1 package org.apache.maven.plugins.shade.mojo;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.io.File;
23 import java.util.ArrayList;
24 import java.util.Collections;
25 import java.util.List;
26
27 /**
28 *
29 */
30 public final class RelativizePath
31 {
32 private RelativizePath()
33 {
34 //
35 }
36
37 /**
38 * relativize a pathname.
39 * @param thing Absolute File of something. (e.g., a parent pom)
40 * @param relativeTo base to relativize it do. (e.g., a pom into which a relative pathname to the 'thing' is to be installed).
41 * @return
42 */
43 static String convertToRelativePath( File thing, File relativeTo )
44 {
45 StringBuilder relativePath = null;
46
47 if ( thing.getParentFile().equals( relativeTo.getParentFile() ) )
48 {
49 return thing.getName(); // a very simple relative path.
50 }
51
52 List<String> thingDirectories = RelativizePath.parentDirs( thing );
53 List<String> relativeToDirectories = RelativizePath.parentDirs( relativeTo );
54
55 //Get the shortest of the two paths
56 int length = thingDirectories.size() < relativeToDirectories.size() ? thingDirectories.size() : relativeToDirectories.size();
57
58 int lastCommonRoot = -1; // index of the lowest directory down from the root that the two have in common.
59 int index;
60
61 //Find common root
62 for ( index = 0; index < length; index++ )
63 {
64 if ( thingDirectories.get( index ).equals( relativeToDirectories.get( index ) ) )
65 {
66 lastCommonRoot = index;
67 }
68 else
69 {
70 break;
71 }
72 }
73 if ( lastCommonRoot != -1 )
74 { // possible on Windows or other multi-root cases.
75 // Build up the relative path
76 relativePath = new StringBuilder();
77 // add ..'s to get from the base up to the common point
78 for ( index = lastCommonRoot + 1; index < relativeToDirectories.size(); index++ )
79 {
80 relativePath.append( "../" );
81 }
82
83 // now add down from the common point to the actual 'thing' item.
84 for ( index = lastCommonRoot + 1; index < thingDirectories.size(); index++ )
85 {
86 relativePath.append( thingDirectories.get( index ) + '/' );
87 }
88 relativePath.append( thing.getName() );
89 return relativePath.toString();
90 }
91 return null;
92 }
93
94 static List<String> parentDirs( File of )
95 {
96 List<String> results = new ArrayList<String>();
97 for ( File p = of.getParentFile() ; p != null ; p = p.getParentFile() )
98 {
99 if ( !"".equals( p.getName() ) )
100 {
101 results.add( p.getName() );
102 }
103 }
104
105 Collections.reverse( results );
106 return results;
107 }
108 }