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1   /*
2    * Copyright (c) 1997, 2012, 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.org.jvnet.mimepull;
27  
28  import java.io.IOException;
29  import java.util.NoSuchElementException;
30  import java.util.List;
31  
32  /**
33   * InternetHeaders is a utility class that manages RFC822 style
34   * headers. Given an RFC822 format message stream, it reads lines
35   * until the blank line that indicates end of header. The input stream
36   * is positioned at the start of the body. The lines are stored
37   * within the object and can be extracted as either Strings or
38   * {@link Header} objects. <p>
39   * <p/>
40   * This class is mostly intended for service providers. MimeMessage
41   * and MimeBody use this class for holding their headers. <p>
42   * <p/>
43   * <hr> <strong>A note on RFC822 and MIME headers</strong><p>
44   * <p/>
45   * RFC822 and MIME header fields <strong>must</strong> contain only
46   * US-ASCII characters. If a header contains non US-ASCII characters,
47   * it must be encoded as per the rules in RFC 2047. The MimeUtility
48   * class provided in this package can be used to to achieve this.
49   * Callers of the <code>setHeader</code>, <code>addHeader</code>, and
50   * <code>addHeaderLine</code> methods are responsible for enforcing
51   * the MIME requirements for the specified headers.  In addition, these
52   * header fields must be folded (wrapped) before being sent if they
53   * exceed the line length limitation for the transport (1000 bytes for
54   * SMTP).  Received headers may have been folded.  The application is
55   * responsible for folding and unfolding headers as appropriate. <p>
56   *
57   * @author John Mani
58   * @author Bill Shannon
59   */
60  final class InternetHeaders {
61  
62      private final FinalArrayList<Hdr> headers = new FinalArrayList<Hdr>();
63  
64      /**
65       * Read and parse the given RFC822 message stream till the
66       * blank line separating the header from the body. Store the
67       * header lines inside this InternetHeaders object. <p>
68       * <p/>
69       * Note that the header lines are added into this InternetHeaders
70       * object, so any existing headers in this object will not be
71       * affected.
72       *
73       * @param   lis RFC822 input stream
74       */
75      InternetHeaders(MIMEParser.LineInputStream lis) {
76          // Read header lines until a blank line. It is valid
77          // to have BodyParts with no header lines.
78          String line;
79          String prevline = null; // the previous header line, as a string
80          // a buffer to accumulate the header in, when we know it's needed
81          StringBuilder lineBuffer = new StringBuilder();
82  
83          try {
84              //while ((line = lis.readLine()) != null) {
85              do {
86                  line = lis.readLine();
87                  if (line != null &&
88                          (line.startsWith(" ") || line.startsWith("\t"))) {
89                      // continuation of header
90                      if (prevline != null) {
91                          lineBuffer.append(prevline);
92                          prevline = null;
93                      }
94                      lineBuffer.append("\r\n");
95                      lineBuffer.append(line);
96                  } else {
97                      // new header
98                      if (prevline != null) {
99                          addHeaderLine(prevline);
100                     } else if (lineBuffer.length() > 0) {
101                         // store previous header first
102                         addHeaderLine(lineBuffer.toString());
103                         lineBuffer.setLength(0);
104                     }
105                     prevline = line;
106                 }
107             } while (line != null && line.length() > 0);
108         } catch (IOException ioex) {
109             throw new MIMEParsingException("Error in input stream", ioex);
110         }
111     }
112 
113     /**
114      * Return all the values for the specified header. The
115      * values are String objects.  Returns <code>null</code>
116      * if no headers with the specified name exist.
117      *
118      * @param   name header name
119      * @return          array of header values, or null if none
120      */
121     List<String> getHeader(String name) {
122         // XXX - should we just step through in index order?
123         FinalArrayList<String> v = new FinalArrayList<String>(); // accumulate return values
124 
125         int len = headers.size();
126         for( int i=0; i<len; i++ ) {
127             Hdr h = (Hdr) headers.get(i);
128             if (name.equalsIgnoreCase(h.name)) {
129                 v.add(h.getValue());
130             }
131         }
132         return (v.size() == 0) ? null : v;
133     }
134 
135     /**
136      * Return all the headers as an Enumeration of
137      * {@link Header} objects.
138      *
139      * @return  Header objects
140      */
141     FinalArrayList<? extends Header> getAllHeaders() {
142         return headers; // conceptually it should be read-only, but for performance reason I'm not wrapping it here
143     }
144 
145     /**
146      * Add an RFC822 header line to the header store.
147      * If the line starts with a space or tab (a continuation line),
148      * add it to the last header line in the list. <p>
149      * <p/>
150      * Note that RFC822 headers can only contain US-ASCII characters
151      *
152      * @param   line    raw RFC822 header line
153      */
154     void addHeaderLine(String line) {
155         try {
156             char c = line.charAt(0);
157             if (c == ' ' || c == '\t') {
158                 Hdr h = (Hdr) headers.get(headers.size() - 1);
159                 h.line += "\r\n" + line;
160             } else {
161                 headers.add(new Hdr(line));
162             }
163         } catch (StringIndexOutOfBoundsException e) {
164             // line is empty, ignore it
165         } catch (NoSuchElementException e) {
166             // XXX - vector is empty?
167         }
168     }
169 
170 }
171 
172 /*
173  * A private utility class to represent an individual header.
174  */
175 
176 class Hdr implements Header {
177 
178     String name;    // the canonicalized (trimmed) name of this header
179     // XXX - should name be stored in lower case?
180     String line;    // the entire RFC822 header "line"
181 
182     /*
183      * Constructor that takes a line and splits out
184      * the header name.
185      */
186     Hdr(String l) {
187         int i = l.indexOf(':');
188         if (i < 0) {
189             // should never happen
190             name = l.trim();
191         } else {
192             name = l.substring(0, i).trim();
193         }
194         line = l;
195     }
196 
197     /*
198      * Constructor that takes a header name and value.
199      */
200     Hdr(String n, String v) {
201         name = n;
202         line = n + ": " + v;
203     }
204 
205     /*
206      * Return the "name" part of the header line.
207      */
208     @Override
209     public String getName() {
210         return name;
211     }
212 
213     /*
214      * Return the "value" part of the header line.
215      */
216     @Override
217     public String getValue() {
218         int i = line.indexOf(':');
219         if (i < 0) {
220             return line;
221         }
222 
223         int j;
224         if (name.equalsIgnoreCase("Content-Description")) {
225             // Content-Description should retain the folded whitespace after header unfolding -
226             // rf. RFC2822 section 2.2.3, rf. RFC2822 section 3.2.3
227             for (j = i + 1; j < line.length(); j++) {
228                 char c = line.charAt(j);
229                 if (!(/*c == ' ' ||*/c == '\t' || c == '\r' || c == '\n')) {
230                     break;
231                 }
232             }
233         } else {
234             // skip whitespace after ':'
235             for (j = i + 1; j < line.length(); j++) {
236                 char c = line.charAt(j);
237                 if (!(c == ' ' || c == '\t' || c == '\r' || c == '\n')) {
238                     break;
239                 }
240             }
241         }
242         return line.substring(j);
243     }
244 }