org.eclipse.jgit.dircache.DirCacheBuildIterator.java Source code

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Here is the source code for org.eclipse.jgit.dircache.DirCacheBuildIterator.java

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/*
 * Copyright (C) 2008-2009, Google Inc.
 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * 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.dircache;

import java.io.IOException;

import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;

/**
 * Iterate and update a {@link org.eclipse.jgit.dircache.DirCache} as part of a
 * <code>TreeWalk</code>.
 * <p>
 * Like {@link org.eclipse.jgit.dircache.DirCacheIterator} this iterator allows
 * a DirCache to be used in parallel with other sorts of iterators in a
 * TreeWalk. However any entry which appears in the source DirCache and which is
 * skipped by the TreeFilter is automatically copied into
 * {@link org.eclipse.jgit.dircache.DirCacheBuilder}, thus retaining it in the
 * newly updated index.
 * <p>
 * This iterator is suitable for update processes, or even a simple delete
 * algorithm. For example deleting a path:
 *
 * <pre>
 * final DirCache dirc = db.lockDirCache();
 * final DirCacheBuilder edit = dirc.builder();
 *
 * final TreeWalk walk = new TreeWalk(db);
 * walk.reset();
 * walk.setRecursive(true);
 * walk.setFilter(PathFilter.create(&quot;name/to/remove&quot;));
 * walk.addTree(new DirCacheBuildIterator(edit));
 *
 * while (walk.next())
 *    ; // do nothing on a match as we want to remove matches
 * edit.commit();
 * </pre>
 */
public class DirCacheBuildIterator extends DirCacheIterator {
    private final DirCacheBuilder builder;

    /**
     * Create a new iterator for an already loaded DirCache instance.
     * <p>
     * The iterator implementation may copy part of the cache's data during
     * construction, so the cache must be read in prior to creating the
     * iterator.
     *
     * @param dcb
     *            the cache builder for the cache to walk. The cache must be
     *            already loaded into memory.
     */
    public DirCacheBuildIterator(DirCacheBuilder dcb) {
        super(dcb.getDirCache());
        builder = dcb;
    }

    DirCacheBuildIterator(final DirCacheBuildIterator p, final DirCacheTree dct) {
        super(p, dct);
        builder = p.builder;
    }

    /** {@inheritDoc} */
    @Override
    public AbstractTreeIterator createSubtreeIterator(ObjectReader reader)
            throws IncorrectObjectTypeException, IOException {
        if (currentSubtree == null)
            throw new IncorrectObjectTypeException(getEntryObjectId(), Constants.TYPE_TREE);
        return new DirCacheBuildIterator(this, currentSubtree);
    }

    /** {@inheritDoc} */
    @Override
    public void skip() throws CorruptObjectException {
        if (currentSubtree != null)
            builder.keep(ptr, currentSubtree.getEntrySpan());
        else
            builder.keep(ptr, 1);
        next(1);
    }

    /** {@inheritDoc} */
    @Override
    public void stopWalk() {
        final int cur = ptr;
        final int cnt = cache.getEntryCount();
        if (cur < cnt)
            builder.keep(cur, cnt - cur);
    }

    /** {@inheritDoc} */
    @Override
    protected boolean needsStopWalk() {
        return ptr < cache.getEntryCount();
    }
}