1 /*
   2  * Copyright (c) 2012, 2020, 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.internal.loader;
  27 
  28 import java.io.File;
  29 
  30 class ClassLoaderHelper {
  31 
  32     private ClassLoaderHelper() {}
  33 
  34     /**
  35      * Returns an alternate path name for the given file
  36      * such that if the original pathname did not exist, then the
  37      * file may be located at the alternate location.
  38      * For most platforms, this behavior is not supported and returns null.
  39      */
  40     static File mapAlternativeName(File lib) {
  41         return null;
  42     }
  43 
  44     /**
  45      * Parse a PATH env variable. Windows allows quoted elements in a PATH,
  46      * so special care needs to be taken.
  47      *
  48      * Empty elements will be replaced by dot.
  49      */
  50     static String[] parsePath(String ldPath) {
  51         int ldLen = ldPath.length();
  52         char ps = File.pathSeparatorChar;
  53         int psCount = 0;
  54 
  55         if (ldPath.indexOf('\"') >= 0) {
  56             // First, remove quotes put around quoted parts of paths.
  57             // Second, use a quotation mark as a new path separator.
  58             // This will preserve any quoted old path separators.
  59             char[] buf = new char[ldLen];
  60             int bufLen = 0;
  61             for (int i = 0; i < ldLen; ++i) {
  62                 char ch = ldPath.charAt(i);
  63                 if (ch == '\"') {
  64                     while (++i < ldLen &&
  65                             (ch = ldPath.charAt(i)) != '\"') {
  66                         buf[bufLen++] = ch;
  67                     }
  68                 } else {
  69                     if (ch == ps) {
  70                         psCount++;
  71                         ch = '\"';
  72                     }
  73                     buf[bufLen++] = ch;
  74                 }
  75             }
  76             ldPath = new String(buf, 0, bufLen);
  77             ldLen = bufLen;
  78             ps = '\"';
  79         } else {
  80             for (int i = ldPath.indexOf(ps); i >= 0;
  81                  i = ldPath.indexOf(ps, i + 1)) {
  82                 psCount++;
  83             }
  84         }
  85 
  86         String[] paths = new String[psCount + 1];
  87         int pathStart = 0;
  88         for (int j = 0; j < psCount; ++j) {
  89             int pathEnd = ldPath.indexOf(ps, pathStart);
  90             paths[j] = (pathStart < pathEnd) ?
  91                     ldPath.substring(pathStart, pathEnd) : ".";
  92             pathStart = pathEnd + 1;
  93         }
  94         paths[psCount] = (pathStart < ldLen) ?
  95                 ldPath.substring(pathStart, ldLen) : ".";
  96         return paths;
  97     }
  98 }