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- /*
- * Copyright (C) 2013, Google Inc. 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.internal.storage.file;
-
- import java.util.Collections;
- import java.util.Iterator;
- import java.util.NoSuchElementException;
-
- import org.eclipse.jgit.internal.storage.file.BasePackBitmapIndex.StoredBitmap;
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.BitmapIndex;
- import org.eclipse.jgit.lib.ObjectId;
-
- import com.googlecode.javaewah.EWAHCompressedBitmap;
- import com.googlecode.javaewah.IntIterator;
-
- /**
- * A PackBitmapIndex that remaps the bitmaps in the previous index to the
- * positions in the new pack index. Note, unlike typical PackBitmapIndex
- * implementations this implementation is not thread safe, as it is intended to
- * be used with a PackBitmapIndexBuilder, which is also not thread safe.
- */
- public class PackBitmapIndexRemapper extends PackBitmapIndex
- implements Iterable<PackBitmapIndexRemapper.Entry> {
-
- private final BasePackBitmapIndex oldPackIndex;
- final PackBitmapIndex newPackIndex;
- private final BitSet inflated;
- private final int[] prevToNewMapping;
-
- /**
- * A PackBitmapIndex that maps the positions in the prevBitmapIndex to the
- * ones in the newIndex.
- *
- * @param prevBitmapIndex
- * the bitmap index with the old mapping.
- * @param newIndex
- * the bitmap index with the new mapping.
- * @return a bitmap index that attempts to do the mapping between the two.
- */
- public static PackBitmapIndexRemapper newPackBitmapIndex(
- BitmapIndex prevBitmapIndex, PackBitmapIndex newIndex) {
- if (!(prevBitmapIndex instanceof BitmapIndexImpl))
- return new PackBitmapIndexRemapper(newIndex);
-
- PackBitmapIndex prevIndex = ((BitmapIndexImpl) prevBitmapIndex)
- .getPackBitmapIndex();
- if (!(prevIndex instanceof BasePackBitmapIndex))
- return new PackBitmapIndexRemapper(newIndex);
-
- return new PackBitmapIndexRemapper(
- (BasePackBitmapIndex) prevIndex, newIndex);
- }
-
- private PackBitmapIndexRemapper(PackBitmapIndex newPackIndex) {
- this.oldPackIndex = null;
- this.newPackIndex = newPackIndex;
- this.inflated = null;
- this.prevToNewMapping = null;
- }
-
- private PackBitmapIndexRemapper(
- BasePackBitmapIndex oldPackIndex, PackBitmapIndex newPackIndex) {
- this.oldPackIndex = oldPackIndex;
- this.newPackIndex = newPackIndex;
- inflated = new BitSet(newPackIndex.getObjectCount());
-
- prevToNewMapping = new int[oldPackIndex.getObjectCount()];
- for (int pos = 0; pos < prevToNewMapping.length; pos++)
- prevToNewMapping[pos] = newPackIndex.findPosition(
- oldPackIndex.getObject(pos));
- }
-
- /** {@inheritDoc} */
- @Override
- public int findPosition(AnyObjectId objectId) {
- return newPackIndex.findPosition(objectId);
- }
-
- /** {@inheritDoc} */
- @Override
- public ObjectId getObject(int position) throws IllegalArgumentException {
- return newPackIndex.getObject(position);
- }
-
- /** {@inheritDoc} */
- @Override
- public int getObjectCount() {
- return newPackIndex.getObjectCount();
- }
-
- /** {@inheritDoc} */
- @Override
- public EWAHCompressedBitmap ofObjectType(
- EWAHCompressedBitmap bitmap, int type) {
- return newPackIndex.ofObjectType(bitmap, type);
- }
-
- /** {@inheritDoc} */
- @Override
- public Iterator<Entry> iterator() {
- if (oldPackIndex == null)
- return Collections.<Entry> emptyList().iterator();
-
- final Iterator<StoredBitmap> it = oldPackIndex.getBitmaps().iterator();
- return new Iterator<Entry>() {
- private Entry entry;
-
- @Override
- public boolean hasNext() {
- while (entry == null && it.hasNext()) {
- StoredBitmap sb = it.next();
- if (newPackIndex.findPosition(sb) != -1)
- entry = new Entry(sb, sb.getFlags());
- }
- return entry != null;
- }
-
- @Override
- public Entry next() {
- if (!hasNext())
- throw new NoSuchElementException();
-
- Entry res = entry;
- entry = null;
- return res;
- }
-
- @Override
- public void remove() {
- throw new UnsupportedOperationException();
- }
- };
- }
-
- /** {@inheritDoc} */
- @Override
- public EWAHCompressedBitmap getBitmap(AnyObjectId objectId) {
- EWAHCompressedBitmap bitmap = newPackIndex.getBitmap(objectId);
- if (bitmap != null || oldPackIndex == null)
- return bitmap;
-
- StoredBitmap oldBitmap = oldPackIndex.getBitmaps().get(objectId);
- if (oldBitmap == null)
- return null;
-
- if (newPackIndex.findPosition(objectId) == -1)
- return null;
-
- inflated.clear();
- for (IntIterator i = oldBitmap.getBitmapWithoutCaching()
- .intIterator(); i.hasNext();)
- inflated.set(prevToNewMapping[i.next()]);
- bitmap = inflated.toEWAHCompressedBitmap();
- bitmap.trim();
- return bitmap;
- }
-
- /** An entry in the old PackBitmapIndex. */
- public static final class Entry extends ObjectId {
- private final int flags;
-
- Entry(AnyObjectId src, int flags) {
- super(src);
- this.flags = flags;
- }
-
- /** @return the flags associated with the bitmap. */
- public int getFlags() {
- return flags;
- }
- }
-
- /** {@inheritDoc} */
- @Override
- public int getBitmapCount() {
- // The count is only useful for the end index, not the remapper.
- return 0;
- }
- }
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