gradle-master/subprojects/native/src/main/java/org/gradle/internal/nativeintegration/filesystem/jdk7/WindowsJdk7Symlink.java
/*
 * Copyright 2016 the original author or authors.
 *
 * 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 org.gradle.internal.nativeintegration.filesystem.jdk7;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * Represents the Symlink facilities available on JDK 7 or better on Windows.
 * <p>
 * This subclass is used so that we don't accidentally start creating Symlinks
 * on Windows where it is often not safe to assume that a normal user will
 * have permission to use them.
 */
public class WindowsJdk7Symlink extends Jdk7Symlink {

    public WindowsJdk7Symlink() {
        super(false);
    }

    @Override
    public void symlink(File link, File target) throws IOException {
        throw new IOException("Creation of symlinks is not supported on this platform.");
    }

    @Override
    public boolean isSymlink(File suspect) {
        try {
            BasicFileAttributes attrs = Files.readAttributes(suspect.toPath(), BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
            boolean isJunction = attrs.isDirectory() && attrs.isOther();
            // Handles both junctions and real symlinks (https://www.2brightsparks.com/resources/articles/NTFS-Hard-Links-Junctions-and-Symbolic-Links.pdf)
            return isJunction || super.isSymlink(suspect);
        } catch (IOException e) {
            return super.isSymlink(suspect);
        }
    }
}
