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- /*
- * 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 java.io.DataInput;
- import java.io.IOException;
- import java.io.InputStream;
- import java.text.MessageFormat;
- import java.util.Arrays;
-
- import com.googlecode.javaewah.EWAHCompressedBitmap;
-
- 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;
-
- /**
- * 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;
- }
- }
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