org.eclipse.jgit/src/org/eclipse/jgit/api/ResetCommand.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2011-2013, Chris Aniszczyk <caniszczyk@gmail.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.IOException;
 import java.text.MessageFormat;
 import java.util.Collection;
 import java.util.LinkedList;

 import org.eclipse.jgit.api.errors.CheckoutConflictException;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.api.errors.JGitInternalException;
 import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheBuildIterator;
 import org.eclipse.jgit.dircache.DirCacheBuilder;
 import org.eclipse.jgit.dircache.DirCacheCheckout;
 import org.eclipse.jgit.dircache.DirCacheEntry;
 import org.eclipse.jgit.dircache.DirCacheIterator;
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.RepositoryState;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.AbstractTreeIterator;
 import org.eclipse.jgit.treewalk.CanonicalTreeParser;
 import org.eclipse.jgit.treewalk.EmptyTreeIterator;
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.treewalk.filter.PathFilterGroup;

 /**
  * A class used to execute a {@code Reset} 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()})
  *
  * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-reset.html"
  *      >Git documentation about Reset</a>
  */
 public class ResetCommand extends GitCommand<Ref> {

 	/**
 	 * Kind of reset
 	 */
 	public enum ResetType {
 		/**
 		 * Just change the ref, the index and workdir are not changed.
 		 */
 		SOFT,

 		/**
 		 * Change the ref and the index, the workdir is not changed.
 		 */
 		MIXED,

 		/**
 		 * Change the ref, the index and the workdir
 		 */
 		HARD,

 		/**
 		 * Resets the index and updates the files in the working tree that are
 		 * different between respective commit and HEAD, but keeps those which
 		 * are different between the index and working tree
 		 */
 		MERGE, // TODO not implemented yet

 		/**
 		 * Change the ref, the index and the workdir that are different between
 		 * respective commit and HEAD
 		 */
 		KEEP // TODO not implemented yet
 	}

 	// We need to be able to distinguish whether the caller set the ref
 	// explicitly or not, so we apply the default (HEAD) only later.
 	private String ref = null;

 	private ResetType mode;

 	private Collection<String> filepaths = new LinkedList<>();

 	private boolean isReflogDisabled;

 	/**
 	 *
 	 * @param repo
 	 */
 	public ResetCommand(Repository repo) {
 		super(repo);
 	}

 	/**
 	 * Executes the {@code Reset} command. 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 Ref after reset
 	 * @throws GitAPIException
 	 */
 	@Override
 	public Ref call() throws GitAPIException, CheckoutConflictException {
 		checkCallable();

 		try {
 			RepositoryState state = repo.getRepositoryState();
 			final boolean merging = state.equals(RepositoryState.MERGING)
 					|| state.equals(RepositoryState.MERGING_RESOLVED);
 			final boolean cherryPicking = state
 					.equals(RepositoryState.CHERRY_PICKING)
 					|| state.equals(RepositoryState.CHERRY_PICKING_RESOLVED);
 			final boolean reverting = state.equals(RepositoryState.REVERTING)
 					|| state.equals(RepositoryState.REVERTING_RESOLVED);

 			final ObjectId commitId = resolveRefToCommitId();
 			// When ref is explicitly specified, it has to resolve
 			if (ref != null && commitId == null) {
 				// @TODO throw an InvalidRefNameException. We can't do that
 				// now because this would break the API
 				throw new JGitInternalException(MessageFormat
 						.format(JGitText.get().invalidRefName, ref));
 			}

 			final ObjectId commitTree;
 			if (commitId != null)
 				commitTree = parseCommit(commitId).getTree();
 			else
 				commitTree = null;

 			if (!filepaths.isEmpty()) {
 				// reset [commit] -- paths
 				resetIndexForPaths(commitTree);
 				setCallable(false);
 				return repo.exactRef(Constants.HEAD);
 			}

 			final Ref result;
 			if (commitId != null) {
 				// write the ref
 				final RefUpdate ru = repo.updateRef(Constants.HEAD);
 				ru.setNewObjectId(commitId);

 				String refName = Repository.shortenRefName(getRefOrHEAD());
 				if (isReflogDisabled) {
 					ru.disableRefLog();
 				} else {
 					String message = refName + ": updating " + Constants.HEAD; //$NON-NLS-1$
 					ru.setRefLogMessage(message, false);
 				}
 				if (ru.forceUpdate() == RefUpdate.Result.LOCK_FAILURE)
 					throw new JGitInternalException(MessageFormat.format(
 							JGitText.get().cannotLock, ru.getName()));

 				ObjectId origHead = ru.getOldObjectId();
 				if (origHead != null)
 					repo.writeOrigHead(origHead);
 			}
 			result = repo.exactRef(Constants.HEAD);

 			if (mode == null)
 				mode = ResetType.MIXED;

 			switch (mode) {
 				case HARD:
 					checkoutIndex(commitTree);
 					break;
 				case MIXED:
 					resetIndex(commitTree);
 					break;
 				case SOFT: // do nothing, only the ref was changed
 					break;
 				case KEEP: // TODO
 				case MERGE: // TODO
 					throw new UnsupportedOperationException();

 			}

 			if (mode != ResetType.SOFT) {
 				if (merging)
 					resetMerge();
 				else if (cherryPicking)
 					resetCherryPick();
 				else if (reverting)
 					resetRevert();
 				else if (repo.readSquashCommitMsg() != null)
 					repo.writeSquashCommitMsg(null /* delete */);
 			}

 			setCallable(false);
 			return result;
 		} catch (IOException e) {
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().exceptionCaughtDuringExecutionOfResetCommand,
 					e.getMessage()), e);
 		}
 	}

 	private RevCommit parseCommit(final ObjectId commitId) {
 		try (RevWalk rw = new RevWalk(repo)) {
 			return rw.parseCommit(commitId);
 		} catch (IOException e) {
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().cannotReadCommit, commitId.toString()), e);
 		}
 	}

 	private ObjectId resolveRefToCommitId() {
 		try {
 			return repo.resolve(getRefOrHEAD() + "^{commit}"); //$NON-NLS-1$
 		} catch (IOException e) {
 			throw new JGitInternalException(
 					MessageFormat.format(JGitText.get().cannotRead, getRefOrHEAD()),
 					e);
 		}
 	}

 	/**
 	 * @param ref
 	 *            the ref to reset to, defaults to HEAD if not specified
 	 * @return this instance
 	 */
 	public ResetCommand setRef(String ref) {
 		this.ref = ref;
 		return this;
 	}

 	/**
 	 * @param mode
 	 *            the mode of the reset command
 	 * @return this instance
 	 */
 	public ResetCommand setMode(ResetType mode) {
 		if (!filepaths.isEmpty())
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().illegalCombinationOfArguments,
 					"[--mixed | --soft | --hard]", "<paths>...")); //$NON-NLS-1$ //$NON-NLS-2$
 		this.mode = mode;
 		return this;
 	}

 	/**
 	 * @param path
 	 *            repository-relative path of file/directory to reset (with
 	 *            <code>/</code> as separator)
 	 * @return this instance
 	 */
 	public ResetCommand addPath(String path) {
 		if (mode != null)
 			throw new JGitInternalException(MessageFormat.format(
 					JGitText.get().illegalCombinationOfArguments, "<paths>...", //$NON-NLS-1$
 					"[--mixed | --soft | --hard]")); //$NON-NLS-1$
 		filepaths.add(path);
 		return this;
 	}

 	/**
 	 * @param disable
 	 *            if {@code true} disables writing a reflog entry for this reset
 	 *            command
 	 * @return this instance
 	 * @since 4.5
 	 */
 	public ResetCommand disableRefLog(boolean disable) {
 		this.isReflogDisabled = disable;
 		return this;
 	}

 	/**
 	 * @return {@code true} if writing reflog is disabled for this reset command
 	 * @since 4.5
 	 */
 	public boolean isReflogDisabled() {
 		return this.isReflogDisabled;
 	}

 	private String getRefOrHEAD() {
 		if (ref != null)
 			return ref;
 		else
 			return Constants.HEAD;
 	}

 	private void resetIndexForPaths(ObjectId commitTree) {
 		DirCache dc = null;
 		try (final TreeWalk tw = new TreeWalk(repo)) {
 			dc = repo.lockDirCache();
 			DirCacheBuilder builder = dc.builder();

 			tw.addTree(new DirCacheBuildIterator(builder));
 			if (commitTree != null)
 				tw.addTree(commitTree);
 			else
 				tw.addTree(new EmptyTreeIterator());
 			tw.setFilter(PathFilterGroup.createFromStrings(filepaths));
 			tw.setRecursive(true);

 			while (tw.next()) {
 				final CanonicalTreeParser tree = tw.getTree(1,
 						CanonicalTreeParser.class);
 				// only keep file in index if it's in the commit
 				if (tree != null) {
 				    // revert index to commit
 					DirCacheEntry entry = new DirCacheEntry(tw.getRawPath());
 					entry.setFileMode(tree.getEntryFileMode());
 					entry.setObjectId(tree.getEntryObjectId());
 					builder.add(entry);
 				}
 			}

 			builder.commit();
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		} finally {
 			if (dc != null)
 				dc.unlock();
 		}
 	}

 	private void resetIndex(ObjectId commitTree) throws IOException {
 		DirCache dc = repo.lockDirCache();
 		try (TreeWalk walk = new TreeWalk(repo)) {
 			DirCacheBuilder builder = dc.builder();

 			if (commitTree != null)
 				walk.addTree(commitTree);
 			else
 				walk.addTree(new EmptyTreeIterator());
 			walk.addTree(new DirCacheIterator(dc));
 			walk.setRecursive(true);

 			while (walk.next()) {
 				AbstractTreeIterator cIter = walk.getTree(0,
 						AbstractTreeIterator.class);
 				if (cIter == null) {
 					// Not in commit, don't add to new index
 					continue;
 				}

 				final DirCacheEntry entry = new DirCacheEntry(walk.getRawPath());
 				entry.setFileMode(cIter.getEntryFileMode());
 				entry.setObjectIdFromRaw(cIter.idBuffer(), cIter.idOffset());

 				DirCacheIterator dcIter = walk.getTree(1,
 						DirCacheIterator.class);
 				if (dcIter != null && dcIter.idEqual(cIter)) {
 					DirCacheEntry indexEntry = dcIter.getDirCacheEntry();
 					entry.setLastModified(indexEntry.getLastModified());
 					entry.setLength(indexEntry.getLength());
 				}

 				builder.add(entry);
 			}

 			builder.commit();
 		} finally {
 			dc.unlock();
 		}
 	}

 	private void checkoutIndex(ObjectId commitTree) throws IOException,
 			GitAPIException {
 		DirCache dc = repo.lockDirCache();
 		try {
 			DirCacheCheckout checkout = new DirCacheCheckout(repo, dc,
 					commitTree);
 			checkout.setFailOnConflict(false);
 			try {
 				checkout.checkout();
 			} catch (org.eclipse.jgit.errors.CheckoutConflictException cce) {
 				throw new CheckoutConflictException(checkout.getConflicts(),
 						cce);
 			}
 		} finally {
 			dc.unlock();
 		}
 	}

 	private void resetMerge() throws IOException {
 		repo.writeMergeHeads(null);
 		repo.writeMergeCommitMsg(null);
 	}

 	private void resetCherryPick() throws IOException {
 		repo.writeCherryPickHead(null);
 		repo.writeMergeCommitMsg(null);
 	}

 	private void resetRevert() throws IOException {
 		repo.writeRevertHead(null);
 		repo.writeMergeCommitMsg(null);
 	}

 	@SuppressWarnings("nls")
 	@Override
 	public String toString() {
 		return "ResetCommand [repo=" + repo + ", ref=" + ref + ", mode=" + mode
 				+ ", isReflogDisabled=" + isReflogDisabled + ", filepaths="
 				+ filepaths + "]";
 	}

 }
	/*
	* Copyright (C) 2011-2013, Chris Aniszczyk <caniszczyk@gmail.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.IOException;
	import java.text.MessageFormat;
	import java.util.Collection;
	import java.util.LinkedList;

	import org.eclipse.jgit.api.errors.CheckoutConflictException;
	import org.eclipse.jgit.api.errors.GitAPIException;
	import org.eclipse.jgit.api.errors.JGitInternalException;
	import org.eclipse.jgit.dircache.DirCache;
	import org.eclipse.jgit.dircache.DirCacheBuildIterator;
	import org.eclipse.jgit.dircache.DirCacheBuilder;
	import org.eclipse.jgit.dircache.DirCacheCheckout;
	import org.eclipse.jgit.dircache.DirCacheEntry;
	import org.eclipse.jgit.dircache.DirCacheIterator;
	import org.eclipse.jgit.internal.JGitText;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.ObjectId;
	import org.eclipse.jgit.lib.Ref;
	import org.eclipse.jgit.lib.RefUpdate;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.lib.RepositoryState;
	import org.eclipse.jgit.revwalk.RevCommit;
	import org.eclipse.jgit.revwalk.RevWalk;
	import org.eclipse.jgit.treewalk.AbstractTreeIterator;
	import org.eclipse.jgit.treewalk.CanonicalTreeParser;
	import org.eclipse.jgit.treewalk.EmptyTreeIterator;
	import org.eclipse.jgit.treewalk.TreeWalk;
	import org.eclipse.jgit.treewalk.filter.PathFilterGroup;

	/**
	* A class used to execute a {@code Reset} 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()})
	*
	* @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-reset.html"
	* >Git documentation about Reset</a>
	*/
	public class ResetCommand extends GitCommand<Ref> {

	/**
	* Kind of reset
	*/
	public enum ResetType {
	/**
	* Just change the ref, the index and workdir are not changed.
	*/
	SOFT,

	/**
	* Change the ref and the index, the workdir is not changed.
	*/
	MIXED,

	/**
	* Change the ref, the index and the workdir
	*/
	HARD,

	/**
	* Resets the index and updates the files in the working tree that are
	* different between respective commit and HEAD, but keeps those which
	* are different between the index and working tree
	*/
	MERGE, // TODO not implemented yet

	/**
	* Change the ref, the index and the workdir that are different between
	* respective commit and HEAD
	*/
	KEEP // TODO not implemented yet
	}

	// We need to be able to distinguish whether the caller set the ref
	// explicitly or not, so we apply the default (HEAD) only later.
	private String ref = null;

	private ResetType mode;

	private Collection<String> filepaths = new LinkedList<>();

	private boolean isReflogDisabled;

	/**
	*
	* @param repo
	*/
	public ResetCommand(Repository repo) {
	super(repo);
	}

	/**
	* Executes the {@code Reset} command. 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 Ref after reset
	* @throws GitAPIException
	*/
	@Override
	public Ref call() throws GitAPIException, CheckoutConflictException {
	checkCallable();

	try {
	RepositoryState state = repo.getRepositoryState();
	final boolean merging = state.equals(RepositoryState.MERGING)
	\|\| state.equals(RepositoryState.MERGING_RESOLVED);
	final boolean cherryPicking = state
	.equals(RepositoryState.CHERRY_PICKING)
	\|\| state.equals(RepositoryState.CHERRY_PICKING_RESOLVED);
	final boolean reverting = state.equals(RepositoryState.REVERTING)
	\|\| state.equals(RepositoryState.REVERTING_RESOLVED);

	final ObjectId commitId = resolveRefToCommitId();
	// When ref is explicitly specified, it has to resolve
	if (ref != null && commitId == null) {
	// @TODO throw an InvalidRefNameException. We can't do that
	// now because this would break the API
	throw new JGitInternalException(MessageFormat
	.format(JGitText.get().invalidRefName, ref));
	}

	final ObjectId commitTree;
	if (commitId != null)
	commitTree = parseCommit(commitId).getTree();
	else
	commitTree = null;

	if (!filepaths.isEmpty()) {
	// reset [commit] -- paths
	resetIndexForPaths(commitTree);
	setCallable(false);
	return repo.exactRef(Constants.HEAD);
	}

	final Ref result;
	if (commitId != null) {
	// write the ref
	final RefUpdate ru = repo.updateRef(Constants.HEAD);
	ru.setNewObjectId(commitId);

	String refName = Repository.shortenRefName(getRefOrHEAD());
	if (isReflogDisabled) {
	ru.disableRefLog();
	} else {
	String message = refName + ": updating " + Constants.HEAD; //$NON-NLS-1$
	ru.setRefLogMessage(message, false);
	}
	if (ru.forceUpdate() == RefUpdate.Result.LOCK_FAILURE)
	throw new JGitInternalException(MessageFormat.format(
	JGitText.get().cannotLock, ru.getName()));

	ObjectId origHead = ru.getOldObjectId();
	if (origHead != null)
	repo.writeOrigHead(origHead);
	}
	result = repo.exactRef(Constants.HEAD);

	if (mode == null)
	mode = ResetType.MIXED;

	switch (mode) {
	case HARD:
	checkoutIndex(commitTree);
	break;
	case MIXED:
	resetIndex(commitTree);
	break;
	case SOFT: // do nothing, only the ref was changed
	break;
	case KEEP: // TODO
	case MERGE: // TODO
	throw new UnsupportedOperationException();

	}

	if (mode != ResetType.SOFT) {
	if (merging)
	resetMerge();
	else if (cherryPicking)
	resetCherryPick();
	else if (reverting)
	resetRevert();
	else if (repo.readSquashCommitMsg() != null)
	repo.writeSquashCommitMsg(null /* delete */);
	}

	setCallable(false);
	return result;
	} catch (IOException e) {
	throw new JGitInternalException(MessageFormat.format(
	JGitText.get().exceptionCaughtDuringExecutionOfResetCommand,
	e.getMessage()), e);
	}
	}

	private RevCommit parseCommit(final ObjectId commitId) {
	try (RevWalk rw = new RevWalk(repo)) {
	return rw.parseCommit(commitId);
	} catch (IOException e) {
	throw new JGitInternalException(MessageFormat.format(
	JGitText.get().cannotReadCommit, commitId.toString()), e);
	}
	}

	private ObjectId resolveRefToCommitId() {
	try {
	return repo.resolve(getRefOrHEAD() + "^{commit}"); //$NON-NLS-1$
	} catch (IOException e) {
	throw new JGitInternalException(
	MessageFormat.format(JGitText.get().cannotRead, getRefOrHEAD()),
	e);
	}
	}

	/**
	* @param ref
	* the ref to reset to, defaults to HEAD if not specified
	* @return this instance
	*/
	public ResetCommand setRef(String ref) {
	this.ref = ref;
	return this;
	}

	/**
	* @param mode
	* the mode of the reset command
	* @return this instance
	*/
	public ResetCommand setMode(ResetType mode) {
	if (!filepaths.isEmpty())
	throw new JGitInternalException(MessageFormat.format(
	JGitText.get().illegalCombinationOfArguments,
	"[--mixed \| --soft \| --hard]", "<paths>...")); //$NON-NLS-1$ //$NON-NLS-2$
	this.mode = mode;
	return this;
	}

	/**
	* @param path
	* repository-relative path of file/directory to reset (with
	* <code>/</code> as separator)
	* @return this instance
	*/
	public ResetCommand addPath(String path) {
	if (mode != null)
	throw new JGitInternalException(MessageFormat.format(
	JGitText.get().illegalCombinationOfArguments, "<paths>...", //$NON-NLS-1$
	"[--mixed \| --soft \| --hard]")); //$NON-NLS-1$
	filepaths.add(path);
	return this;
	}

	/**
	* @param disable
	* if {@code true} disables writing a reflog entry for this reset
	* command
	* @return this instance
	* @since 4.5
	*/
	public ResetCommand disableRefLog(boolean disable) {
	this.isReflogDisabled = disable;
	return this;
	}

	/**
	* @return {@code true} if writing reflog is disabled for this reset command
	* @since 4.5
	*/
	public boolean isReflogDisabled() {
	return this.isReflogDisabled;
	}

	private String getRefOrHEAD() {
	if (ref != null)
	return ref;
	else
	return Constants.HEAD;
	}

	private void resetIndexForPaths(ObjectId commitTree) {
	DirCache dc = null;
	try (final TreeWalk tw = new TreeWalk(repo)) {
	dc = repo.lockDirCache();
	DirCacheBuilder builder = dc.builder();

	tw.addTree(new DirCacheBuildIterator(builder));
	if (commitTree != null)
	tw.addTree(commitTree);
	else
	tw.addTree(new EmptyTreeIterator());
	tw.setFilter(PathFilterGroup.createFromStrings(filepaths));
	tw.setRecursive(true);

	while (tw.next()) {
	final CanonicalTreeParser tree = tw.getTree(1,
	CanonicalTreeParser.class);
	// only keep file in index if it's in the commit
	if (tree != null) {
	// revert index to commit
	DirCacheEntry entry = new DirCacheEntry(tw.getRawPath());
	entry.setFileMode(tree.getEntryFileMode());
	entry.setObjectId(tree.getEntryObjectId());
	builder.add(entry);
	}
	}

	builder.commit();
	} catch (IOException e) {
	throw new RuntimeException(e);
	} finally {
	if (dc != null)
	dc.unlock();
	}
	}

	private void resetIndex(ObjectId commitTree) throws IOException {
	DirCache dc = repo.lockDirCache();
	try (TreeWalk walk = new TreeWalk(repo)) {
	DirCacheBuilder builder = dc.builder();

	if (commitTree != null)
	walk.addTree(commitTree);
	else
	walk.addTree(new EmptyTreeIterator());
	walk.addTree(new DirCacheIterator(dc));
	walk.setRecursive(true);

	while (walk.next()) {
	AbstractTreeIterator cIter = walk.getTree(0,
	AbstractTreeIterator.class);
	if (cIter == null) {
	// Not in commit, don't add to new index
	continue;
	}

	final DirCacheEntry entry = new DirCacheEntry(walk.getRawPath());
	entry.setFileMode(cIter.getEntryFileMode());
	entry.setObjectIdFromRaw(cIter.idBuffer(), cIter.idOffset());

	DirCacheIterator dcIter = walk.getTree(1,
	DirCacheIterator.class);
	if (dcIter != null && dcIter.idEqual(cIter)) {
	DirCacheEntry indexEntry = dcIter.getDirCacheEntry();
	entry.setLastModified(indexEntry.getLastModified());
	entry.setLength(indexEntry.getLength());
	}

	builder.add(entry);
	}

	builder.commit();
	} finally {
	dc.unlock();
	}
	}

	private void checkoutIndex(ObjectId commitTree) throws IOException,
	GitAPIException {
	DirCache dc = repo.lockDirCache();
	try {
	DirCacheCheckout checkout = new DirCacheCheckout(repo, dc,
	commitTree);
	checkout.setFailOnConflict(false);
	try {
	checkout.checkout();
	} catch (org.eclipse.jgit.errors.CheckoutConflictException cce) {
	throw new CheckoutConflictException(checkout.getConflicts(),
	cce);
	}
	} finally {
	dc.unlock();
	}
	}

	private void resetMerge() throws IOException {
	repo.writeMergeHeads(null);
	repo.writeMergeCommitMsg(null);
	}

	private void resetCherryPick() throws IOException {
	repo.writeCherryPickHead(null);
	repo.writeMergeCommitMsg(null);
	}

	private void resetRevert() throws IOException {
	repo.writeRevertHead(null);
	repo.writeMergeCommitMsg(null);
	}

	@SuppressWarnings("nls")
	@Override
	public String toString() {
	return "ResetCommand [repo=" + repo + ", ref=" + ref + ", mode=" + mode
	+ ", isReflogDisabled=" + isReflogDisabled + ", filepaths="
	+ filepaths + "]";
	}

	}