/*
* 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.
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package org.eclipse.jgit.internal.storage.pack;
import java.io.IOException;
import java.util.Set;
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.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.revwalk.ObjectWalk;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevFlag;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.revwalk.filter.RevFilter;
/** Helper class for PackWriter to do ObjectWalks with pack index bitmaps. */
final class PackWriterBitmapWalker {
private final ObjectWalk walker;
private final BitmapIndex bitmapIndex;
private final ProgressMonitor pm;
private long countOfBitmapIndexMisses;
PackWriterBitmapWalker(
ObjectWalk walker, BitmapIndex bitmapIndex, ProgressMonitor pm) {
this.walker = walker;
this.bitmapIndex = bitmapIndex;
this.pm = (pm == null) ? NullProgressMonitor.INSTANCE : pm;
}
long getCountOfBitmapIndexMisses() {
return countOfBitmapIndexMisses;
}
BitmapBuilder findObjects(Set<? extends ObjectId> start, BitmapBuilder seen, boolean ignoreMissingStart)
throws MissingObjectException, IncorrectObjectTypeException,
IOException {
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));
}
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;
}
void reset() {
walker.reset();
}
/**
* A RevFilter that adds the visited commits to {@code bitmap} as a side
* effect.
* <p>
* When the walk hits a commit that is part of {@code bitmap}'s
* BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
* commit and its parents are marked as SEEN so that the walk does not
* have to visit its ancestors. This ensures the walk is very short if
* there is good bitmap coverage.
*/
static class AddToBitmapFilter extends RevFilter {
private final BitmapBuilder bitmap;
AddToBitmapFilter(BitmapBuilder bitmap) {
this.bitmap = bitmap;
}
@Override
public final boolean include(RevWalk walker, RevCommit cmit) {
Bitmap visitedBitmap;
if (bitmap.contains(cmit)) {
// already included
} else if ((visitedBitmap = bitmap.getBitmapIndex()
.getBitmap(cmit)) != null) {
bitmap.or(visitedBitmap);
} else {
bitmap.addObject(cmit, Constants.OBJ_COMMIT);
return true;
}
for (RevCommit p : cmit.getParents()) {
p.add(RevFlag.SEEN);
}
return false;
}
@Override
public final RevFilter clone() {
throw new UnsupportedOperationException();
}
@Override
public final boolean requiresCommitBody() {
return false;
}
}
/**
* A RevFilter that adds the visited commits to {@code bitmap} as a side
* effect.
* <p>
* When the walk hits a commit that is part of {@code bitmap}'s
* BitmapIndex, that entire bitmap is ORed into {@code bitmap} and the
* commit and its parents are marked as SEEN so that the walk does not
* have to visit its ancestors. This ensures the walk is very short if
* there is good bitmap coverage.
* <p>
* Commits named in {@code seen} are considered already seen. If one is
* encountered, that commit and its parents will be marked with the SEEN
* flag to prevent the walk from visiting its ancestors.
*/
static class AddUnseenToBitmapFilter extends RevFilter {
private final BitmapBuilder seen;
private final BitmapBuilder bitmap;
AddUnseenToBitmapFilter(BitmapBuilder seen, BitmapBuilder bitmapResult) {
this.seen = seen;
this.bitmap = bitmapResult;
}
@Override
public final boolean include(RevWalk walker, RevCommit cmit) {
Bitmap visitedBitmap;
if (seen.contains(cmit) || bitmap.contains(cmit)) {
// already seen or included
} else if ((visitedBitmap = bitmap.getBitmapIndex()
.getBitmap(cmit)) != null) {
bitmap.or(visitedBitmap);
} else {
bitmap.addObject(cmit, Constants.OBJ_COMMIT);
return true;
}
for (RevCommit p : cmit.getParents()) {
p.add(RevFlag.SEEN);
}
return false;
}
@Override
public final RevFilter clone() {
throw new UnsupportedOperationException();
}
@Override
public final boolean requiresCommitBody() {
return false;
}
}
}