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1   /*
2    * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  package com.sun.xml.internal.xsom.parser;
27  
28  import java.io.IOException;
29  import java.net.URL;
30  import java.util.logging.Level;
31  import java.util.logging.Logger;
32  
33  import javax.xml.parsers.ParserConfigurationException;
34  import javax.xml.parsers.SAXParser;
35  import javax.xml.parsers.SAXParserFactory;
36  
37  import org.xml.sax.*;
38  import org.xml.sax.helpers.XMLFilterImpl;
39  
40  import com.sun.xml.internal.xsom.impl.parser.Messages;
41  
42  /**
43   * Standard XMLParser implemented by using JAXP.
44   *
45   * @author
46   *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
47   */
48  public class JAXPParser implements XMLParser {
49  
50      // not in older JDK, so must be duplicated here, otherwise javax.xml.XMLConstants should be used
51      private static final String ACCESS_EXTERNAL_SCHEMA = "http://javax.xml.XMLConstants/property/accessExternalSchema";
52  
53      private static final Logger LOGGER = Logger.getLogger(JAXPParser.class.getName());
54  
55      private final SAXParserFactory factory;
56  
57      public JAXPParser( SAXParserFactory factory ) {
58          factory.setNamespaceAware(true);    // just in case
59          this.factory = factory;
60      }
61  
62      /**
63       * @deprecated Unsafe, use JAXPParser(factory) instead with
64       * security features initialized by setting
65       * XMLConstants.FEATURE_SECURE_PROCESSING feature.
66       */
67      public JAXPParser() {
68          this( SAXParserFactory.newInstance());
69      }
70  
71      public void parse( InputSource source, ContentHandler handler,
72          ErrorHandler errorHandler, EntityResolver entityResolver )
73  
74          throws SAXException, IOException {
75  
76          try {
77              SAXParser saxParser = allowFileAccess(factory.newSAXParser(), false);
78              XMLReader reader = new XMLReaderEx(saxParser.getXMLReader());
79  
80              reader.setContentHandler(handler);
81              if(errorHandler!=null)
82                  reader.setErrorHandler(errorHandler);
83              if(entityResolver!=null)
84                  reader.setEntityResolver(entityResolver);
85              reader.parse(source);
86          } catch( ParserConfigurationException e ) {
87              // in practice this won't happen
88              SAXParseException spe = new SAXParseException(e.getMessage(),null,e);
89              errorHandler.fatalError(spe);
90              throw spe;
91          }
92      }
93  
94      private static SAXParser allowFileAccess(SAXParser saxParser, boolean disableSecureProcessing) throws SAXException {
95  
96          // if feature secure processing enabled, nothing to do, file is allowed,
97          // or user is able to control access by standard JAXP mechanisms
98          if (disableSecureProcessing) {
99              return saxParser;
100         }
101 
102         try {
103             saxParser.setProperty(ACCESS_EXTERNAL_SCHEMA, "file");
104             LOGGER.log(Level.FINE, Messages.format(Messages.JAXP_SUPPORTED_PROPERTY, ACCESS_EXTERNAL_SCHEMA));
105         } catch (SAXException ignored) {
106             // nothing to do; support depends on version JDK or SAX implementation
107             LOGGER.log(Level.CONFIG, Messages.format(Messages.JAXP_UNSUPPORTED_PROPERTY, ACCESS_EXTERNAL_SCHEMA), ignored);
108         }
109         return saxParser;
110     }
111 
112     /**
113      * XMLReader with improved error message for entity resolution failure.
114      *
115      * TODO: this class is completely stand-alone, so it shouldn't be
116      * an inner class.
117      */
118     private static class XMLReaderEx extends XMLFilterImpl {
119 
120         private Locator locator;
121 
122         XMLReaderEx( XMLReader parent ) {
123             this.setParent(parent);
124         }
125 
126         /**
127          * Resolves entities and reports user-friendly error messages.
128          *
129          * <p>
130          * Some XML parser (at least Xerces) does not report much information
131          * when it fails to resolve an entity, which is often quite
132          * frustrating. For example, if you are behind a firewall and the
133          * schema contains a reference to www.w3.org, and there is no
134          * entity resolver, the parser will just throw an IOException
135          * that doesn't contain any information about where that reference
136          * occurs nor what it is accessing.
137          *
138          * <p>
139          * By implementing an EntityResolver and resolving the reference
140          * by ourselves, we can report an error message with all the
141          * necessary information to fix the problem.
142          *
143          * <p>
144          * Note that we still need to the client-specified entity resolver
145          * to let the application handle entity resolution. Here we just catch
146          * an IOException and add more information.
147          */
148         @Override
149         public InputSource resolveEntity(String publicId, String systemId) throws SAXException {
150             try {
151                 InputSource is=null;
152 
153                 // ask the client-specified entity resolver first
154                 if( this.getEntityResolver()!=null)
155                     is = this.getEntityResolver().resolveEntity(publicId,systemId);
156                 if( is!=null )  return is;  // if that succeeds, fine.
157 
158                 // rather than returning null, resolve it now
159                 // so that we can detect errors.
160                 is = new InputSource( new URL(systemId).openStream() );
161                 is.setSystemId(systemId);
162                 is.setPublicId(publicId);
163                 return is;
164             } catch( IOException e ) {
165                 // catch this error and provide a nice error message, rather than
166                 // just throwing this IOException.
167                 SAXParseException spe = new SAXParseException(
168                     Messages.format(Messages.ERR_ENTITY_RESOLUTION_FAILURE,
169                         systemId, e.toString()),    // use the toString method to get the class name
170                     locator, e );
171                 if(this.getErrorHandler()!=null)
172                     this.getErrorHandler().fatalError(spe);
173                 throw spe;
174             }
175         }
176 
177         @Override
178         public void setDocumentLocator(Locator locator) {
179             super.setDocumentLocator(locator);
180             this.locator = locator;
181         }
182     }
183 }