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184 lines
5.6 KiB
184 lines
5.6 KiB
/* |
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* Copyright (C) 2016, Google Inc. |
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* and other copyright owners as documented in the project's IP log. |
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* |
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* This program and the accompanying materials are made available |
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* under the terms of the Eclipse Distribution License v1.0 which |
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* accompanies this distribution, is reproduced below, and is |
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* available at http://www.eclipse.org/org/documents/edl-v10.php |
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* |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or |
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* without modification, are permitted provided that the following |
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* conditions are met: |
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* |
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* - Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* - Redistributions in binary form must reproduce the above |
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* copyright notice, this list of conditions and the following |
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* disclaimer in the documentation and/or other materials provided |
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* with the distribution. |
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* |
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* - Neither the name of the Eclipse Foundation, Inc. nor the |
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* names of its contributors may be used to endorse or promote |
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* products derived from this software without specific prior |
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* written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
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* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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package org.eclipse.jgit.internal.ketch; |
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import static org.eclipse.jgit.internal.ketch.KetchReplica.State.AHEAD; |
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import static org.eclipse.jgit.internal.ketch.KetchReplica.State.DIVERGENT; |
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import static org.eclipse.jgit.internal.ketch.KetchReplica.State.LAGGING; |
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import static org.eclipse.jgit.internal.ketch.KetchReplica.State.UNKNOWN; |
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import static org.eclipse.jgit.lib.Constants.OBJ_COMMIT; |
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import java.io.IOException; |
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import java.util.Collections; |
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import java.util.Map; |
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import org.eclipse.jgit.errors.MissingObjectException; |
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import org.eclipse.jgit.lib.AnyObjectId; |
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import org.eclipse.jgit.lib.ObjectId; |
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import org.eclipse.jgit.lib.Ref; |
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import org.eclipse.jgit.lib.Repository; |
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import org.eclipse.jgit.revwalk.RevCommit; |
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import org.eclipse.jgit.revwalk.RevWalk; |
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import org.eclipse.jgit.transport.ReceiveCommand; |
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/** |
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* A helper to check if a {@link KetchReplica} is ahead or behind the leader. |
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*/ |
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class LagCheck implements AutoCloseable { |
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private final KetchReplica replica; |
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private final Repository repo; |
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private RevWalk rw; |
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private ObjectId remoteId; |
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LagCheck(KetchReplica replica, Repository repo) { |
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this.replica = replica; |
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this.repo = repo; |
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initRevWalk(); |
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} |
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private void initRevWalk() { |
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if (rw != null) { |
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rw.close(); |
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} |
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rw = new RevWalk(repo); |
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rw.setRetainBody(false); |
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} |
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/** {@inheritDoc} */ |
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@Override |
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public void close() { |
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if (rw != null) { |
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rw.close(); |
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rw = null; |
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} |
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} |
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ObjectId getRemoteId() { |
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return remoteId; |
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} |
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KetchReplica.State check(ObjectId acceptId, ReceiveCommand acceptCmd) { |
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remoteId = acceptId; |
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if (remoteId == null) { |
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// Nothing advertised by the replica, value is unknown. |
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return UNKNOWN; |
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} |
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if (AnyObjectId.isEqual(remoteId, ObjectId.zeroId())) { |
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// Replica does not have the txnAccepted reference. |
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return LAGGING; |
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} |
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try { |
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RevCommit remote; |
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try { |
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remote = parseRemoteCommit(acceptCmd.getRefName()); |
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} catch (RefGoneException gone) { |
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// Replica does not have the txnAccepted reference. |
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return LAGGING; |
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} catch (MissingObjectException notFound) { |
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// Local repository does not know this commit so it cannot |
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// be including the replica's log. |
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return DIVERGENT; |
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} |
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RevCommit head = rw.parseCommit(acceptCmd.getNewId()); |
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if (rw.isMergedInto(remote, head)) { |
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return LAGGING; |
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} |
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// TODO(sop) Check term to see if my leader was deposed. |
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if (rw.isMergedInto(head, remote)) { |
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return AHEAD; |
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} |
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return DIVERGENT; |
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} catch (IOException err) { |
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KetchReplica.log.error(String.format( |
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"Cannot compare %s", //$NON-NLS-1$ |
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acceptCmd.getRefName()), err); |
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return UNKNOWN; |
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} |
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} |
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private RevCommit parseRemoteCommit(String refName) |
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throws IOException, MissingObjectException, RefGoneException { |
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try { |
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return rw.parseCommit(remoteId); |
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} catch (MissingObjectException notLocal) { |
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// Fall through and try to acquire the object by fetching it. |
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} |
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ReplicaFetchRequest fetch = new ReplicaFetchRequest( |
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Collections.singleton(refName), |
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Collections.<ObjectId> emptySet()); |
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try { |
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replica.blockingFetch(repo, fetch); |
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} catch (IOException fetchErr) { |
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KetchReplica.log.error(String.format( |
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"Cannot fetch %s (%s) from %s", //$NON-NLS-1$ |
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remoteId.abbreviate(8).name(), refName, |
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replica.describeForLog()), fetchErr); |
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throw new MissingObjectException(remoteId, OBJ_COMMIT); |
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} |
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Map<String, Ref> adv = fetch.getRefs(); |
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if (adv == null) { |
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throw new MissingObjectException(remoteId, OBJ_COMMIT); |
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} |
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Ref ref = adv.get(refName); |
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if (ref == null || ref.getObjectId() == null) { |
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throw new RefGoneException(); |
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} |
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initRevWalk(); |
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remoteId = ref.getObjectId(); |
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return rw.parseCommit(remoteId); |
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} |
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private static class RefGoneException extends Exception { |
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private static final long serialVersionUID = 1L; |
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} |
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}
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