Source for gnu.java.net.protocol.jar.Handler

   1: /* gnu.java.net.protocol.jar.Handler - jar protocol handler for java.net
   2:    Copyright (C) 1999, 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10:  
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.java.net.protocol.jar;
  40: 
  41: import gnu.java.net.URLParseError;
  42: 
  43: import java.io.IOException;
  44: import java.net.MalformedURLException;
  45: import java.net.URL;
  46: import java.net.URLConnection;
  47: import java.net.URLStreamHandler;
  48: import java.util.ArrayList;
  49: import java.util.Iterator;
  50: import java.util.StringTokenizer;
  51: 
  52: /**
  53:  * @author Kresten Krab Thorup (krab@gnu.org)
  54:  */
  55: public class Handler extends URLStreamHandler
  56: {
  57:   /**
  58:    * A do nothing constructor
  59:    */
  60:   public Handler()
  61:   {
  62:   }
  63: 
  64:   /**
  65:    * This method returs a new JarURLConnection for the specified URL
  66:    *
  67:    * @param url The URL to return a connection for
  68:    *
  69:    * @return The URLConnection
  70:    *
  71:    * @exception IOException If an error occurs
  72:    */
  73:   protected URLConnection openConnection(URL url) throws IOException
  74:   {
  75:     return new Connection(url);
  76:   }
  77: 
  78:   /**
  79:    * This method overrides URLStreamHandler's for parsing url of protocol "jar"
  80:    *
  81:    * @param url The URL object in which to store the results
  82:    * @param url_string The String-ized URL to parse
  83:    * @param start The position in the string to start scanning from
  84:    * @param end The position in the string to stop scanning
  85:    */
  86:   protected void parseURL (URL url, String url_string, int start, int end)
  87:   {
  88:     // This method does not throw an exception or return a value.  Thus our
  89:     // strategy when we encounter an error in parsing is to return without
  90:     // doing anything.
  91:     String file = url.getFile();
  92:     
  93:     if (!file.equals(""))
  94:       { //has context url
  95:     url_string = url_string.substring (start, end);
  96:         if (url_string.startsWith("/"))
  97:           { //url string is an absolute path
  98:             int idx = file.lastIndexOf ("!/");
  99:         
 100:         if (idx < 0)
 101:           throw new URLParseError("no !/ in spec");
 102:         
 103:         file = file.substring (0, idx + 1) + url_string;
 104:           }
 105:         else if (url_string.length() > 0)
 106:           {
 107:             int idx = file.lastIndexOf ("/");
 108:             if (idx == -1) //context path is weird
 109:               file = "/" + url_string; 
 110:             else if (idx == (file.length() - 1))
 111:               //just concatenate two parts
 112:               file = file + url_string;
 113:             else
 114:               // according to Java API Documentation, here is a little different 
 115:               // with URLStreamHandler.parseURL
 116:               // but JDK seems doesn't handle it well
 117:               file = file.substring(0, idx + 1) + url_string;
 118:           }
 119:         
 120:         setURL (url, "jar", url.getHost(), url.getPort(), flat(file), null);
 121:         return;
 122:       }
 123: 
 124:     // Bunches of things should be true.  Make sure.
 125:     if (end < start)
 126:       return;
 127:     if (end - start < 2)
 128:       return;
 129:     if (start > url_string.length())
 130:       return;
 131:     
 132:     // Skip remains of protocol
 133:     url_string = url_string.substring (start, end);
 134: 
 135:     int jar_stop;
 136:     if ((jar_stop = url_string.indexOf("!/")) < 0)
 137:       throw new URLParseError("no !/ in spec");
 138: 
 139:     try
 140:       {
 141:     new URL(url_string.substring (0, jar_stop));
 142:       }
 143:     catch (MalformedURLException e)
 144:       {
 145:     throw new URLParseError("invalid inner URL: " + e.getMessage());
 146:       }
 147:     
 148:     if (!url.getProtocol().equals ("jar") )
 149:       throw new URLParseError("unexpected protocol " + url.getProtocol());
 150:         
 151:     setURL (url, "jar", url.getHost(), url.getPort(), url_string, null);
 152:   }
 153: 
 154:   /**
 155:    * Makes the given jar url string 'flat' by removing any . and .. from
 156:    * jar file path because ZipFile entries can only handle flat paths.
 157:    * Inside jar files '/' is always the path separator.
 158:    */
 159:   private static String flat(String url_string)
 160:   {
 161:     int jar_stop = url_string.indexOf("!/");
 162:     String jar_path = url_string.substring(jar_stop + 1, url_string.length());
 163: 
 164:     if (jar_path.indexOf("/.") < 0)
 165:       return url_string;
 166: 
 167:     ArrayList<String> tokens = new ArrayList<String>();
 168:     StringTokenizer st = new StringTokenizer(jar_path, "/");
 169:     while (st.hasMoreTokens())
 170:       {
 171:     String token = st.nextToken();
 172:         if (token.equals("."))
 173:           continue;
 174:         else if (token.equals(".."))
 175:       {
 176:         if (! tokens.isEmpty())
 177:           tokens.remove(tokens.size() - 1);
 178:       }
 179:         else 
 180:       tokens.add(token);
 181:       }
 182: 
 183:     StringBuffer path = new StringBuffer(url_string.length());
 184:     path.append(url_string.substring(0, jar_stop + 1));
 185: 
 186:     Iterator<String> it = tokens.iterator();
 187:     while (it.hasNext())
 188:       path.append('/').append(it.next());
 189: 
 190:     return path.toString();
 191:   }
 192: 
 193:   /**
 194:    * This method converts a Jar URL object into a String.
 195:    *
 196:    * @param url The URL object to convert
 197:    */
 198:   protected String toExternalForm (URL url)
 199:   {
 200:     String file = url.getFile();
 201:     String ref = url.getRef();
 202: 
 203:     // return "jar:" + file;
 204:     // Performance!!: 
 205:     //  Do the concatenation manually to avoid resize StringBuffer's 
 206:     //  internal buffer.  The length of ref is not taken into consideration
 207:     //  as it's a rare path.
 208:     StringBuffer sb = new StringBuffer (file.length() + 5);
 209:     sb.append ("jar:");
 210:     sb.append (file);
 211:     if (ref != null)
 212:       sb.append('#').append(ref);
 213:     return sb.toString();
 214:   }
 215: }