/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.nio.fs;

import java.nio.file.*;

import java.io.IOException;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * File type detector that does lookup of file extension using Windows Registry.

 */

public class RegistryFileTypeDetector

    extends AbstractFileTypeDetector

{

    public RegistryFileTypeDetector() {

        super();

    }

    @Override

    public String implProbeContentType(Path file) throws IOException {

        if (!(file instanceof Path))

            return null;

        // get file extension

        Path name = file.getFileName();

        if (name == null)

            return null;

        String filename = name.toString();

        int dot = filename.lastIndexOf('.');

        if ((dot < 0) || (dot == (filename.length()-1)))

            return null;

        // query HKEY_CLASSES_ROOT\<ext>

        String key = filename.substring(dot);

        NativeBuffer keyBuffer = WindowsNativeDispatcher.asNativeBuffer(key);

        NativeBuffer nameBuffer = WindowsNativeDispatcher.asNativeBuffer("Content Type");

        try {

            return queryStringValue(keyBuffer.address(), nameBuffer.address());

        } finally {

            nameBuffer.release();

            keyBuffer.release();

        }

    }

    private static native String queryStringValue(long subKey, long name);

    static {

        AccessController.doPrivileged(new PrivilegedAction<Void>() {

            @Override

            public Void run() {

                // nio.dll has dependency on net.dll

                System.loadLibrary("net");

                System.loadLibrary("nio");

                return null;

        }});

    }

}