org.jboss.forge.git.Clone.java Source code

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/*
 * Copyright (C) 2008-2010, 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.jboss.forge.git;

import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.eclipse.jgit.dircache.DirCache;
import org.eclipse.jgit.dircache.DirCacheCheckout;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.NotSupportedException;
import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefComparator;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.TextProgressMonitor;
import org.eclipse.jgit.pgm.CLIText;
import org.eclipse.jgit.pgm.Die;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.storage.file.FileBasedConfig;
import org.eclipse.jgit.storage.file.FileRepository;
import org.eclipse.jgit.transport.FetchResult;
import org.eclipse.jgit.transport.RefSpec;
import org.eclipse.jgit.transport.RemoteConfig;
import org.eclipse.jgit.transport.TagOpt;
import org.eclipse.jgit.transport.Transport;
import org.eclipse.jgit.transport.URIish;

/**
 * @author <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
 * 
 */
public class Clone {
    private final String remoteName = Constants.DEFAULT_REMOTE_NAME;

    private FileRepository db;

    public void run(File projectDir, String sourceUri) throws IOException {
        try {
            final URIish uri = new URIish(sourceUri);
            File gitdir = new File(projectDir, Constants.DOT_GIT);
            db = new FileRepository(gitdir);
            db.create();
            final FileBasedConfig dstcfg = db.getConfig();
            dstcfg.setBoolean("core", null, "bare", false);
            dstcfg.save();

            saveRemote(uri);
            final FetchResult r = runFetch();
            final Ref branch = guessHEAD(r);
            doCheckout(branch);
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException("Failed to parse remote repository URI", e);
        }
    }

    private void saveRemote(final URIish uri) throws URISyntaxException, IOException {
        final FileBasedConfig dstcfg = db.getConfig();
        final RemoteConfig rc = new RemoteConfig(dstcfg, remoteName);
        rc.addURI(uri);
        rc.addFetchRefSpec(new RefSpec().setForceUpdate(true).setSourceDestination(Constants.R_HEADS + "*",
                Constants.R_REMOTES + remoteName + "/*"));
        rc.update(dstcfg);
        dstcfg.save();
    }

    private FetchResult runFetch() throws NotSupportedException, URISyntaxException, TransportException {
        final Transport tn = Transport.open(db, remoteName);
        final FetchResult r;
        try {
            tn.setTagOpt(TagOpt.FETCH_TAGS);
            r = tn.fetch(new TextProgressMonitor(), null);
        } finally {
            tn.close();
        }
        return r;
    }

    private Ref guessHEAD(final FetchResult result) {
        final Ref idHEAD = result.getAdvertisedRef(Constants.HEAD);
        final List<Ref> availableRefs = new ArrayList<Ref>();
        Ref head = null;
        for (final Ref r : result.getAdvertisedRefs()) {
            final String n = r.getName();
            if (!n.startsWith(Constants.R_HEADS))
                continue;
            availableRefs.add(r);
            if (idHEAD == null || head != null)
                continue;
            if (r.getObjectId().equals(idHEAD.getObjectId()))
                head = r;
        }
        Collections.sort(availableRefs, RefComparator.INSTANCE);
        if (idHEAD != null && head == null)
            head = idHEAD;
        return head;
    }

    private void doCheckout(final Ref branch) throws IOException {
        if (branch == null)
            throw new Die(CLIText.get().cannotChekoutNoHeadsAdvertisedByRemote);
        if (!Constants.HEAD.equals(branch.getName())) {
            RefUpdate u = db.updateRef(Constants.HEAD);
            u.disableRefLog();
            u.link(branch.getName());
        }

        final RevCommit commit = parseCommit(branch);
        final RefUpdate u = db.updateRef(Constants.HEAD);
        u.setNewObjectId(commit);
        u.forceUpdate();

        DirCache dc = db.lockDirCache();
        DirCacheCheckout co = new DirCacheCheckout(db, dc, commit.getTree());
        co.checkout();
    }

    private RevCommit parseCommit(final Ref branch)
            throws MissingObjectException, IncorrectObjectTypeException, IOException {
        final RevWalk rw = new RevWalk(db);
        final RevCommit commit;
        try {
            commit = rw.parseCommit(branch.getObjectId());
        } finally {
            rw.release();
        }
        return commit;
    }
}