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 
ClassLoaderHelper()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      */
mapAlternativeName(File lib)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      */
parsePath(String ldPath)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 }
99