BitmapWalker.java
- /*
- * Copyright (C) 2012, Google Inc.
- * and other copyright owners as documented in the project's IP log.
- *
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Distribution License v1.0 which
- * accompanies this distribution, is reproduced below, and is
- * available at http://www.eclipse.org/org/documents/edl-v10.php
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * - Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following
- * disclaimer in the documentation and/or other materials provided
- * with the distribution.
- *
- * - Neither the name of the Eclipse Foundation, Inc. nor the
- * names of its contributors may be used to endorse or promote
- * products derived from this software without specific prior
- * written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
- * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- package org.eclipse.jgit.revwalk;
- import java.io.IOException;
- import java.util.Arrays;
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.errors.MissingObjectException;
- import org.eclipse.jgit.internal.revwalk.AddToBitmapFilter;
- import org.eclipse.jgit.internal.revwalk.AddUnseenToBitmapFilter;
- import org.eclipse.jgit.lib.AnyObjectId;
- 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.NullProgressMonitor;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.ProgressMonitor;
- import org.eclipse.jgit.revwalk.filter.ObjectFilter;
- /**
- * Helper class to do ObjectWalks with pack index bitmaps.
- *
- * @since 4.10
- */
- public final class BitmapWalker {
- private final ObjectWalk walker;
- private final BitmapIndex bitmapIndex;
- private final ProgressMonitor pm;
- private long countOfBitmapIndexMisses;
- /**
- * Create a BitmapWalker.
- *
- * @param walker walker to use when traversing the object graph.
- * @param bitmapIndex index to obtain bitmaps from.
- * @param pm progress monitor to report progress on.
- */
- public BitmapWalker(
- ObjectWalk walker, BitmapIndex bitmapIndex, ProgressMonitor pm) {
- this.walker = walker;
- this.bitmapIndex = bitmapIndex;
- this.pm = (pm == null) ? NullProgressMonitor.INSTANCE : pm;
- }
- /**
- * Return the number of objects that had to be walked because they were not covered by a
- * bitmap.
- *
- * @return the number of objects that had to be walked because they were not covered by a
- * bitmap.
- */
- public long getCountOfBitmapIndexMisses() {
- return countOfBitmapIndexMisses;
- }
- /**
- * Return, as a bitmap, the objects reachable from the objects in start.
- *
- * @param start
- * the objects to start the object traversal from.
- * @param seen
- * the objects to skip if encountered during traversal.
- * @param ignoreMissing
- * true to ignore missing objects, false otherwise.
- * @return as a bitmap, the objects reachable from the objects in start.
- * @throws org.eclipse.jgit.errors.MissingObjectException
- * the object supplied is not available from the object
- * database. This usually indicates the supplied object is
- * invalid, but the reference was constructed during an earlier
- * invocation to
- * {@link org.eclipse.jgit.revwalk.RevWalk#lookupAny(AnyObjectId, int)}.
- * @throws org.eclipse.jgit.errors.IncorrectObjectTypeException
- * the object was not parsed yet and it was discovered during
- * parsing that it is not actually the type of the instance
- * passed in. This usually indicates the caller used the wrong
- * type in a
- * {@link org.eclipse.jgit.revwalk.RevWalk#lookupAny(AnyObjectId, int)}
- * call.
- * @throws java.io.IOException
- * a pack file or loose object could not be read.
- */
- public BitmapBuilder findObjects(Iterable<? extends ObjectId> start, BitmapBuilder seen,
- boolean ignoreMissing)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException {
- if (!ignoreMissing) {
- return findObjectsWalk(start, seen, false);
- }
- try {
- return findObjectsWalk(start, seen, true);
- } catch (MissingObjectException ignore) {
- // An object reachable from one of the "start"s is missing.
- // Walk from the "start"s one at a time so it can be excluded.
- }
- final BitmapBuilder result = bitmapIndex.newBitmapBuilder();
- for (ObjectId obj : start) {
- Bitmap bitmap = bitmapIndex.getBitmap(obj);
- if (bitmap != null) {
- result.or(bitmap);
- }
- }
- for (ObjectId obj : start) {
- if (result.contains(obj)) {
- continue;
- }
- try {
- result.or(findObjectsWalk(Arrays.asList(obj), result, false));
- } catch (MissingObjectException ignore) {
- // An object reachable from this "start" is missing.
- //
- // This can happen when the client specified a "have" line
- // pointing to an object that is present but unreachable:
- // "git prune" and "git fsck" only guarantee that the object
- // database will continue to contain all objects reachable
- // from a ref and does not guarantee connectivity for other
- // objects in the object database.
- //
- // In this situation, skip the relevant "start" and move on
- // to the next one.
- //
- // TODO(czhen): Make findObjectsWalk resume the walk instead
- // once RevWalk and ObjectWalk support that.
- }
- }
- return result;
- }
- private BitmapBuilder findObjectsWalk(Iterable<? extends ObjectId> start, BitmapBuilder seen,
- boolean ignoreMissingStart)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException {
- walker.reset();
- final BitmapBuilder bitmapResult = bitmapIndex.newBitmapBuilder();
- for (ObjectId obj : start) {
- Bitmap bitmap = bitmapIndex.getBitmap(obj);
- if (bitmap != null)
- bitmapResult.or(bitmap);
- }
- boolean marked = false;
- for (ObjectId obj : start) {
- try {
- if (!bitmapResult.contains(obj)) {
- walker.markStart(walker.parseAny(obj));
- marked = true;
- }
- } catch (MissingObjectException e) {
- if (ignoreMissingStart)
- continue;
- throw e;
- }
- }
- if (marked) {
- if (seen == null) {
- walker.setRevFilter(new AddToBitmapFilter(bitmapResult));
- } else {
- walker.setRevFilter(
- new AddUnseenToBitmapFilter(seen, bitmapResult));
- }
- walker.setObjectFilter(new BitmapObjectFilter(bitmapResult));
- while (walker.next() != null) {
- // Iterate through all of the commits. The BitmapRevFilter does
- // the work.
- //
- // filter.include returns true for commits that do not have
- // a bitmap in bitmapIndex and are not reachable from a
- // bitmap in bitmapIndex encountered earlier in the walk.
- // Thus the number of commits returned by next() measures how
- // much history was traversed without being able to make use
- // of bitmaps.
- pm.update(1);
- countOfBitmapIndexMisses++;
- }
- RevObject ro;
- while ((ro = walker.nextObject()) != null) {
- bitmapResult.addObject(ro, ro.getType());
- pm.update(1);
- }
- }
- return bitmapResult;
- }
- /**
- * Filter that excludes objects already in the given bitmap.
- */
- static class BitmapObjectFilter extends ObjectFilter {
- private final BitmapBuilder bitmap;
- BitmapObjectFilter(BitmapBuilder bitmap) {
- this.bitmap = bitmap;
- }
- @Override
- public final boolean include(ObjectWalk walker, AnyObjectId objid)
- throws MissingObjectException, IncorrectObjectTypeException,
- IOException {
- return !bitmap.contains(objid);
- }
- }
- }