/*
* Copyright (C) 2008-2010, Google Inc.
* Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
* Copyright (C) 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.transport;
import java.io.IOException;
import java.io.InputStream;
import java.text.MessageFormat;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Set;
import org.eclipse.jgit.JGitText;
import org.eclipse.jgit.errors.PackProtocolException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.MutableObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Config.SectionParser;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevCommitList;
import org.eclipse.jgit.revwalk.RevFlag;
import org.eclipse.jgit.revwalk.RevObject;
import org.eclipse.jgit.revwalk.RevSort;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.revwalk.filter.CommitTimeRevFilter;
import org.eclipse.jgit.revwalk.filter.RevFilter;
import org.eclipse.jgit.storage.file.PackLock;
import org.eclipse.jgit.transport.PacketLineIn.AckNackResult;
import org.eclipse.jgit.util.TemporaryBuffer;
/**
* Fetch implementation using the native Git pack transfer service.
* <p>
* This is the canonical implementation for transferring objects from the remote
* repository to the local repository by talking to the 'git-upload-pack'
* service. Objects are packed on the remote side into a pack file and then sent
* down the pipe to us.
* <p>
* This connection requires only a bi-directional pipe or socket, and thus is
* easily wrapped up into a local process pipe, anonymous TCP socket, or a
* command executed through an SSH tunnel.
* <p>
* If {@link BasePackConnection#statelessRPC} is {@code true}, this connection
* can be tunneled over a request-response style RPC system like HTTP. The RPC
* call boundary is determined by this class switching from writing to the
* OutputStream to reading from the InputStream.
* <p>
* Concrete implementations should just call
* {@link #init(java.io.InputStream, java.io.OutputStream)} and
* {@link #readAdvertisedRefs()} methods in constructor or before any use. They
* should also handle resources releasing in {@link #close()} method if needed.
*/
public abstract class BasePackFetchConnection extends BasePackConnection
implements FetchConnection {
/**
* Maximum number of 'have' lines to send before giving up.
* <p>
* During {@link #negotiate(ProgressMonitor)} we send at most this many
* commits to the remote peer as 'have' lines without an ACK response before
* we give up.
*/
private static final int MAX_HAVES = 256;
/**
* Amount of data the client sends before starting to read.
* <p>
* Any output stream given to the client must be able to buffer this many
* bytes before the client will stop writing and start reading from the
* input stream. If the output stream blocks before this many bytes are in
* the send queue, the system will deadlock.
*/
protected static final int MIN_CLIENT_BUFFER = 2 * 32 * 46 + 8;
static final String OPTION_INCLUDE_TAG = "include-tag";
static final String OPTION_MULTI_ACK = "multi_ack";
static final String OPTION_MULTI_ACK_DETAILED = "multi_ack_detailed";
static final String OPTION_THIN_PACK = "thin-pack";
static final String OPTION_SIDE_BAND = "side-band";
static final String OPTION_SIDE_BAND_64K = "side-band-64k";
static final String OPTION_OFS_DELTA = "ofs-delta";
static final String OPTION_SHALLOW = "shallow";
static final String OPTION_NO_PROGRESS = "no-progress";
static final String OPTION_NO_DONE = "no-done";
static enum MultiAck {
OFF, CONTINUE, DETAILED;
}
private final RevWalk walk;
/** All commits that are immediately reachable by a local ref. */
private RevCommitList<RevCommit> reachableCommits;
/** Marks an object as having all its dependencies. */
final RevFlag REACHABLE;
/** Marks a commit known to both sides of the connection. */
final RevFlag COMMON;
/** Like {@link #COMMON} but means its also in {@link #pckState}. */
private final RevFlag STATE;
/** Marks a commit listed in the advertised refs. */
final RevFlag ADVERTISED;
private MultiAck multiAck = MultiAck.OFF;
private boolean thinPack;
private boolean sideband;
private boolean includeTags;
private boolean allowOfsDelta;
private boolean noDone;
private String lockMessage;
private PackLock packLock;
/** RPC state, if {@link BasePackConnection#statelessRPC} is true. */
private TemporaryBuffer.Heap state;
private PacketLineOut pckState;
/**
* Create a new connection to fetch using the native git transport.
*
* @param packTransport
* the transport.
*/
public BasePackFetchConnection(final PackTransport packTransport) {
super(packTransport);
final FetchConfig cfg = local.getConfig().get(FetchConfig.KEY);
includeTags = transport.getTagOpt() != TagOpt.NO_TAGS;
thinPack = transport.isFetchThin();
allowOfsDelta = cfg.allowOfsDelta;
walk = new RevWalk(local);
reachableCommits = new RevCommitList<RevCommit>();
REACHABLE = walk.newFlag("REACHABLE");
COMMON = walk.newFlag("COMMON");
STATE = walk.newFlag("STATE");
ADVERTISED = walk.newFlag("ADVERTISED");
walk.carry(COMMON);
walk.carry(REACHABLE);
walk.carry(ADVERTISED);
}
private static class FetchConfig {
static final SectionParser<FetchConfig> KEY = new SectionParser<FetchConfig>() {
public FetchConfig parse(final Config cfg) {
return new FetchConfig(cfg);
}
};
final boolean allowOfsDelta;
FetchConfig(final Config c) {
allowOfsDelta = c.getBoolean("repack", "usedeltabaseoffset", true);
}
}
public final void fetch(final ProgressMonitor monitor,
final Collection<Ref> want, final Set<ObjectId> have)
throws TransportException {
markStartedOperation();
doFetch(monitor, want, have);
}
public boolean didFetchIncludeTags() {
return false;
}
public boolean didFetchTestConnectivity() {
return false;
}
public void setPackLockMessage(final String message) {
lockMessage = message;
}
public Collection<PackLock> getPackLocks() {
if (packLock != null)
return Collections.singleton(packLock);
return Collections.<PackLock> emptyList();
}
/**
* Execute common ancestor negotiation and fetch the objects.
*
* @param monitor
* progress monitor to receive status updates.
* @param want
* the advertised remote references the caller wants to fetch.
* @param have
* additional objects to assume that already exist locally. This
* will be added to the set of objects reachable from the
* destination repository's references.
* @throws TransportException
* if any exception occurs.
*/
protected void doFetch(final ProgressMonitor monitor,
final Collection<Ref> want, final Set<ObjectId> have)
throws TransportException {
try {
markRefsAdvertised();
markReachable(have, maxTimeWanted(want));
if (statelessRPC) {
state = new TemporaryBuffer.Heap(Integer.MAX_VALUE);
pckState = new PacketLineOut(state);
}
if (sendWants(want)) {
negotiate(monitor);
walk.dispose();
reachableCommits = null;
state = null;
pckState = null;
receivePack(monitor);
}
} catch (CancelledException ce) {
close();
return; // Caller should test (or just know) this themselves.
} catch (IOException err) {
close();
throw new TransportException(err.getMessage(), err);
} catch (RuntimeException err) {
close();
throw new TransportException(err.getMessage(), err);
}
}
@Override
public void close() {
walk.release();
super.close();
}
private int maxTimeWanted(final Collection<Ref> wants) {
int maxTime = 0;
for (final Ref r : wants) {
try {
final RevObject obj = walk.parseAny(r.getObjectId());
if (obj instanceof RevCommit) {
final int cTime = ((RevCommit) obj).getCommitTime();
if (maxTime < cTime)
maxTime = cTime;
}
} catch (IOException error) {
// We don't have it, but we want to fetch (thus fixing error).
}
}
return maxTime;
}
private void markReachable(final Set<ObjectId> have, final int maxTime)
throws IOException {
for (final Ref r : local.getAllRefs().values()) {
ObjectId id = r.getPeeledObjectId();
if (id == null)
id = r.getObjectId();
if (id == null)
continue;
parseReachable(id);
}
for (ObjectId id : local.getAdditionalHaves())
parseReachable(id);
for (ObjectId id : have)
parseReachable(id);
if (maxTime > 0) {
// Mark reachable commits until we reach maxTime. These may
// wind up later matching up against things we want and we
// can avoid asking for something we already happen to have.
//
final Date maxWhen = new Date(maxTime * 1000L);
walk.sort(RevSort.COMMIT_TIME_DESC);
walk.markStart(reachableCommits);
walk.setRevFilter(CommitTimeRevFilter.after(maxWhen));
for (;;) {
final RevCommit c = walk.next();
if (c == null)
break;
if (c.has(ADVERTISED) && !c.has(COMMON)) {
// This is actually going to be a common commit, but
// our peer doesn't know that fact yet.
//
c.add(COMMON);
c.carry(COMMON);
reachableCommits.add(c);
}
}
}
}
private void parseReachable(ObjectId id) {
try {
RevCommit o = walk.parseCommit(id);
if (!o.has(REACHABLE)) {
o.add(REACHABLE);
reachableCommits.add(o);
}
} catch (IOException readError) {
// If we cannot read the value of the ref skip it.
}
}
private boolean sendWants(final Collection<Ref> want) throws IOException {
final PacketLineOut p = statelessRPC ? pckState : pckOut;
boolean first = true;
for (final Ref r : want) {
try {
if (walk.parseAny(r.getObjectId()).has(REACHABLE)) {
// We already have this object. Asking for it is
// not a very good idea.
//
continue;
}
} catch (IOException err) {
// Its OK, we don't have it, but we want to fix that
// by fetching the object from the other side.
}
final StringBuilder line = new StringBuilder(46);
line.append("want ");
line.append(r.getObjectId().name());
if (first) {
line.append(enableCapabilities());
first = false;
}
line.append('\n');
p.writeString(line.toString());
}
if (first)
return false;
p.end();
outNeedsEnd = false;
return true;
}
private String enableCapabilities() throws TransportException {
final StringBuilder line = new StringBuilder();
if (includeTags)
includeTags = wantCapability(line, OPTION_INCLUDE_TAG);
if (allowOfsDelta)
wantCapability(line, OPTION_OFS_DELTA);
if (wantCapability(line, OPTION_MULTI_ACK_DETAILED)) {
multiAck = MultiAck.DETAILED;
if (statelessRPC)
noDone = wantCapability(line, OPTION_NO_DONE);
} else if (wantCapability(line, OPTION_MULTI_ACK))
multiAck = MultiAck.CONTINUE;
else
multiAck = MultiAck.OFF;
if (thinPack)
thinPack = wantCapability(line, OPTION_THIN_PACK);
if (wantCapability(line, OPTION_SIDE_BAND_64K))
sideband = true;
else if (wantCapability(line, OPTION_SIDE_BAND))
sideband = true;
if (statelessRPC && multiAck != MultiAck.DETAILED) {
// Our stateless RPC implementation relies upon the detailed
// ACK status to tell us common objects for reuse in future
// requests. If its not enabled, we can't talk to the peer.
//
throw new PackProtocolException(uri, MessageFormat.format(
JGitText.get().statelessRPCRequiresOptionToBeEnabled,
OPTION_MULTI_ACK_DETAILED));
}
return line.toString();
}
private void negotiate(final ProgressMonitor monitor) throws IOException,
CancelledException {
final MutableObjectId ackId = new MutableObjectId();
int resultsPending = 0;
int havesSent = 0;
int havesSinceLastContinue = 0;
boolean receivedContinue = false;
boolean receivedAck = false;
boolean receivedReady = false;
if (statelessRPC)
state.writeTo(out, null);
negotiateBegin();
SEND_HAVES: for (;;) {
final RevCommit c = walk.next();
if (c == null)
break SEND_HAVES;
pckOut.writeString("have " + c.getId().name() + "\n");
havesSent++;
havesSinceLastContinue++;
if ((31 & havesSent) != 0) {
// We group the have lines into blocks of 32, each marked
// with a flush (aka end). This one is within a block so
// continue with another have line.
//
continue;
}
if (monitor.isCancelled())
throw new CancelledException();
pckOut.end();
resultsPending++; // Each end will cause a result to come back.
if (havesSent == 32 && !statelessRPC) {
// On the first block we race ahead and try to send
// more of the second block while waiting for the
// remote to respond to our first block request.
// This keeps us one block ahead of the peer.
//
continue;
}
READ_RESULT: for (;;) {
final AckNackResult anr = pckIn.readACK(ackId);
switch (anr) {
case NAK:
// More have lines are necessary to compute the
// pack on the remote side. Keep doing that.
//
resultsPending--;
break READ_RESULT;
case ACK:
// The remote side is happy and knows exactly what
// to send us. There is no further negotiation and
// we can break out immediately.
//
multiAck = MultiAck.OFF;
resultsPending = 0;
receivedAck = true;
if (statelessRPC)
state.writeTo(out, null);
break SEND_HAVES;
case ACK_CONTINUE:
case ACK_COMMON:
case ACK_READY:
// The server knows this commit (ackId). We don't
// need to send any further along its ancestry, but
// we need to continue to talk about other parts of
// our local history.
//
markCommon(walk.parseAny(ackId), anr);
receivedAck = true;
receivedContinue = true;
havesSinceLastContinue = 0;
if (anr == AckNackResult.ACK_READY)
receivedReady = true;
break;
}
if (monitor.isCancelled())
throw new CancelledException();
}
if (noDone & receivedReady)
break SEND_HAVES;
if (statelessRPC)
state.writeTo(out, null);
if (receivedContinue && havesSinceLastContinue > MAX_HAVES) {
// Our history must be really different from the remote's.
// We just sent a whole slew of have lines, and it did not
// recognize any of them. Avoid sending our entire history
// to them by giving up early.
//
break SEND_HAVES;
}
}
// Tell the remote side we have run out of things to talk about.
//
if (monitor.isCancelled())
throw new CancelledException();
if (!receivedReady || !noDone) {
// When statelessRPC is true we should always leave SEND_HAVES
// loop above while in the middle of a request. This allows us
// to just write done immediately.
//
pckOut.writeString("done\n");
pckOut.flush();
}
if (!receivedAck) {
// Apparently if we have never received an ACK earlier
// there is one more result expected from the done we
// just sent to the remote.
//
multiAck = MultiAck.OFF;
resultsPending++;
}
READ_RESULT: while (resultsPending > 0 || multiAck != MultiAck.OFF) {
final AckNackResult anr = pckIn.readACK(ackId);
resultsPending--;
switch (anr) {
case NAK:
// A NAK is a response to an end we queued earlier
// we eat it and look for another ACK/NAK message.
//
break;
case ACK:
// A solitary ACK at this point means the remote won't
// speak anymore, but is going to send us a pack now.
//
break READ_RESULT;
case ACK_CONTINUE:
case ACK_COMMON:
case ACK_READY:
// We will expect a normal ACK to break out of the loop.
//
multiAck = MultiAck.CONTINUE;
break;
}
if (monitor.isCancelled())
throw new CancelledException();
}
}
private void negotiateBegin() throws IOException {
walk.resetRetain(REACHABLE, ADVERTISED);
walk.markStart(reachableCommits);
walk.sort(RevSort.COMMIT_TIME_DESC);
walk.setRevFilter(new RevFilter() {
@Override
public RevFilter clone() {
return this;
}
@Override
public boolean include(final RevWalk walker, final RevCommit c) {
final boolean remoteKnowsIsCommon = c.has(COMMON);
if (c.has(ADVERTISED)) {
// Remote advertised this, and we have it, hence common.
// Whether or not the remote knows that fact is tested
// before we added the flag. If the remote doesn't know
// we have to still send them this object.
//
c.add(COMMON);
}
return !remoteKnowsIsCommon;
}
@Override
public boolean requiresCommitBody() {
return false;
}
});
}
private void markRefsAdvertised() {
for (final Ref r : getRefs()) {
markAdvertised(r.getObjectId());
if (r.getPeeledObjectId() != null)
markAdvertised(r.getPeeledObjectId());
}
}
private void markAdvertised(final AnyObjectId id) {
try {
walk.parseAny(id).add(ADVERTISED);
} catch (IOException readError) {
// We probably just do not have this object locally.
}
}
private void markCommon(final RevObject obj, final AckNackResult anr)
throws IOException {
if (statelessRPC && anr == AckNackResult.ACK_COMMON && !obj.has(STATE)) {
StringBuilder s;
s = new StringBuilder(6 + Constants.OBJECT_ID_STRING_LENGTH);
s.append("have "); //$NON-NLS-1$
s.append(obj.name());
s.append('\n');
pckState.writeString(s.toString());
obj.add(STATE);
}
obj.add(COMMON);
if (obj instanceof RevCommit)
((RevCommit) obj).carry(COMMON);
}
private void receivePack(final ProgressMonitor monitor) throws IOException {
InputStream input = in;
if (sideband)
input = new SideBandInputStream(input, monitor, getMessageWriter());
ObjectInserter ins = local.newObjectInserter();
try {
PackParser parser = ins.newPackParser(input);
parser.setAllowThin(thinPack);
parser.setObjectChecking(transport.isCheckFetchedObjects());
parser.setLockMessage(lockMessage);
packLock = parser.parse(monitor);
ins.flush();
} finally {
ins.release();
}
}
private static class CancelledException extends Exception {
private static final long serialVersionUID = 1L;
}
}