/*

 * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.

 * 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.Path;

import java.io.IOException;

import java.security.AccessController;

import java.security.PrivilegedAction;

/**

 * File type detector that uses the GNOME I/O library or the deprecated

 * GNOME VFS to guess the MIME type of a file.

 */

public class GnomeFileTypeDetector

    extends AbstractFileTypeDetector

{

    private static final String GNOME_VFS_MIME_TYPE_UNKNOWN =

        "application/octet-stream";

    // true if GIO available

    private final boolean gioAvailable;

    // true if GNOME VFS available and GIO is not available

    private final boolean gnomeVfsAvailable;

    public GnomeFileTypeDetector() {

        gioAvailable = initializeGio();

        if (gioAvailable) {

            gnomeVfsAvailable = false;

        } else {

            gnomeVfsAvailable = initializeGnomeVfs();

        }

    }

    @Override

    public String implProbeContentType(Path obj) throws IOException {

        if (!gioAvailable && !gnomeVfsAvailable)

            return null;

        if (!(obj instanceof UnixPath))

            return null;

        UnixPath path = (UnixPath)obj;

        NativeBuffer buffer = NativeBuffers.asNativeBuffer(path.getByteArrayForSysCalls());

        try {

            if (gioAvailable) {

                // GIO may access file so need permission check

                path.checkRead();

                byte[] type = probeUsingGio(buffer.address());

            } else {

                byte[] type = probeUsingGnomeVfs(buffer.address());

                if (type == null)

                    return null;

                return s.equals(GNOME_VFS_MIME_TYPE_UNKNOWN) ? null : s;

            }

        } finally {

            buffer.release();

        }

    }

    // GIO

    private static native boolean initializeGio();

    private static native byte[] probeUsingGio(long pathAddress);

    // GNOME VFS

    private static native boolean initializeGnomeVfs();

    private static native byte[] probeUsingGnomeVfs(long pathAddress);

    static {

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

            public Void run() {

                System.loadLibrary("nio");

                return null;

        }});

    }

}