1 /*

     2  * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.

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

     4  *

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

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

     7  * published by the Free Software Foundation.  Oracle designates this

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

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

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

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

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

    23  * questions.

    24  */

    25 

    26 package sun.nio.fs;

    27 

    28 import java.nio.file.Path;

    29 import java.io.IOException;

    30 import java.security.AccessController;

    31 import java.security.PrivilegedAction;

    32 

    33 /**

    34  * File type detector that uses the GNOME I/O library to guess the

    35  * MIME type of a file.

    36  */

    37 

    38 public class GioFileTypeDetector

    39     extends AbstractFileTypeDetector

    40 {

    41     // true if GIO is available

    42     private final boolean gioAvailable;

    43 

    44     public GioFileTypeDetector() {

    45         gioAvailable = initializeGio();

    46     }

    47 

    48     @Override

    49     public String implProbeContentType(Path obj) throws IOException {

    50         if (!gioAvailable)

    51             return null;

    52         if (!(obj instanceof UnixPath))

    53             return null;

    54 

    55         UnixPath path = (UnixPath)obj;

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

    57         try {

    58             // GIO may access file so need permission check

    59             path.checkRead();

    60             byte[] type = probeGio(buffer.address());

    61             return (type == null) ? null : Util.toString(type);

    62         } finally {

    63             buffer.release();

    64         }

    65 

    66     }

    67 

    68     // GIO

    69     private static native boolean initializeGio();

    70     //

    71     // The probeGIO() method is synchronized to avert potential problems

    72     // such as crashes due to a suspected lack of thread safety in GIO.

    73     //

    74     private static synchronized native byte[] probeGio(long pathAddress);

    75 

    76     static {

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

    78             public Void run() {

    79                 System.loadLibrary("nio");

    80                 return null;

    81         }});

    82     }

    83 }