1 /*
2 * Copyright (C) 2008-2009, Google Inc.
3 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com>
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.lib.ObjectId;
50 import org.eclipse.jgit.lib.Repository;
51
52 /**
53 * Trivial merge strategy to make the resulting tree exactly match an input.
54 * <p>
55 * This strategy can be used to cauterize an entire side branch of history, by
56 * setting the output tree to one of the inputs, and ignoring any of the paths
57 * of the other inputs.
58 */
59 public class StrategyOneSided extends MergeStrategy {
60 private final String strategyName;
61
62 private final int treeIndex;
63
64 /**
65 * Create a new merge strategy to select a specific input tree.
66 *
67 * @param name
68 * name of this strategy.
69 * @param index
70 * the position of the input tree to accept as the result.
71 */
72 protected StrategyOneSided(final String name, final int index) {
73 strategyName = name;
74 treeIndex = index;
75 }
76
77 @Override
78 public String getName() {
79 return strategyName;
80 }
81
82 @Override
83 public Merger newMerger(final Repository db) {
84 return new OneSide(db, treeIndex);
85 }
86
87 @Override
88 public Merger newMerger(final Repository db, boolean inCore) {
89 return new OneSide(db, treeIndex);
90 }
91
92 static class OneSide extends Merger {
93 private final int treeIndex;
94
95 protected OneSide(final Repository local, final int index) {
96 super(local);
97 treeIndex = index;
98 }
99
100 @Override
101 protected boolean mergeImpl() throws IOException {
102 return treeIndex < sourceTrees.length;
103 }
104
105 @Override
106 public ObjectId getResultTreeId() {
107 return sourceTrees[treeIndex];
108 }
109
110 @Override
111 public ObjectId getBaseCommitId() {
112 return null;
113 }
114 }
115 }