LocalReplica.java
/*
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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.internal.ketch.KetchReplica.CommitMethod.TXN_COMMITTED;
import static org.eclipse.jgit.lib.RefDatabase.ALL;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.OK;
import static org.eclipse.jgit.transport.ReceiveCommand.Result.REJECTED_OTHER_REASON;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.eclipse.jgit.internal.storage.reftree.RefTreeDatabase;
import org.eclipse.jgit.lib.BatchRefUpdate;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefDatabase;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.ReceiveCommand;
import org.eclipse.jgit.util.time.MonotonicClock;
import org.eclipse.jgit.util.time.ProposedTimestamp;
/**
* Ketch replica running on the same system as the
* {@link org.eclipse.jgit.internal.ketch.KetchLeader}.
*/
public class LocalReplica extends KetchReplica {
/**
* Configure a local replica.
*
* @param leader
* instance this replica follows.
* @param name
* unique-ish name identifying this replica for debugging.
* @param cfg
* how Ketch should treat the local system.
*/
public LocalReplica(KetchLeader leader, String name, ReplicaConfig cfg) {
super(leader, name, cfg);
}
/** {@inheritDoc} */
@Override
protected String describeForLog() {
return String.format("%s (leader)", getName()); //$NON-NLS-1$
}
/**
* Initializes local replica by reading accepted and committed references.
* <p>
* Loads accepted and committed references from the reference database of
* the local replica and stores their current ObjectIds in memory.
*
* @param repo
* repository to initialize state from.
* @throws IOException
* cannot read repository state.
*/
void initialize(Repository repo) throws IOException {
RefDatabase refdb = repo.getRefDatabase();
if (refdb instanceof RefTreeDatabase) {
RefTreeDatabase treeDb = (RefTreeDatabase) refdb;
String txnNamespace = getSystem().getTxnNamespace();
if (!txnNamespace.equals(treeDb.getTxnNamespace())) {
throw new IOException(MessageFormat.format(
KetchText.get().mismatchedTxnNamespace,
txnNamespace, treeDb.getTxnNamespace()));
}
refdb = treeDb.getBootstrap();
}
initialize(refdb.exactRef(
getSystem().getTxnAccepted(),
getSystem().getTxnCommitted()));
}
/** {@inheritDoc} */
@Override
protected void startPush(ReplicaPushRequest req) {
getSystem().getExecutor().execute(new Runnable() {
@Override
public void run() {
MonotonicClock clk = getSystem().getClock();
try (Repository git = getLeader().openRepository();
ProposedTimestamp ts = clk.propose()) {
try {
update(git, req, ts);
req.done(git);
} catch (Throwable err) {
req.setException(git, err);
}
} catch (IOException err) {
req.setException(null, err);
}
}
});
}
/** {@inheritDoc} */
@Override
protected void blockingFetch(Repository repo, ReplicaFetchRequest req)
throws IOException {
throw new IOException(KetchText.get().cannotFetchFromLocalReplica);
}
private void update(Repository git, ReplicaPushRequest req,
ProposedTimestamp ts) throws IOException {
RefDatabase refdb = git.getRefDatabase();
CommitMethod method = getCommitMethod();
// Local replica probably uses RefTreeDatabase, the request should
// be only for the txnNamespace, so drop to the bootstrap layer.
if (refdb instanceof RefTreeDatabase) {
if (!isOnlyTxnNamespace(req.getCommands())) {
return;
}
refdb = ((RefTreeDatabase) refdb).getBootstrap();
method = TXN_COMMITTED;
}
BatchRefUpdate batch = refdb.newBatchUpdate();
batch.addProposedTimestamp(ts);
batch.setRefLogIdent(getSystem().newCommitter(ts));
batch.setRefLogMessage("ketch", false); //$NON-NLS-1$
batch.setAllowNonFastForwards(true);
// RefDirectory updates multiple references sequentially.
// Run everything else first, then accepted (if present),
// then committed (if present). This ensures an earlier
// failure will not update these critical references.
ReceiveCommand accepted = null;
ReceiveCommand committed = null;
for (ReceiveCommand cmd : req.getCommands()) {
String name = cmd.getRefName();
if (name.equals(getSystem().getTxnAccepted())) {
accepted = cmd;
} else if (name.equals(getSystem().getTxnCommitted())) {
committed = cmd;
} else {
batch.addCommand(cmd);
}
}
if (committed != null && method == ALL_REFS) {
Map<String, Ref> refs = refdb.getRefs(ALL);
batch.addCommand(prepareCommit(git, refs, committed.getNewId()));
}
if (accepted != null) {
batch.addCommand(accepted);
}
if (committed != null) {
batch.addCommand(committed);
}
try (RevWalk rw = new RevWalk(git)) {
batch.execute(rw, NullProgressMonitor.INSTANCE);
}
// KetchReplica only cares about accepted and committed in
// advertisement. If they failed, store the current values
// back in the ReplicaPushRequest.
List<String> failed = new ArrayList<>(2);
checkFailed(failed, accepted);
checkFailed(failed, committed);
if (!failed.isEmpty()) {
String[] arr = failed.toArray(new String[0]);
req.setRefs(refdb.exactRef(arr));
}
}
private static void checkFailed(List<String> failed, ReceiveCommand cmd) {
if (cmd != null && cmd.getResult() != OK) {
failed.add(cmd.getRefName());
}
}
private boolean isOnlyTxnNamespace(Collection<ReceiveCommand> cmdList) {
// Be paranoid and reject non txnNamespace names, this
// is a programming error in Ketch that should not occur.
String txnNamespace = getSystem().getTxnNamespace();
for (ReceiveCommand cmd : cmdList) {
if (!cmd.getRefName().startsWith(txnNamespace)) {
cmd.setResult(REJECTED_OTHER_REASON,
MessageFormat.format(
KetchText.get().outsideTxnNamespace,
cmd.getRefName(), txnNamespace));
ReceiveCommand.abort(cmdList);
return false;
}
}
return true;
}
}