Kernel32Utils.java

/*
 * The MIT License
 *
 * Copyright (c) 2010, CloudBees, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package hudson.util.jna;

import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.WString;
import com.sun.jna.ptr.IntByReference;

import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author Kohsuke Kawaguchi
 */
public class Kernel32Utils
{
    //~ Static fields/initializers ---------------------------------------------

    private static final Logger LOGGER = Logger.getLogger(
            Kernel32Utils.class.getName());

    //~ Methods ----------------------------------------------------------------
    /**
     * @param target
     *               If relative, resolved against the location of the symlink.
     *               If absolute, it's absolute.
     */
    public static void createSymbolicLink (File symlink,
                                           String target,
                                           boolean dirLink)
            throws IOException
    {
        if (!Kernel32.INSTANCE.CreateSymbolicLinkW(
                new WString(symlink.getPath()),
                new WString(target),
                dirLink ? Kernel32.SYMBOLIC_LINK_FLAG_DIRECTORY : 0)) {
            throw new WinIOException(
                    "Failed to create a symlink " + symlink + " to " + target);
        }
    }

    public static int getWin32FileAttributes (File file)
            throws IOException
    {
        // allow lookup of paths longer than MAX_PATH
        // http://msdn.microsoft.com/en-us/library/aa365247(v=VS.85).aspx
        String canonicalPath = file.getCanonicalPath();
        String path;

        if (canonicalPath.length() < 260) {
            // path is short, use as-is
            path = canonicalPath;
        } else if (canonicalPath.startsWith("\\\\")) {
            // network share
            // \\server\share --> \\?\UNC\server\share
            path = "\\\\?\\UNC\\" + canonicalPath.substring(2);
        } else {
            // prefix, canonical path should be normalized and absolute so this should work.
            path = "\\\\?\\" + canonicalPath;
        }

        return Kernel32.INSTANCE.GetFileAttributesW(new WString(path));
    }

    public static boolean isJunctionOrSymlink (File file)
            throws IOException
    {
        return (file.exists()
                && ((Kernel32.FILE_ATTRIBUTE_REPARSE_POINT
                     & getWin32FileAttributes(file)) != 0));
    }

    /**
     * Given the process handle, waits for its completion and returns the exit
     * code.
     */
    public static int waitForExitProcess (Pointer hProcess)
            throws InterruptedException
    {
        while (true) {
            if (Thread.interrupted()) {
                throw new InterruptedException();
            }

            Kernel32.INSTANCE.WaitForSingleObject(hProcess, 1000);

            IntByReference exitCode = new IntByReference();
            exitCode.setValue(-1);
            Kernel32.INSTANCE.GetExitCodeProcess(hProcess, exitCode);

            int v = exitCode.getValue();

            if (v != Kernel32.STILL_ACTIVE) {
                return v;
            }
        }
    }

    /* package */ static Kernel32 load ()
    {
        try {
            return (Kernel32) Native.loadLibrary("kernel32", Kernel32.class);
        } catch (Throwable e) {
            LOGGER.log(Level.SEVERE, "Failed to load Kernel32", e);

            return InitializationErrorInvocationHandler.create(
                    Kernel32.class,
                    e);
        }
    }
}