org.eclipse.jgit.storage.file.WindowCursor Maven / Gradle / Ivy
/*
* Copyright (C) 2008-2009, Google Inc.
* Copyright (C) 2006-2008, Shawn O. Pearce
* 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.storage.file;
import java.io.IOException;
import java.security.MessageDigest;
import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.StoredObjectRepresentationNotAvailableException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AbbreviatedObjectId;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.InflaterCache;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.storage.pack.CachedPack;
import org.eclipse.jgit.storage.pack.ObjectReuseAsIs;
import org.eclipse.jgit.storage.pack.ObjectToPack;
import org.eclipse.jgit.storage.pack.PackOutputStream;
import org.eclipse.jgit.storage.pack.PackWriter;
/** Active handle to a ByteWindow. */
final class WindowCursor extends ObjectReader implements ObjectReuseAsIs {
/** Temporary buffer large enough for at least one raw object id. */
final byte[] tempId = new byte[Constants.OBJECT_ID_LENGTH];
private Inflater inf;
private ByteWindow window;
private DeltaBaseCache baseCache;
final FileObjectDatabase db;
WindowCursor(FileObjectDatabase db) {
this.db = db;
}
DeltaBaseCache getDeltaBaseCache() {
if (baseCache == null)
baseCache = new DeltaBaseCache();
return baseCache;
}
@Override
public ObjectReader newReader() {
return new WindowCursor(db);
}
@Override
public Collection resolve(AbbreviatedObjectId id)
throws IOException {
if (id.isComplete())
return Collections.singleton(id.toObjectId());
HashSet matches = new HashSet(4);
db.resolve(matches, id);
return matches;
}
public boolean has(AnyObjectId objectId) throws IOException {
return db.has(objectId);
}
public ObjectLoader open(AnyObjectId objectId, int typeHint)
throws MissingObjectException, IncorrectObjectTypeException,
IOException {
final ObjectLoader ldr = db.openObject(this, objectId);
if (ldr == null) {
if (typeHint == OBJ_ANY)
throw new MissingObjectException(objectId.copy(), "unknown");
throw new MissingObjectException(objectId.copy(), typeHint);
}
if (typeHint != OBJ_ANY && ldr.getType() != typeHint)
throw new IncorrectObjectTypeException(objectId.copy(), typeHint);
return ldr;
}
public long getObjectSize(AnyObjectId objectId, int typeHint)
throws MissingObjectException, IncorrectObjectTypeException,
IOException {
long sz = db.getObjectSize(this, objectId);
if (sz < 0) {
if (typeHint == OBJ_ANY)
throw new MissingObjectException(objectId.copy(), "unknown");
throw new MissingObjectException(objectId.copy(), typeHint);
}
return sz;
}
public LocalObjectToPack newObjectToPack(RevObject obj) {
return new LocalObjectToPack(obj);
}
public void selectObjectRepresentation(PackWriter packer,
ProgressMonitor monitor, Iterable objects)
throws IOException, MissingObjectException {
for (ObjectToPack otp : objects) {
db.selectObjectRepresentation(packer, otp, this);
monitor.update(1);
}
}
public void copyObjectAsIs(PackOutputStream out, ObjectToPack otp,
boolean validate) throws IOException,
StoredObjectRepresentationNotAvailableException {
LocalObjectToPack src = (LocalObjectToPack) otp;
src.pack.copyAsIs(out, src, validate, this);
}
public void writeObjects(PackOutputStream out, List list)
throws IOException {
for (ObjectToPack otp : list)
out.writeObject(otp);
}
@SuppressWarnings("unchecked")
public Collection getCachedPacks() throws IOException {
return (Collection) db.getCachedPacks();
}
/**
* Copy bytes from the window to a caller supplied buffer.
*
* @param pack
* the file the desired window is stored within.
* @param position
* position within the file to read from.
* @param dstbuf
* destination buffer to copy into.
* @param dstoff
* offset within dstbuf to start copying into.
* @param cnt
* number of bytes to copy. This value may exceed the number of
* bytes remaining in the window starting at offset
* pos.
* @return number of bytes actually copied; this may be less than
* cnt if cnt exceeded the number of bytes
* available.
* @throws IOException
* this cursor does not match the provider or id and the proper
* window could not be acquired through the provider's cache.
*/
int copy(final PackFile pack, long position, final byte[] dstbuf,
int dstoff, final int cnt) throws IOException {
final long length = pack.length;
int need = cnt;
while (need > 0 && position < length) {
pin(pack, position);
final int r = window.copy(position, dstbuf, dstoff, need);
position += r;
dstoff += r;
need -= r;
}
return cnt - need;
}
public void copyPackAsIs(PackOutputStream out, CachedPack pack,
boolean validate) throws IOException {
((LocalCachedPack) pack).copyAsIs(out, validate, this);
}
void copyPackAsIs(final PackFile pack, final long length, boolean validate,
final PackOutputStream out) throws IOException {
MessageDigest md = null;
if (validate) {
md = Constants.newMessageDigest();
byte[] buf = out.getCopyBuffer();
pin(pack, 0);
if (window.copy(0, buf, 0, 12) != 12) {
pack.setInvalid();
throw new IOException(JGitText.get().packfileIsTruncated);
}
md.update(buf, 0, 12);
}
long position = 12;
long remaining = length - (12 + 20);
while (0 < remaining) {
pin(pack, position);
int ptr = (int) (position - window.start);
int n = (int) Math.min(window.size() - ptr, remaining);
window.write(out, position, n, md);
position += n;
remaining -= n;
}
if (md != null) {
byte[] buf = new byte[20];
byte[] actHash = md.digest();
pin(pack, position);
if (window.copy(position, buf, 0, 20) != 20) {
pack.setInvalid();
throw new IOException(JGitText.get().packfileIsTruncated);
}
if (!Arrays.equals(actHash, buf)) {
pack.setInvalid();
throw new IOException(MessageFormat.format(
JGitText.get().packfileCorruptionDetected, pack
.getPackFile().getPath()));
}
}
}
/**
* Inflate a region of the pack starting at {@code position}.
*
* @param pack
* the file the desired window is stored within.
* @param position
* position within the file to read from.
* @param dstbuf
* destination buffer the inflater should output decompressed
* data to.
* @param dstoff
* current offset within dstbuf to inflate into.
* @return updated dstoff based on the number of bytes
* successfully inflated into dstbuf.
* @throws IOException
* this cursor does not match the provider or id and the proper
* window could not be acquired through the provider's cache.
* @throws DataFormatException
* the inflater encountered an invalid chunk of data. Data
* stream corruption is likely.
*/
int inflate(final PackFile pack, long position, final byte[] dstbuf,
int dstoff) throws IOException, DataFormatException {
prepareInflater();
pin(pack, position);
position += window.setInput(position, inf);
do {
int n = inf.inflate(dstbuf, dstoff, dstbuf.length - dstoff);
if (n == 0) {
if (inf.needsInput()) {
pin(pack, position);
position += window.setInput(position, inf);
} else if (inf.finished())
return dstoff;
else
throw new DataFormatException();
}
dstoff += n;
} while (dstoff < dstbuf.length);
return dstoff;
}
ByteArrayWindow quickCopy(PackFile p, long pos, long cnt)
throws IOException {
pin(p, pos);
if (window instanceof ByteArrayWindow
&& window.contains(p, pos + (cnt - 1)))
return (ByteArrayWindow) window;
return null;
}
Inflater inflater() {
prepareInflater();
return inf;
}
private void prepareInflater() {
if (inf == null)
inf = InflaterCache.get();
else
inf.reset();
}
void pin(final PackFile pack, final long position)
throws IOException {
final ByteWindow w = window;
if (w == null || !w.contains(pack, position)) {
// If memory is low, we may need what is in our window field to
// be cleaned up by the GC during the get for the next window.
// So we always clear it, even though we are just going to set
// it again.
//
window = null;
window = WindowCache.get(pack, position);
}
}
int getStreamFileThreshold() {
return WindowCache.getStreamFileThreshold();
}
/** Release the current window cursor. */
public void release() {
window = null;
baseCache = null;
try {
InflaterCache.release(inf);
} finally {
inf = null;
}
}
}
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