/**
* This file is part of muCommander, http://www.mucommander.com
* Copyright (C) 2002-2016 Maxence Bernard
*
* muCommander is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* muCommander is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.mucommander.commons.file;
import java.util.Vector;
/**
* @author Maxence Bernard
*/
public class DefaultPathCanonizer implements PathCanonizer {
/** Path separator */
private String separator;
/** The string replacement for '~' path fragments, null for no tilde replacement */
private String tildeReplacement;
/**
* Creates a new path canonizer using the specified path separator and no tilde replacement.
*
* @param separator the path separator that delimits path fragments
*/
public DefaultPathCanonizer(String separator) {
this(separator, null);
}
/**
* Creates a new path canonizer using the specified path separator and tilde replacement string
* (if not <code>null</code>).
*
* @param separator the path separator that delimits path fragments
* @param tildeReplacement if not <code>null</code>, path fragments equal to '~' will be replaced by this string.
*/
public DefaultPathCanonizer(String separator, String tildeReplacement) {
this.separator = separator;
this.tildeReplacement = tildeReplacement;
}
//////////////////////////////////
// PathCanonizer implementation //
//////////////////////////////////
/**
* Returns a canonical value of the given path, where '.' and '..' path fragments are factored out,
* and '~' fragments replaced by the string specified in the constructor (if not <code>null</code>).
*
* @param path the path to canonize
* @return the canonized path
*/
public String canonize(String path) {
// Todo: use PathTokenizer?
if(!path.equals("/")) {
int pos; // position of current path separator
int pos2 = 0; // position of next path separator
int separatorLen = separator.length();
String dir; // Current directory
String dirWS; // Current directory without trailing separator
Vector<String> pathV = new Vector<String>(); // Will contain directory hierachy
while((pos=pos2)!=-1) {
// Get the index of the next path separator occurrence
pos2 = path.indexOf(separator, pos);
if(pos2==-1) { // Last dir (or empty string)
dir = path.substring(pos);
dirWS = dir;
}
else {
pos2 += separatorLen;
dir = path.substring(pos, pos2); // Dir name includes trailing separator
dirWS = dir.substring(0, dir.length()-separatorLen);
}
// Discard '.' and empty directories
if((dirWS.equals("") && pathV.size()>0) || dirWS.equals(".")) {
continue;
}
// Remove last directory
else if(dirWS.equals("..")) {
if(pathV.size()>0)
pathV.removeElementAt(pathV.size()-1);
continue;
}
// Replace '~' by the provided replacement string, only if one was specified
else if(tildeReplacement!=null && dirWS.equals("~")) {
path = path.substring(0, pos) + tildeReplacement + path.substring(pos+1);
// Will perform another pass at the same position
pos2 = pos;
continue;
}
// Add directory to the end of the list
pathV.add(dir);
}
// Reconstruct path from directory list
path = "";
int nbDirs = pathV.size();
for(int i=0; i<nbDirs; i++)
path += pathV.elementAt(i);
// We now have a path free of "." and ".." (and "~" if tilde replacement is enabled)
}
return path;
}
}