org.sonar.process.FileUtils.java Source code

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Here is the source code for org.sonar.process.FileUtils.java

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/*
 * SonarQube
 * Copyright (C) 2009-2016 SonarSource SA
 * mailto:contact AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.process;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileVisitOption;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.EnumSet;
import javax.annotation.Nullable;

import static java.lang.String.format;
import static java.util.Objects.requireNonNull;

/**
 * This utility class provides Java NIO based replacement for some methods of
 * {@link org.apache.commons.io.FileUtils Common IO FileUtils} class.
 */
public final class FileUtils {
    private static final String DIRECTORY_CAN_NOT_BE_NULL = "Directory can not be null";
    private static final EnumSet<FileVisitOption> FOLLOW_LINKS = EnumSet.of(FileVisitOption.FOLLOW_LINKS);

    private FileUtils() {
        // prevents instantiation
    }

    /**
     * Cleans a directory recursively.
     *
     * @param directory  directory to delete
     * @throws IOException in case deletion is unsuccessful
     */
    public static void cleanDirectory(File directory) throws IOException {
        requireNonNull(directory, DIRECTORY_CAN_NOT_BE_NULL);
        if (!directory.exists()) {
            return;
        }

        cleanDirectoryImpl(directory.toPath());
    }

    /**
     * Deletes a file, never throwing an exception. If file is a directory, delete it and all sub-directories.
     * <p>
     * The difference between File.delete() and this method are:
     * <ul>
     * <li>A directory to be deleted does not have to be empty.</li>
     * <li>No exceptions are thrown when a file or directory cannot be deleted.</li>
     * </ul>
     *
     * @param file  file or directory to delete, can be {@code null}
     * @return {@code true} if the file or directory was deleted, otherwise {@code false}
     */
    public static boolean deleteQuietly(@Nullable File file) {
        if (file == null) {
            return false;
        }

        try {
            if (file.isDirectory()) {
                deleteDirectory(file);
            } else {
                Files.delete(file.toPath());
            }
            return true;
        } catch (IOException | SecurityException ignored) {
            return false;
        }
    }

    /**
     * Deletes a directory recursively. Does not support symbolic link to directories.
     *
     * @param directory  directory to delete
     * @throws IOException in case deletion is unsuccessful
     */
    public static void deleteDirectory(File directory) throws IOException {
        requireNonNull(directory, DIRECTORY_CAN_NOT_BE_NULL);

        if (!directory.exists()) {
            return;
        }

        Path path = directory.toPath();
        if (Files.isSymbolicLink(path)) {
            throw new IOException(format("Directory '%s' is a symbolic link", directory));
        }
        if (directory.isFile()) {
            throw new IOException(format("Directory '%s' is a file", directory));
        }
        deleteDirectoryImpl(path);

        if (directory.exists()) {
            throw new IOException(format("Unable to delete directory '%s'", directory));
        }
    }

    private static void cleanDirectoryImpl(Path path) throws IOException {
        if (!path.toFile().isDirectory()) {
            throw new IllegalArgumentException(format("'%s' is not a directory", path));
        }
        Files.walkFileTree(path, FOLLOW_LINKS, CleanDirectoryFileVisitor.VISIT_MAX_DEPTH,
                new CleanDirectoryFileVisitor(path));
    }

    private static void deleteDirectoryImpl(Path path) throws IOException {
        Files.walkFileTree(path, DeleteRecursivelyFileVisitor.INSTANCE);
    }

    /**
     * This visitor is intended to be used to visit direct children of directory <strong>or a symLink to a directory</strong>,
     * so, with a max depth of {@link #VISIT_MAX_DEPTH 1}. Each direct children will either be directly deleted (if file)
     * or recursively deleted (if directory).
     */
    private static class CleanDirectoryFileVisitor extends SimpleFileVisitor<Path> {
        public static final int VISIT_MAX_DEPTH = 1;

        private final Path path;
        private final boolean symLink;

        public CleanDirectoryFileVisitor(Path path) {
            this.path = path;
            this.symLink = Files.isSymbolicLink(path);
        }

        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            if (file.toFile().isDirectory()) {
                deleteDirectoryImpl(file);
            } else if (!symLink || !file.equals(path)) {
                Files.delete(file);
            }
            return FileVisitResult.CONTINUE;
        }

        @Override
        public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
            if (!dir.equals(path)) {
                deleteDirectoryImpl(dir);
            }
            return FileVisitResult.CONTINUE;
        }
    }

    private static final class DeleteRecursivelyFileVisitor extends SimpleFileVisitor<Path> {
        public static final DeleteRecursivelyFileVisitor INSTANCE = new DeleteRecursivelyFileVisitor();

        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            Files.delete(file);
            return FileVisitResult.CONTINUE;
        }

        @Override
        public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
            Files.delete(dir);
            return FileVisitResult.CONTINUE;
        }
    }
}