    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.io.file;
    019
    020import java.io.IOException;
    021import java.nio.file.FileVisitResult;
    022import java.nio.file.Files;
    023import java.nio.file.LinkOption;
    024import java.nio.file.NoSuchFileException;
    025import java.nio.file.Path;
    026import java.nio.file.attribute.BasicFileAttributes;
    027import java.util.Arrays;
    028import java.util.Objects;
    029
    030import org.apache.commons.io.file.Counters.PathCounters;
    031
    032/**
    033 * Deletes files and directories as a visit proceeds.
    034 *
    035 * @since 2.7
    036 */
    037public class DeletingPathVisitor extends CountingPathVisitor {
    038
    039    /**
    040     * Creates a new instance configured with a BigInteger {@link PathCounters}.
    041     *
    042     * @return a new instance configured with a BigInteger {@link PathCounters}.
    043     */
    044    public static DeletingPathVisitor withBigIntegerCounters() {
    045        return new DeletingPathVisitor(Counters.bigIntegerPathCounters());
    046    }
    047
    048    /**
    049     * Creates a new instance configured with a long {@link PathCounters}.
    050     *
    051     * @return a new instance configured with a long {@link PathCounters}.
    052     */
    053    public static DeletingPathVisitor withLongCounters() {
    054        return new DeletingPathVisitor(Counters.longPathCounters());
    055    }
    056
    057    private final String[] skip;
    058    private final boolean overrideReadOnly;
    059    private final LinkOption[] linkOptions;
    060
    061    /**
    062     * Constructs a new visitor that deletes files except for the files and directories explicitly given.
    063     *
    064     * @param pathCounter How to count visits.
    065     * @param deleteOption How deletion is handled.
    066     * @param skip The files to skip deleting.
    067     * @since 2.8.0
    068     */
    069    public DeletingPathVisitor(final PathCounters pathCounter, final DeleteOption[] deleteOption,
    070        final String... skip) {
    071        this(pathCounter, PathUtils.NOFOLLOW_LINK_OPTION_ARRAY, deleteOption, skip);
    072    }
    073
    074    /**
    075     * Constructs a new visitor that deletes files except for the files and directories explicitly given.
    076     *
    077     * @param pathCounter How to count visits.
    078     * @param linkOptions How symbolic links are handled.
    079     * @param deleteOption How deletion is handled.
    080     * @param skip The files to skip deleting.
    081     * @since 2.9.0
    082     */
    083    public DeletingPathVisitor(final PathCounters pathCounter, final LinkOption[] linkOptions,
    084        final DeleteOption[] deleteOption, final String... skip) {
    085        super(pathCounter);
    086        final String[] temp = skip != null ? skip.clone() : EMPTY_STRING_ARRAY;
    087        Arrays.sort(temp);
    088        this.skip = temp;
    089        this.overrideReadOnly = StandardDeleteOption.overrideReadOnly(deleteOption);
    090        // TODO Files.deleteIfExists() never follows links, so use LinkOption.NOFOLLOW_LINKS in other calls to Files.
    091        this.linkOptions = linkOptions == null ? PathUtils.NOFOLLOW_LINK_OPTION_ARRAY : linkOptions.clone();
    092    }
    093
    094    /**
    095     * Constructs a new visitor that deletes files except for the files and directories explicitly given.
    096     *
    097     * @param pathCounter How to count visits.
    098     *
    099     * @param skip The files to skip deleting.
    100     */
    101    public DeletingPathVisitor(final PathCounters pathCounter, final String... skip) {
    102        this(pathCounter, PathUtils.EMPTY_DELETE_OPTION_ARRAY, skip);
    103    }
    104
    105    /**
    106     * Returns true to process the given path, false if not.
    107     *
    108     * @param path the path to test.
    109     * @return true to process the given path, false if not.
    110     */
    111    private boolean accept(final Path path) {
    112        return Arrays.binarySearch(skip, Objects.toString(path.getFileName(), null)) < 0;
    113    }
    114
    115    @Override
    116    public boolean equals(final Object obj) {
    117        if (this == obj) {
    118            return true;
    119        }
    120        if (!super.equals(obj)) {
    121            return false;
    122        }
    123        if (getClass() != obj.getClass()) {
    124            return false;
    125        }
    126        final DeletingPathVisitor other = (DeletingPathVisitor) obj;
    127        return overrideReadOnly == other.overrideReadOnly && Arrays.equals(skip, other.skip);
    128    }
    129
    130    @Override
    131    public int hashCode() {
    132        final int prime = 31;
    133        int result = super.hashCode();
    134        result = prime * result + Arrays.hashCode(skip);
    135        result = prime * result + Objects.hash(overrideReadOnly);
    136        return result;
    137    }
    138
    139    @Override
    140    public FileVisitResult postVisitDirectory(final Path dir, final IOException exc) throws IOException {
    141        if (PathUtils.isEmptyDirectory(dir)) {
    142            Files.deleteIfExists(dir);
    143        }
    144        return super.postVisitDirectory(dir, exc);
    145    }
    146
    147    @Override
    148    public FileVisitResult preVisitDirectory(final Path dir, final BasicFileAttributes attrs) throws IOException {
    149        super.preVisitDirectory(dir, attrs);
    150        return accept(dir) ? FileVisitResult.CONTINUE : FileVisitResult.SKIP_SUBTREE;
    151    }
    152
    153    @Override
    154    public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
    155        if (accept(file)) {
    156            // delete files and valid links, respecting linkOptions
    157            if (Files.exists(file, linkOptions)) {
    158                if (overrideReadOnly) {
    159                    PathUtils.setReadOnly(file, false, linkOptions);
    160                }
    161                Files.deleteIfExists(file);
    162            }
    163            // invalid links will survive previous delete, different approach needed:
    164            if (Files.isSymbolicLink(file)) {
    165                try {
    166                    // deleteIfExists does not work for this case
    167                    Files.delete(file);
    168                } catch (final NoSuchFileException e) {
    169                    // ignore
    170                }
    171            }
    172        }
    173        updateFileCounters(file, attrs);
    174        return FileVisitResult.CONTINUE;
    175    }
    176}