content: /*
   * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package javac.internal.jrtfs;
  
  import java.util.regex.PatternSyntaxException;
  
  /**
   * @implNote This class needs to maintain JDK 8 source compatibility.
   *
   * It is used internally in the JDK to implement jimage/jrtfs access,
   * but also compiled and delivered as part of the jrtfs.jar to support access
   * to the jimage file provided by the shipped JDK by tools running on JDK 8.
   */
  final class JrtUtils {
      private JrtUtils() {}
  
      private static final String regexMetaChars = ".^$+{[]|()";
      private static final String globMetaChars = "\\*?[{";
      private static boolean isRegexMeta(char c) {
          return regexMetaChars.indexOf(c) != -1;
      }
      private static boolean isGlobMeta(char c) {
          return globMetaChars.indexOf(c) != -1;
      }
      private static final char EOL = 0;
      private static char next(String glob, int i) {
          if (i < glob.length()) {
              return glob.charAt(i);
          }
          return EOL;
      }
  
      /*
       * Creates a regex pattern from the given glob expression.
       *
       * @throws  PatternSyntaxException
       */
      public static String toRegexPattern(String globPattern) {
          boolean inGroup = false;
          StringBuilder regex = new StringBuilder("^");
  
          int i = 0;
          while (i < globPattern.length()) {
              char c = globPattern.charAt(i++);
              switch (c) {
                  case '\\':
                      // escape special characters
                      if (i == globPattern.length()) {
                          throw new PatternSyntaxException("No character to escape",
                                  globPattern, i - 1);
                      }
                      char next = globPattern.charAt(i++);
                      if (isGlobMeta(next) || isRegexMeta(next)) {
                          regex.append('\\');
                      }
                      regex.append(next);
                      break;
                  case '/':
                      regex.append(c);
                      break;
                  case '[':
                      // don't match name separator in class
                      regex.append("[[^/]&&[");
                      if (next(globPattern, i) == '^') {
                          // escape the regex negation char if it appears
                          regex.append("\\^");
                          i++;
                      } else {
                          // negation
                          if (next(globPattern, i) == '!') {
                              regex.append('^');
                              i++;
                          }
                          // hyphen allowed at start
                          if (next(globPattern, i) == '-') {
                              regex.append('-');
                              i++;
                          }
                      }
                      boolean hasRangeStart = false;
                      char last = 0;
                      while (i < globPattern.length()) {
                          c = globPattern.charAt(i++);
                          if (c == ']') {
                              break;
                          }
                          if (c == '/') {
                              throw new PatternSyntaxException("Explicit 'name separator' in class",
                                      globPattern, i - 1);
                          }
                          // TBD: how to specify ']' in a class?
                          if (c == '\\' || c == '[' ||
                                  c == '&' && next(globPattern, i) == '&') {
                              // escape '\', '[' or "&&" for regex class
                              regex.append('\\');
                          }
                          regex.append(c);
  
                          if (c == '-') {
                              if (!hasRangeStart) {
                                  throw new PatternSyntaxException("Invalid range",
                                          globPattern, i - 1);
                              }
                              if ((c = next(globPattern, i++)) == EOL || c == ']') {
                                  break;
                              }
                              if (c < last) {
                                  throw new PatternSyntaxException("Invalid range",
                                          globPattern, i - 3);
                              }
                              regex.append(c);
                              hasRangeStart = false;
                          } else {
                              hasRangeStart = true;
                              last = c;
                          }
                      }
                      if (c != ']') {
                          throw new PatternSyntaxException("Missing ']", globPattern, i - 1);
                      }
                      regex.append("]]");
                      break;
                  case '{':
                      if (inGroup) {
                          throw new PatternSyntaxException("Cannot nest groups",
                                  globPattern, i - 1);
                      }
                      regex.append("(?:(?:");
                      inGroup = true;
                      break;
                  case '}':
                      if (inGroup) {
                          regex.append("))");
                          inGroup = false;
                      } else {
                          regex.append('}');
                      }
                      break;
                  case ',':
                      if (inGroup) {
                          regex.append(")|(?:");
                      } else {
                          regex.append(',');
                      }
                      break;
                  case '*':
                      if (next(globPattern, i) == '*') {
                          // crosses directory boundaries
                          regex.append(".*");
                          i++;
                      } else {
                          // within directory boundary
                          regex.append("[^/]*");
                      }
                      break;
                  case '?':
                     regex.append("[^/]");
                     break;
                  default:
                      if (isRegexMeta(c)) {
                          regex.append('\\');
                      }
                      regex.append(c);
              }
          }
          if (inGroup) {
              throw new PatternSyntaxException("Missing '}", globPattern, i - 1);
          }
          return regex.append('$').toString();
      }
  }
  