tika-core/src/main/java/org/apache/tika/io/FilenameUtils.java

/*
 * 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.tika.io;

import java.util.HashSet;
import java.util.Locale;

import org.apache.tika.utils.StringUtils;


public class FilenameUtils {


    /**
     * Reserved characters
     */
    public final static char[] RESERVED_FILENAME_CHARACTERS =
            {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D,
                    0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A,
                    0x1B, 0x1C, 0x1D, 0x1E, 0x1F, '?', ':', '*', '<', '>', '|'};

    private final static HashSet<Character> RESERVED = new HashSet<>(38);


    static {
        for (char reservedFilenameCharacter : RESERVED_FILENAME_CHARACTERS) {
            RESERVED.add(reservedFilenameCharacter);
        }
    }


    /**
     * Scans the given file name for reserved characters on different OSs and
     * file systems and returns a sanitized version of the name with the
     * reserved chars replaced by their hexadecimal value.
     * <p>
     * For example <code>why?.zip</code> will be converted into <code>why%3F.zip</code>
     *
     * @param name the file name to be normalized - NOT NULL
     * @return the normalized file name
     * @throws IllegalArgumentException if name is null
     */
    public static String normalize(final String name) {
        if (name == null) {
            throw new IllegalArgumentException("name cannot be null");
        }

        StringBuilder sb = new StringBuilder();

        for (char c : name.toCharArray()) {
            if (RESERVED.contains(c)) {
                sb.append('%').append((c < 16) ? "0" : "")
                        .append(Integer.toHexString(c).toUpperCase(Locale.ROOT));
            } else {
                sb.append(c);
            }
        }

        return sb.toString();
    }

    /**
     * This is a duplication of the algorithm and functionality
     * available in commons io FilenameUtils.  If Java's File were
     * able handle Windows file paths correctly in linux,
     * we wouldn't need this.
     * <p>
     * The goal of this is to get a filename from a path.
     * The package parsers and some other embedded doc
     * extractors could put anything into TikaCoreProperties.RESOURCE_NAME_KEY.
     * <p>
     * If a careless client used that filename as if it were a
     * filename and not a path when writing embedded files,
     * bad things could happen.  Consider: "../../../my_ppt.ppt".
     * <p>
     * Consider using this in combination with {@link #normalize(String)}.
     *
     * @param path path to strip
     * @return empty string or a filename, never null
     */
    public static String getName(final String path) {

        if (path == null || path.length() == 0) {
            return StringUtils.EMPTY;
        }
        int unix = path.lastIndexOf("/");
        int windows = path.lastIndexOf("\\");
        //some macintosh file names are stored with : as the delimiter
        //also necessary to properly handle C:somefilename
        int colon = path.lastIndexOf(":");
        String cand = path.substring(Math.max(colon, Math.max(unix, windows)) + 1);
        if (cand.equals("..") || cand.equals(".")) {
            return StringUtils.EMPTY;
        }
        return cand;
    }

    /**
     * This includes the period, e.g. ".pdf"
     * @param path
     * @return the suffix or an empty string if one could not be found
     */
    public static String getSuffixFromPath(String path) {
        String n = getName(path);
        int i = n.lastIndexOf(".");
        //arbitrarily sets max extension length
        if (i > -1 && n.length() - i < 6) {
            return n.substring(i);
        }
        return StringUtils.EMPTY;
    }
}