1 /*
2 * Copyright (C) 2010, Garmin International
3 * Copyright (C) 2010, Matt Fischer <matt.fischer@garmin.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.revwalk;
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.ObjectId;
52
53 /**
54 * Only produce commits which are below a specified depth.
55 *
56 * @see DepthWalk
57 */
58 class DepthGenerator extends Generator {
59 private final FIFORevQueue pending;
60
61 private final int depth;
62
63 private final int deepenSince;
64
65 private final RevWalk walk;
66
67 /**
68 * Commits which used to be shallow in the client, but which are
69 * being extended as part of this fetch. These commits should be
70 * returned to the caller as UNINTERESTING so that their blobs/trees
71 * can be marked appropriately in the pack writer.
72 */
73 private final RevFlag UNSHALLOW;
74
75 /**
76 * Commits which the normal framework has marked as UNINTERESTING,
77 * but which we now care about again. This happens if a client is
78 * extending a shallow checkout to become deeper--the new commits at
79 * the bottom of the graph need to be sent, even though they are
80 * below other commits which the client already has.
81 */
82 private final RevFlag REINTERESTING;
83
84 /**
85 * Commits reachable from commits that the client specified using --shallow-exclude.
86 */
87 private final RevFlag DEEPEN_NOT;
88
89 /**
90 * @param w
91 * @param s Parent generator
92 * @throws MissingObjectException
93 * @throws IncorrectObjectTypeException
94 * @throws IOException
95 */
96 DepthGenerator(DepthWalk w, Generator s) throws MissingObjectException,
97 IncorrectObjectTypeException, IOException {
98 super(s.firstParent);
99 pending = new FIFORevQueue(firstParent);
100 walk = (RevWalk)w;
101
102 this.depth = w.getDepth();
103 this.deepenSince = w.getDeepenSince();
104 this.UNSHALLOW = w.getUnshallowFlag();
105 this.REINTERESTING = w.getReinterestingFlag();
106 this.DEEPEN_NOT = w.getDeepenNotFlag();
107
108 s.shareFreeList(pending);
109
110 // Begin by sucking out all of the source's commits, and
111 // adding them to the pending queue
112 FIFORevQueue unshallowCommits = new FIFORevQueue();
113 for (;;) {
114 RevCommit c = s.next();
115 if (c == null)
116 break;
117 if (c.has(UNSHALLOW)) {
118 unshallowCommits.add(c);
119 } else if (((DepthWalk.Commit) c).getDepth() == 0) {
120 pending.add(c);
121 }
122 }
123 // Move unshallow commits to the front so that the REINTERESTING flag
124 // carry over code is executed first.
125 for (;;) {
126 RevCommit c = unshallowCommits.next();
127 if (c == null) {
128 break;
129 }
130 pending.unpop(c);
131 }
132
133 // Mark DEEPEN_NOT on all deepen-not commits and their ancestors.
134 // TODO(jonathantanmy): This implementation is somewhat
135 // inefficient in that any "deepen-not <ref>" in the request
136 // results in all commits reachable from that ref being parsed
137 // and marked, even if the commit topology is such that it is
138 // not necessary.
139 for (ObjectId oid : w.getDeepenNots()) {
140 RevCommit c;
141 try {
142 c = walk.parseCommit(oid);
143 } catch (IncorrectObjectTypeException notCommit) {
144 // The C Git implementation silently tolerates
145 // non-commits, so do the same here.
146 continue;
147 }
148
149 FIFORevQueue queue = new FIFORevQueue();
150 queue.add(c);
151 while ((c = queue.next()) != null) {
152 if (c.has(DEEPEN_NOT)) {
153 continue;
154 }
155
156 walk.parseHeaders(c);
157 c.add(DEEPEN_NOT);
158 for (RevCommit p : c.getParents()) {
159 queue.add(p);
160 }
161 }
162 }
163 }
164
165 @Override
166 int outputType() {
167 return pending.outputType() | HAS_UNINTERESTING;
168 }
169
170 @Override
171 void shareFreeList(BlockRevQueue q) {
172 pending.shareFreeList(q);
173 }
174
175 @Override
176 RevCommit next() throws MissingObjectException,
177 IncorrectObjectTypeException, IOException {
178 // Perform a breadth-first descent into the commit graph,
179 // marking depths as we go. This means that if a commit is
180 // reachable by more than one route, we are guaranteed to
181 // arrive by the shortest route first.
182 for (;;) {
183 final DepthWalk.Commit c = (DepthWalk.Commit) pending.next();
184 if (c == null)
185 return null;
186
187 if ((c.flags & RevWalk.PARSED) == 0)
188 c.parseHeaders(walk);
189
190 if (c.getCommitTime() < deepenSince) {
191 continue;
192 }
193
194 if (c.has(DEEPEN_NOT)) {
195 continue;
196 }
197
198 int newDepth = c.depth + 1;
199
200 for (int i = 0; i < c.parents.length; i++) {
201 if (firstParent && i > 0) {
202 break;
203 }
204 RevCommit p = c.parents[i];
205 DepthWalk.Commit dp = (DepthWalk.Commit) p;
206
207 // If no depth has been assigned to this commit, assign
208 // it now. Since we arrive by the shortest route first,
209 // this depth is guaranteed to be the smallest value that
210 // any path could produce.
211 if (dp.depth == -1) {
212 boolean failsDeepenSince = false;
213 if (deepenSince != 0) {
214 if ((p.flags & RevWalk.PARSED) == 0) {
215 p.parseHeaders(walk);
216 }
217 failsDeepenSince =
218 p.getCommitTime() < deepenSince;
219 }
220
221 dp.depth = newDepth;
222
223 // If the parent is not too deep and was not excluded, add
224 // it to the queue so that we can produce it later
225 if (newDepth <= depth && !failsDeepenSince &&
226 !p.has(DEEPEN_NOT)) {
227 pending.add(p);
228 } else {
229 dp.makesChildBoundary = true;
230 }
231 }
232
233 if (dp.makesChildBoundary) {
234 c.isBoundary = true;
235 }
236
237 // If the current commit has become unshallowed, everything
238 // below us is new to the client. Mark its parent as
239 // re-interesting, and carry that flag downward to all
240 // of its ancestors.
241 if(c.has(UNSHALLOW) || c.has(REINTERESTING)) {
242 p.add(REINTERESTING);
243 p.flags &= ~RevWalk.UNINTERESTING;
244 }
245 }
246
247 boolean produce = true;
248
249 // Unshallow commits are uninteresting, but still need to be sent
250 // up to the PackWriter so that it will exclude objects correctly.
251 // All other uninteresting commits should be omitted.
252 if ((c.flags & RevWalk.UNINTERESTING) != 0 && !c.has(UNSHALLOW))
253 produce = false;
254
255 if (c.getCommitTime() < deepenSince) {
256 produce = false;
257 }
258
259 if (produce)
260 return c;
261 }
262 }
263 }