org.eclipse.orion.server.git.jobs.StashApplyCommand.java Source code

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/*
 * Copyright (C) 2012, GitHub 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.orion.server.git.jobs;

import java.io.File;
import java.io.IOException;
import java.text.MessageFormat;

import org.eclipse.jgit.api.GitCommand;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.api.errors.InvalidRefNameException;
import org.eclipse.jgit.api.errors.JGitInternalException;
import org.eclipse.jgit.api.errors.NoHeadException;
import org.eclipse.jgit.api.errors.StashApplyFailureException;
import org.eclipse.jgit.api.errors.WrongRepositoryStateException;
import org.eclipse.jgit.dircache.DirCache;
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.errors.CheckoutConflictException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.lib.RepositoryState;
import org.eclipse.jgit.merge.MergeStrategy;
import org.eclipse.jgit.merge.ResolveMerger;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.FileTreeIterator;
import org.eclipse.jgit.treewalk.TreeWalk;

/**
 * Command class to apply a stashed commit.
 *
 * This class behaves like <em>git stash apply --index</em>, i.e. it tries to recover the stashed index state in addition to the working tree state.
 *
 * @see <a href="http://www.kernel.org/pub/software/scm/git/docs/git-stash.html" >Git documentation about Stash</a>
 *
 * @since 2.0
 */
public class StashApplyCommand extends GitCommand<ObjectId> {

    private static final String DEFAULT_REF = Constants.STASH + "@{0}"; //$NON-NLS-1$

    private String stashRef;

    private boolean applyIndex = true;

    private boolean applyUntracked = true;

    private boolean ignoreRepositoryState;

    private MergeStrategy strategy = MergeStrategy.RECURSIVE;

    /**
     * Create command to apply the changes of a stashed commit
     *
     * @param repo
     */
    public StashApplyCommand(final Repository repo) {
        super(repo);
    }

    /**
     * Set the stash reference to apply
     * <p>
     * This will default to apply the latest stashed commit (stash@{0}) if unspecified
     *
     * @param stashRef
     * @return {@code this}
     */
    public StashApplyCommand setStashRef(final String stashRef) {
        this.stashRef = stashRef;
        return this;
    }

    /**
     * @param ignoreRepositoryState
     * @return {@code this}
     * @since 3.2
     */
    public StashApplyCommand ignoreRepositoryState(boolean ignoreRepositoryState) {
        this.ignoreRepositoryState = ignoreRepositoryState;
        return this;
    }

    private ObjectId getStashId() throws GitAPIException {
        final String revision = stashRef != null ? stashRef : DEFAULT_REF;
        final ObjectId stashId;
        try {
            stashId = repo.resolve(revision);
        } catch (IOException e) {
            throw new InvalidRefNameException(MessageFormat.format(JGitText.get().stashResolveFailed, revision), e);
        }
        if (stashId == null)
            throw new InvalidRefNameException(MessageFormat.format(JGitText.get().stashResolveFailed, revision));
        return stashId;
    }

    /**
     * Apply the changes in a stashed commit to the working directory and index
     *
     * @return id of stashed commit that was applied TODO: Does anyone depend on this, or could we make it more like Merge/CherryPick/Revert?
     * @throws GitAPIException
     * @throws WrongRepositoryStateException
     * @throws NoHeadException
     * @throws StashApplyFailureException
     */
    @Override
    public ObjectId call()
            throws GitAPIException, WrongRepositoryStateException, NoHeadException, StashApplyFailureException {
        checkCallable();

        if (!ignoreRepositoryState && repo.getRepositoryState() != RepositoryState.SAFE)
            throw new WrongRepositoryStateException(
                    MessageFormat.format(JGitText.get().stashApplyOnUnsafeRepository, repo.getRepositoryState()));

        ObjectReader reader = repo.newObjectReader();
        try {
            RevWalk revWalk = new RevWalk(reader);

            ObjectId headCommit = repo.resolve(Constants.HEAD);
            if (headCommit == null)
                throw new NoHeadException(JGitText.get().stashApplyWithoutHead);

            final ObjectId stashId = getStashId();
            RevCommit stashCommit = revWalk.parseCommit(stashId);
            if (stashCommit.getParentCount() < 2 || stashCommit.getParentCount() > 3)
                throw new JGitInternalException(
                        MessageFormat.format(JGitText.get().stashCommitIncorrectNumberOfParents, stashId.name(),
                                Integer.valueOf(stashCommit.getParentCount())));

            ObjectId headTree = repo.resolve(Constants.HEAD + "^{tree}"); //$NON-NLS-1$
            ObjectId stashIndexCommit = revWalk.parseCommit(stashCommit.getParent(1));
            ObjectId stashHeadCommit = stashCommit.getParent(0);
            ObjectId untrackedCommit = null;
            if (applyUntracked && stashCommit.getParentCount() == 3)
                untrackedCommit = revWalk.parseCommit(stashCommit.getParent(2));

            ResolveMerger merger = (ResolveMerger) strategy.newMerger(repo);
            merger.setCommitNames(new String[] { "stashed HEAD", "HEAD", "stash" });
            merger.setBase(stashHeadCommit);
            merger.setWorkingTreeIterator(new FileTreeIterator(repo));
            if (merger.merge(headCommit, stashCommit)) {
                DirCache dc = repo.lockDirCache();
                DirCacheCheckout dco = new DirCacheCheckout(repo, headTree, dc, merger.getResultTreeId());
                dco.setFailOnConflict(true);
                dco.checkout(); // Ignoring failed deletes....
                if (applyIndex) {
                    ResolveMerger ixMerger = (ResolveMerger) strategy.newMerger(repo, true);
                    ixMerger.setCommitNames(new String[] { "stashed HEAD", "HEAD", "stashed index" });
                    ixMerger.setBase(stashHeadCommit);
                    boolean ok = ixMerger.merge(headCommit, stashIndexCommit);
                    if (ok) {
                        resetIndex(revWalk.parseTree(ixMerger.getResultTreeId()));
                    } else {
                        throw new StashApplyFailureException(JGitText.get().stashApplyConflict);
                    }
                }

                if (untrackedCommit != null) {
                    ResolveMerger untrackedMerger = (ResolveMerger) strategy.newMerger(repo, true);
                    untrackedMerger.setCommitNames(new String[] { "stashed HEAD", "HEAD", "untracked files" }); //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
                    untrackedMerger.setBase(stashHeadCommit);
                    boolean ok = untrackedMerger.merge(stashHeadCommit, untrackedCommit);
                    if (ok)
                        try {
                            RevTree untrackedTree = revWalk.parseTree(untrackedMerger.getResultTreeId());
                            resetUntracked(untrackedTree);
                        } catch (CheckoutConflictException e) {
                            throw new StashApplyFailureException(JGitText.get().stashApplyConflict);
                        }
                    else
                        throw new StashApplyFailureException(JGitText.get().stashApplyConflict);
                }
            } else {
                throw new StashApplyFailureException(JGitText.get().stashApplyConflict);
            }
            return stashId;

        } catch (JGitInternalException e) {
            throw e;
        } catch (IOException e) {
            throw new JGitInternalException(JGitText.get().stashApplyFailed, e);
        } finally {
            reader.release();
        }
    }

    /**
     * @param applyIndex
     *            true (default) if the command should restore the index state
     */
    public void setApplyIndex(boolean applyIndex) {
        this.applyIndex = applyIndex;
    }

    /**
     * @param strategy
     *            The merge strategy to use in order to merge during this command execution.
     * @return {@code this}
     * @since 3.4
     */
    public StashApplyCommand setStrategy(MergeStrategy strategy) {
        this.strategy = strategy;
        return this;
    }

    /**
     * @param applyUntracked
     *            true (default) if the command should restore untracked files
     * @since 3.4
     */
    public void setApplyUntracked(boolean applyUntracked) {
        this.applyUntracked = applyUntracked;
    }

    private void resetIndex(RevTree tree) throws IOException {
        DirCache dc = repo.lockDirCache();
        TreeWalk walk = null;
        try {
            DirCacheBuilder builder = dc.builder();

            walk = new TreeWalk(repo);
            walk.addTree(tree);
            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();
            if (walk != null)
                walk.release();
        }
    }

    private void resetUntracked(RevTree tree) throws CheckoutConflictException, IOException {
        TreeWalk walk = null;
        try {
            walk = new TreeWalk(repo); // maybe NameConflictTreeWalk?
            walk.addTree(tree);
            walk.addTree(new FileTreeIterator(repo));
            walk.setRecursive(true);

            final ObjectReader reader = walk.getObjectReader();

            while (walk.next()) {
                final AbstractTreeIterator cIter = walk.getTree(0, AbstractTreeIterator.class);
                if (cIter == null)
                    // Not in commit, don't create untracked
                    continue;

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

                FileTreeIterator fIter = walk.getTree(1, FileTreeIterator.class);
                if (fIter != null) {
                    if (fIter.isModified(entry, true, reader)) {
                        // file exists and is dirty
                        throw new CheckoutConflictException(entry.getPathString());
                    }
                }

                checkoutPath(entry, reader);
            }
        } finally {
            if (walk != null)
                walk.release();
        }
    }

    private void checkoutPath(DirCacheEntry entry, ObjectReader reader) {
        try {
            File file = new File(repo.getWorkTree(), entry.getPathString());
            DirCacheCheckout.checkoutEntry(repo, file, entry, reader);
        } catch (IOException e) {
            throw new JGitInternalException(
                    MessageFormat.format(JGitText.get().checkoutConflictWithFile, entry.getPathString()), e);
        }
    }
}