1 /*
2 * Copyright (C) 2017, Google Inc. and others
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Distribution License v. 1.0 which is available at
6 * https://www.eclipse.org/org/documents/edl-v10.php.
7 *
8 * SPDX-License-Identifier: BSD-3-Clause
9 */
10
11 package org.eclipse.jgit.internal.revwalk;
12
13 import org.eclipse.jgit.lib.BitmapIndex.Bitmap;
14 import org.eclipse.jgit.lib.BitmapIndex.BitmapBuilder;
15 import org.eclipse.jgit.lib.Constants;
16 import org.eclipse.jgit.revwalk.filter.RevFilter;
17 import org.eclipse.jgit.revwalk.RevWalk;
18 import org.eclipse.jgit.revwalk.RevCommit;
19 import org.eclipse.jgit.revwalk.RevFlag;
20
21 /**
22 * A RevFilter that adds the visited commits to {@code bitmap} as a side
23 * effect.
24 * <p>
25 * When the walk hits a commit that is part of {@code bitmap}'s
26 * BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
27 * commit and its parents are marked as SEEN so that the walk does not
28 * have to visit its ancestors. This ensures the walk is very short if
29 * there is good bitmap coverage.
30 * <p>
31 * Commits named in {@code seen} are considered already seen. If one is
32 * encountered, that commit and its parents will be marked with the SEEN
33 * flag to prevent the walk from visiting its ancestors.
34 */
35 public class AddUnseenToBitmapFilter extends RevFilter {
36 private final BitmapBuilder seen;
37 private final BitmapBuilder bitmap;
38
39 /**
40 * Create a filter that adds visited commits to the given bitmap, but does not walk
41 * through the objects in {@code seen}.
42 *
43 * @param seen objects that are already seen
44 * @param bitmap bitmap to write visited commits to
45 */
46 public AddUnseenToBitmapFilter(BitmapBuilder seen, BitmapBuilder bitmap) {
47 this.seen = seen;
48 this.bitmap = bitmap;
49 }
50
51 /** {@inheritDoc} */
52 @Override
53 public final boolean include(RevWalk walker, RevCommit cmit) {
54 Bitmap visitedBitmap;
55
56 if (seen.contains(cmit) || bitmap.contains(cmit)) {
57 // already seen or included
58 } else if ((visitedBitmap = bitmap.getBitmapIndex()
59 .getBitmap(cmit)) != null) {
60 bitmap.or(visitedBitmap);
61 } else {
62 bitmap.addObject(cmit, Constants.OBJ_COMMIT);
63 return true;
64 }
65
66 for (RevCommit p : cmit.getParents()) {
67 p.add(RevFlag.SEEN);
68 }
69 return false;
70 }
71
72 /** {@inheritDoc} */
73 @Override
74 public final RevFilter clone() {
75 throw new UnsupportedOperationException();
76 }
77
78 /** {@inheritDoc} */
79 @Override
80 public final boolean requiresCommitBody() {
81 return false;
82 }
83 }