com.google.cloud.tools.appengine.cloudsdk.internal.FileUtil.java Source code

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Here is the source code for com.google.cloud.tools.appengine.cloudsdk.internal.FileUtil.java

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/*
 * Copyright 2016 Google Inc.
 *
 * Licensed 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
 *
 *     http://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 com.google.cloud.tools.appengine.cloudsdk.internal;

import com.google.common.base.Preconditions;

import java.io.IOException;
import java.nio.file.CopyOption;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.StandardCopyOption;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * Internal file utilities.
 */
public class FileUtil {

    /**
     * Implementation of recursive directory copy, does NOT overwrite
     *
     * @param source an existing source directory to copy from.
     * @param destination an existing destination directory to copy to.
     */
    public static void copyDirectory(final Path source, final Path destination) throws IOException {
        Preconditions.checkNotNull(source);
        Preconditions.checkNotNull(destination);
        Preconditions.checkArgument(Files.isDirectory(source));
        Preconditions.checkArgument(Files.isDirectory(destination));
        Preconditions.checkArgument(!source.equals(destination));
        Preconditions.checkArgument(!destination.startsWith(source), "destination is child of source");

        Files.walkFileTree(source, new SimpleFileVisitor<Path>() {
            final CopyOption[] copyOptions = new CopyOption[] { StandardCopyOption.COPY_ATTRIBUTES };

            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {

                if (dir.equals(source)) {
                    return FileVisitResult.CONTINUE;
                }

                Files.copy(dir, destination.resolve(source.relativize(dir)), copyOptions);
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {

                Files.copy(file, destination.resolve(source.relativize(file)), copyOptions);
                return FileVisitResult.CONTINUE;
            }
        });

    }

}