| /* |
| * Copyright (C) 2019, Google LLC and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| package org.eclipse.jgit.revwalk; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Optional; |
| import java.util.stream.Stream; |
| |
| import org.eclipse.jgit.errors.IncorrectObjectTypeException; |
| import org.eclipse.jgit.errors.MissingObjectException; |
| import org.eclipse.jgit.lib.BitmapIndex; |
| import org.eclipse.jgit.lib.BitmapIndex.Bitmap; |
| import org.eclipse.jgit.lib.BitmapIndex.BitmapBuilder; |
| import org.eclipse.jgit.lib.Constants; |
| import org.eclipse.jgit.revwalk.filter.RevFilter; |
| |
| /** |
| * Checks the reachability using bitmaps. |
| */ |
| class BitmappedReachabilityChecker implements ReachabilityChecker { |
| |
| private final RevWalk walk; |
| |
| /** |
| * @param walk |
| * walk on the repository to get or create the bitmaps for the |
| * commits. It must have bitmaps. |
| * @throws AssertionError |
| * runtime exception if walk is over a repository without |
| * bitmaps |
| * @throws IOException |
| * if the index or the object reader cannot be opened. |
| */ |
| public BitmappedReachabilityChecker(RevWalk walk) |
| throws IOException { |
| this.walk = walk; |
| if (walk.getObjectReader().getBitmapIndex() == null) { |
| throw new AssertionError( |
| "Trying to use bitmapped reachability check " //$NON-NLS-1$ |
| + "on a repository without bitmaps"); //$NON-NLS-1$ |
| } |
| } |
| |
| /** |
| * Check all targets are reachable from the starters. |
| * <p> |
| * In this implementation, it is recommended to put the most popular |
| * starters (e.g. refs/heads tips) at the beginning. |
| */ |
| @Override |
| public Optional<RevCommit> areAllReachable(Collection<RevCommit> targets, |
| Stream<RevCommit> starters) throws MissingObjectException, |
| IncorrectObjectTypeException, IOException { |
| |
| List<RevCommit> remainingTargets = new ArrayList<>(targets); |
| |
| walk.reset(); |
| walk.sort(RevSort.TOPO); |
| |
| // Filter emits only commits that are unreachable from previously |
| // visited commits. Internally it keeps a bitmap of everything |
| // reachable so far, which we use to discard reachable targets. |
| BitmapIndex repoBitmaps = walk.getObjectReader().getBitmapIndex(); |
| ReachedFilter reachedFilter = new ReachedFilter(repoBitmaps); |
| walk.setRevFilter(reachedFilter); |
| |
| Iterator<RevCommit> startersIter = starters.iterator(); |
| while (startersIter.hasNext()) { |
| walk.markStart(startersIter.next()); |
| while (walk.next() != null) { |
| remainingTargets.removeIf(reachedFilter::isReachable); |
| |
| if (remainingTargets.isEmpty()) { |
| return Optional.empty(); |
| } |
| } |
| walk.reset(); |
| } |
| |
| return Optional.of(remainingTargets.get(0)); |
| } |
| |
| /** |
| * This filter emits commits that were not bitmap-reachable from anything |
| * visited before. Or in other words, commits that add something (themselves |
| * or their bitmap) to the "reached" bitmap. |
| * |
| * Current progress can be queried via {@link #isReachable(RevCommit)}. |
| */ |
| private static class ReachedFilter extends RevFilter { |
| |
| private final BitmapIndex repoBitmaps; |
| private final BitmapBuilder reached; |
| |
| /** |
| * Create a filter that emits only previously unreachable commits. |
| * |
| * @param repoBitmaps |
| * bitmap index of the repo |
| */ |
| public ReachedFilter(BitmapIndex repoBitmaps) { |
| this.repoBitmaps = repoBitmaps; |
| this.reached = repoBitmaps.newBitmapBuilder(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public final boolean include(RevWalk walker, RevCommit cmit) { |
| Bitmap commitBitmap; |
| |
| if (reached.contains(cmit)) { |
| // already seen or included |
| dontFollow(cmit); |
| return false; |
| } |
| |
| if ((commitBitmap = repoBitmaps.getBitmap(cmit)) != null) { |
| reached.or(commitBitmap); |
| // Emit the commit because there are new contents in the bitmap |
| // but don't follow parents (they are already in the bitmap) |
| dontFollow(cmit); |
| return true; |
| } |
| |
| // No bitmaps, keep going |
| reached.addObject(cmit, Constants.OBJ_COMMIT); |
| return true; |
| } |
| |
| private static final void dontFollow(RevCommit cmit) { |
| for (RevCommit p : cmit.getParents()) { |
| p.add(RevFlag.SEEN); |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public final RevFilter clone() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public final boolean requiresCommitBody() { |
| return false; |
| } |
| |
| boolean isReachable(RevCommit commit) { |
| return reached.contains(commit); |
| } |
| } |
| } |