DeletingPathVisitor.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
*
* https://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.commons.io.file;
import java.io.IOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Arrays;
import java.util.Objects;
import org.apache.commons.io.file.Counters.PathCounters;
/**
* Deletes files and directories as a visit proceeds.
*
* <p>
* Read-only overrides use {@link LinkOption#NOFOLLOW_LINKS}, independently of the constructor's link options, so DOS attribute changes apply to the
* link itself instead of its target. On POSIX file systems, the parent directory may be made writable and searchable to allow deletion.
* The caller controls whether the file tree walk follows symbolic links.
* </p>
*
* <p>
* Directory reparse points reported as {@link BasicFileAttributes#isOther()} are deleted without visiting their contents. Checks and deletion are
* not atomic, so this visitor does not guarantee confinement when directories or path components can be replaced concurrently.
* </p>
*
* @since 2.7
*/
public class DeletingPathVisitor extends CountingPathVisitor {
/**
* Constructs a new instance configured with a BigInteger {@link PathCounters}.
*
* @return A new instance configured with a BigInteger {@link PathCounters}.
*/
public static DeletingPathVisitor withBigIntegerCounters() {
return new DeletingPathVisitor(Counters.bigIntegerPathCounters());
}
/**
* Constructs a new instance configured with a long {@link PathCounters}.
*
* @return A new instance configured with a long {@link PathCounters}.
*/
public static DeletingPathVisitor withLongCounters() {
return new DeletingPathVisitor(Counters.longPathCounters());
}
private final String[] skip;
private final boolean overrideReadOnly;
private final LinkOption[] linkOptions;
/**
* Constructs a instance that deletes files except for the files and directories explicitly given.
*
* @param pathCounter How to count visits.
* @param deleteOption How deletion is handled.
* @param skip The files to skip deleting.
* @since 2.8.0
*/
public DeletingPathVisitor(final PathCounters pathCounter, final DeleteOption[] deleteOption, final String... skip) {
this(pathCounter, PathUtils.noFollowLinkOptionArray(), deleteOption, skip);
}
/**
* Constructs a instance that deletes files except for the files and directories explicitly given.
*
* @param pathCounter How to count visits.
* @param linkOptions How symbolic links are handled.
* @param deleteOption How deletion is handled.
* @param skip The files to skip deleting.
* @since 2.9.0
*/
public DeletingPathVisitor(final PathCounters pathCounter, final LinkOption[] linkOptions, final DeleteOption[] deleteOption, final String... skip) {
super(pathCounter);
final String[] temp = skip != null ? skip.clone() : EMPTY_STRING_ARRAY;
Arrays.sort(temp);
this.skip = temp;
this.overrideReadOnly = StandardDeleteOption.overrideReadOnly(deleteOption);
// TODO Files.deleteIfExists() never follows links, so use LinkOption.NOFOLLOW_LINKS in other calls to Files.
this.linkOptions = linkOptions == null ? PathUtils.noFollowLinkOptionArray() : linkOptions.clone();
}
/**
* Constructs a instance that deletes files except for the files and directories explicitly given.
*
* @param pathCounter How to count visits.
* @param skip The files to skip deleting.
*/
public DeletingPathVisitor(final PathCounters pathCounter, final String... skip) {
this(pathCounter, PathUtils.EMPTY_DELETE_OPTION_ARRAY, skip);
}
/**
* Returns true to process the given path, false if not.
*
* @param path The path to test.
* @return true to process the given path, false if not.
*/
private boolean accept(final Path path) {
return Arrays.binarySearch(skip, PathUtils.getFileNameString(path)) < 0;
}
@Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (!super.equals(obj)) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final DeletingPathVisitor other = (DeletingPathVisitor) obj;
return overrideReadOnly == other.overrideReadOnly && Arrays.equals(skip, other.skip);
}
@Override
public int hashCode() {
final int prime = 31;
int result = super.hashCode();
result = prime * result + Arrays.hashCode(skip);
result = prime * result + Objects.hash(overrideReadOnly);
return result;
}
@Override
public FileVisitResult postVisitDirectory(final Path dir, final IOException exc) throws IOException {
if (PathUtils.isEmptyDirectory(dir)) {
Files.deleteIfExists(dir);
}
return super.postVisitDirectory(dir, exc);
}
@Override
public FileVisitResult preVisitDirectory(final Path dir, final BasicFileAttributes attrs) throws IOException {
super.preVisitDirectory(dir, attrs);
if (!accept(dir)) {
return FileVisitResult.SKIP_SUBTREE;
}
if (attrs.isOther()) {
// Windows junctions are directories as well as other file system objects, even without FOLLOW_LINKS.
Files.delete(dir);
updateDirCounter(dir, null);
return FileVisitResult.SKIP_SUBTREE;
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
if (accept(file)) {
// Include dangling links so their parent permissions can also be overridden.
if (Files.exists(file, linkOptions) || Files.isSymbolicLink(file)) {
// An absolute path supplies the parent needed by the POSIX permission override.
PathUtils.withReadOnlyOverride(overrideReadOnly ? file.toAbsolutePath() : file, PathUtils.noFollowLinkOptionArray(), overrideReadOnly,
() -> Files.deleteIfExists(file));
}
// invalid links will survive previous delete, different approach needed:
if (Files.isSymbolicLink(file)) {
try {
// deleteIfExists does not work for this case
Files.delete(file);
} catch (final NoSuchFileException ignored) {
// ignore
}
}
}
updateFileCounters(file, attrs);
return FileVisitResult.CONTINUE;
}
}