| /* |
| * Copyright (C) 2012, 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 org.eclipse.jgit.lib.AnyObjectId; |
| import org.eclipse.jgit.lib.ObjectIdOwnerMap; |
| |
| import com.googlecode.javaewah.EWAHCompressedBitmap; |
| |
| /** |
| * Base implementation of the PackBitmapIndex. |
| */ |
| abstract class BasePackBitmapIndex extends PackBitmapIndex { |
| private final ObjectIdOwnerMap<StoredBitmap> bitmaps; |
| |
| BasePackBitmapIndex(ObjectIdOwnerMap<StoredBitmap> bitmaps) { |
| this.bitmaps = bitmaps; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public EWAHCompressedBitmap getBitmap(AnyObjectId objectId) { |
| StoredBitmap sb = bitmaps.get(objectId); |
| return sb != null ? sb.getBitmap() : null; |
| } |
| |
| ObjectIdOwnerMap<StoredBitmap> getBitmaps() { |
| return bitmaps; |
| } |
| |
| /** |
| * Data representation of the bitmap entry restored from a pack index. The |
| * commit of the bitmap is the map key. |
| */ |
| static final class StoredBitmap extends ObjectIdOwnerMap.Entry { |
| private volatile Object bitmapContainer; |
| private final int flags; |
| |
| StoredBitmap(AnyObjectId objectId, EWAHCompressedBitmap bitmap, |
| StoredBitmap xorBitmap, int flags) { |
| super(objectId); |
| this.bitmapContainer = xorBitmap == null |
| ? bitmap |
| : new XorCompressedBitmap(bitmap, xorBitmap); |
| this.flags = flags; |
| } |
| |
| /** |
| * Computes and returns the full bitmap. |
| * |
| * @return the full bitmap |
| */ |
| EWAHCompressedBitmap getBitmap() { |
| // Fast path to immediately return the expanded result. |
| Object r = bitmapContainer; |
| if (r instanceof EWAHCompressedBitmap) |
| return (EWAHCompressedBitmap) r; |
| |
| // Expand the bitmap and cache the result. |
| XorCompressedBitmap xb = (XorCompressedBitmap) r; |
| EWAHCompressedBitmap out = xb.bitmap; |
| for (;;) { |
| r = xb.xorBitmap.bitmapContainer; |
| if (r instanceof EWAHCompressedBitmap) { |
| out = out.xor((EWAHCompressedBitmap) r); |
| out.trim(); |
| bitmapContainer = out; |
| return out; |
| } |
| xb = (XorCompressedBitmap) r; |
| out = out.xor(xb.bitmap); |
| } |
| } |
| |
| /** @return the flags associated with the bitmap */ |
| int getFlags() { |
| return flags; |
| } |
| } |
| |
| private static final class XorCompressedBitmap { |
| final EWAHCompressedBitmap bitmap; |
| final StoredBitmap xorBitmap; |
| |
| XorCompressedBitmap(EWAHCompressedBitmap b, StoredBitmap xb) { |
| bitmap = b; |
| xorBitmap = xb; |
| } |
| } |
| } |