1 /*
   2  * Copyright (c) 2008, 2019, 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 
  31 /**
  32  * File type detector that does lookup of file extension using Windows Registry.
  33  */
  34 
  35 public class RegistryFileTypeDetector
  36     extends AbstractFileTypeDetector
  37 {
  38     public RegistryFileTypeDetector() {
  39         super();
  40     }
  41 
  42     @Override
  43     public String implProbeContentType(Path file) throws IOException {
  44         if (!(file instanceof Path))
  45             return null;
  46 
  47         // get file extension
  48         Path name = file.getFileName();
  49         if (name == null)
  50             return null;
  51         String filename = name.toString();
  52         int dot = filename.lastIndexOf('.');
  53         if ((dot < 0) || (dot == (filename.length()-1)))
  54             return null;
  55 
  56         // query HKEY_CLASSES_ROOT\<ext>
  57         String key = filename.substring(dot);
  58         NativeBuffer keyBuffer = WindowsNativeDispatcher.asNativeBuffer(key);
  59         NativeBuffer nameBuffer = WindowsNativeDispatcher.asNativeBuffer("Content Type");
  60         try {
  61             return queryStringValue(keyBuffer.address(), nameBuffer.address());
  62         } finally {
  63             nameBuffer.release();
  64             keyBuffer.release();
  65         }
  66     }
  67 
  68     private static native String queryStringValue(long subKey, long name);
  69 
  70     static {
  71         // nio.dll has dependency on net.dll
  72         jdk.internal.loader.BootLoader.loadLibrary("net");
  73         jdk.internal.loader.BootLoader.loadLibrary("nio");
  74     }
  75 }