/*
* Copyright (c) 2012 Google Inc.
*
* 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
*/
package com.google.eclipse.protobuf.resource;
import static com.google.common.base.Objects.equal;
import org.eclipse.core.runtime.IPath;
import org.eclipse.emf.common.util.URI;
import org.eclipse.xtext.resource.IResourceDescription;
import org.eclipse.xtext.resource.IResourceDescriptions;
import com.google.common.annotations.VisibleForTesting;
import com.google.inject.Inject;
/**
* Simplified Xtext index lookups.
*
* @author alruiz@google.com (Alex Ruiz)
*/
public class IndexLookup {
@Inject private IResourceDescriptions xtextIndex;
/**
* Finds the resource description for the given path.
* @param path the given path.
* @return the found resource description, or {@code null} if a resource description with a matching path could not be
* found.
*/
public IResourceDescription resourceIn(IPath path) {
IResourceDescription description = lookup(path);
if (description != null) {
return description;
}
return segmentMatching(path);
}
private IResourceDescription lookup(IPath path) {
URI uri = URI.createPlatformResourceURI(path.toPortableString(), true);
return xtextIndex.getResourceDescription(uri);
}
private IResourceDescription segmentMatching(IPath path) {
for (IResourceDescription description : xtextIndex.getAllResourceDescriptions()) {
URI resourceUri = description.getURI();
if (areReferringToSameFile(path, resourceUri)) {
return description;
}
}
return null;
}
@VisibleForTesting boolean areReferringToSameFile(IPath p, URI u) {
int pIndex = p.segmentCount() - 1;
int uIndex = u.segmentCount() - 1;
while (pIndex >= 0 && uIndex >= 0) {
if (!equal(p.segment(pIndex--), u.segment(uIndex--))) {
return false;
}
}
return true;
}
@VisibleForTesting IResourceDescriptions getXtextIndex() {
return xtextIndex;
}
}