1 /*
2 * Copyright (C) 2017, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.internal.revwalk;
45
46 import org.eclipse.jgit.lib.BitmapIndex.Bitmap;
47 import org.eclipse.jgit.lib.BitmapIndex.BitmapBuilder;
48 import org.eclipse.jgit.lib.Constants;
49 import org.eclipse.jgit.revwalk.filter.RevFilter;
50 import org.eclipse.jgit.revwalk.RevWalk;
51 import org.eclipse.jgit.revwalk.RevCommit;
52 import org.eclipse.jgit.revwalk.RevFlag;
53
54 /**
55 * A RevFilter that adds the visited commits to {@code bitmap} as a side
56 * effect.
57 * <p>
58 * When the walk hits a commit that is part of {@code bitmap}'s
59 * BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
60 * commit and its parents are marked as SEEN so that the walk does not
61 * have to visit its ancestors. This ensures the walk is very short if
62 * there is good bitmap coverage.
63 * <p>
64 * Commits named in {@code seen} are considered already seen. If one is
65 * encountered, that commit and its parents will be marked with the SEEN
66 * flag to prevent the walk from visiting its ancestors.
67 */
68 public class AddUnseenToBitmapFilter extends RevFilter {
69 private final BitmapBuilder seen;
70 private final BitmapBuilder bitmap;
71
72 /**
73 * Create a filter that adds visited commits to the given bitmap, but does not walk
74 * through the objects in {@code seen}.
75 *
76 * @param seen objects that are already seen
77 * @param bitmap bitmap to write visited commits to
78 */
79 public AddUnseenToBitmapFilter(BitmapBuilder seen, BitmapBuilder bitmap) {
80 this.seen = seen;
81 this.bitmap = bitmap;
82 }
83
84 /** {@inheritDoc} */
85 @Override
86 public final boolean include(RevWalk walker, RevCommit cmit) {
87 Bitmap visitedBitmap;
88
89 if (seen.contains(cmit) || bitmap.contains(cmit)) {
90 // already seen or included
91 } else if ((visitedBitmap = bitmap.getBitmapIndex()
92 .getBitmap(cmit)) != null) {
93 bitmap.or(visitedBitmap);
94 } else {
95 bitmap.addObject(cmit, Constants.OBJ_COMMIT);
96 return true;
97 }
98
99 for (RevCommit p : cmit.getParents()) {
100 p.add(RevFlag.SEEN);
101 }
102 return false;
103 }
104
105 /** {@inheritDoc} */
106 @Override
107 public final RevFilter clone() {
108 throw new UnsupportedOperationException();
109 }
110
111 /** {@inheritDoc} */
112 @Override
113 public final boolean requiresCommitBody() {
114 return false;
115 }
116 }