RemoteGitReplica.java
/*
* Copyright (C) 2016, Google Inc.
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
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* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
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package org.eclipse.jgit.internal.ketch;
import static org.eclipse.jgit.internal.ketch.KetchReplica.CommitMethod.ALL_REFS;
import static org.eclipse.jgit.lib.Ref.Storage.NETWORK;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.LOCK_FAILURE;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.NOT_ATTEMPTED;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.OK;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_NODELETE;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_NONFASTFORWARD;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.eclipse.jgit.annotations.Nullable;
import org.eclipse.jgit.errors.NotSupportedException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectIdRef;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.transport.FetchConnection;
import org.eclipse.jgit.transport.PushConnection;
import org.eclipse.jgit.transport.ReceiveCommand;
import org.eclipse.jgit.transport.RemoteConfig;
import org.eclipse.jgit.transport.RemoteRefUpdate;
import org.eclipse.jgit.transport.Transport;
import org.eclipse.jgit.transport.URIish;
/**
* Representation of a Git repository on a remote replica system.
* <p>
* {@link org.eclipse.jgit.internal.ketch.KetchLeader} will contact the replica
* using the Git wire protocol.
* <p>
* The remote replica may be fully Ketch-aware, or a standard Git server.
*/
public class RemoteGitReplica extends KetchReplica {
private final URIish uri;
private final RemoteConfig remoteConfig;
/**
* Configure a new remote.
*
* @param leader
* instance this replica follows.
* @param name
* unique-ish name identifying this remote for debugging.
* @param uri
* URI to connect to the follower's repository.
* @param cfg
* how Ketch should treat the remote system.
* @param rc
* optional remote configuration describing how to contact the
* peer repository.
*/
public RemoteGitReplica(KetchLeader leader, String name, URIish uri,
ReplicaConfig cfg, @Nullable RemoteConfig rc) {
super(leader, name, cfg);
this.uri = uri;
this.remoteConfig = rc;
}
/**
* Get URI to contact the remote peer repository.
*
* @return URI to contact the remote peer repository.
*/
public URIish getURI() {
return uri;
}
/**
* Get optional configuration describing how to contact the peer.
*
* @return optional configuration describing how to contact the peer.
*/
@Nullable
protected RemoteConfig getRemoteConfig() {
return remoteConfig;
}
/** {@inheritDoc} */
@Override
protected String describeForLog() {
return String.format("%s @ %s", getName(), getURI()); //$NON-NLS-1$
}
/** {@inheritDoc} */
@Override
protected void startPush(ReplicaPushRequest req) {
getSystem().getExecutor().execute(new Runnable() {
@Override
public void run() {
try (Repository git = getLeader().openRepository()) {
try {
push(git, req);
req.done(git);
} catch (Throwable err) {
req.setException(git, err);
}
} catch (IOException err) {
req.setException(null, err);
}
}
});
}
private void push(Repository repo, ReplicaPushRequest req)
throws NotSupportedException, TransportException, IOException {
Map<String, Ref> adv;
List<RemoteCommand> cmds = asUpdateList(req.getCommands());
try (Transport transport = Transport.open(repo, uri)) {
RemoteConfig rc = getRemoteConfig();
if (rc != null) {
transport.applyConfig(rc);
}
transport.setPushAtomic(true);
adv = push(repo, transport, cmds);
}
for (RemoteCommand c : cmds) {
c.copyStatusToResult();
}
req.setRefs(adv);
}
private Map<String, Ref> push(Repository git, Transport transport,
List<RemoteCommand> cmds) throws IOException {
Map<String, RemoteRefUpdate> updates = asUpdateMap(cmds);
try (PushConnection connection = transport.openPush()) {
Map<String, Ref> adv = connection.getRefsMap();
RemoteRefUpdate accepted = updates.get(getSystem().getTxnAccepted());
if (accepted != null && !isExpectedValue(adv, accepted)) {
abort(cmds);
return adv;
}
RemoteRefUpdate committed = updates.get(getSystem().getTxnCommitted());
if (committed != null && !isExpectedValue(adv, committed)) {
abort(cmds);
return adv;
}
if (committed != null && getCommitMethod() == ALL_REFS) {
prepareCommit(git, cmds, updates, adv,
committed.getNewObjectId());
}
connection.push(NullProgressMonitor.INSTANCE, updates);
return adv;
}
}
private static boolean isExpectedValue(Map<String, Ref> adv,
RemoteRefUpdate u) {
Ref r = adv.get(u.getRemoteName());
if (!AnyObjectId.equals(getId(r), u.getExpectedOldObjectId())) {
((RemoteCommand) u).cmd.setResult(LOCK_FAILURE);
return false;
}
return true;
}
private void prepareCommit(Repository git, List<RemoteCommand> cmds,
Map<String, RemoteRefUpdate> updates, Map<String, Ref> adv,
ObjectId committed) throws IOException {
for (ReceiveCommand cmd : prepareCommit(git, adv, committed)) {
RemoteCommand c = new RemoteCommand(cmd);
cmds.add(c);
updates.put(c.getRemoteName(), c);
}
}
private static List<RemoteCommand> asUpdateList(
Collection<ReceiveCommand> cmds) {
try {
List<RemoteCommand> toPush = new ArrayList<>(cmds.size());
for (ReceiveCommand cmd : cmds) {
toPush.add(new RemoteCommand(cmd));
}
return toPush;
} catch (IOException e) {
// Cannot occur as no IO was required to build the command.
throw new IllegalStateException(e);
}
}
private static Map<String, RemoteRefUpdate> asUpdateMap(
List<RemoteCommand> cmds) {
Map<String, RemoteRefUpdate> m = new LinkedHashMap<>();
for (RemoteCommand cmd : cmds) {
m.put(cmd.getRemoteName(), cmd);
}
return m;
}
private static void abort(List<RemoteCommand> cmds) {
List<ReceiveCommand> tmp = new ArrayList<>(cmds.size());
for (RemoteCommand cmd : cmds) {
tmp.add(cmd.cmd);
}
ReceiveCommand.abort(tmp);
}
/** {@inheritDoc} */
@Override
protected void blockingFetch(Repository repo, ReplicaFetchRequest req)
throws NotSupportedException, TransportException {
try (Transport transport = Transport.open(repo, uri)) {
RemoteConfig rc = getRemoteConfig();
if (rc != null) {
transport.applyConfig(rc);
}
fetch(transport, req);
}
}
private void fetch(Transport transport, ReplicaFetchRequest req)
throws NotSupportedException, TransportException {
try (FetchConnection conn = transport.openFetch()) {
Map<String, Ref> remoteRefs = conn.getRefsMap();
req.setRefs(remoteRefs);
List<Ref> want = new ArrayList<>();
for (String name : req.getWantRefs()) {
Ref ref = remoteRefs.get(name);
if (ref != null && ref.getObjectId() != null) {
want.add(ref);
}
}
for (ObjectId id : req.getWantObjects()) {
want.add(new ObjectIdRef.Unpeeled(NETWORK, id.name(), id));
}
conn.fetch(NullProgressMonitor.INSTANCE, want,
Collections.<ObjectId> emptySet());
}
}
static class RemoteCommand extends RemoteRefUpdate {
final ReceiveCommand cmd;
RemoteCommand(ReceiveCommand cmd) throws IOException {
super(null, null,
cmd.getNewId(), cmd.getRefName(),
true /* force update */,
null /* no local tracking ref */,
cmd.getOldId());
this.cmd = cmd;
}
void copyStatusToResult() {
if (cmd.getResult() == NOT_ATTEMPTED) {
switch (getStatus()) {
case OK:
case UP_TO_DATE:
case NON_EXISTING:
cmd.setResult(OK);
break;
case REJECTED_NODELETE:
cmd.setResult(REJECTED_NODELETE);
break;
case REJECTED_NONFASTFORWARD:
cmd.setResult(REJECTED_NONFASTFORWARD);
break;
case REJECTED_OTHER_REASON:
cmd.setResult(REJECTED_OTHER_REASON, getMessage());
break;
default:
cmd.setResult(REJECTED_OTHER_REASON, getStatus().name());
break;
}
}
}
}
}