1 /*
2 * Copyright (C) 2010, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.lib;
45
46 import org.eclipse.jgit.annotations.NonNull;
47 import org.eclipse.jgit.annotations.Nullable;
48
49 /**
50 * A reference that indirectly points at another
51 * {@link org.eclipse.jgit.lib.Ref}.
52 * <p>
53 * A symbolic reference always derives its current value from the target
54 * reference.
55 */
56 public class SymbolicRef implements Ref {
57 private final String name;
58
59 private final Ref target;
60
61 /**
62 * Create a new ref pairing.
63 *
64 * @param refName
65 * name of this ref.
66 * @param target
67 * the ref we reference and derive our value from.
68 */
69 public SymbolicRef(@NonNull String refName, @NonNull Ref target) {
70 this.name = refName;
71 this.target = target;
72 }
73
74 /** {@inheritDoc} */
75 @Override
76 @NonNull
77 public String getName() {
78 return name;
79 }
80
81 /** {@inheritDoc} */
82 @Override
83 public boolean isSymbolic() {
84 return true;
85 }
86
87 /** {@inheritDoc} */
88 @Override
89 @NonNull
90 public Ref getLeaf() {
91 Ref dst = getTarget();
92 while (dst.isSymbolic())
93 dst = dst.getTarget();
94 return dst;
95 }
96
97 /** {@inheritDoc} */
98 @Override
99 @NonNull
100 public Ref getTarget() {
101 return target;
102 }
103
104 /** {@inheritDoc} */
105 @Override
106 @Nullable
107 public ObjectId getObjectId() {
108 return getLeaf().getObjectId();
109 }
110
111 /** {@inheritDoc} */
112 @Override
113 @NonNull
114 public Storage getStorage() {
115 return Storage.LOOSE;
116 }
117
118 /** {@inheritDoc} */
119 @Override
120 @Nullable
121 public ObjectId getPeeledObjectId() {
122 return getLeaf().getPeeledObjectId();
123 }
124
125 /** {@inheritDoc} */
126 @Override
127 public boolean isPeeled() {
128 return getLeaf().isPeeled();
129 }
130
131 /** {@inheritDoc} */
132 @SuppressWarnings("nls")
133 @Override
134 public String toString() {
135 StringBuilder r = new StringBuilder();
136 r.append("SymbolicRef[");
137 Ref cur = this;
138 while (cur.isSymbolic()) {
139 r.append(cur.getName());
140 r.append(" -> ");
141 cur = cur.getTarget();
142 }
143 r.append(cur.getName());
144 r.append('=');
145 r.append(ObjectId.toString(cur.getObjectId()));
146 r.append("]");
147 return r.toString();
148 }
149 }