io.undertow.util.CanonicalPathUtils Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.undertow.util;
import java.util.ArrayList;
import java.util.List;
/**
* @author Stuart Douglas
*/
public class CanonicalPathUtils {
/**
* System property the revert to legacy behaviour of ignoring backslash
*/
private static final boolean DONT_CANONICALIZE_BACKSLASH = Boolean.parseBoolean("io.undertow.DONT_CANONICALIZE_BACKSLASH");
public static String canonicalize(final String path) {
int state = START;
for (int i = path.length() - 1; i >= 0; --i) {
final char c = path.charAt(i);
switch (c) {
case '/':
if (state == FIRST_SLASH) {
return realCanonicalize(path, i + 1, FIRST_SLASH);
} else if (state == ONE_DOT) {
return realCanonicalize(path, i + 2, FIRST_SLASH);
} else if (state == TWO_DOT) {
return realCanonicalize(path, i + 3, FIRST_SLASH);
}
state = FIRST_SLASH;
break;
case '.':
if (state == FIRST_SLASH || state == START || state == FIRST_BACKSLASH) {
state = ONE_DOT;
} else if(state == ONE_DOT) {
state = TWO_DOT;
} else {
state = NORMAL;
}
break;
case '\\':
if(!DONT_CANONICALIZE_BACKSLASH) {
if (state == FIRST_BACKSLASH) {
return realCanonicalize(path, i + 1, FIRST_BACKSLASH);
} else if (state == ONE_DOT) {
return realCanonicalize(path, i + 2, FIRST_BACKSLASH);
} else if (state == TWO_DOT) {
return realCanonicalize(path, i + 3, FIRST_BACKSLASH);
}
state = FIRST_BACKSLASH;
break;
}
//fall through
default:
state = NORMAL;
break;
}
}
return path;
}
static final int START = -1;
static final int NORMAL = 0;
static final int FIRST_SLASH = 1;
static final int ONE_DOT = 2;
static final int TWO_DOT = 3;
static final int FIRST_BACKSLASH = 4;
private static String realCanonicalize(final String path, final int lastDot, final int initialState) {
int state = initialState;
int eatCount = 0;
int tokenEnd = path.length();
final List parts = new ArrayList<>();
for (int i = lastDot - 1; i >= 0; --i) {
final char c = path.charAt(i);
switch (state) {
case NORMAL: {
if (c == '/') {
state = FIRST_SLASH;
if (eatCount > 0) {
--eatCount;
tokenEnd = i;
}
} else if (c == '\\' && !DONT_CANONICALIZE_BACKSLASH) {
state = FIRST_BACKSLASH;
if (eatCount > 0) {
--eatCount;
tokenEnd = i;
}
}
break;
}
case FIRST_SLASH: {
if (c == '.') {
state = ONE_DOT;
} else if (c == '/') {
if (eatCount > 0) {
--eatCount;
tokenEnd = i;
} else {
parts.add(path.substring(i + 1, tokenEnd));
tokenEnd = i;
}
} else {
state = NORMAL;
}
break;
}
case FIRST_BACKSLASH: {
if (c == '.') {
state = ONE_DOT;
} else if (c == '\\') {
if (eatCount > 0) {
--eatCount;
tokenEnd = i;
} else {
parts.add(path.substring(i + 1, tokenEnd));
tokenEnd = i;
}
} else {
state = NORMAL;
}
break;
}
case ONE_DOT: {
if (c == '.') {
state = TWO_DOT;
} else if (c == '/' || (c == '\\' && !DONT_CANONICALIZE_BACKSLASH)) {
if (i + 2 != tokenEnd) {
parts.add(path.substring(i + 2, tokenEnd));
}
tokenEnd = i;
state = c == '/' ? FIRST_SLASH : FIRST_BACKSLASH;
} else {
state = NORMAL;
}
break;
}
case TWO_DOT: {
if (c == '/' || (c == '\\' && !DONT_CANONICALIZE_BACKSLASH)) {
if (i + 3 != tokenEnd) {
parts.add(path.substring(i + 3, tokenEnd));
}
tokenEnd = i;
eatCount++;
state = c == '/' ? FIRST_SLASH : FIRST_BACKSLASH;
} else {
state = NORMAL;
}
}
}
}
final StringBuilder result = new StringBuilder();
if (tokenEnd != 0) {
result.append(path.substring(0, tokenEnd));
}
for (int i = parts.size() - 1; i >= 0; --i) {
result.append(parts.get(i));
}
if(result.length() == 0) {
return "/";
}
return result.toString();
}
private CanonicalPathUtils() {
}
}