1 /*
   2  * Copyright (c) 2008, 2009, 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 or the deprecated
  35  * GNOME VFS to guess the MIME type of a file.
  36  */
  37 
  38 public class GnomeFileTypeDetector
  39     extends AbstractFileTypeDetector
  40 {
  41     private static final String GNOME_VFS_MIME_TYPE_UNKNOWN =
  42         "application/octet-stream";
  43 
  44     // true if GIO available
  45     private final boolean gioAvailable;
  46 
  47     // true if GNOME VFS available and GIO is not available
  48     private final boolean gnomeVfsAvailable;
  49 
  50     public GnomeFileTypeDetector() {
  51         gioAvailable = initializeGio();
  52         if (gioAvailable) {
  53             gnomeVfsAvailable = false;
  54         } else {
  55             gnomeVfsAvailable = initializeGnomeVfs();
  56         }
  57     }
  58 
  59     @Override
  60     public String implProbeContentType(Path obj) throws IOException {
  61         if (!gioAvailable && !gnomeVfsAvailable)
  62             return null;
  63         if (!(obj instanceof UnixPath))
  64             return null;
  65 
  66         UnixPath path = (UnixPath)obj;
  67         NativeBuffer buffer = NativeBuffers.asNativeBuffer(path.getByteArrayForSysCalls());
  68         try {
  69             if (gioAvailable) {
  70                 byte[] type = probeUsingGio(buffer.address());
  71                 return (type == null) ? null : new String(type);
  72             } else {
  73                 byte[] type = probeUsingGnomeVfs(buffer.address());
  74                 if (type == null)
  75                     return null;
  76                 String s = new String(type);
  77                 return s.equals(GNOME_VFS_MIME_TYPE_UNKNOWN) ? null : s;
  78             }
  79 
  80         } finally {
  81             buffer.release();
  82         }
  83 
  84     }
  85 
  86     // GIO
  87     private static native boolean initializeGio();
  88     private static native byte[] probeUsingGio(long pathAddress);
  89 
  90     // GNOME VFS
  91     private static native boolean initializeGnomeVfs();
  92     private static native byte[] probeUsingGnomeVfs(long pathAddress);
  93 
  94     static {
  95         AccessController.doPrivileged(new PrivilegedAction<Void>() {
  96             public Void run() {
  97                 System.loadLibrary("nio");
  98                 return null;
  99         }});
 100     }
 101 }