1 /*
2 * Copyright (C) 2009, Google Inc.
3 * Copyright (C) 2012, Research In Motion Limited
4 * and other copyright owners as documented in the project's IP log.
5 *
6 * This program and the accompanying materials are made available
7 * under the terms of the Eclipse Distribution License v1.0 which
8 * accompanies this distribution, is reproduced below, and is
9 * available at http://www.eclipse.org/org/documents/edl-v10.php
10 *
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or
14 * without modification, are permitted provided that the following
15 * conditions are met:
16 *
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * - Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials provided
23 * with the distribution.
24 *
25 * - Neither the name of the Eclipse Foundation, Inc. nor the
26 * names of its contributors may be used to endorse or promote
27 * products derived from this software without specific prior
28 * written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
31 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
32 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
35 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
38 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
39 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
42 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 package org.eclipse.jgit.merge;
46
47 import java.io.IOException;
48
49 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
50 import org.eclipse.jgit.errors.MissingObjectException;
51 import org.eclipse.jgit.lib.AnyObjectId;
52 import org.eclipse.jgit.lib.ObjectId;
53 import org.eclipse.jgit.lib.ObjectInserter;
54 import org.eclipse.jgit.lib.Repository;
55 import org.eclipse.jgit.revwalk.RevCommit;
56 import org.eclipse.jgit.revwalk.RevTree;
57 import org.eclipse.jgit.treewalk.AbstractTreeIterator;
58 import org.eclipse.jgit.treewalk.EmptyTreeIterator;
59
60 /**
61 * A merge of 2 trees, using a common base ancestor tree.
62 */
63 public abstract class ThreeWayMerger extends Merger {
64 private RevTree baseTree;
65
66 private ObjectId baseCommitId;
67
68 /**
69 * Create a new merge instance for a repository.
70 *
71 * @param local
72 * the repository this merger will read and write data on.
73 */
74 protected ThreeWayMerger(final Repository local) {
75 super(local);
76 }
77
78 /**
79 * Create a new merge instance for a repository.
80 *
81 * @param local
82 * the repository this merger will read and write data on.
83 * @param inCore
84 * perform the merge in core with no working folder involved
85 */
86 protected ThreeWayMerger(final Repository local, boolean inCore) {
87 this(local);
88 }
89
90 /**
91 * Create a new in-core merge instance from an inserter.
92 *
93 * @param inserter
94 * the inserter to write objects to.
95 * @since 4.8
96 */
97 protected ThreeWayMerger(ObjectInserter inserter) {
98 super(inserter);
99 }
100
101 /**
102 * Set the common ancestor tree.
103 *
104 * @param id
105 * common base treeish; null to automatically compute the common
106 * base from the input commits during
107 * {@link #merge(AnyObjectId...)}.
108 * @throws org.eclipse.jgit.errors.IncorrectObjectTypeException
109 * the object is not a treeish.
110 * @throws org.eclipse.jgit.errors.MissingObjectException
111 * the object does not exist.
112 * @throws java.io.IOException
113 * the object could not be read.
114 */
115 public void setBase(final AnyObjectId id) throws MissingObjectException,
116 IncorrectObjectTypeException, IOException {
117 if (id != null) {
118 baseTree = walk.parseTree(id);
119 } else {
120 baseTree = null;
121 }
122 }
123
124 /** {@inheritDoc} */
125 @Override
126 public boolean merge(final AnyObjectId... tips) throws IOException {
127 if (tips.length != 2)
128 return false;
129 return super.merge(tips);
130 }
131
132 /** {@inheritDoc} */
133 @Override
134 public ObjectId getBaseCommitId() {
135 return baseCommitId;
136 }
137
138 /**
139 * Create an iterator to walk the merge base.
140 *
141 * @return an iterator over the caller-specified merge base, or the natural
142 * merge base of the two input commits.
143 * @throws java.io.IOException
144 */
145 protected AbstractTreeIterator mergeBase() throws IOException {
146 if (baseTree != null)
147 return openTree(baseTree);
148 RevCommit baseCommit = (baseCommitId != null) ? walk
149 .parseCommit(baseCommitId) : getBaseCommit(sourceCommits[0],
150 sourceCommits[1]);
151 if (baseCommit == null) {
152 baseCommitId = null;
153 return new EmptyTreeIterator();
154 } else {
155 baseCommitId = baseCommit.toObjectId();
156 return openTree(baseCommit.getTree());
157 }
158 }
159 }