/*
* Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
* Copyright (C) 2010, Stefan Lay <stefan.lay@sap.com>
* 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.api;
import java.io.File;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.LinkedList;
import java.util.List;
import org.eclipse.jgit.JGitText;
import org.eclipse.jgit.api.MergeResult.MergeStatus;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.GitIndex;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectIdRef;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Ref.Storage;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.RefUpdate.Result;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.WorkDirCheckout;
import org.eclipse.jgit.merge.MergeStrategy;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
/**
* A class used to execute a {@code Merge} command. It has setters for all
* supported options and arguments of this command and a {@link #call()} method
* to finally execute the command. Each instance of this class should only be
* used for one invocation of the command (means: one call to {@link #call()})
* <p>
* This is currently a very basic implementation which takes only one commits to
* merge with as option. Furthermore it does supports only fast forward.
*
* @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-merge.html"
* >Git documentation about Merge</a>
*/
public class MergeCommand extends GitCommand<MergeResult> {
private MergeStrategy mergeStrategy = MergeStrategy.SIMPLE_TWO_WAY_IN_CORE;
private List<Ref> commits = new LinkedList<Ref>();
/**
* @param repo
*/
protected MergeCommand(Repository repo) {
super(repo);
}
/**
* Executes the {@code Merge} command with all the options and parameters
* collected by the setter methods (e.g. {@link #include(Ref)}) of this
* class. Each instance of this class should only be used for one invocation
* of the command. Don't call this method twice on an instance.
*
* @return the result of the merge
*/
public MergeResult call() throws NoHeadException,
ConcurrentRefUpdateException, CheckoutConflictException,
InvalidMergeHeadsException {
checkCallable();
if (commits.size() != 1)
throw new InvalidMergeHeadsException(
commits.isEmpty() ? JGitText.get().noMergeHeadSpecified
: MessageFormat.format(
JGitText.get().mergeStrategyDoesNotSupportHeads,
mergeStrategy.getName(), commits.size()));
try {
Ref head = repo.getRef(Constants.HEAD);
if (head == null)
throw new NoHeadException(JGitText.get().commitOnRepoWithoutHEADCurrentlyNotSupported);
StringBuilder refLogMessage = new StringBuilder("merge ");
// Check for FAST_FORWARD, ALREADY_UP_TO_DATE
RevWalk revWalk = new RevWalk(repo);
try {
RevCommit headCommit = revWalk.lookupCommit(head.getObjectId());
Ref ref = commits.get(0);
refLogMessage.append(ref.getName());
// handle annotated tags
ObjectId objectId = ref.getPeeledObjectId();
if (objectId == null)
objectId = ref.getObjectId();
RevCommit srcCommit = revWalk.lookupCommit(objectId);
if (revWalk.isMergedInto(srcCommit, headCommit)) {
setCallable(false);
return new MergeResult(headCommit,
MergeStatus.ALREADY_UP_TO_DATE, mergeStrategy);
} else if (revWalk.isMergedInto(headCommit, srcCommit)) {
// FAST_FORWARD detected: skip doing a real merge but only
// update HEAD
refLogMessage.append(": " + MergeStatus.FAST_FORWARD);
checkoutNewHead(revWalk, headCommit, srcCommit);
updateHead(refLogMessage, srcCommit, head.getObjectId());
setCallable(false);
return new MergeResult(srcCommit, MergeStatus.FAST_FORWARD,
mergeStrategy);
} else {
return new MergeResult(
headCommit,
MergeResult.MergeStatus.NOT_SUPPORTED,
mergeStrategy,
JGitText.get().onlyAlreadyUpToDateAndFastForwardMergesAreAvailable);
}
} finally {
revWalk.release();
}
} catch (IOException e) {
throw new JGitInternalException(
MessageFormat.format(
JGitText.get().exceptionCaughtDuringExecutionOfMergeCommand,
e));
}
}
private void checkoutNewHead(RevWalk revWalk, RevCommit headCommit,
RevCommit newHeadCommit) throws IOException, CheckoutConflictException {
GitIndex index = repo.getIndex();
File workDir = repo.getWorkTree();
if (workDir != null) {
WorkDirCheckout workDirCheckout = new WorkDirCheckout(repo,
workDir, headCommit.asCommit(revWalk).getTree(), index,
newHeadCommit.asCommit(revWalk).getTree());
workDirCheckout.setFailOnConflict(true);
try {
workDirCheckout.checkout();
} catch (org.eclipse.jgit.errors.CheckoutConflictException e) {
throw new CheckoutConflictException(
JGitText.get().couldNotCheckOutBecauseOfConflicts,
workDirCheckout.getConflicts(), e);
}
index.write();
}
}
private void updateHead(StringBuilder refLogMessage,
ObjectId newHeadId, ObjectId oldHeadID) throws IOException,
ConcurrentRefUpdateException {
RefUpdate refUpdate = repo.updateRef(Constants.HEAD);
refUpdate.setNewObjectId(newHeadId);
refUpdate.setRefLogMessage(refLogMessage.toString(), false);
refUpdate.setExpectedOldObjectId(oldHeadID);
Result rc = refUpdate.update();
switch (rc) {
case NEW:
case FAST_FORWARD:
return;
case REJECTED:
case LOCK_FAILURE:
throw new ConcurrentRefUpdateException(
JGitText.get().couldNotLockHEAD, refUpdate.getRef(), rc);
default:
throw new JGitInternalException(MessageFormat.format(
JGitText.get().updatingRefFailed, Constants.HEAD,
newHeadId.toString(), rc));
}
}
/**
*
* @param mergeStrategy
* the {@link MergeStrategy} to be used
* @return {@code this}
*/
public MergeCommand setStrategy(MergeStrategy mergeStrategy) {
checkCallable();
this.mergeStrategy = mergeStrategy;
return this;
}
/**
* @param commit
* a reference to a commit which is merged with the current
* head
* @return {@code this}
*/
public MergeCommand include(Ref commit) {
checkCallable();
commits.add(commit);
return this;
}
/**
* @param commit
* the Id of a commit which is merged with the current head
* @return {@code this}
*/
public MergeCommand include(AnyObjectId commit) {
return include(commit.getName(), commit);
}
/**
* @param name a name given to the commit
* @param commit
* the Id of a commit which is merged with the current head
* @return {@code this}
*/
public MergeCommand include(String name, AnyObjectId commit) {
return include(new ObjectIdRef.Unpeeled(Storage.LOOSE, name,
commit.copy()));
}
}