/*
 * Copyright (C) 2008-2009, Google Inc.
 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.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.
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 * 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
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package org.eclipse.jgit.merge;

import java.io.IOException;

import org.eclipse.jgit.lib.Config;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.Repository;

Trivial merge strategy to make the resulting tree exactly match an input.

This strategy can be used to cauterize an entire side branch of history, by
setting the output tree to one of the inputs, and ignoring any of the paths
of the other inputs.
/**
 * Trivial merge strategy to make the resulting tree exactly match an input.
 * <p>
 * This strategy can be used to cauterize an entire side branch of history, by
 * setting the output tree to one of the inputs, and ignoring any of the paths
 * of the other inputs.
 */
public class StrategyOneSided extends MergeStrategy {
	private final String strategyName;

	private final int treeIndex;

	
Create a new merge strategy to select a specific input tree.
Params:
name – 
           name of this strategy.
index – 
           the position of the input tree to accept as the result./**
	 * Create a new merge strategy to select a specific input tree.
	 *
	 * @param name
	 *            name of this strategy.
	 * @param index
	 *            the position of the input tree to accept as the result.
	 */
	protected StrategyOneSided(String name, int index) {
		strategyName = name;
		treeIndex = index;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public String getName() {
		return strategyName;
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public Merger newMerger(Repository db) {
		return new OneSide(db, treeIndex);
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public Merger newMerger(Repository db, boolean inCore) {
		return new OneSide(db, treeIndex);
	}

	
{@inheritDoc} /** {@inheritDoc} */
	@Override
	public Merger newMerger(ObjectInserter inserter, Config config) {
		return new OneSide(inserter, treeIndex);
	}

	static class OneSide extends Merger {
		private final int treeIndex;

		protected OneSide(Repository local, int index) {
			super(local);
			treeIndex = index;
		}

		protected OneSide(ObjectInserter inserter, int index) {
			super(inserter);
			treeIndex = index;
		}

		@Override
		protected boolean mergeImpl() throws IOException {
			return treeIndex < sourceTrees.length;
		}

		@Override
		public ObjectId getResultTreeId() {
			return sourceTrees[treeIndex];
		}

		@Override
		public ObjectId getBaseCommitId() {
			return null;
		}
	}
}