1 /*
   2  * Copyright (c) 2008, 2011, 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.*;
  29 import java.io.IOException;
  30 import java.security.AccessController;
  31 import java.security.PrivilegedAction;
  32 
  33 /**
  34  * File type detector that does lookup of file extension using Windows Registry.
  35  */
  36 
  37 public class RegistryFileTypeDetector
  38     extends AbstractFileTypeDetector
  39 {
  40     public RegistryFileTypeDetector() {
  41         super();
  42     }
  43 
  44     @Override
  45     public String implProbeContentType(Path file) throws IOException {
  46         if (!(file instanceof Path))
  47             return null;
  48 
  49         // get file extension
  50         Path name = file.getFileName();
  51         if (name == null)
  52             return null;
  53         String filename = name.toString();
  54         int dot = filename.lastIndexOf('.');
  55         if ((dot < 0) || (dot == (filename.length()-1)))
  56             return null;
  57 
  58         // query HKEY_CLASSES_ROOT\<ext>
  59         String key = filename.substring(dot);
  60         NativeBuffer keyBuffer = WindowsNativeDispatcher.asNativeBuffer(key);
  61         NativeBuffer nameBuffer = WindowsNativeDispatcher.asNativeBuffer("Content Type");
  62         try {
  63             return queryStringValue(keyBuffer.address(), nameBuffer.address());
  64         } finally {
  65             nameBuffer.release();
  66             keyBuffer.release();
  67         }
  68     }
  69 
  70     private static native String queryStringValue(long subKey, long name);
  71 
  72     static {
  73         AccessController.doPrivileged(new PrivilegedAction<Void>() {
  74             @Override
  75             public Void run() {
  76                 // nio.dll has dependency on net.dll
  77                 System.loadLibrary("net");
  78                 System.loadLibrary("nio");
  79                 return null;
  80         }});
  81     }
  82 }