1 /*

     2  * Copyright (c) 2012, 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.io.IOException;

    29 import java.nio.file.Path;

    30 import java.security.AccessController;

    31 import java.security.PrivilegedAction;

    32 

    33 /**

    34  * File type detector that uses the libmagic to guess the MIME type of a file.

    35  */

    36 

    37 class MagicFileTypeDetector extends AbstractFileTypeDetector {

    38 

    39     private static final String UNKNOWN_MIME_TYPE = "application/octet-stream";

    40 

    41     // true if libmagic is available and successfully loaded

    42     private final boolean libmagicAvailable;

    43 

    44     public MagicFileTypeDetector() {

    45         libmagicAvailable = initialize0();

    46     }

    47 

    48     @Override

    49     protected String implProbeContentType(Path obj) throws IOException {

    50         if (!libmagicAvailable || !(obj instanceof UnixPath))

    51             return null;

    52 

    53         UnixPath path = (UnixPath) obj;

    54         path.checkRead();

    55 

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

    57         try {

    58             byte[] type = probe0(buffer.address());

    59             String mimeType = (type == null) ? null : new String(type);

    60             return UNKNOWN_MIME_TYPE.equals(mimeType) ? null : mimeType;

    61         } finally {

    62             buffer.release();

    63         }

    64     }

    65 

    66     private static native boolean initialize0();

    67 

    68     private static native byte[] probe0(long pathAddress);

    69 

    70     static {

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

    72             @Override

    73             public Void run() {

    74                 System.loadLibrary("nio");

    75                 return null;

    76             }

    77         });

    78     }

    79 }