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/*******************************************************************************
* Copyright (c) 2011 protos software gmbh (http://www.protos.de).
* 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:
* Thomas Schuetz and Henrik Rentz-Reichert (initial contribution)
*
*******************************************************************************/
package org.eclipse.etrice.core.common.base.util;
import org.eclipse.emf.common.util.URI;
/**
* @author Henrik Rentz-Reichert
*
*/
public class RelativePathHelpers {
private static boolean bothNullOrEqual(String s1, String s2) {
if (s1==null && s2==null)
return true;
if (s1==null || s2==null)
return false;
return s1.equals(s2);
}
/**
* the given paths are converted to file URIs (using {@link URI#createFileURI(String)}
* and then {@link #getRelativePath(URI, URI, boolean)} is called with <code>goUpIfNeeded=false</code>.
*
* @param base the base path
* @param path the path for which the relative path is computed
* @return relative path (<code>null</code>if there is none)
*/
public static String getRelativePath(String base, String path) {
return getRelativePath(URI.createFileURI(base), URI.createFileURI(path), false);
}
/**
* the given paths are converted to file URIs (using {@link URI#createFileURI(String)}
* and then {@link #getRelativePath(URI, URI, boolean)} is called.
*
* @param base the base path
* @param path the path for which the relative path is computed
* @param goUpIfNeeded allow also ascending to parent directories
* @return relative path (<code>null</code>if there is none)
*/
public static String getRelativePath(String base, String path, boolean goUpIfNeeded) {
return getRelativePath(URI.createFileURI(base), URI.createFileURI(path), goUpIfNeeded);
}
/**
* {@link #getRelativePath(URI, URI, boolean)} is called with
* <code>goUpIfNeeded=false</code>
*
* @param base the base path
* @param path the path for which the relative path is computed
* @return relative path (<code>null</code>if there is none)
*/
public static String getRelativePath(URI base, URI path) {
return getRelativePath(base, path, false);
}
/**
* compute a relative path to a given base path.
* Both paths must be of the same scheme and absolute and the given
* path has to have the first segments identical with the base path.
* Returned is a relative path separated by / characters.
* If there is no such relative path <code>null</code> is returned.
*
* @param base the base path
* @param path the path for which the relative path is computed
* @param goUpIfNeeded allow also ascending to parent directories
* @return relative path (<code>null</code>if there is none)
*/
public static String getRelativePath(URI base, URI path, boolean goUpIfNeeded) {
if (base==null || path==null)
return null;
if (!bothNullOrEqual(base.scheme(),path.scheme()))
return null;
if (!base.hasAbsolutePath())
return null;
if (!path.hasAbsolutePath())
return null;
if (!bothNullOrEqual(path.device(), base.device()))
return null;
StringBuffer result = new StringBuffer();
if (goUpIfNeeded) {
int max = base.segmentCount()<path.segmentCount()? base.segmentCount():path.segmentCount();
int common;
for (common=0; common<max; ++common) {
if (!base.segment(common).equals(path.segment(common)))
break;
}
for (int i=common; i<base.segmentCount(); ++i) {
result.append("../");
}
for (int i=common; i<path.segmentCount(); ++i) {
result.append(path.segment(i)+"/");
}
if (result.length()==0)
return "";
return result.substring(0, result.length()-1);
}
else {
if (path.segmentCount()<base.segmentCount())
return null;
for (int i=0; i<base.segmentCount(); ++i) {
if (!base.segment(i).equals(path.segment(i)))
return null;
}
for (int i=base.segmentCount(); i<path.segmentCount(); ++i) {
result.append(path.segment(i)+"/");
}
if(result.length()==0)
return "";
return result.substring(0, result.length()-1);
}
}
}
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