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 java.util.ArrayList;
import java.util.List;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ISynchronizer;
import org.eclipse.core.resources.IWorkspaceRunnable;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.QualifiedName;
import org.eclipse.team.core.TeamException;

A ResourceVariantByteStore that caches the variant bytes using
the org.eclipse.core.resources.ISynchronizer so that the tree is
cached across workbench invocations.
Since:
3.0
@noextend
This class is not intended to be subclassed by clients./**
 * A <code>ResourceVariantByteStore</code> that caches the variant bytes using
 * the <code>org.eclipse.core.resources.ISynchronizer</code> so that the tree is
 * cached across workbench invocations.
 *
 * @since 3.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public class PersistantResourceVariantByteStore extends ResourceVariantByteStore {

	private static final byte[] NO_REMOTE = new byte[0];

	private QualifiedName syncName;

	
Create a persistent tree that uses the given qualified name
as the key in the org.eclipse.core.resources.ISynchronizer.
It must be unique and should use the plugin as the local name
and a unique id within the plugin as the qualifier name.
Params:
name – the key used in the Core synchronizer/**
	 * Create a persistent tree that uses the given qualified name
	 * as the key in the <code>org.eclipse.core.resources.ISynchronizer</code>.
	 * It must be unique and should use the plugin as the local name
	 * and a unique id within the plugin as the qualifier name.
	 * @param name the key used in the Core synchronizer
	 */
	public PersistantResourceVariantByteStore(QualifiedName name) {
		syncName = name;
		getSynchronizer().add(syncName);
	}

	@Override
	public void dispose() {
		getSynchronizer().remove(getSyncName());
	}

	
Return the qualified name that uniquely identifies this tree.
Returns:
the qualified name that uniquely identifies this tree./**
	 * Return the qualified name that uniquely identifies this tree.
	 * @return the qualified name that uniquely identifies this tree.
	 */
	public QualifiedName getSyncName() {
		return syncName;
	}

	@Override
	public byte[] getBytes(IResource resource) throws TeamException {
		byte[] syncBytes = internalGetSyncBytes(resource);
		if (syncBytes != null && equals(syncBytes, NO_REMOTE)) {
			// If it is known that there is no remote, return null
			return null;
		}
		return syncBytes;
	}

	@Override
	public boolean setBytes(IResource resource, byte[] bytes) throws TeamException {
		Assert.isNotNull(bytes);
		byte[] oldBytes = internalGetSyncBytes(resource);
		if (oldBytes != null && equals(oldBytes, bytes)) return false;
		try {
			getSynchronizer().setSyncInfo(getSyncName(), resource, bytes);
			return true;
		} catch (CoreException e) {
			throw TeamException.asTeamException(e);
		}
	}

	@Override
	public boolean flushBytes(IResource resource, int depth) throws TeamException {
		if (resource.exists() || resource.isPhantom()) {
			try {
				if (depth != IResource.DEPTH_ZERO || internalGetSyncBytes(resource) != null) {
					getSynchronizer().flushSyncInfo(getSyncName(), resource, depth);
					return true;
				}
			} catch (CoreException e) {
				throw TeamException.asTeamException(e);
			}
		}
		return false;
	}

	
Return whether the resource variant state for this resource is known.
This is used to differentiate the case where a resource variant has never been fetched
from the case where the resource variant is known to not exist. In the later
case, this method returns true while getBytes returns null
Params:
resource – the local resource
Throws:
TeamException – 
Returns:
whether the resource variant state for this resource is known/**
	 * Return whether the resource variant state for this resource is known.
	 * This is used to differentiate the case where a resource variant has never been fetched
	 * from the case where the resource variant is known to not exist. In the later
	 * case, this method returns <code>true</code> while <code>getBytes</code> returns <code>null</code>
	 * @param resource the local resource
	 * @return whether the resource variant state for this resource is known
	 * @throws TeamException
	 */
	public boolean isVariantKnown(IResource resource) throws TeamException {
		return internalGetSyncBytes(resource) != null;
	}

	
This method should be invoked by a client to indicate that it is known that
there is no remote resource associated with the local resource. After this method
is invoked, isVariantKnown(resource) will return true and
getBytes(resource) will return null.
Returns:
true if this changes the remote sync bytes/**
	 * This method should be invoked by a client to indicate that it is known that
	 * there is no remote resource associated with the local resource. After this method
	 * is invoked, <code>isVariantKnown(resource)</code> will return <code>true</code> and
	 * <code>getBytes(resource)</code> will return <code>null</code>.
	 * @return <code>true</code> if this changes the remote sync bytes
	 */
	@Override
	public boolean deleteBytes(IResource resource) throws TeamException {
		return setBytes(resource, NO_REMOTE);
	}

	@Override
	public IResource[] members(IResource resource) throws TeamException {
		if(resource.getType() == IResource.FILE) {
			return new IResource[0];
		}
		try {
			// Filter and return only resources that have sync bytes in the cache.
			IResource[] members = ((IContainer)resource).members(true /* include phantoms */);
			List<IResource> filteredMembers = new ArrayList<>(members.length);
			for (IResource member : members) {
				if(getBytes(member) != null) {
					filteredMembers.add(member);
				}
			}
			return filteredMembers.toArray(new IResource[filteredMembers.size()]);
		} catch (CoreException e) {
			throw TeamException.asTeamException(e);
		}
	}

	private ISynchronizer getSynchronizer() {
		return ResourcesPlugin.getWorkspace().getSynchronizer();
	}

	private byte[] internalGetSyncBytes(IResource resource) throws TeamException {
		try {
			return getSynchronizer().getSyncInfo(getSyncName(), resource);
		} catch (CoreException e) {
			throw TeamException.asTeamException(e);
		}
	}

	@Override
	public void run(IResource root, IWorkspaceRunnable runnable, IProgressMonitor monitor)
			throws TeamException {
		try {
			ResourcesPlugin.getWorkspace().run(runnable, root, 0, monitor);
		} catch (CoreException e) {
			throw TeamException.asTeamException(e);
		}
	}
}