DfsPackFile.java
/*
* Copyright (C) 2008-2011, Google Inc.
* Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
* Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
* 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.dfs;
import static org.eclipse.jgit.internal.storage.dfs.DfsObjDatabase.PackSource.UNREACHABLE_GARBAGE;
import static org.eclipse.jgit.internal.storage.pack.PackExt.BITMAP_INDEX;
import static org.eclipse.jgit.internal.storage.pack.PackExt.INDEX;
import static org.eclipse.jgit.internal.storage.pack.PackExt.PACK;
import java.io.BufferedInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.text.MessageFormat;
import java.util.Set;
import java.util.zip.CRC32;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.PackInvalidException;
import org.eclipse.jgit.errors.StoredObjectRepresentationNotAvailableException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.internal.storage.file.PackBitmapIndex;
import org.eclipse.jgit.internal.storage.file.PackIndex;
import org.eclipse.jgit.internal.storage.file.PackReverseIndex;
import org.eclipse.jgit.internal.storage.pack.BinaryDelta;
import org.eclipse.jgit.internal.storage.pack.PackOutputStream;
import org.eclipse.jgit.internal.storage.pack.StoredObjectRepresentation;
import org.eclipse.jgit.lib.AbbreviatedObjectId;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.util.LongList;
/**
* A Git version 2 pack file representation. A pack file contains Git objects in
* delta packed format yielding high compression of lots of object where some
* objects are similar.
*/
public final class DfsPackFile extends BlockBasedFile {
private static final int REC_SIZE = Constants.OBJECT_ID_LENGTH + 8;
/**
* Lock for initialization of {@link #index} and {@link #corruptObjects}.
* <p>
* This lock ensures only one thread can perform the initialization work.
*/
private final Object initLock = new Object();
/** Index mapping {@link ObjectId} to position within the pack stream. */
private volatile PackIndex index;
/** Reverse version of {@link #index} mapping position to {@link ObjectId}. */
private volatile PackReverseIndex reverseIndex;
/** Index of compressed bitmap mapping entire object graph. */
private volatile PackBitmapIndex bitmapIndex;
/**
* Objects we have tried to read, and discovered to be corrupt.
* <p>
* The list is allocated after the first corruption is found, and filled in
* as more entries are discovered. Typically this list is never used, as
* pack files do not usually contain corrupt objects.
*/
private volatile LongList corruptObjects;
/**
* Construct a reader for an existing, packfile.
*
* @param cache
* cache that owns the pack data.
* @param desc
* description of the pack within the DFS.
*/
DfsPackFile(DfsBlockCache cache, DfsPackDescription desc) {
super(cache, desc, PACK);
int bs = desc.getBlockSize(PACK);
if (bs > 0) {
setBlockSize(bs);
}
long sz = desc.getFileSize(PACK);
length = sz > 0 ? sz : -1;
}
/**
* Get description that was originally used to configure this pack file.
*
* @return description that was originally used to configure this pack file.
*/
public DfsPackDescription getPackDescription() {
return desc;
}
/**
* Whether the pack index file is loaded and cached in memory.
*
* @return whether the pack index file is loaded and cached in memory.
*/
public boolean isIndexLoaded() {
return index != null;
}
void setPackIndex(PackIndex idx) {
long objCnt = idx.getObjectCount();
int recSize = Constants.OBJECT_ID_LENGTH + 8;
long sz = objCnt * recSize;
cache.putRef(desc.getStreamKey(INDEX), sz, idx);
index = idx;
}
/**
* Get the PackIndex for this PackFile.
*
* @param ctx
* reader context to support reading from the backing store if
* the index is not already loaded in memory.
* @return the PackIndex.
* @throws java.io.IOException
* the pack index is not available, or is corrupt.
*/
public PackIndex getPackIndex(DfsReader ctx) throws IOException {
return idx(ctx);
}
private PackIndex idx(DfsReader ctx) throws IOException {
if (index != null) {
return index;
}
if (invalid) {
throw new PackInvalidException(getFileName(), invalidatingCause);
}
Repository.getGlobalListenerList()
.dispatch(new BeforeDfsPackIndexLoadedEvent(this));
synchronized (initLock) {
if (index != null) {
return index;
}
try {
DfsStreamKey idxKey = desc.getStreamKey(INDEX);
DfsBlockCache.Ref<PackIndex> idxref = cache.getOrLoadRef(idxKey,
() -> {
try {
ctx.stats.readIdx++;
long start = System.nanoTime();
try (ReadableChannel rc = ctx.db.openFile(desc,
INDEX)) {
InputStream in = Channels
.newInputStream(rc);
int wantSize = 8192;
int bs = rc.blockSize();
if (0 < bs && bs < wantSize) {
bs = (wantSize / bs) * bs;
} else if (bs <= 0) {
bs = wantSize;
}
PackIndex idx = PackIndex.read(
new BufferedInputStream(in, bs));
int sz = (int) Math.min(
idx.getObjectCount() * REC_SIZE,
Integer.MAX_VALUE);
ctx.stats.readIdxBytes += rc.position();
index = idx;
return new DfsBlockCache.Ref<>(idxKey, 0,
sz, idx);
} finally {
ctx.stats.readIdxMicros += elapsedMicros(
start);
}
} catch (EOFException e) {
throw new IOException(MessageFormat.format(
DfsText.get().shortReadOfIndex,
desc.getFileName(INDEX)), e);
} catch (IOException e) {
throw new IOException(MessageFormat.format(
DfsText.get().cannotReadIndex,
desc.getFileName(INDEX)), e);
}
});
PackIndex idx = idxref.get();
if (index == null && idx != null) {
index = idx;
}
return index;
} catch (IOException e) {
invalid = true;
invalidatingCause = e;
throw e;
}
}
}
final boolean isGarbage() {
return desc.getPackSource() == UNREACHABLE_GARBAGE;
}
PackBitmapIndex getBitmapIndex(DfsReader ctx) throws IOException {
if (invalid || isGarbage() || !desc.hasFileExt(BITMAP_INDEX)) {
return null;
}
if (bitmapIndex != null) {
return bitmapIndex;
}
synchronized (initLock) {
if (bitmapIndex != null) {
return bitmapIndex;
}
PackIndex idx = idx(ctx);
PackReverseIndex revidx = getReverseIdx(ctx);
DfsStreamKey bitmapKey = desc.getStreamKey(BITMAP_INDEX);
DfsBlockCache.Ref<PackBitmapIndex> idxref = cache
.getOrLoadRef(bitmapKey, () -> {
ctx.stats.readBitmap++;
long start = System.nanoTime();
try (ReadableChannel rc = ctx.db.openFile(desc,
BITMAP_INDEX)) {
long size;
PackBitmapIndex bmidx;
try {
InputStream in = Channels.newInputStream(rc);
int wantSize = 8192;
int bs = rc.blockSize();
if (0 < bs && bs < wantSize) {
bs = (wantSize / bs) * bs;
} else if (bs <= 0) {
bs = wantSize;
}
in = new BufferedInputStream(in, bs);
bmidx = PackBitmapIndex.read(in, idx, revidx);
} finally {
size = rc.position();
ctx.stats.readIdxBytes += size;
ctx.stats.readIdxMicros += elapsedMicros(start);
}
int sz = (int) Math.min(size, Integer.MAX_VALUE);
bitmapIndex = bmidx;
return new DfsBlockCache.Ref<>(bitmapKey, 0, sz,
bmidx);
} catch (EOFException e) {
throw new IOException(MessageFormat.format(
DfsText.get().shortReadOfIndex,
desc.getFileName(BITMAP_INDEX)), e);
} catch (IOException e) {
throw new IOException(MessageFormat.format(
DfsText.get().cannotReadIndex,
desc.getFileName(BITMAP_INDEX)), e);
}
});
PackBitmapIndex bmidx = idxref.get();
if (bitmapIndex == null && bmidx != null) {
bitmapIndex = bmidx;
}
return bitmapIndex;
}
}
PackReverseIndex getReverseIdx(DfsReader ctx) throws IOException {
if (reverseIndex != null) {
return reverseIndex;
}
synchronized (initLock) {
if (reverseIndex != null) {
return reverseIndex;
}
PackIndex idx = idx(ctx);
DfsStreamKey revKey = new DfsStreamKey.ForReverseIndex(
desc.getStreamKey(INDEX));
DfsBlockCache.Ref<PackReverseIndex> revref = cache
.getOrLoadRef(revKey, () -> {
PackReverseIndex revidx = new PackReverseIndex(idx);
int sz = (int) Math.min(idx.getObjectCount() * 8,
Integer.MAX_VALUE);
reverseIndex = revidx;
return new DfsBlockCache.Ref<>(revKey, 0, sz, revidx);
});
PackReverseIndex revidx = revref.get();
if (reverseIndex == null && revidx != null) {
reverseIndex = revidx;
}
return reverseIndex;
}
}
/**
* Check if an object is stored within this pack.
*
* @param ctx
* reader context to support reading from the backing store if
* the index is not already loaded in memory.
* @param id
* object to be located.
* @return true if the object exists in this pack; false if it does not.
* @throws java.io.IOException
* the pack index is not available, or is corrupt.
*/
public boolean hasObject(DfsReader ctx, AnyObjectId id) throws IOException {
final long offset = idx(ctx).findOffset(id);
return 0 < offset && !isCorrupt(offset);
}
/**
* Get an object from this pack.
*
* @param ctx
* temporary working space associated with the calling thread.
* @param id
* the object to obtain from the pack. Must not be null.
* @return the object loader for the requested object if it is contained in
* this pack; null if the object was not found.
* @throws IOException
* the pack file or the index could not be read.
*/
ObjectLoader get(DfsReader ctx, AnyObjectId id)
throws IOException {
long offset = idx(ctx).findOffset(id);
return 0 < offset && !isCorrupt(offset) ? load(ctx, offset) : null;
}
long findOffset(DfsReader ctx, AnyObjectId id) throws IOException {
return idx(ctx).findOffset(id);
}
void resolve(DfsReader ctx, Set<ObjectId> matches, AbbreviatedObjectId id,
int matchLimit) throws IOException {
idx(ctx).resolve(matches, id, matchLimit);
}
/**
* Obtain the total number of objects available in this pack. This method
* relies on pack index, giving number of effectively available objects.
*
* @param ctx
* current reader for the calling thread.
* @return number of objects in index of this pack, likewise in this pack
* @throws IOException
* the index file cannot be loaded into memory.
*/
long getObjectCount(DfsReader ctx) throws IOException {
return idx(ctx).getObjectCount();
}
private byte[] decompress(long position, int sz, DfsReader ctx)
throws IOException, DataFormatException {
byte[] dstbuf;
try {
dstbuf = new byte[sz];
} catch (OutOfMemoryError noMemory) {
// The size may be larger than our heap allows, return null to
// let the caller know allocation isn't possible and it should
// use the large object streaming approach instead.
//
// For example, this can occur when sz is 640 MB, and JRE
// maximum heap size is only 256 MB. Even if the JRE has
// 200 MB free, it cannot allocate a 640 MB byte array.
return null;
}
if (ctx.inflate(this, position, dstbuf, false) != sz) {
throw new EOFException(MessageFormat.format(
JGitText.get().shortCompressedStreamAt,
Long.valueOf(position)));
}
return dstbuf;
}
void copyPackAsIs(PackOutputStream out, DfsReader ctx) throws IOException {
// If the length hasn't been determined yet, pin to set it.
if (length == -1) {
ctx.pin(this, 0);
ctx.unpin();
}
try (ReadableChannel rc = ctx.db.openFile(desc, PACK)) {
int sz = ctx.getOptions().getStreamPackBufferSize();
if (sz > 0) {
rc.setReadAheadBytes(sz);
}
if (cache.shouldCopyThroughCache(length)) {
copyPackThroughCache(out, ctx, rc);
} else {
copyPackBypassCache(out, rc);
}
}
}
private void copyPackThroughCache(PackOutputStream out, DfsReader ctx,
ReadableChannel rc) throws IOException {
long position = 12;
long remaining = length - (12 + 20);
while (0 < remaining) {
DfsBlock b = cache.getOrLoad(this, position, ctx, () -> rc);
int ptr = (int) (position - b.start);
if (b.size() <= ptr) {
throw packfileIsTruncated();
}
int n = (int) Math.min(b.size() - ptr, remaining);
b.write(out, position, n);
position += n;
remaining -= n;
}
}
private long copyPackBypassCache(PackOutputStream out, ReadableChannel rc)
throws IOException {
ByteBuffer buf = newCopyBuffer(out, rc);
long position = 12;
long remaining = length - (12 + 20);
boolean packHeadSkipped = false;
while (0 < remaining) {
DfsBlock b = cache.get(key, alignToBlock(position));
if (b != null) {
int ptr = (int) (position - b.start);
if (b.size() <= ptr) {
throw packfileIsTruncated();
}
int n = (int) Math.min(b.size() - ptr, remaining);
b.write(out, position, n);
position += n;
remaining -= n;
rc.position(position);
packHeadSkipped = true;
continue;
}
// Need to skip the 'PACK' header for the first read
int ptr = packHeadSkipped ? 0 : 12;
buf.position(0);
int bufLen = read(rc, buf);
if (bufLen <= ptr) {
throw packfileIsTruncated();
}
int n = (int) Math.min(bufLen - ptr, remaining);
out.write(buf.array(), ptr, n);
position += n;
remaining -= n;
packHeadSkipped = true;
}
return position;
}
private ByteBuffer newCopyBuffer(PackOutputStream out, ReadableChannel rc) {
int bs = blockSize(rc);
byte[] copyBuf = out.getCopyBuffer();
if (bs > copyBuf.length) {
copyBuf = new byte[bs];
}
return ByteBuffer.wrap(copyBuf, 0, bs);
}
void copyAsIs(PackOutputStream out, DfsObjectToPack src,
boolean validate, DfsReader ctx) throws IOException,
StoredObjectRepresentationNotAvailableException {
final CRC32 crc1 = validate ? new CRC32() : null;
final CRC32 crc2 = validate ? new CRC32() : null;
final byte[] buf = out.getCopyBuffer();
// Rip apart the header so we can discover the size.
//
try {
readFully(src.offset, buf, 0, 20, ctx);
} catch (IOException ioError) {
throw new StoredObjectRepresentationNotAvailableException(src,
ioError);
}
int c = buf[0] & 0xff;
final int typeCode = (c >> 4) & 7;
long inflatedLength = c & 15;
int shift = 4;
int headerCnt = 1;
while ((c & 0x80) != 0) {
c = buf[headerCnt++] & 0xff;
inflatedLength += ((long) (c & 0x7f)) << shift;
shift += 7;
}
if (typeCode == Constants.OBJ_OFS_DELTA) {
do {
c = buf[headerCnt++] & 0xff;
} while ((c & 128) != 0);
if (validate) {
assert(crc1 != null && crc2 != null);
crc1.update(buf, 0, headerCnt);
crc2.update(buf, 0, headerCnt);
}
} else if (typeCode == Constants.OBJ_REF_DELTA) {
if (validate) {
assert(crc1 != null && crc2 != null);
crc1.update(buf, 0, headerCnt);
crc2.update(buf, 0, headerCnt);
}
readFully(src.offset + headerCnt, buf, 0, 20, ctx);
if (validate) {
assert(crc1 != null && crc2 != null);
crc1.update(buf, 0, 20);
crc2.update(buf, 0, 20);
}
headerCnt += 20;
} else if (validate) {
assert(crc1 != null && crc2 != null);
crc1.update(buf, 0, headerCnt);
crc2.update(buf, 0, headerCnt);
}
final long dataOffset = src.offset + headerCnt;
final long dataLength = src.length;
final long expectedCRC;
final DfsBlock quickCopy;
// Verify the object isn't corrupt before sending. If it is,
// we report it missing instead.
//
try {
quickCopy = ctx.quickCopy(this, dataOffset, dataLength);
if (validate && idx(ctx).hasCRC32Support()) {
assert(crc1 != null);
// Index has the CRC32 code cached, validate the object.
//
expectedCRC = idx(ctx).findCRC32(src);
if (quickCopy != null) {
quickCopy.crc32(crc1, dataOffset, (int) dataLength);
} else {
long pos = dataOffset;
long cnt = dataLength;
while (cnt > 0) {
final int n = (int) Math.min(cnt, buf.length);
readFully(pos, buf, 0, n, ctx);
crc1.update(buf, 0, n);
pos += n;
cnt -= n;
}
}
if (crc1.getValue() != expectedCRC) {
setCorrupt(src.offset);
throw new CorruptObjectException(MessageFormat.format(
JGitText.get().objectAtHasBadZlibStream,
Long.valueOf(src.offset), getFileName()));
}
} else if (validate) {
assert(crc1 != null);
// We don't have a CRC32 code in the index, so compute it
// now while inflating the raw data to get zlib to tell us
// whether or not the data is safe.
//
Inflater inf = ctx.inflater();
byte[] tmp = new byte[1024];
if (quickCopy != null) {
quickCopy.check(inf, tmp, dataOffset, (int) dataLength);
} else {
long pos = dataOffset;
long cnt = dataLength;
while (cnt > 0) {
final int n = (int) Math.min(cnt, buf.length);
readFully(pos, buf, 0, n, ctx);
crc1.update(buf, 0, n);
inf.setInput(buf, 0, n);
while (inf.inflate(tmp, 0, tmp.length) > 0) {
continue;
}
pos += n;
cnt -= n;
}
}
if (!inf.finished() || inf.getBytesRead() != dataLength) {
setCorrupt(src.offset);
throw new EOFException(MessageFormat.format(
JGitText.get().shortCompressedStreamAt,
Long.valueOf(src.offset)));
}
expectedCRC = crc1.getValue();
} else {
expectedCRC = -1;
}
} catch (DataFormatException dataFormat) {
setCorrupt(src.offset);
CorruptObjectException corruptObject = new CorruptObjectException(
MessageFormat.format(
JGitText.get().objectAtHasBadZlibStream,
Long.valueOf(src.offset), getFileName()),
dataFormat);
throw new StoredObjectRepresentationNotAvailableException(src,
corruptObject);
} catch (IOException ioError) {
throw new StoredObjectRepresentationNotAvailableException(src,
ioError);
}
if (quickCopy != null) {
// The entire object fits into a single byte array window slice,
// and we have it pinned. Write this out without copying.
//
out.writeHeader(src, inflatedLength);
quickCopy.write(out, dataOffset, (int) dataLength);
} else if (dataLength <= buf.length) {
// Tiny optimization: Lots of objects are very small deltas or
// deflated commits that are likely to fit in the copy buffer.
//
if (!validate) {
long pos = dataOffset;
long cnt = dataLength;
while (cnt > 0) {
final int n = (int) Math.min(cnt, buf.length);
readFully(pos, buf, 0, n, ctx);
pos += n;
cnt -= n;
}
}
out.writeHeader(src, inflatedLength);
out.write(buf, 0, (int) dataLength);
} else {
// Now we are committed to sending the object. As we spool it out,
// check its CRC32 code to make sure there wasn't corruption between
// the verification we did above, and us actually outputting it.
//
out.writeHeader(src, inflatedLength);
long pos = dataOffset;
long cnt = dataLength;
while (cnt > 0) {
final int n = (int) Math.min(cnt, buf.length);
readFully(pos, buf, 0, n, ctx);
if (validate) {
assert(crc2 != null);
crc2.update(buf, 0, n);
}
out.write(buf, 0, n);
pos += n;
cnt -= n;
}
if (validate) {
assert(crc2 != null);
if (crc2.getValue() != expectedCRC) {
throw new CorruptObjectException(MessageFormat.format(
JGitText.get().objectAtHasBadZlibStream,
Long.valueOf(src.offset), getFileName()));
}
}
}
}
private IOException packfileIsTruncated() {
invalid = true;
IOException exc = new IOException(MessageFormat.format(
JGitText.get().packfileIsTruncated, getFileName()));
invalidatingCause = exc;
return exc;
}
private void readFully(long position, byte[] dstbuf, int dstoff, int cnt,
DfsReader ctx) throws IOException {
if (ctx.copy(this, position, dstbuf, dstoff, cnt) != cnt)
throw new EOFException();
}
ObjectLoader load(DfsReader ctx, long pos)
throws IOException {
try {
final byte[] ib = ctx.tempId;
Delta delta = null;
byte[] data = null;
int type = Constants.OBJ_BAD;
boolean cached = false;
SEARCH: for (;;) {
readFully(pos, ib, 0, 20, ctx);
int c = ib[0] & 0xff;
final int typeCode = (c >> 4) & 7;
long sz = c & 15;
int shift = 4;
int p = 1;
while ((c & 0x80) != 0) {
c = ib[p++] & 0xff;
sz += ((long) (c & 0x7f)) << shift;
shift += 7;
}
switch (typeCode) {
case Constants.OBJ_COMMIT:
case Constants.OBJ_TREE:
case Constants.OBJ_BLOB:
case Constants.OBJ_TAG: {
if (delta != null) {
data = decompress(pos + p, (int) sz, ctx);
type = typeCode;
break SEARCH;
}
if (sz < ctx.getStreamFileThreshold()) {
data = decompress(pos + p, (int) sz, ctx);
if (data != null) {
return new ObjectLoader.SmallObject(typeCode, data);
}
}
return new LargePackedWholeObject(typeCode, sz, pos, p, this, ctx.db);
}
case Constants.OBJ_OFS_DELTA: {
c = ib[p++] & 0xff;
long base = c & 127;
while ((c & 128) != 0) {
base += 1;
c = ib[p++] & 0xff;
base <<= 7;
base += (c & 127);
}
base = pos - base;
delta = new Delta(delta, pos, (int) sz, p, base);
if (sz != delta.deltaSize) {
break SEARCH;
}
DeltaBaseCache.Entry e = ctx.getDeltaBaseCache().get(key, base);
if (e != null) {
type = e.type;
data = e.data;
cached = true;
break SEARCH;
}
pos = base;
continue SEARCH;
}
case Constants.OBJ_REF_DELTA: {
readFully(pos + p, ib, 0, 20, ctx);
long base = findDeltaBase(ctx, ObjectId.fromRaw(ib));
delta = new Delta(delta, pos, (int) sz, p + 20, base);
if (sz != delta.deltaSize) {
break SEARCH;
}
DeltaBaseCache.Entry e = ctx.getDeltaBaseCache().get(key, base);
if (e != null) {
type = e.type;
data = e.data;
cached = true;
break SEARCH;
}
pos = base;
continue SEARCH;
}
default:
throw new IOException(MessageFormat.format(
JGitText.get().unknownObjectType, Integer.valueOf(typeCode)));
}
}
// At this point there is at least one delta to apply to data.
// (Whole objects with no deltas to apply return early above.)
if (data == null)
throw new LargeObjectException();
assert(delta != null);
do {
// Cache only the base immediately before desired object.
if (cached) {
cached = false;
} else if (delta.next == null) {
ctx.getDeltaBaseCache().put(key, delta.basePos, type, data);
}
pos = delta.deltaPos;
byte[] cmds = decompress(pos + delta.hdrLen, delta.deltaSize, ctx);
if (cmds == null) {
data = null; // Discard base in case of OutOfMemoryError
throw new LargeObjectException();
}
final long sz = BinaryDelta.getResultSize(cmds);
if (Integer.MAX_VALUE <= sz) {
throw new LargeObjectException.ExceedsByteArrayLimit();
}
final byte[] result;
try {
result = new byte[(int) sz];
} catch (OutOfMemoryError tooBig) {
data = null; // Discard base in case of OutOfMemoryError
cmds = null;
throw new LargeObjectException.OutOfMemory(tooBig);
}
BinaryDelta.apply(data, cmds, result);
data = result;
delta = delta.next;
} while (delta != null);
return new ObjectLoader.SmallObject(type, data);
} catch (DataFormatException dfe) {
throw new CorruptObjectException(
MessageFormat.format(
JGitText.get().objectAtHasBadZlibStream, Long.valueOf(pos),
getFileName()),
dfe);
}
}
private long findDeltaBase(DfsReader ctx, ObjectId baseId)
throws IOException, MissingObjectException {
long ofs = idx(ctx).findOffset(baseId);
if (ofs < 0) {
throw new MissingObjectException(baseId,
JGitText.get().missingDeltaBase);
}
return ofs;
}
private static class Delta {
/** Child that applies onto this object. */
final Delta next;
/** Offset of the delta object. */
final long deltaPos;
/** Size of the inflated delta stream. */
final int deltaSize;
/** Total size of the delta's pack entry header (including base). */
final int hdrLen;
/** Offset of the base object this delta applies onto. */
final long basePos;
Delta(Delta next, long ofs, int sz, int hdrLen, long baseOffset) {
this.next = next;
this.deltaPos = ofs;
this.deltaSize = sz;
this.hdrLen = hdrLen;
this.basePos = baseOffset;
}
}
byte[] getDeltaHeader(DfsReader wc, long pos)
throws IOException, DataFormatException {
// The delta stream starts as two variable length integers. If we
// assume they are 64 bits each, we need 16 bytes to encode them,
// plus 2 extra bytes for the variable length overhead. So 18 is
// the longest delta instruction header.
//
final byte[] hdr = new byte[32];
wc.inflate(this, pos, hdr, true /* header only */);
return hdr;
}
int getObjectType(DfsReader ctx, long pos) throws IOException {
final byte[] ib = ctx.tempId;
for (;;) {
readFully(pos, ib, 0, 20, ctx);
int c = ib[0] & 0xff;
final int type = (c >> 4) & 7;
switch (type) {
case Constants.OBJ_COMMIT:
case Constants.OBJ_TREE:
case Constants.OBJ_BLOB:
case Constants.OBJ_TAG:
return type;
case Constants.OBJ_OFS_DELTA: {
int p = 1;
while ((c & 0x80) != 0) {
c = ib[p++] & 0xff;
}
c = ib[p++] & 0xff;
long ofs = c & 127;
while ((c & 128) != 0) {
ofs += 1;
c = ib[p++] & 0xff;
ofs <<= 7;
ofs += (c & 127);
}
pos = pos - ofs;
continue;
}
case Constants.OBJ_REF_DELTA: {
int p = 1;
while ((c & 0x80) != 0) {
c = ib[p++] & 0xff;
}
readFully(pos + p, ib, 0, 20, ctx);
pos = findDeltaBase(ctx, ObjectId.fromRaw(ib));
continue;
}
default:
throw new IOException(MessageFormat.format(
JGitText.get().unknownObjectType, Integer.valueOf(type)));
}
}
}
long getObjectSize(DfsReader ctx, AnyObjectId id) throws IOException {
final long offset = idx(ctx).findOffset(id);
return 0 < offset ? getObjectSize(ctx, offset) : -1;
}
long getObjectSize(DfsReader ctx, long pos)
throws IOException {
final byte[] ib = ctx.tempId;
readFully(pos, ib, 0, 20, ctx);
int c = ib[0] & 0xff;
final int type = (c >> 4) & 7;
long sz = c & 15;
int shift = 4;
int p = 1;
while ((c & 0x80) != 0) {
c = ib[p++] & 0xff;
sz += ((long) (c & 0x7f)) << shift;
shift += 7;
}
long deltaAt;
switch (type) {
case Constants.OBJ_COMMIT:
case Constants.OBJ_TREE:
case Constants.OBJ_BLOB:
case Constants.OBJ_TAG:
return sz;
case Constants.OBJ_OFS_DELTA:
c = ib[p++] & 0xff;
while ((c & 128) != 0) {
c = ib[p++] & 0xff;
}
deltaAt = pos + p;
break;
case Constants.OBJ_REF_DELTA:
deltaAt = pos + p + 20;
break;
default:
throw new IOException(MessageFormat.format(
JGitText.get().unknownObjectType, Integer.valueOf(type)));
}
try {
return BinaryDelta.getResultSize(getDeltaHeader(ctx, deltaAt));
} catch (DataFormatException dfe) {
throw new CorruptObjectException(
MessageFormat.format(
JGitText.get().objectAtHasBadZlibStream, Long.valueOf(pos),
getFileName()),
dfe);
}
}
void representation(DfsObjectRepresentation r, final long pos,
DfsReader ctx, PackReverseIndex rev)
throws IOException {
r.offset = pos;
final byte[] ib = ctx.tempId;
readFully(pos, ib, 0, 20, ctx);
int c = ib[0] & 0xff;
int p = 1;
final int typeCode = (c >> 4) & 7;
while ((c & 0x80) != 0) {
c = ib[p++] & 0xff;
}
long len = rev.findNextOffset(pos, length - 20) - pos;
switch (typeCode) {
case Constants.OBJ_COMMIT:
case Constants.OBJ_TREE:
case Constants.OBJ_BLOB:
case Constants.OBJ_TAG:
r.format = StoredObjectRepresentation.PACK_WHOLE;
r.baseId = null;
r.length = len - p;
return;
case Constants.OBJ_OFS_DELTA: {
c = ib[p++] & 0xff;
long ofs = c & 127;
while ((c & 128) != 0) {
ofs += 1;
c = ib[p++] & 0xff;
ofs <<= 7;
ofs += (c & 127);
}
r.format = StoredObjectRepresentation.PACK_DELTA;
r.baseId = rev.findObject(pos - ofs);
r.length = len - p;
return;
}
case Constants.OBJ_REF_DELTA: {
readFully(pos + p, ib, 0, 20, ctx);
r.format = StoredObjectRepresentation.PACK_DELTA;
r.baseId = ObjectId.fromRaw(ib);
r.length = len - p - 20;
return;
}
default:
throw new IOException(MessageFormat.format(
JGitText.get().unknownObjectType, Integer.valueOf(typeCode)));
}
}
boolean isCorrupt(long offset) {
LongList list = corruptObjects;
if (list == null) {
return false;
}
synchronized (list) {
return list.contains(offset);
}
}
private void setCorrupt(long offset) {
LongList list = corruptObjects;
if (list == null) {
synchronized (initLock) {
list = corruptObjects;
if (list == null) {
list = new LongList();
corruptObjects = list;
}
}
}
synchronized (list) {
list.add(offset);
}
}
}