml.transform.TransformerException;
32
33 import com.sun.org.apache.xml.internal.security.transforms.implementations.FuncHere;
34 import com.sun.org.apache.xml.internal.utils.PrefixResolver;
35 import com.sun.org.apache.xml.internal.utils.PrefixResolverDefault;
36 import com.sun.org.apache.xpath.internal.Expression;
37 import com.sun.org.apache.xpath.internal.XPath;
38 import com.sun.org.apache.xpath.internal.XPathContext;
39 import com.sun.org.apache.xpath.internal.compiler.FunctionTable;
40 import com.sun.org.apache.xpath.internal.objects.XObject;
41 import org.w3c.dom.Document;
42 import org.w3c.dom.Node;
43 import org.w3c.dom.NodeList;
44
45 /**
46 * An implementation of XPathAPI using Xalan. This supports the "here()" function defined in the digital
47 * signature spec.
48 */
49 public class XalanXPathAPI implements XPathAPI {
50
51 private static java.util.logging.Logger log =
52 java.util.logging.Logger.getLogger(XalanXPathAPI.class.getName());
53
54 private String xpathStr = null;
55
56 private XPath xpath = null;
57
58 private static FunctionTable funcTable = null;
59
60 private static boolean installed;
61
62 private XPathContext context;
63
64 static {
65 fixupFunctionTable();
66 }
67
68
69 /**
70 * Use an XPath string to select a nodelist.
71 * XPath namespace prefixes are resolved from the namespaceNode.
72 *
73 * @param contextNode The node to start searching from.
74 * @param xpathnode
75 * @param str
76 * @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
77 * @return A NodeIterator, should never be null.
78 *
79 * @throws TransformerException
80 */
81 public NodeList selectNodeList(
82 Node contextNode, Node xpathnode, String str, Node namespaceNode
83 ) throws TransformerException {
84
85 // Execute the XPath, and have it return the result
86 XObject list = eval(contextNode, xpathnode, str, namespaceNode);
87
88 // Return a NodeList.
89 return list.nodelist();
90 }
91
92 /**
93 * Evaluate an XPath string and return true if the output is to be included or not.
94 * @param contextNode The node to start searching from.
95 * @param xpathnode The XPath node
96 * @param str The XPath expression
97 * @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
98 */
99 public boolean evaluate(Node contextNode, Node xpathnode, String str, Node namespaceNode)
100 throws TransformerException {
101 XObject object = eval(contextNode, xpathnode, str, namespaceNode);
102 return object.bool();
103 }
104
105 /**
106 * Clear any context information from this object
107 */
108 public void clear() {
109 xpathStr = null;
110 xpath = null;
111 context = null;
112 }
113
114 public synchronized static boolean isInstalled() {
115 return installed;
116 }
117
118 private XObject eval(Node contextNode, Node xpathnode, String str, Node namespaceNode)
119 throws TransformerException {
120 if (context == null) {
121 context = new XPathContext(xpathnode);
122 context.setSecureProcessing(true);
123 }
124
125 // Create an object to resolve namespace prefixes.
126 // XPath namespaces are resolved from the input context node's document element
127 // if it is a root node, or else the current context node (for lack of a better
128 // resolution space, given the simplicity of this sample code).
129 Node resolverNode =
130 (namespaceNode.getNodeType() == Node.DOCUMENT_NODE)
131 ? ((Document) namespaceNode).getDocumentElement() : namespaceNode;
132 PrefixResolverDefault prefixResolver = new PrefixResolverDefault(resolverNode);
133
134 if (!str.equals(xpathStr)) {
135 if (str.indexOf("here()") > 0) {
136 context.reset();
137 }
138 xpath = createXPath(str, prefixResolver);
139 xpathStr = str;
140 }
141
142 // Execute the XPath, and have it return the result
143 int ctxtNode = context.getDTMHandleFromNode(contextNode);
144
145 return xpath.execute(context, ctxtNode, prefixResolver);
146 }
147
148 private XPath createXPath(String str, PrefixResolver prefixResolver) throws TransformerException {
149 XPath xpath = null;
150 Class<?>[] classes = new Class<?>[]{String.class, SourceLocator.class, PrefixResolver.class, int.class,
151 ErrorListener.class, FunctionTable.class};
152 Object[] objects =
153 new Object[]{str, null, prefixResolver, Integer.valueOf(XPath.SELECT), null, funcTable};
154 try {
155 Constructor<?> constructor = XPath.class.getConstructor(classes);
156 xpath = (XPath) constructor.newInstance(objects);
157 } catch (Exception ex) {
158 if (log.isLoggable(java.util.logging.Level.FINE)) {
159 log.log(java.util.logging.Level.FINE, ex.getMessage(), ex);
160 }
161 }
162 if (xpath == null) {
163 xpath = new XPath(str, null, prefixResolver, XPath.SELECT, null);
164 }
165 return xpath;
166 }
167
168 private synchronized static void fixupFunctionTable() {
169 installed = false;
170 if (log.isLoggable(java.util.logging.Level.FINE)) {
171 log.log(java.util.logging.Level.FINE, "Registering Here function");
172 }
173 /**
174 * Try to register our here() implementation as internal function.
175 */
176 try {
177 Class<?>[] args = {String.class, Expression.class};
178 Method installFunction = FunctionTable.class.getMethod("installFunction", args);
179 if ((installFunction.getModifiers() & Modifier.STATIC) != 0) {
180 Object[] params = {"here", new FuncHere()};
181 installFunction.invoke(null, params);
182 installed = true;
183 }
184 } catch (Exception ex) {
185 log.log(java.util.logging.Level.FINE, "Error installing function using the static installFunction method", ex);
186 }
187 if (!installed) {
188 try {
189 funcTable = new FunctionTable();
190 Class<?>[] args = {String.class, Class.class};
191 Method installFunction = FunctionTable.class.getMethod("installFunction", args);
192 Object[] params = {"here", FuncHere.class};
193 installFunction.invoke(funcTable, params);
194 installed = true;
195 } catch (Exception ex) {
196 log.log(java.util.logging.Level.FINE, "Error installing function using the static installFunction method", ex);
197 }
198 }
199 if (log.isLoggable(java.util.logging.Level.FINE)) {
200 if (installed) {
201 log.log(java.util.logging.Level.FINE, "Registered class " + FuncHere.class.getName()
202 + " for XPath function 'here()' function in internal table");
203 } else {
204 log.log(java.util.logging.Level.FINE, "Unable to register class " + FuncHere.class.getName()
205 + " for XPath function 'here()' function in internal table");
206 }
207 }
208 }
209
210 }