org.eclipse.jgit.storage.dfs.DfsReader Maven / Gradle / Ivy
/*
* Copyright (C) 2008-2011, 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.dfs;
import static org.eclipse.jgit.lib.Constants.OBJECT_ID_LENGTH;
import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
import static org.eclipse.jgit.lib.Constants.OBJ_TREE;
import static org.eclipse.jgit.storage.pack.PackExt.PACK;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.security.MessageDigest;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ExecutionException;
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.AsyncObjectLoaderQueue;
import org.eclipse.jgit.lib.AsyncObjectSizeQueue;
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.ObjectWalk;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevWalk;
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;
import org.eclipse.jgit.util.BlockList;
/**
* Reader to access repository content through.
*
* See the base {@link ObjectReader} documentation for details. Notably, a
* reader is not thread safe.
*/
public final class DfsReader extends ObjectReader implements ObjectReuseAsIs {
/** Temporary buffer large enough for at least one raw object id. */
final byte[] tempId = new byte[OBJECT_ID_LENGTH];
/** Database this reader loads objects from. */
final DfsObjDatabase db;
private Inflater inf;
private DfsBlock block;
private DeltaBaseCache baseCache;
private DfsPackFile last;
private boolean wantReadAhead;
private List pendingReadAhead;
DfsReader(DfsObjDatabase db) {
this.db = db;
}
DfsReaderOptions getOptions() {
return db.getReaderOptions();
}
DeltaBaseCache getDeltaBaseCache() {
if (baseCache == null)
baseCache = new DeltaBaseCache(this);
return baseCache;
}
int getStreamFileThreshold() {
return getOptions().getStreamFileThreshold();
}
@Override
public ObjectReader newReader() {
return new DfsReader(db);
}
@Override
public Collection resolve(AbbreviatedObjectId id)
throws IOException {
if (id.isComplete())
return Collections.singleton(id.toObjectId());
HashSet matches = new HashSet(4);
for (DfsPackFile pack : db.getPacks()) {
pack.resolve(this, matches, id, 256);
if (256 <= matches.size())
break;
}
return matches;
}
@Override
public boolean has(AnyObjectId objectId) throws IOException {
if (last != null && last.hasObject(this, objectId))
return true;
for (DfsPackFile pack : db.getPacks()) {
if (last == pack)
continue;
if (pack.hasObject(this, objectId)) {
last = pack;
return true;
}
}
return false;
}
@Override
public ObjectLoader open(AnyObjectId objectId, int typeHint)
throws MissingObjectException, IncorrectObjectTypeException,
IOException {
if (last != null) {
ObjectLoader ldr = last.get(this, objectId);
if (ldr != null)
return ldr;
}
for (DfsPackFile pack : db.getPacks()) {
if (pack == last)
continue;
ObjectLoader ldr = pack.get(this, objectId);
if (ldr != null) {
last = pack;
return ldr;
}
}
if (typeHint == OBJ_ANY)
throw new MissingObjectException(objectId.copy(), "unknown");
throw new MissingObjectException(objectId.copy(), typeHint);
}
@Override
public Set getShallowCommits() {
return Collections.emptySet();
}
private static final Comparator> FOUND_OBJECT_SORT = new Comparator>() {
public int compare(FoundObject a, FoundObject b) {
int cmp = a.packIndex - b.packIndex;
if (cmp == 0)
cmp = Long.signum(a.offset - b.offset);
return cmp;
}
};
private static class FoundObject {
final T id;
final DfsPackFile pack;
final long offset;
final int packIndex;
FoundObject(T objectId, int packIdx, DfsPackFile pack, long offset) {
this.id = objectId;
this.pack = pack;
this.offset = offset;
this.packIndex = packIdx;
}
FoundObject(T objectId) {
this.id = objectId;
this.pack = null;
this.offset = 0;
this.packIndex = 0;
}
}
private Iterable> findAll(
Iterable objectIds) throws IOException {
ArrayList> r = new ArrayList>();
DfsPackFile[] packList = db.getPacks();
if (packList.length == 0) {
for (T t : objectIds)
r.add(new FoundObject(t));
return r;
}
int lastIdx = 0;
DfsPackFile lastPack = packList[lastIdx];
OBJECT_SCAN: for (T t : objectIds) {
try {
long p = lastPack.findOffset(this, t);
if (0 < p) {
r.add(new FoundObject(t, lastIdx, lastPack, p));
continue;
}
} catch (IOException e) {
// Fall though and try to examine other packs.
}
for (int i = 0; i < packList.length; i++) {
if (i == lastIdx)
continue;
DfsPackFile pack = packList[i];
try {
long p = pack.findOffset(this, t);
if (0 < p) {
r.add(new FoundObject(t, i, pack, p));
lastIdx = i;
lastPack = pack;
continue OBJECT_SCAN;
}
} catch (IOException e) {
// Examine other packs.
}
}
r.add(new FoundObject(t));
}
Collections.sort(r, FOUND_OBJECT_SORT);
last = lastPack;
return r;
}
@Override
public AsyncObjectLoaderQueue open(
Iterable objectIds, final boolean reportMissing) {
wantReadAhead = true;
Iterable> order;
IOException error = null;
try {
order = findAll(objectIds);
} catch (IOException e) {
order = Collections.emptyList();
error = e;
}
final Iterator> idItr = order.iterator();
final IOException findAllError = error;
return new AsyncObjectLoaderQueue() {
private FoundObject cur;
public boolean next() throws MissingObjectException, IOException {
if (idItr.hasNext()) {
cur = idItr.next();
return true;
} else if (findAllError != null) {
throw findAllError;
} else {
cancelReadAhead();
return false;
}
}
public T getCurrent() {
return cur.id;
}
public ObjectId getObjectId() {
return cur.id;
}
public ObjectLoader open() throws IOException {
if (cur.pack == null)
throw new MissingObjectException(cur.id, "unknown");
return cur.pack.load(DfsReader.this, cur.offset);
}
public boolean cancel(boolean mayInterruptIfRunning) {
cancelReadAhead();
return true;
}
public void release() {
cancelReadAhead();
}
};
}
@Override
public AsyncObjectSizeQueue getObjectSize(
Iterable objectIds, final boolean reportMissing) {
wantReadAhead = true;
Iterable> order;
IOException error = null;
try {
order = findAll(objectIds);
} catch (IOException e) {
order = Collections.emptyList();
error = e;
}
final Iterator> idItr = order.iterator();
final IOException findAllError = error;
return new AsyncObjectSizeQueue() {
private FoundObject cur;
private long sz;
public boolean next() throws MissingObjectException, IOException {
if (idItr.hasNext()) {
cur = idItr.next();
if (cur.pack == null)
throw new MissingObjectException(cur.id, "unknown");
sz = cur.pack.getObjectSize(DfsReader.this, cur.offset);
return true;
} else if (findAllError != null) {
throw findAllError;
} else {
cancelReadAhead();
return false;
}
}
public T getCurrent() {
return cur.id;
}
public ObjectId getObjectId() {
return cur.id;
}
public long getSize() {
return sz;
}
public boolean cancel(boolean mayInterruptIfRunning) {
cancelReadAhead();
return true;
}
public void release() {
cancelReadAhead();
}
};
}
@Override
public void walkAdviceBeginCommits(RevWalk walk, Collection roots) {
wantReadAhead = true;
}
@Override
public void walkAdviceBeginTrees(ObjectWalk ow, RevCommit min, RevCommit max) {
wantReadAhead = true;
}
@Override
public void walkAdviceEnd() {
cancelReadAhead();
}
@Override
public long getObjectSize(AnyObjectId objectId, int typeHint)
throws MissingObjectException, IncorrectObjectTypeException,
IOException {
if (last != null) {
long sz = last.getObjectSize(this, objectId);
if (0 <= sz)
return sz;
}
for (DfsPackFile pack : db.getPacks()) {
if (pack == last)
continue;
long sz = pack.getObjectSize(this, objectId);
if (0 <= sz) {
last = pack;
return sz;
}
}
if (typeHint == OBJ_ANY)
throw new MissingObjectException(objectId.copy(), "unknown");
throw new MissingObjectException(objectId.copy(), typeHint);
}
public DfsObjectToPack newObjectToPack(RevObject obj) {
return new DfsObjectToPack(obj);
}
private static final Comparator REPRESENTATION_SORT = new Comparator() {
public int compare(DfsObjectRepresentation a, DfsObjectRepresentation b) {
int cmp = a.packIndex - b.packIndex;
if (cmp == 0)
cmp = Long.signum(a.offset - b.offset);
return cmp;
}
};
public void selectObjectRepresentation(PackWriter packer,
ProgressMonitor monitor, Iterable objects)
throws IOException, MissingObjectException {
DfsPackFile[] packList = db.getPacks();
if (packList.length == 0) {
Iterator itr = objects.iterator();
if (itr.hasNext())
throw new MissingObjectException(itr.next(), "unknown");
return;
}
int objectCount = 0;
int updated = 0;
int posted = 0;
List all = new BlockList();
for (ObjectToPack otp : objects) {
boolean found = false;
for (int packIndex = 0; packIndex < packList.length; packIndex++) {
DfsPackFile pack = packList[packIndex];
long p = pack.findOffset(this, otp);
if (0 < p) {
DfsObjectRepresentation r = new DfsObjectRepresentation(otp);
r.pack = pack;
r.packIndex = packIndex;
r.offset = p;
all.add(r);
found = true;
}
}
if (!found)
throw new MissingObjectException(otp, otp.getType());
if ((++updated & 1) == 1) {
monitor.update(1); // Update by 50%, the other 50% is below.
posted++;
}
objectCount++;
}
Collections.sort(all, REPRESENTATION_SORT);
try {
wantReadAhead = true;
for (DfsObjectRepresentation r : all) {
r.pack.representation(this, r);
packer.select(r.object, r);
if ((++updated & 1) == 1 && posted < objectCount) {
monitor.update(1);
posted++;
}
}
} finally {
cancelReadAhead();
}
if (posted < objectCount)
monitor.update(objectCount - posted);
}
public void copyObjectAsIs(PackOutputStream out, ObjectToPack otp,
boolean validate) throws IOException,
StoredObjectRepresentationNotAvailableException {
DfsObjectToPack src = (DfsObjectToPack) otp;
src.pack.copyAsIs(out, src, validate, this);
}
private static final Comparator WRITE_SORT = new Comparator() {
public int compare(ObjectToPack o1, ObjectToPack o2) {
DfsObjectToPack a = (DfsObjectToPack) o1;
DfsObjectToPack b = (DfsObjectToPack) o2;
int cmp = a.packIndex - b.packIndex;
if (cmp == 0)
cmp = Long.signum(a.offset - b.offset);
return cmp;
}
};
public void writeObjects(PackOutputStream out, List list)
throws IOException {
if (list.isEmpty())
return;
// Sorting objects by order in the current packs is usually
// worthwhile. Most packs are going to be OFS_DELTA style,
// where the base must appear before the deltas. If both base
// and delta are to be reused, this ensures the base writes in
// the output first without the recursive write-base-first logic
// used by PackWriter to ensure OFS_DELTA can be used.
//
// Sorting by pack also ensures newer objects go first, which
// typically matches the desired order.
//
// Only do this sorting for OBJ_TREE and OBJ_BLOB. Commits
// are very likely to already be sorted in a good order in the
// incoming list, and if they aren't, JGit's PackWriter has fixed
// the order to be more optimal for readers, so honor that.
switch (list.get(0).getType()) {
case OBJ_TREE:
case OBJ_BLOB:
Collections.sort(list, WRITE_SORT);
}
try {
wantReadAhead = true;
for (ObjectToPack otp : list)
out.writeObject(otp);
} finally {
cancelReadAhead();
}
}
public Collection getCachedPacks() throws IOException {
DfsPackFile[] packList = db.getPacks();
List cached = new ArrayList(packList.length);
for (DfsPackFile pack : packList) {
DfsPackDescription desc = pack.getPackDescription();
if (canBeCachedPack(desc))
cached.add(new DfsCachedPack(pack));
}
return cached;
}
private static boolean canBeCachedPack(DfsPackDescription desc) {
return desc.getTips() != null && !desc.getTips().isEmpty();
}
public void copyPackAsIs(PackOutputStream out, CachedPack pack,
boolean validate) throws IOException {
try {
wantReadAhead = true;
((DfsCachedPack) pack).copyAsIs(out, validate, this);
} finally {
cancelReadAhead();
}
}
/**
* 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(DfsPackFile pack, long position, byte[] dstbuf, int dstoff, int cnt)
throws IOException {
if (cnt == 0)
return 0;
long length = pack.length;
if (0 <= length && length <= position)
return 0;
int need = cnt;
do {
pin(pack, position);
int r = block.copy(position, dstbuf, dstoff, need);
position += r;
dstoff += r;
need -= r;
if (length < 0)
length = pack.length;
} while (0 < need && position < length);
return cnt - need;
}
void copyPackAsIs(DfsPackFile pack, long length, boolean validate,
PackOutputStream out) throws IOException {
MessageDigest md = null;
if (validate) {
md = Constants.newMessageDigest();
byte[] buf = out.getCopyBuffer();
pin(pack, 0);
if (block.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 - block.start);
int n = (int) Math.min(block.size() - ptr, remaining);
block.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 (block.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.getPackDescription().getFileName(PACK)));
}
}
}
/**
* 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 headerOnly
* if true the caller wants only {@code dstbuf.length} bytes.
* @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(DfsPackFile pack, long position, byte[] dstbuf,
boolean headerOnly) throws IOException, DataFormatException {
prepareInflater();
pin(pack, position);
int dstoff = 0;
for (;;) {
dstoff = block.inflate(inf, position, dstbuf, dstoff);
if (headerOnly && dstoff == dstbuf.length)
return dstoff;
if (inf.needsInput()) {
position += block.remaining(position);
pin(pack, position);
} else if (inf.finished())
return dstoff;
else
throw new DataFormatException();
}
}
DfsBlock quickCopy(DfsPackFile p, long pos, long cnt)
throws IOException {
pin(p, pos);
if (block.contains(p.key, pos + (cnt - 1)))
return block;
return null;
}
Inflater inflater() {
prepareInflater();
return inf;
}
private void prepareInflater() {
if (inf == null)
inf = InflaterCache.get();
else
inf.reset();
}
void pin(DfsPackFile pack, long position) throws IOException {
DfsBlock b = block;
if (b == null || !b.contains(pack.key, 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.
//
block = null;
if (pendingReadAhead != null)
waitForBlock(pack.key, position);
block = pack.getOrLoadBlock(position, this);
}
}
boolean wantReadAhead() {
return wantReadAhead;
}
void startedReadAhead(List blocks) {
if (pendingReadAhead == null)
pendingReadAhead = new LinkedList();
pendingReadAhead.addAll(blocks);
}
private void cancelReadAhead() {
if (pendingReadAhead != null) {
for (ReadAheadTask.BlockFuture f : pendingReadAhead)
f.cancel(true);
pendingReadAhead = null;
}
wantReadAhead = false;
}
private void waitForBlock(DfsPackKey key, long position)
throws InterruptedIOException {
Iterator itr = pendingReadAhead.iterator();
while (itr.hasNext()) {
ReadAheadTask.BlockFuture f = itr.next();
if (f.contains(key, position)) {
try {
f.get();
} catch (InterruptedException e) {
throw new InterruptedIOException();
} catch (ExecutionException e) {
// Exceptions should never be thrown by get(). Ignore
// this and let the normal load paths identify any error.
}
itr.remove();
if (pendingReadAhead.isEmpty())
pendingReadAhead = null;
break;
}
}
}
/** Release the current window cursor. */
@Override
public void release() {
cancelReadAhead();
last = null;
block = null;
baseCache = null;
try {
InflaterCache.release(inf);
} finally {
inf = null;
}
}
}