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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
package org.apache.commons.configuration2.io;
import java.io.File;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
/**
* This class is a subset of org.apache.commons.io.FileUtils, git-svn-id:
* https://svn.apache.org/repos/asf/commons/proper/io/trunk@1423916 13f79535-47bb-0310-9956-ffa450edef68. The subset is
* determined by {@link FileLocatorUtils}. The copied constants and methods are literally copied.
*
* See CONFIGURATION-521 for a discussion.
*/
final class FileUtils {
/**
* The UTF-8 character set, used to decode octets in URLs.
*/
private static final Charset UTF8 = StandardCharsets.UTF_8;
/**
* Decodes the specified URL as per RFC 3986, i.e. transforms percent-encoded octets to characters by decoding with the
* UTF-8 character set. This function is primarily intended for usage with {@link java.net.URL} which unfortunately does
* not enforce proper URLs. As such, this method will leniently accept invalid characters or malformed percent-encoded
* octets and simply pass them literally through to the result string. Except for rare edge cases, this will make
* unencoded URLs pass through unaltered.
*
* @param url The URL to decode, may be {@code null}.
* @return The decoded URL or {@code null} if the input was {@code null}.
*/
static String decodeUrl(final String url) {
String decoded = url;
if (url != null && url.indexOf('%') >= 0) {
final int n = url.length();
final StringBuilder buffer = new StringBuilder();
final ByteBuffer bytes = ByteBuffer.allocate(n);
for (int i = 0; i < n;) {
if (url.charAt(i) == '%') {
try {
do {
final byte octet = (byte) Integer.parseInt(url.substring(i + 1, i + 3), 16);
bytes.put(octet);
i += 3;
} while (i < n && url.charAt(i) == '%');
continue;
} catch (final RuntimeException ignored) {
// malformed percent-encoded octet, fall through and
// append characters literally
} finally {
if (bytes.position() > 0) {
bytes.flip();
buffer.append(UTF8.decode(bytes));
bytes.clear();
}
}
}
buffer.append(url.charAt(i++));
}
decoded = buffer.toString();
}
return decoded;
}
/**
* Convert from a {@code URL} to a {@code File}.
*
* From version 1.1 this method will decode the URL. Syntax such as {@code file:///my%20docs/file.txt} will be correctly
* decoded to {@code /my docs/file.txt}. Starting with version 1.5, this method uses UTF-8 to decode percent-encoded
* octets to characters. Additionally, malformed percent-encoded octets are handled leniently by passing them through
* literally.
*
* @param url the file URL to convert, {@code null} returns {@code null}
* @return the equivalent {@code File} object, or {@code null} if the URL's protocol is not {@code file}
*/
public static File toFile(final URL url) {
if (url == null || !"file".equalsIgnoreCase(url.getProtocol())) {
return null;
}
String fileName = url.getFile().replace('/', File.separatorChar);
fileName = decodeUrl(fileName);
return new File(fileName);
}
}