org.jboss.modules.PathUtils Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source.
* Copyright 2011, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This 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 2.1 of
* the License, or (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.modules;
/**
* General helpful path utility methods.
*
* @author David M. Lloyd
*/
public final class PathUtils {
private PathUtils() {
}
/**
* Canonicalize the given path. Removes all {@code .} and {@code ..} segments from the path.
*
* @param path the relative or absolute possibly non-canonical path
* @return the canonical path
*/
public static String canonicalize(String path) {
final int length = path.length();
// 0 - start
// 1 - got one .
// 2 - got two .
// 3 - got /
int state = 0;
if (length == 0) {
return path;
}
final char[] targetBuf = new char[length];
// string segment end exclusive
int e = length;
// string cursor position
int i = length;
// buffer cursor position
int a = length - 1;
// number of segments to skip
int skip = 0;
loop: while (--i >= 0) {
char c = path.charAt(i);
outer: switch (c) {
case '/': {
inner: switch (state) {
case 0: state = 3; e = i; break outer;
case 1: state = 3; e = i; break outer;
case 2: state = 3; e = i; skip ++; break outer;
case 3: e = i; break outer;
default: throw new IllegalStateException();
}
// not reached!
}
case '.': {
inner: switch (state) {
case 0: state = 1; break outer;
case 1: state = 2; break outer;
case 2: break inner; // emit!
case 3: state = 1; break outer;
default: throw new IllegalStateException();
}
// fall thru
}
default: {
final int newE = e > 0 ? path.lastIndexOf('/', e - 1) : -1;
final int segmentLength = e - newE - 1;
if (skip > 0) {
skip--;
} else {
if (state == 3) {
targetBuf[a--] = '/';
}
path.getChars(newE + 1, e, targetBuf, (a -= segmentLength) + 1);
}
state = 0;
i = newE + 1;
e = newE;
break;
}
}
}
if (state == 3) {
targetBuf[a--] = '/';
}
return new String(targetBuf, a + 1, length - a - 1);
}
}