/*
* 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.internal.storage.file;
import com.googlecode.javaewah.EWAHCompressedBitmap;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectIdOwnerMap;
/**
* Base implementation of the PackBitmapIndex.
*/
abstract class BasePackBitmapIndex extends PackBitmapIndex {
private final ObjectIdOwnerMap<StoredBitmap> bitmaps;
BasePackBitmapIndex(ObjectIdOwnerMap<StoredBitmap> bitmaps) {
this.bitmaps = bitmaps;
}
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);
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;
}
}
}