FileStoreRoot.java

/*******************************************************************************
 * Copyright (c) 2005, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Serge Beauchamp (Freescale Semiconductor) - [229633] Project Path Variable Support
 *******************************************************************************/
package org.eclipse.core.internal.localstore;

import java.io.File;
import java.net.URI;
import org.eclipse.core.filesystem.*;
import org.eclipse.core.filesystem.URIUtil;
import org.eclipse.core.internal.utils.FileUtil;
import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.*;

/**
 * Represents the root of a file system that is connected to the workspace. A file system can be
 * rooted on any resource.
 */
public class FileStoreRoot {
	private int chop;

	/**
	 * When a root is changed, the old root object is marked invalid so that other resources with a
	 * cache of the root will know they need to update.
	 */
	private boolean isValid= true;

	/**
	 * If this root represents a resource in the local file system, this path represents the root
	 * location. This value is null if the root represents a non-local file system
	 */
	private IPath localRoot= null;

	private URI root;

	/**
	 * Defines the root of a file system within the workspace tree.
	 * 
	 * @param rootURI The virtual file representing the root of the file system that has been
	 *            mounted
	 * @param workspacePath The workspace path at which this file system has been mounted
	 */
	FileStoreRoot(URI rootURI, IPath workspacePath) {
		Assert.isNotNull(rootURI);
		Assert.isNotNull(workspacePath);
		this.root= rootURI;
		this.chop= workspacePath.segmentCount();
		this.localRoot= toLocalPath(root);
	}

	private IPathVariableManager getManager(IPath workspacePath) {
		if (workspacePath.segmentCount() > 0) {
			IWorkspaceRoot workspaceRoot= ResourcesPlugin.getWorkspace()
					.getRoot();
			IPath path= (IPath)workspacePath.clone();
			while (path.segmentCount() > 0) {
				IResource resource= workspaceRoot.findMember(path);
				if (resource != null) {
					if (path.segmentCount() < workspacePath.segmentCount())
						resource= ((IContainer)resource).getFile(workspacePath.removeFirstSegments(path.segmentCount()));
					return resource.getPathVariableManager();
				}
				path= path.removeLastSegments(1);
			}
		}
		return ResourcesPlugin.getWorkspace().getPathVariableManager();
	}

	/**
	 * Returns the resolved, absolute file system location of the resource corresponding to the
	 * given workspace path, or null if none could be computed.
	 */
	public URI computeURI(IPath workspacePath) {
		IPath childPath= workspacePath.removeFirstSegments(chop);
		final URI rootURI= getManager(workspacePath).resolveURI(root);
		if (childPath.segmentCount() == 0)
			return rootURI;
		try {
			return EFS.getStore(rootURI).getChild(childPath).toURI();
		} catch (CoreException e) {
			return null;
		}
	}

	/**
	 * Creates an IFileStore for a given workspace path.
	 * 
	 * @exception CoreException If the file system for that resource is undefined
	 */
	IFileStore createStore(IPath workspacePath, IResource resource) throws CoreException {
		IPath childPath= workspacePath.removeFirstSegments(chop);
		IFileStore rootStore;
		final URI uri= resource.getPathVariableManager().resolveURI(root);
		if (!uri.isAbsolute()) {
			//handles case where resource location cannot be resolved
			//such as unresolved path variable or invalid file system scheme
			return EFS.getNullFileSystem().getStore(workspacePath);
		}
		rootStore= EFS.getStore(uri);
		if (childPath.segmentCount() == 0)
			return rootStore;
		return rootStore.getChild(childPath);
	}

	boolean isValid() {
		return isValid;
	}

	IPath localLocation(IPath workspacePath, IResource resource) {
		if (localRoot == null)
			return null;
		IPath location;
		if (workspacePath.segmentCount() <= chop)
			location= localRoot;
		else
			location= localRoot.append(workspacePath.removeFirstSegments(chop));
		location= URIUtil.toPath(resource.getPathVariableManager().resolveURI(URIUtil.toURI(location)));
		//if path is still relative then path variable could not be resolved
		if (!location.isAbsolute())
			return null;
		return location;
	}

	void setValid(boolean value) {
		this.isValid= value;
	}

	/**
	 * Returns the local path for the given URI, or null if not possible.
	 */
	private IPath toLocalPath(URI uri) {
		try {
			final File localFile= EFS.getStore(uri).toLocalFile(EFS.NONE, null);
			return localFile == null ? null : new Path(localFile.getAbsolutePath());
		} catch (CoreException e) {
			return FileUtil.toPath(uri);
		}
	}
}