1 /*
2 * Copyright (C) 2008-2013, Google Inc.
3 * Copyright (C) 2016, Laurent Delaigue <laurent.delaigue@obeo.fr>
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 import java.text.MessageFormat;
49
50 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
51 import org.eclipse.jgit.errors.NoMergeBaseException;
52 import org.eclipse.jgit.errors.NoMergeBaseException.MergeBaseFailureReason;
53 import org.eclipse.jgit.internal.JGitText;
54 import org.eclipse.jgit.lib.AnyObjectId;
55 import org.eclipse.jgit.lib.NullProgressMonitor;
56 import org.eclipse.jgit.lib.ObjectId;
57 import org.eclipse.jgit.lib.ObjectInserter;
58 import org.eclipse.jgit.lib.ObjectReader;
59 import org.eclipse.jgit.lib.ProgressMonitor;
60 import org.eclipse.jgit.lib.Repository;
61 import org.eclipse.jgit.revwalk.RevCommit;
62 import org.eclipse.jgit.revwalk.RevObject;
63 import org.eclipse.jgit.revwalk.RevTree;
64 import org.eclipse.jgit.revwalk.RevWalk;
65 import org.eclipse.jgit.revwalk.filter.RevFilter;
66 import org.eclipse.jgit.treewalk.AbstractTreeIterator;
67 import org.eclipse.jgit.treewalk.CanonicalTreeParser;
68
69 /**
70 * Instance of a specific {@link MergeStrategy} for a single {@link Repository}.
71 */
72 public abstract class Merger {
73 /** The repository this merger operates on. */
74 protected final Repository db;
75
76 /** Reader to support {@link #walk} and other object loading. */
77 protected ObjectReader reader;
78
79 /** A RevWalk for computing merge bases, or listing incoming commits. */
80 protected RevWalk walk;
81
82 private ObjectInserter inserter;
83
84 /** The original objects supplied in the merge; this can be any tree-ish. */
85 protected RevObject[] sourceObjects;
86
87 /** If {@link #sourceObjects}[i] is a commit, this is the commit. */
88 protected RevCommit[] sourceCommits;
89
90 /** The trees matching every entry in {@link #sourceObjects}. */
91 protected RevTree[] sourceTrees;
92
93 /**
94 * A progress monitor.
95 *
96 * @since 4.2
97 */
98 protected ProgressMonitor monitor = NullProgressMonitor.INSTANCE;
99
100 /**
101 * Create a new merge instance for a repository.
102 *
103 * @param local
104 * the repository this merger will read and write data on.
105 */
106 protected Merger(final Repository local) {
107 db = local;
108 inserter = db.newObjectInserter();
109 reader = inserter.newReader();
110 walk = new RevWalk(reader);
111 }
112
113 /**
114 * @return the repository this merger operates on.
115 */
116 public Repository getRepository() {
117 return db;
118 }
119
120 /** @return an object writer to create objects in {@link #getRepository()}. */
121 public ObjectInserter getObjectInserter() {
122 return inserter;
123 }
124
125 /**
126 * Set the inserter this merger will use to create objects.
127 * <p>
128 * If an inserter was already set on this instance (such as by a prior set,
129 * or a prior call to {@link #getObjectInserter()}), the prior inserter as
130 * well as the in-progress walk will be released.
131 *
132 * @param oi
133 * the inserter instance to use. Must be associated with the
134 * repository instance returned by {@link #getRepository()}.
135 */
136 public void setObjectInserter(ObjectInserter oi) {
137 walk.close();
138 reader.close();
139 inserter.close();
140 inserter = oi;
141 reader = oi.newReader();
142 walk = new RevWalk(reader);
143 }
144
145 /**
146 * Merge together two or more tree-ish objects.
147 * <p>
148 * Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
149 * trees or commits may be passed as input objects.
150 *
151 * @param tips
152 * source trees to be combined together. The merge base is not
153 * included in this set.
154 * @return true if the merge was completed without conflicts; false if the
155 * merge strategy cannot handle this merge or there were conflicts
156 * preventing it from automatically resolving all paths.
157 * @throws IncorrectObjectTypeException
158 * one of the input objects is not a commit, but the strategy
159 * requires it to be a commit.
160 * @throws IOException
161 * one or more sources could not be read, or outputs could not
162 * be written to the Repository.
163 */
164 public boolean merge(final AnyObjectId... tips) throws IOException {
165 return merge(true, tips);
166 }
167
168 /**
169 * Merge together two or more tree-ish objects.
170 * <p>
171 * Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
172 * trees or commits may be passed as input objects.
173 *
174 * @since 3.5
175 * @param flush
176 * whether to flush the underlying object inserter when finished to
177 * store any content-merged blobs and virtual merged bases; if
178 * false, callers are responsible for flushing.
179 * @param tips
180 * source trees to be combined together. The merge base is not
181 * included in this set.
182 * @return true if the merge was completed without conflicts; false if the
183 * merge strategy cannot handle this merge or there were conflicts
184 * preventing it from automatically resolving all paths.
185 * @throws IncorrectObjectTypeException
186 * one of the input objects is not a commit, but the strategy
187 * requires it to be a commit.
188 * @throws IOException
189 * one or more sources could not be read, or outputs could not
190 * be written to the Repository.
191 */
192 public boolean merge(final boolean flush, final AnyObjectId... tips)
193 throws IOException {
194 sourceObjects = new RevObject[tips.length];
195 for (int i = 0; i < tips.length; i++)
196 sourceObjects[i] = walk.parseAny(tips[i]);
197
198 sourceCommits = new RevCommit[sourceObjects.length];
199 for (int i = 0; i < sourceObjects.length; i++) {
200 try {
201 sourceCommits[i] = walk.parseCommit(sourceObjects[i]);
202 } catch (IncorrectObjectTypeException err) {
203 sourceCommits[i] = null;
204 }
205 }
206
207 sourceTrees = new RevTree[sourceObjects.length];
208 for (int i = 0; i < sourceObjects.length; i++)
209 sourceTrees[i] = walk.parseTree(sourceObjects[i]);
210
211 try {
212 boolean ok = mergeImpl();
213 if (ok && flush)
214 inserter.flush();
215 return ok;
216 } finally {
217 if (flush)
218 inserter.close();
219 reader.close();
220 }
221 }
222
223 /**
224 * @return the ID of the commit that was used as merge base for merging, or
225 * null if no merge base was used or it was set manually
226 * @since 3.2
227 */
228 public abstract ObjectId getBaseCommitId();
229
230 /**
231 * Return the merge base of two commits.
232 *
233 * @param a
234 * the first commit in {@link #sourceObjects}.
235 * @param b
236 * the second commit in {@link #sourceObjects}.
237 * @return the merge base of two commits
238 * @throws IncorrectObjectTypeException
239 * one of the input objects is not a commit.
240 * @throws IOException
241 * objects are missing or multiple merge bases were found.
242 * @since 3.0
243 */
244 protected RevCommit getBaseCommit(RevCommit a, RevCommit b)
245 throws IncorrectObjectTypeException, IOException {
246 walk.reset();
247 walk.setRevFilter(RevFilter.MERGE_BASE);
248 walk.markStart(a);
249 walk.markStart(b);
250 final RevCommit base = walk.next();
251 if (base == null)
252 return null;
253 final RevCommit base2 = walk.next();
254 if (base2 != null) {
255 throw new NoMergeBaseException(
256 MergeBaseFailureReason.MULTIPLE_MERGE_BASES_NOT_SUPPORTED,
257 MessageFormat.format(
258 JGitText.get().multipleMergeBasesFor, a.name(), b.name(),
259 base.name(), base2.name()));
260 }
261 return base;
262 }
263
264 /**
265 * Open an iterator over a tree.
266 *
267 * @param treeId
268 * the tree to scan; must be a tree (not a treeish).
269 * @return an iterator for the tree.
270 * @throws IncorrectObjectTypeException
271 * the input object is not a tree.
272 * @throws IOException
273 * the tree object is not found or cannot be read.
274 */
275 protected AbstractTreeIterator openTree(final AnyObjectId treeId)
276 throws IncorrectObjectTypeException, IOException {
277 return new CanonicalTreeParser(null, reader, treeId);
278 }
279
280 /**
281 * Execute the merge.
282 * <p>
283 * This method is called from {@link #merge(AnyObjectId[])} after the
284 * {@link #sourceObjects}, {@link #sourceCommits} and {@link #sourceTrees}
285 * have been populated.
286 *
287 * @return true if the merge was completed without conflicts; false if the
288 * merge strategy cannot handle this merge or there were conflicts
289 * preventing it from automatically resolving all paths.
290 * @throws IncorrectObjectTypeException
291 * one of the input objects is not a commit, but the strategy
292 * requires it to be a commit.
293 * @throws IOException
294 * one or more sources could not be read, or outputs could not
295 * be written to the Repository.
296 */
297 protected abstract boolean mergeImpl() throws IOException;
298
299 /**
300 * @return resulting tree, if {@link #merge(AnyObjectId[])} returned true.
301 */
302 public abstract ObjectId getResultTreeId();
303
304 /**
305 * Set a progress monitor.
306 *
307 * @param monitor
308 * Monitor to use, can be null to indicate no progress reporting
309 * is desired.
310 * @since 4.2
311 */
312 public void setProgressMonitor(ProgressMonitor monitor) {
313 if (monitor == null) {
314 this.monitor = NullProgressMonitor.INSTANCE;
315 } else {
316 this.monitor = monitor;
317 }
318 }
319 }