| /* |
| * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.nio.fs; |
| |
| import java.nio.file.Path; |
| import java.nio.file.spi.FileTypeDetector; |
| import java.util.Locale; |
| import java.io.IOException; |
| |
| /** |
| * Base implementation of FileTypeDetector |
| */ |
| |
| public abstract class AbstractFileTypeDetector |
| extends FileTypeDetector |
| { |
| protected AbstractFileTypeDetector() { |
| super(); |
| } |
| |
| /** |
| * Invokes the appropriate probe method to guess a file's content type, |
| * and checks that the content type's syntax is valid. |
| */ |
| @Override |
| public final String probeContentType(Path file) throws IOException { |
| if (file == null) |
| throw new NullPointerException("'file' is null"); |
| String result = implProbeContentType(file); |
| return (result == null) ? null : parse(result); |
| } |
| |
| /** |
| * Probes the given file to guess its content type. |
| */ |
| protected abstract String implProbeContentType(Path file) |
| throws IOException; |
| |
| /** |
| * Parses a candidate content type into its type and subtype, returning |
| * null if either token is invalid. |
| */ |
| private static String parse(String s) { |
| int slash = s.indexOf('/'); |
| int semicolon = s.indexOf(';'); |
| if (slash < 0) |
| return null; // no subtype |
| String type = s.substring(0, slash).trim().toLowerCase(Locale.ENGLISH); |
| if (!isValidToken(type)) |
| return null; // invalid type |
| String subtype = (semicolon < 0) ? s.substring(slash + 1) : |
| s.substring(slash + 1, semicolon); |
| subtype = subtype.trim().toLowerCase(Locale.ENGLISH); |
| if (!isValidToken(subtype)) |
| return null; // invalid subtype |
| StringBuilder sb = new StringBuilder(type.length() + subtype.length() + 1); |
| sb.append(type); |
| sb.append('/'); |
| sb.append(subtype); |
| return sb.toString(); |
| } |
| |
| /** |
| * Special characters |
| */ |
| private static final String TSPECIALS = "()<>@,;:/[]?=\\\""; |
| |
| /** |
| * Returns true if the character is a valid token character. |
| */ |
| private static boolean isTokenChar(char c) { |
| return (c > 040) && (c < 0177) && (TSPECIALS.indexOf(c) < 0); |
| } |
| |
| /** |
| * Returns true if the given string is a legal type or subtype. |
| */ |
| private static boolean isValidToken(String s) { |
| int len = s.length(); |
| if (len == 0) |
| return false; |
| for (int i = 0; i < len; i++) { |
| if (!isTokenChar(s.charAt(i))) |
| return false; |
| } |
| return true; |
| } |
| } |