/*
* Licensed to CRATE Technology GmbH ("Crate") under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership. Crate licenses
* this file to you 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.
*
* However, if you have executed another commercial license agreement
* with Crate these terms will supersede the license and you may use the
* software solely pursuant to the terms of the relevant commercial agreement.
*/
package io.crate.operation.collect.files;
import java.util.regex.PatternSyntaxException;
/**
* This is a copy of {@link sun.nio.fs.Globs} to make the methods public available.
*/
public class Globs {
private Globs() { }
private static final String regexMetaChars = ".^$+{[]|()";
private static final String globMetaChars = "\\*?[{";
private static boolean isRegexMeta(char c) {
return regexMetaChars.indexOf(c) != -1;
}
private static boolean isGlobMeta(char c) {
return globMetaChars.indexOf(c) != -1;
}
private static char EOL = 0; //TBD
private static char next(String glob, int i) {
if (i < glob.length()) {
return glob.charAt(i);
}
return EOL;
}
/**
* Creates a regex pattern from the given glob expression.
*
* @throws PatternSyntaxException
*/
private static String toRegexPattern(String globPattern, boolean isDos) {
boolean inGroup = false;
StringBuilder regex = new StringBuilder("^");
int i = 0;
while (i < globPattern.length()) {
char c = globPattern.charAt(i++);
switch (c) {
case '\\':
// escape special characters
if (i == globPattern.length()) {
throw new PatternSyntaxException("No character to escape",
globPattern, i - 1);
}
char next = globPattern.charAt(i++);
if (isGlobMeta(next) || isRegexMeta(next)) {
regex.append('\\');
}
regex.append(next);
break;
case '/':
if (isDos) {
regex.append("\\\\");
} else {
regex.append(c);
}
break;
case '[':
// don't match name separator in class
if (isDos) {
regex.append("[[^\\\\]&&[");
} else {
regex.append("[[^/]&&[");
}
if (next(globPattern, i) == '^') {
// escape the regex negation char if it appears
regex.append("\\^");
i++;
} else {
// negation
if (next(globPattern, i) == '!') {
regex.append('^');
i++;
}
// hyphen allowed at start
if (next(globPattern, i) == '-') {
regex.append('-');
i++;
}
}
boolean hasRangeStart = false;
char last = 0;
while (i < globPattern.length()) {
c = globPattern.charAt(i++);
if (c == ']') {
break;
}
if (c == '/' || (isDos && c == '\\')) {
throw new PatternSyntaxException("Explicit 'name separator' in class",
globPattern, i - 1);
}
// TBD: how to specify ']' in a class?
if (c == '\\' || c == '[' ||
c == '&' && next(globPattern, i) == '&') {
// escape '\', '[' or "&&" for regex class
regex.append('\\');
}
regex.append(c);
if (c == '-') {
if (!hasRangeStart) {
throw new PatternSyntaxException("Invalid range",
globPattern, i - 1);
}
if ((c = next(globPattern, i++)) == EOL || c == ']') {
break;
}
if (c < last) {
throw new PatternSyntaxException("Invalid range",
globPattern, i - 3);
}
regex.append(c);
hasRangeStart = false;
} else {
hasRangeStart = true;
last = c;
}
}
if (c != ']') {
throw new PatternSyntaxException("Missing ']", globPattern, i - 1);
}
regex.append("]]");
break;
case '{':
if (inGroup) {
throw new PatternSyntaxException("Cannot nest groups",
globPattern, i - 1);
}
regex.append("(?:(?:");
inGroup = true;
break;
case '}':
if (inGroup) {
regex.append("))");
inGroup = false;
} else {
regex.append('}');
}
break;
case ',':
if (inGroup) {
regex.append(")|(?:");
} else {
regex.append(',');
}
break;
case '*':
if (next(globPattern, i) == '*') {
// crosses directory boundaries
regex.append(".*");
i++;
} else {
// within directory boundary
if (isDos) {
regex.append("[^\\\\]*");
} else {
regex.append("[^/]*");
}
}
break;
case '?':
if (isDos) {
regex.append("[^\\\\]");
} else {
regex.append("[^/]");
}
break;
default:
if (isRegexMeta(c)) {
regex.append('\\');
}
regex.append(c);
}
}
if (inGroup) {
throw new PatternSyntaxException("Missing '}", globPattern, i - 1);
}
return regex.append('$').toString();
}
public static String toUnixRegexPattern(String globPattern) {
return toRegexPattern(globPattern, false);
}
public static String toWindowsRegexPattern(String globPattern) {
return toRegexPattern(globPattern, true);
}
}