/*
* 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.file;
import java.io.DataInput;
import java.io.IOException;
import java.io.InputStream;
import java.text.MessageFormat;
import java.util.Arrays;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectIdOwnerMap;
import org.eclipse.jgit.util.IO;
import org.eclipse.jgit.util.NB;
import com.googlecode.javaewah.EWAHCompressedBitmap;
/**
* Support for the pack bitmap index v1 format.
*
* @see PackBitmapIndex
*/
class PackBitmapIndexV1 extends BasePackBitmapIndex {
static final byte[] MAGIC = { 'B', 'I', 'T', 'M' };
static final int OPT_FULL = 1;
private static final int MAX_XOR_OFFSET = 126;
private final PackIndex packIndex;
private final PackReverseIndex reverseIndex;
private final EWAHCompressedBitmap commits;
private final EWAHCompressedBitmap trees;
private final EWAHCompressedBitmap blobs;
private final EWAHCompressedBitmap tags;
private final ObjectIdOwnerMap<StoredBitmap> bitmaps;
PackBitmapIndexV1(final InputStream fd, PackIndex packIndex,
PackReverseIndex reverseIndex) throws IOException {
super(new ObjectIdOwnerMap<StoredBitmap>());
this.packIndex = packIndex;
this.reverseIndex = reverseIndex;
this.bitmaps = getBitmaps();
final byte[] scratch = new byte[32];
IO.readFully(fd, scratch, 0, scratch.length);
// Check the magic bytes
for (int i = 0; i < MAGIC.length; i++) {
if (scratch[i] != MAGIC[i]) {
byte[] actual = new byte[MAGIC.length];
System.arraycopy(scratch, 0, actual, 0, MAGIC.length);
throw new IOException(MessageFormat.format(
JGitText.get().expectedGot, Arrays.toString(MAGIC),
Arrays.toString(actual)));
}
}
// Read the version (2 bytes)
final int version = NB.decodeUInt16(scratch, 4);
if (version != 1)
throw new IOException(MessageFormat.format(
JGitText.get().unsupportedPackIndexVersion,
Integer.valueOf(version)));
// Read the options (2 bytes)
final int opts = NB.decodeUInt16(scratch, 6);
if ((opts & OPT_FULL) == 0)
throw new IOException(MessageFormat.format(
JGitText.get().expectedGot, Integer.valueOf(OPT_FULL),
Integer.valueOf(opts)));
// Read the number of entries (1 int32)
long numEntries = NB.decodeUInt32(scratch, 8);
if (numEntries > Integer.MAX_VALUE)
throw new IOException(JGitText.get().indexFileIsTooLargeForJgit);
// Checksum applied on the bottom of the corresponding pack file.
this.packChecksum = new byte[20];
System.arraycopy(scratch, 12, packChecksum, 0, packChecksum.length);
// Read the bitmaps for the Git types
SimpleDataInput dataInput = new SimpleDataInput(fd);
this.commits = readBitmap(dataInput);
this.trees = readBitmap(dataInput);
this.blobs = readBitmap(dataInput);
this.tags = readBitmap(dataInput);
// An entry is object id, xor offset, flag byte, and a length encoded
// bitmap. The object id is an int32 of the nth position sorted by name.
// The xor offset is a single byte offset back in the list of entries.
StoredBitmap[] recentBitmaps = new StoredBitmap[MAX_XOR_OFFSET];
for (int i = 0; i < (int) numEntries; i++) {
IO.readFully(fd, scratch, 0, 6);
int nthObjectId = NB.decodeInt32(scratch, 0);
int xorOffset = scratch[4];
int flags = scratch[5];
EWAHCompressedBitmap bitmap = readBitmap(dataInput);
if (nthObjectId < 0)
throw new IOException(MessageFormat.format(
JGitText.get().invalidId, String.valueOf(nthObjectId)));
if (xorOffset < 0)
throw new IOException(MessageFormat.format(
JGitText.get().invalidId, String.valueOf(xorOffset)));
if (xorOffset > MAX_XOR_OFFSET)
throw new IOException(MessageFormat.format(
JGitText.get().expectedLessThanGot,
String.valueOf(MAX_XOR_OFFSET),
String.valueOf(xorOffset)));
if (xorOffset > i)
throw new IOException(MessageFormat.format(
JGitText.get().expectedLessThanGot, String.valueOf(i),
String.valueOf(xorOffset)));
ObjectId objectId = packIndex.getObjectId(nthObjectId);
StoredBitmap xorBitmap = null;
if (xorOffset > 0) {
int index = (i - xorOffset);
xorBitmap = recentBitmaps[index % recentBitmaps.length];
if (xorBitmap == null)
throw new IOException(MessageFormat.format(
JGitText.get().invalidId,
String.valueOf(xorOffset)));
}
StoredBitmap sb = new StoredBitmap(
objectId, bitmap, xorBitmap, flags);
bitmaps.add(sb);
recentBitmaps[i % recentBitmaps.length] = sb;
}
}
@Override
public int findPosition(AnyObjectId objectId) {
long offset = packIndex.findOffset(objectId);
if (offset == -1)
return -1;
return reverseIndex.findPostion(offset);
}
@Override
public ObjectId getObject(int position) throws IllegalArgumentException {
ObjectId objectId = reverseIndex.findObjectByPosition(position);
if (objectId == null)
throw new IllegalArgumentException();
return objectId;
}
@Override
public int getObjectCount() {
return (int) packIndex.getObjectCount();
}
@Override
public EWAHCompressedBitmap ofObjectType(
EWAHCompressedBitmap bitmap, int type) {
switch (type) {
case Constants.OBJ_BLOB:
return blobs.and(bitmap);
case Constants.OBJ_TREE:
return trees.and(bitmap);
case Constants.OBJ_COMMIT:
return commits.and(bitmap);
case Constants.OBJ_TAG:
return tags.and(bitmap);
}
throw new IllegalArgumentException();
}
@Override
public int getBitmapCount() {
return bitmaps.size();
}
@Override
public boolean equals(Object o) {
// TODO(cranger): compare the pack checksum?
if (o instanceof PackBitmapIndexV1)
return getPackIndex() == ((PackBitmapIndexV1) o).getPackIndex();
return false;
}
@Override
public int hashCode() {
return getPackIndex().hashCode();
}
PackIndex getPackIndex() {
return packIndex;
}
private static EWAHCompressedBitmap readBitmap(DataInput dataInput)
throws IOException {
EWAHCompressedBitmap bitmap = new EWAHCompressedBitmap();
bitmap.deserialize(dataInput);
return bitmap;
}
}