- /*
- * 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
- * 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.internal.ketch;
-
- import static java.util.concurrent.TimeUnit.SECONDS;
- import static org.eclipse.jgit.internal.ketch.KetchConstants.TERM;
-
- import java.io.IOException;
- import java.util.List;
- import java.util.concurrent.TimeoutException;
-
- import org.eclipse.jgit.lib.CommitBuilder;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.ObjectInserter;
- import org.eclipse.jgit.lib.Repository;
- import org.eclipse.jgit.lib.TreeFormatter;
- import org.eclipse.jgit.revwalk.RevCommit;
- import org.eclipse.jgit.revwalk.RevWalk;
- import org.eclipse.jgit.util.time.ProposedTimestamp;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
-
- /**
- * The initial {@link Round} for a leaderless repository, used to establish a
- * leader.
- */
- class ElectionRound extends Round {
- private static final Logger log = LoggerFactory.getLogger(ElectionRound.class);
-
- private long term;
-
- ElectionRound(KetchLeader leader, LogIndex head) {
- super(leader, head);
- }
-
- @Override
- void start() throws IOException {
- ObjectId id;
- try (Repository git = leader.openRepository();
- ProposedTimestamp ts = getSystem().getClock().propose();
- ObjectInserter inserter = git.newObjectInserter()) {
- id = bumpTerm(git, ts, inserter);
- inserter.flush();
- blockUntil(ts);
- }
- runAsync(id);
- }
-
- @Override
- void success() {
- // Do nothing upon election, KetchLeader will copy the term.
- }
-
- long getTerm() {
- return term;
- }
-
- private ObjectId bumpTerm(Repository git, ProposedTimestamp ts,
- ObjectInserter inserter) throws IOException {
- CommitBuilder b = new CommitBuilder();
- if (!ObjectId.zeroId().equals(acceptedOldIndex)) {
- try (RevWalk rw = new RevWalk(git)) {
- RevCommit c = rw.parseCommit(acceptedOldIndex);
- if (getSystem().requireMonotonicLeaderElections()) {
- if (ts.read(SECONDS) < c.getCommitTime()) {
- throw new TimeIsUncertainException();
- }
- }
- b.setTreeId(c.getTree());
- b.setParentId(acceptedOldIndex);
- term = parseTerm(c.getFooterLines(TERM)) + 1;
- }
- } else {
- term = 1;
- b.setTreeId(inserter.insert(new TreeFormatter()));
- }
-
- StringBuilder msg = new StringBuilder();
- msg.append(KetchConstants.TERM.getName())
- .append(": ") //$NON-NLS-1$
- .append(term);
-
- String tag = leader.getSystem().newLeaderTag();
- if (tag != null && !tag.isEmpty()) {
- msg.append(' ').append(tag);
- }
-
- b.setAuthor(leader.getSystem().newCommitter(ts));
- b.setCommitter(b.getAuthor());
- b.setMessage(msg.toString());
-
- if (log.isDebugEnabled()) {
- log.debug("Trying to elect myself " + b.getMessage()); //$NON-NLS-1$
- }
- return inserter.insert(b);
- }
-
- private static long parseTerm(List<String> footer) {
- if (footer.isEmpty()) {
- return 0;
- }
-
- String s = footer.get(0);
- int p = s.indexOf(' ');
- if (p > 0) {
- s = s.substring(0, p);
- }
- return Long.parseLong(s, 10);
- }
-
- private void blockUntil(ProposedTimestamp ts) throws IOException {
- try {
- ts.blockUntil(getSystem().getMaxWaitForMonotonicClock());
- } catch (InterruptedException | TimeoutException e) {
- throw new TimeIsUncertainException(e);
- }
- }
- }
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