/*******************************************************************************
* Copyright (c) 2012-2017 Codenvy, S.A.
* 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:
* Codenvy, S.A. - initial API and implementation
*******************************************************************************/
package org.eclipse.che.commons.lang;
import java.io.File;
import java.io.IOException;
import java.util.function.Supplier;
/**
* Set of util methods for path strings.
*/
public class PathUtil {
/**
* Converts path to canonical form via traversing '..' and eliminating '.' and removing duplicate separators.
* <b>Note:</b> This method works for Unix paths only.
*/
public static String toCanonicalPath(String path, boolean removeLastSlash) {
if (path == null || path.isEmpty()) {
return path;
}
if (path.charAt(0) == '.') {
if (path.length() == 1) {
return "";
}
char c = path.charAt(1);
if (c == '/') {
path = path.substring(2);
}
}
int index = -1;
do {
index = path.indexOf('/', index + 1);
char next = index == path.length() - 1 ? 0 : path.charAt(index + 1);
if (next == '.' || next == '/') {
break;
}
} while (index != -1);
if (index == -1) {
if (removeLastSlash) {
int start = processRoot(path, NullWriter.INSTANCE);
int slashIndex = path.lastIndexOf('/');
return slashIndex != -1 && slashIndex > start ? StringUtils.trimEnd(path, '/') : path;
}
return path;
}
String finalPath = path;
Supplier<String> canonicalPath = () -> {
try {
return new File(finalPath).getCanonicalPath();
} catch (IOException ignore) {
return toCanonicalPath(finalPath, removeLastSlash);
}
};
StringBuilder result = new StringBuilder(path.length());
int start = processRoot(path, result);
int dots = 0;
boolean separator = true;
for (int i = start; i < path.length(); ++i) {
char c = path.charAt(i);
if (c == '/') {
if (!separator) {
if (!processDots(result, dots, start)) {
return canonicalPath.get();
}
dots = 0;
}
separator = true;
} else if (c == '.') {
if (separator || dots > 0) {
++dots;
} else {
result.append('.');
}
separator = false;
} else {
if (dots > 0) {
StringUtils.repeatSymbol(result, '.', dots);
dots = 0;
}
result.append(c);
separator = false;
}
}
if (dots > 0) {
if (!processDots(result, dots, start)) {
return canonicalPath.get();
}
}
int lastChar = result.length() - 1;
if (removeLastSlash && lastChar >= 0 && result.charAt(lastChar) == '/' && lastChar > start) {
result.deleteCharAt(lastChar);
}
return result.toString();
}
private static boolean processDots(StringBuilder result, int dots, int start) {
if (dots == 2) {
int pos = -1;
if (!StringUtils.endWith(result, "/../") && !StringUtils.equals(result, "../")) {
pos = StringUtils.lastIndexOf(result, '/', start, result.length() - 1);
if (pos >= 0) {
++pos;
} else if (start > 0) {
pos = start;
} else if (result.length() > 0) {
pos = 0;
}
}
if (pos >= 0) {
result.delete(pos, result.length());
} else {
result.append("../");
}
} else if (dots != 1) {
StringUtils.repeatSymbol(result, '.', dots);
result.append('/');
}
return true;
}
private static int processRoot(String path, Appendable appendable) {
try {
if (!path.isEmpty() && path.charAt(0) == '/') {
appendable.append('/');
return 1;
}
if (path.length() > 2 && path.charAt(1) == ':' && path.charAt(2) == '/') {
appendable.append(path, 0, 3);
return 3;
}
} catch (IOException e) {
throw new RuntimeException(e);
}
return 0;
}
private static final class NullWriter implements Appendable {
public static final NullWriter INSTANCE = new NullWriter();
@Override
public Appendable append(CharSequence csq) throws IOException {
return this;
}
@Override
public Appendable append(CharSequence csq, int start, int end) throws IOException {
return this;
}
@Override
public Appendable append(char c) throws IOException {
return this;
}
}
}