/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.toolkit.util.regex;
import org.apache.oro.text.regex.MalformedPatternException;
/**
* 这个类将一个包含通配符的文件路径, 编译成Perl5的正则表达式. 格式描述如下:
* <ul>
* <li>合法的<em>文件名字符</em>包括: 字母/数字/下划线/小数点/短横线;</li>
* <li>合法的<em>路径分隔符</em>为斜杠"/";</li>
* <li>"＊"代表0个或多个<em>文件名字符</em>;</li>
* <li>"？"代表1个<em>文件名字符</em>;</li>
* <li>"＊＊"代表0个或多个<em>文件名字符</em>或<em>路径分隔符</em>;</li>
* <li>不能连续出现3个"＊";</li>
* <li>不能连续出现2个<em>路径分隔符</em>;</li>
* <li>"＊＊"的前后只能是<em>路径分隔符</em>.</li>
* </ul>
* 转换后的正则表达式, 对每一个通配符建立<em>引用变量</em>, 依次为<code>$1</code>, <code>$2</code>, ...
*
* @author Michael Zhou
* @version $Id: PathNameCompiler.java,v 1.1 2003/07/03 07:26:34 baobao Exp $
*/
public class PathNameCompiler extends Perl5CompilerWrapper {
/** 强制使用绝对路径 */
public static final int FORCE_ABSOLUTE_PATH = 0x1;
/** 强制使用相对路径 */
public static final int FORCE_RELATIVE_PATH = 0x2;
/** 从头匹配 */
public static final int FORCE_MATCH_PREFIX = 0x4;
// 私有常量
private static final char SLASH = '/';
private static final char UNDERSCORE = '_';
private static final char DASH = '-';
private static final char DOT = '.';
private static final char STAR = '*';
private static final char QUESTION = '?';
private static final String REGEX_MATCH_PREFIX = "^";
private static final String REGEX_WORD_BOUNDARY = "\\b";
private static final String REGEX_SLASH = "\\/";
private static final String REGEX_SLASH_NO_DUP = "\\/(?!\\/)";
private static final String REGEX_FILE_NAME_CHAR = "[\\w\\-\\.]";
private static final String REGEX_FILE_NAME_SINGLE_CHAR = "(" + REGEX_FILE_NAME_CHAR + ")";
private static final String REGEX_FILE_NAME = "(" + REGEX_FILE_NAME_CHAR + "*)";
private static final String REGEX_FILE_PATH = "(" + REGEX_FILE_NAME_CHAR + "+(?:" + REGEX_SLASH_NO_DUP
+ REGEX_FILE_NAME_CHAR + "*)*(?=" + REGEX_SLASH + "|$)|)" + REGEX_SLASH + "?";
// 上一个token的状态
private static final int LAST_TOKEN_START = 0;
private static final int LAST_TOKEN_SLASH = 1;
private static final int LAST_TOKEN_FILE_NAME = 2;
private static final int LAST_TOKEN_STAR = 3;
private static final int LAST_TOKEN_DOUBLE_STAR = 4;
private static final int LAST_TOKEN_QUESTION = 5;
/**
* 将包含通配符的路径表达式, 编译成perl5正则表达式.
*
* @param pattern 要编译的路径
* @param options 位标志
* @return Perl5正则表达式字符串
* @throws MalformedPatternException 如果路径字符串格式不正确
*/
@Override
public String toPerl5Regex(char[] pattern, int options) throws MalformedPatternException {
int lastToken = LAST_TOKEN_START;
StringBuffer buffer = new StringBuffer(pattern.length * 2);
boolean forceMatchPrefix = (options & FORCE_MATCH_PREFIX) != 0;
boolean forceAbsolutePath = (options & FORCE_ABSOLUTE_PATH) != 0;
boolean forceRelativePath = (options & FORCE_RELATIVE_PATH) != 0;
// 如果第一个字符为slash, 或调用者要求forceMatchPrefix, 则从头匹配
if (forceMatchPrefix || pattern.length > 0 && pattern[0] == SLASH) {
buffer.append(REGEX_MATCH_PREFIX);
}
for (int i = 0; i < pattern.length; i++) {
char ch = pattern[i];
if (forceAbsolutePath && lastToken == LAST_TOKEN_START && ch != SLASH) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
switch (ch) {
case SLASH:
// slash后面不能是slash, slash不能位于首字符(如果指定了force relative path的话)
if (lastToken == LAST_TOKEN_SLASH) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
} else if (forceRelativePath && lastToken == LAST_TOKEN_START) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
// 因为**已经包括了slash, 所以不需要额外地匹配slash
if (lastToken != LAST_TOKEN_DOUBLE_STAR) {
buffer.append(REGEX_SLASH_NO_DUP);
}
lastToken = LAST_TOKEN_SLASH;
break;
case STAR:
int j = i + 1;
if (j < pattern.length && pattern[j] == STAR) {
i = j;
// **前面只能是slash
if (lastToken != LAST_TOKEN_START && lastToken != LAST_TOKEN_SLASH) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
lastToken = LAST_TOKEN_DOUBLE_STAR;
buffer.append(REGEX_FILE_PATH);
} else {
// *前面不能是*或**
if (lastToken == LAST_TOKEN_STAR || lastToken == LAST_TOKEN_DOUBLE_STAR) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
lastToken = LAST_TOKEN_STAR;
buffer.append(REGEX_FILE_NAME);
}
break;
case QUESTION:
lastToken = LAST_TOKEN_QUESTION;
buffer.append(REGEX_FILE_NAME_SINGLE_CHAR);
break;
default:
// **后只能是slash
if (lastToken == LAST_TOKEN_DOUBLE_STAR) {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
if (Character.isLetterOrDigit(ch) || ch == UNDERSCORE || ch == DASH) {
// 加上word边界, 进行整字匹配
if (lastToken == LAST_TOKEN_START) {
buffer.append(REGEX_WORD_BOUNDARY).append(ch); // 前边界
} else if (i + 1 == pattern.length) {
buffer.append(ch).append(REGEX_WORD_BOUNDARY); // 后边界
} else {
buffer.append(ch);
}
} else if (ch == DOT) {
buffer.append(ESCAPE_CHAR).append(DOT);
} else {
throw new MalformedPatternException(getDefaultErrorMessage(pattern, i));
}
lastToken = LAST_TOKEN_FILE_NAME;
}
}
return buffer.toString();
}
}