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}