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     * Constructs 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     * Constructs 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 instance 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, final String... skip) {
070        this(pathCounter, PathUtils.noFollowLinkOptionArray(), deleteOption, skip);
071    }
072
073    /**
074     * Constructs a instance that deletes files except for the files and directories explicitly given.
075     *
076     * @param pathCounter How to count visits.
077     * @param linkOptions How symbolic links are handled.
078     * @param deleteOption How deletion is handled.
079     * @param skip The files to skip deleting.
080     * @since 2.9.0
081     */
082    public DeletingPathVisitor(final PathCounters pathCounter, final LinkOption[] linkOptions, final DeleteOption[] deleteOption, final String... skip) {
083        super(pathCounter);
084        final String[] temp = skip != null ? skip.clone() : EMPTY_STRING_ARRAY;
085        Arrays.sort(temp);
086        this.skip = temp;
087        this.overrideReadOnly = StandardDeleteOption.overrideReadOnly(deleteOption);
088        // TODO Files.deleteIfExists() never follows links, so use LinkOption.NOFOLLOW_LINKS in other calls to Files.
089        this.linkOptions = linkOptions == null ? PathUtils.noFollowLinkOptionArray() : linkOptions.clone();
090    }
091
092    /**
093     * Constructs a instance that deletes files except for the files and directories explicitly given.
094     *
095     * @param pathCounter How to count visits.
096     *
097     * @param skip The files to skip deleting.
098     */
099    public DeletingPathVisitor(final PathCounters pathCounter, final String... skip) {
100        this(pathCounter, PathUtils.EMPTY_DELETE_OPTION_ARRAY, skip);
101    }
102
103    /**
104     * Returns true to process the given path, false if not.
105     *
106     * @param path the path to test.
107     * @return true to process the given path, false if not.
108     */
109    private boolean accept(final Path path) {
110        return Arrays.binarySearch(skip, PathUtils.getFileNameString(path)) < 0;
111    }
112
113    @Override
114    public boolean equals(final Object obj) {
115        if (this == obj) {
116            return true;
117        }
118        if (!super.equals(obj)) {
119            return false;
120        }
121        if (getClass() != obj.getClass()) {
122            return false;
123        }
124        final DeletingPathVisitor other = (DeletingPathVisitor) obj;
125        return overrideReadOnly == other.overrideReadOnly && Arrays.equals(skip, other.skip);
126    }
127
128    @Override
129    public int hashCode() {
130        final int prime = 31;
131        int result = super.hashCode();
132        result = prime * result + Arrays.hashCode(skip);
133        result = prime * result + Objects.hash(overrideReadOnly);
134        return result;
135    }
136
137    @Override
138    public FileVisitResult postVisitDirectory(final Path dir, final IOException exc) throws IOException {
139        if (PathUtils.isEmptyDirectory(dir)) {
140            Files.deleteIfExists(dir);
141        }
142        return super.postVisitDirectory(dir, exc);
143    }
144
145    @Override
146    public FileVisitResult preVisitDirectory(final Path dir, final BasicFileAttributes attrs) throws IOException {
147        super.preVisitDirectory(dir, attrs);
148        return accept(dir) ? FileVisitResult.CONTINUE : FileVisitResult.SKIP_SUBTREE;
149    }
150
151    @Override
152    public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
153        if (accept(file)) {
154            // delete files and valid links, respecting linkOptions
155            if (Files.exists(file, linkOptions)) {
156                if (overrideReadOnly) {
157                    PathUtils.setReadOnly(file, false, linkOptions);
158                }
159                Files.deleteIfExists(file);
160            }
161            // invalid links will survive previous delete, different approach needed:
162            if (Files.isSymbolicLink(file)) {
163                try {
164                    // deleteIfExists does not work for this case
165                    Files.delete(file);
166                } catch (final NoSuchFileException ignored) {
167                    // ignore
168                }
169            }
170        }
171        updateFileCounters(file, attrs);
172        return FileVisitResult.CONTINUE;
173    }
174}