1 /*
   2  * Copyright (c) 2010, 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 jdk.nashorn.internal.runtime.regexp;
  27 
  28 import java.util.regex.MatchResult;
  29 import jdk.nashorn.internal.runtime.BitVector;
  30 import jdk.nashorn.internal.runtime.ECMAErrors;
  31 import jdk.nashorn.internal.runtime.ParserException;
  32 
  33 /**
  34  * This is the base class for representing a parsed regular expression.
  35  *
  36  * Instances of this class are created by a {@link RegExpFactory}.
  37  */
  38 public abstract class RegExp {
  39 
  40     /** Pattern string. */
  41     private final String source;
  42 
  43     /** Global search flag for this regexp.*/
  44     private boolean global;
  45 
  46     /** Case insensitive flag for this regexp */
  47     private boolean ignoreCase;
  48 
  49     /** Multi-line flag for this regexp */
  50     private boolean multiline;
  51 
  52     /** BitVector that keeps track of groups in negative lookahead */
  53     protected BitVector groupsInNegativeLookahead;
  54 
  55     /**
  56      * Constructor.
  57      *
  58      * @param source the source string
  59      * @param flags the flags string
  60      */
  61     protected RegExp(final String source, final String flags) {
  62         this.source = source.length() == 0 ? "(?:)" : source;
  63         for (int i = 0; i < flags.length(); i++) {
  64             final char ch = flags.charAt(i);
  65             switch (ch) {
  66             case 'g':
  67                 if (this.global) {
  68                     throwParserException("repeated.flag", "g");
  69                 }
  70                 this.global = true;
  71                 break;
  72             case 'i':
  73                 if (this.ignoreCase) {
  74                     throwParserException("repeated.flag", "i");
  75                 }
  76                 this.ignoreCase = true;
  77                 break;
  78             case 'm':
  79                 if (this.multiline) {
  80                     throwParserException("repeated.flag", "m");
  81                 }
  82                 this.multiline = true;
  83                 break;
  84             default:
  85                 throwParserException("unsupported.flag", Character.toString(ch));
  86             }
  87         }
  88     }
  89 
  90     /**
  91      * Get the source pattern of this regular expression.
  92      *
  93      * @return the source string
  94      */
  95     public String getSource() {
  96         return source;
  97     }
  98 
  99     /**
 100      * Set the global flag of this regular expression to {@code global}.
 101      *
 102      * @param global the new global flag
 103      */
 104     public void setGlobal(final boolean global) {
 105         this.global = global;
 106     }
 107 
 108     /**
 109      * Get the global flag of this regular expression.
 110      *
 111      * @return the global flag
 112      */
 113     public boolean isGlobal() {
 114         return global;
 115     }
 116 
 117     /**
 118      * Get the ignore-case flag of this regular expression.
 119      *
 120      * @return the ignore-case flag
 121      */
 122     public boolean isIgnoreCase() {
 123         return ignoreCase;
 124     }
 125 
 126     /**
 127      * Get the multiline flag of this regular expression.
 128      *
 129      * @return the multiline flag
 130      */
 131     public boolean isMultiline() {
 132         return multiline;
 133     }
 134 
 135     /**
 136      * Get a bitset indicating which of the groups in this regular expression are inside a negative lookahead.
 137      *
 138      * @return the groups-in-negative-lookahead bitset
 139      */
 140     public BitVector getGroupsInNegativeLookahead() {
 141         return groupsInNegativeLookahead;
 142     }
 143 
 144     /**
 145      * Match this regular expression against {@code str}, starting at index {@code start}
 146      * and return a {@link MatchResult} with the result.
 147      *
 148      * @param str the string
 149      * @return the matcher
 150      */
 151     public abstract RegExpMatcher match(String str);
 152 
 153     /**
 154      * Throw a regexp parser exception.
 155      *
 156      * @param key the message key
 157      * @param str string argument
 158      * @throws jdk.nashorn.internal.runtime.ParserException unconditionally
 159      */
 160     protected static void throwParserException(final String key, final String str) throws ParserException {
 161         throw new ParserException(ECMAErrors.getMessage("parser.error.regex." + key, str));
 162     }
 163 }