/*
 * 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 others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

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 DirCache as part of a TreeWalk.
 Like 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 DirCacheBuilder, thus retaining it in the newly updated index. 

This iterator is suitable for update processes, or even a simple delete
algorithm. For example deleting a path:
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("name/to/remove"));
walk.addTree(new DirCacheBuildIterator(edit));
while (walk.next())
	; // do nothing on a match as we want to remove matches
edit.commit();

/**
 * 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.

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.
Params:
dcb – 
           the cache builder for the cache to walk. The cache must be
           already loaded into memory./**
	 * 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} /** {@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} /** {@inheritDoc} */
	@Override
	public void skip() throws CorruptObjectException {
		if (currentSubtree != null)
			builder.keep(ptr, currentSubtree.getEntrySpan());
		else
			builder.keep(ptr, 1);
		next(1);
	}

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

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