Copyright (c) 2000, 2017 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.team.core.variants;

import org.eclipse.core.resources.IResource;
import org.eclipse.team.core.TeamException;
import org.eclipse.team.internal.core.TeamPlugin;

A resource comparator that uses the ThreeWaySynchronizer
to compare local resources to their resource variants. The local state
is determined using the local modification state and the remote state
is determined by comparing the base bytes to the remote bytes obtained
from the synchronizer.
Since:
3.0/**
 * A resource comparator that uses the <code>ThreeWaySynchronizer</code>
 * to compare local resources to their resource variants. The local state
 * is determined using the local modification state and the remote state
 * is determined by comparing the base bytes to the remote bytes obtained
 * from the synchronizer.
 *
 * @since 3.0
 */
public class ThreeWayResourceComparator implements IResourceVariantComparator {

	private ThreeWaySynchronizer synchronizer;

	
Create a three-way resource comparator that uses the
ThreeWaySynchronizer to compare a local resource to a resource
variant.
Params:
synchronizer – The synchronizer to use./**
	 * Create a three-way resource comparator that uses the
	 * <code>ThreeWaySynchronizer</code> to compare a local resource to a resource
	 * variant.
	 * 
	 * @param synchronizer The synchronizer to use.
	 */
	public ThreeWayResourceComparator(ThreeWaySynchronizer synchronizer) {
		this.synchronizer = synchronizer;
	}

	@Override
	public boolean compare(IResource local, IResourceVariant remote) {
		// First, ensure the resources are the same gender
		if ((local.getType() == IResource.FILE) == remote.isContainer()) {
			return false;
		}
		try {
			// If the file is locally modified, it cannot be in sync
			if (local.getType() == IResource.FILE && getSynchronizer().isLocallyModified(local)) {
				return false;
			}
			// If there is no base, the local cannot match the remote
			if (getSynchronizer().getBaseBytes(local) == null) return false;
			// Otherwise, assume they are the same if the remote equals the base
			return equals(getSynchronizer().getBaseBytes(local), getBytes(remote));
		} catch (TeamException e) {
			TeamPlugin.log(e);
			return false;
		}
	}

	@Override
	public boolean compare(IResourceVariant base, IResourceVariant remote) {
		byte[] bytes1 = getBytes(base);
		byte[] bytes2 = getBytes(remote);
		return equals(bytes1, bytes2);
	}

	@Override
	public boolean isThreeWay() {
		return true;
	}

	private ThreeWaySynchronizer getSynchronizer() {
		return synchronizer;
	}

	private byte[] getBytes(IResourceVariant remote) {
		return remote.asBytes();
	}

	private boolean equals(byte[] syncBytes, byte[] oldBytes) {
		if (syncBytes.length != oldBytes.length) return false;
		for (int i = 0; i < oldBytes.length; i++) {
			if (oldBytes[i] != syncBytes[i]) return false;
		}
		return true;
	}
}