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 private final long updateIndex;
62
63 /**
64 * Create a new ref pairing.
65 *
66 * @param refName
67 * name of this ref.
68 * @param target
69 * the ref we reference and derive our value from.
70 */
71 public SymbolicRef(@NonNull String refName, @NonNull Ref target) {
72 this.name = refName;
73 this.target = target;
74 this.updateIndex = UNDEFINED_UPDATE_INDEX;
75 }
76
77 /**
78 * Create a new ref pairing.
79 *
80 * @param refName
81 * name of this ref.
82 * @param target
83 * the ref we reference and derive our value from.
84 * @param updateIndex
85 * index that increases with each update of the reference
86 * @since 5.3
87 */
88 public SymbolicRef(@NonNull String refName, @NonNull Ref target,
89 long updateIndex) {
90 this.name = refName;
91 this.target = target;
92 this.updateIndex = updateIndex;
93 }
94
95 /** {@inheritDoc} */
96 @Override
97 @NonNull
98 public String getName() {
99 return name;
100 }
101
102 /** {@inheritDoc} */
103 @Override
104 public boolean isSymbolic() {
105 return true;
106 }
107
108 /** {@inheritDoc} */
109 @Override
110 @NonNull
111 public Ref getLeaf() {
112 Ref dst = getTarget();
113 while (dst.isSymbolic())
114 dst = dst.getTarget();
115 return dst;
116 }
117
118 /** {@inheritDoc} */
119 @Override
120 @NonNull
121 public Ref getTarget() {
122 return target;
123 }
124
125 /** {@inheritDoc} */
126 @Override
127 @Nullable
128 public ObjectId getObjectId() {
129 return getLeaf().getObjectId();
130 }
131
132 /** {@inheritDoc} */
133 @Override
134 @NonNull
135 public Storage getStorage() {
136 return Storage.LOOSE;
137 }
138
139 /** {@inheritDoc} */
140 @Override
141 @Nullable
142 public ObjectId getPeeledObjectId() {
143 return getLeaf().getPeeledObjectId();
144 }
145
146 /** {@inheritDoc} */
147 @Override
148 public boolean isPeeled() {
149 return getLeaf().isPeeled();
150 }
151
152 /**
153 * {@inheritDoc}
154 * @since 5.3
155 */
156 @Override
157 public long getUpdateIndex() {
158 if (updateIndex == UNDEFINED_UPDATE_INDEX) {
159 throw new UnsupportedOperationException();
160 }
161 return updateIndex;
162 }
163
164 /** {@inheritDoc} */
165 @SuppressWarnings("nls")
166 @Override
167 public String toString() {
168 StringBuilder r = new StringBuilder();
169 r.append("SymbolicRef[");
170 Ref cur = this;
171 while (cur.isSymbolic()) {
172 r.append(cur.getName());
173 r.append(" -> ");
174 cur = cur.getTarget();
175 }
176 r.append(cur.getName());
177 r.append('=');
178 r.append(ObjectId.toString(cur.getObjectId()));
179 r.append("(");
180 r.append(updateIndex); // Print value, even if -1
181 r.append(")]");
182 return r.toString();
183 }
184 }