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 /** A merge of 2 trees, using a common base ancestor tree. */
61 public abstract class ThreeWayMerger extends Merger {
62 private RevTree baseTree;
63
64 private ObjectId baseCommitId;
65
66 /**
67 * Create a new merge instance for a repository.
68 *
69 * @param local
70 * the repository this merger will read and write data on.
71 */
72 protected ThreeWayMerger(final Repository local) {
73 super(local);
74 }
75
76 /**
77 * Create a new merge instance for a repository.
78 *
79 * @param local
80 * the repository this merger will read and write data on.
81 * @param inCore
82 * perform the merge in core with no working folder involved
83 */
84 protected ThreeWayMerger(final Repository local, boolean inCore) {
85 this(local);
86 }
87
88 /**
89 * Create a new in-core merge instance from an inserter.
90 *
91 * @param inserter
92 * the inserter to write objects to.
93 * @since 4.8
94 */
95 protected ThreeWayMerger(ObjectInserter inserter) {
96 super(inserter);
97 }
98
99 /**
100 * Set the common ancestor tree.
101 *
102 * @param id
103 * common base treeish; null to automatically compute the common
104 * base from the input commits during
105 * {@link #merge(AnyObjectId...)}.
106 * @throws IncorrectObjectTypeException
107 * the object is not a treeish.
108 * @throws MissingObjectException
109 * the object does not exist.
110 * @throws IOException
111 * the object could not be read.
112 */
113 public void setBase(final AnyObjectId id) throws MissingObjectException,
114 IncorrectObjectTypeException, IOException {
115 if (id != null) {
116 baseTree = walk.parseTree(id);
117 } else {
118 baseTree = null;
119 }
120 }
121
122 @Override
123 public boolean merge(final AnyObjectId... tips) throws IOException {
124 if (tips.length != 2)
125 return false;
126 return super.merge(tips);
127 }
128
129 @Override
130 public ObjectId getBaseCommitId() {
131 return baseCommitId;
132 }
133
134 /**
135 * Create an iterator to walk the merge base.
136 *
137 * @return an iterator over the caller-specified merge base, or the natural
138 * merge base of the two input commits.
139 * @throws IOException
140 */
141 protected AbstractTreeIterator mergeBase() throws IOException {
142 if (baseTree != null)
143 return openTree(baseTree);
144 RevCommit baseCommit = (baseCommitId != null) ? walk
145 .parseCommit(baseCommitId) : getBaseCommit(sourceCommits[0],
146 sourceCommits[1]);
147 if (baseCommit == null) {
148 baseCommitId = null;
149 return new EmptyTreeIterator();
150 } else {
151 baseCommitId = baseCommit.toObjectId();
152 return openTree(baseCommit.getTree());
153 }
154 }
155 }