Source for gnu.javax.security.auth.login.ConfigFileTokenizer

   1: /* ConfigFileTokenizer.java -- JAAS Login Configuration default syntax tokenizer
   2:    Copyright (C) 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.javax.security.auth.login;
  40: 
  41: import gnu.java.lang.CPStringBuilder;
  42: 
  43: import gnu.java.security.Configuration;
  44: 
  45: import java.io.BufferedReader;
  46: import java.io.IOException;
  47: import java.io.Reader;
  48: import java.util.logging.Logger;
  49: 
  50: /**
  51:  * A UTF-8 friendly, JAAS Login Module Configuration file tokenizer written in
  52:  * the deault syntax. This class emulates, to a certain extent, the behavior of
  53:  * a {@link java.io.StreamTokenizer} instance <code>st</code>, when set as
  54:  * follows:
  55:  * 
  56:  *  <pre>
  57:  *  st.resetSyntax();
  58:  *  st.lowerCaseMode(false);
  59:  *  st.slashSlashComments(true);
  60:  *  st.slashStarComments(true);
  61:  *  st.eolIsSignificant(false);
  62:  *  st.wordChars('_', '_');
  63:  *  st.wordChars('$', '$');
  64:  *  st.wordChars('A', 'Z');
  65:  *  st.wordChars('a', 'z');
  66:  *  st.wordChars('0', '9');
  67:  *  st.wordChars('.', '.');
  68:  *  st.whitespaceChars(' ', ' ');
  69:  *  st.whitespaceChars('\t', '\t');
  70:  *  st.whitespaceChars('\f', '\f');
  71:  *  st.whitespaceChars('\r', '\r');
  72:  *  st.whitespaceChars('\n', '\n');
  73:  *  st.quoteChar('"');
  74:  *  st.quoteChar('\'');
  75:  *  </pre>
  76:  *
  77:  * <p>The most important (negative) difference with a
  78:  * {@link java.io.StreamTokenizer} is that this tokenizer does not properly
  79:  * handle C++ and Java // style comments in the middle of the line. It only
  80:  * ignores them if/when found at the start of the line.</p>  
  81:  */
  82: public class ConfigFileTokenizer
  83: {
  84:   private static final Logger log = Logger.getLogger(ConfigFileParser.class.getName());
  85:   /** A constant indicating that the end of the stream has been read. */
  86:   public static final int TT_EOF = -1;
  87:   /** A constant indicating that a word token has been read. */
  88:   public static final int TT_WORD = -3;
  89:   /** A constant indicating that no tokens have been read yet. */
  90:   private static final int TT_NONE = -4;
  91: 
  92:   public String sval;
  93:   public int ttype;
  94: 
  95:   private BufferedReader br;
  96:   boolean initialised;
  97:   private CPStringBuilder sb;
  98:   private int sbNdx;
  99: 
 100:   // Constructor(s)
 101:   // --------------------------------------------------------------------------
 102: 
 103:   /** Trivial constructor. */
 104:   ConfigFileTokenizer(Reader r)
 105:   {
 106:     super();
 107: 
 108:     br = r instanceof BufferedReader ? (BufferedReader) r : new BufferedReader(r);
 109:     initialised = false;
 110:   }
 111: 
 112:   // Class methods
 113:   // --------------------------------------------------------------------------
 114: 
 115:   // Instance methods
 116:   // --------------------------------------------------------------------------
 117: 
 118:   public int nextToken() throws IOException
 119:   {
 120:     if (!initialised)
 121:       init();
 122: 
 123:     if (sbNdx >= sb.length())
 124:       return TT_EOF;
 125: 
 126:     skipWhitespace();
 127: 
 128:     if (sbNdx >= sb.length())
 129:       return TT_EOF;
 130: 
 131:     int endNdx;
 132:     if (Character.isJavaIdentifierPart(sb.charAt(sbNdx)))
 133:       {
 134:         endNdx = sbNdx + 1;
 135:         while (Character.isJavaIdentifierPart(sb.charAt(endNdx))
 136:             || sb.charAt(endNdx) == '.')
 137:           endNdx++;
 138: 
 139:         ttype = TT_WORD;
 140:         sval = sb.substring(sbNdx, endNdx);
 141:         sbNdx = endNdx;
 142:         return ttype;
 143:       }
 144: 
 145:     int c = sb.charAt(sbNdx);
 146:     if (c == '{' || c == '}' || c == ';' || c == '=')
 147:       {
 148:         ttype = c;
 149:         sbNdx++;
 150:         return ttype;
 151:       }
 152: 
 153:     if (c == '"' || c == '\'')
 154:       {
 155:         ttype = c;
 156:         String quote = sb.substring(sbNdx, sbNdx + 1);
 157:         int i = sbNdx + 1;
 158:         while (true)
 159:           {
 160:             // find a candidate
 161:             endNdx = sb.indexOf(quote, i);
 162:             if (endNdx == -1)
 163:               abort("Missing closing quote: " + quote);
 164: 
 165:             // found one; is it escaped?
 166:             if (sb.charAt(endNdx - 1) != '\\')
 167:               break;
 168: 
 169:             i++;
 170:             continue;
 171:           }
 172: 
 173:         endNdx++;
 174:         sval = sb.substring(sbNdx, endNdx);
 175:         sbNdx = endNdx;
 176:         return ttype;
 177:       }
 178: 
 179:     abort("Unknown character: " + sb.charAt(sbNdx));
 180:     return Integer.MIN_VALUE;
 181:   }
 182: 
 183:   public void pushBack()
 184:   {
 185:     sbNdx -= ttype != TT_WORD ? 1 : sval.length();
 186:   }
 187: 
 188:   private void init() throws IOException
 189:   {
 190:     sb = new CPStringBuilder();
 191:     String line;
 192:     while ((line = br.readLine()) != null)
 193:       {
 194:         line = line.trim();
 195:         if (line.length() == 0)
 196:           continue;
 197: 
 198:         if (line.startsWith("#") || line.startsWith("//"))
 199:           continue;
 200: 
 201:         sb.append(line).append(" ");
 202:       }
 203: 
 204:     sbNdx = 0;
 205:     sval = null;
 206:     ttype = TT_NONE;
 207: 
 208:     initialised = true;
 209:   }
 210: 
 211:   private void skipWhitespace() throws IOException
 212:   {
 213:     int endNdx;
 214:     while (sbNdx < sb.length())
 215:       if (Character.isWhitespace(sb.charAt(sbNdx)))
 216:         {
 217:           sbNdx++;
 218:           while (sbNdx < sb.length() && Character.isWhitespace(sb.charAt(sbNdx)))
 219:             sbNdx++;
 220: 
 221:           continue;
 222:         }
 223:       else if (sb.charAt(sbNdx) == '/' && sb.charAt(sbNdx + 1) == '*')
 224:         {
 225:           endNdx = sb.indexOf("*/", sbNdx + 2);
 226:           if (endNdx == -1)
 227:             abort("Missing closing */ sequence");
 228: 
 229:           sbNdx = endNdx + 2;
 230:           continue;
 231:         }
 232:       else
 233:         break;
 234:   }
 235: 
 236:   private void abort(String m) throws IOException
 237:   {
 238:     if (Configuration.DEBUG)
 239:       {
 240:         log.fine(m);
 241:         log.fine("sb = " + sb);
 242:         log.fine("sbNdx = " + sbNdx);
 243:       }
 244:     throw new IOException(m);
 245:   }
 246: }