1. Project Clover database Fri Dec 6 2024 13:47:14 GMT
  2. Package org.stackoverflowusers.file

File WindowsShortcut.java

 

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16
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Classes

Class
Line #
Actions
WindowsShortcut 30 71 22
0.00%
 

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1    package org.stackoverflowusers.file;
2   
3    import java.io.ByteArrayOutputStream;
4    import java.io.File;
5    import java.io.FileInputStream;
6    import java.io.IOException;
7    import java.io.InputStream;
8    import java.text.ParseException;
9    import java.util.Locale;
10   
11    /**
12    * Represents a Windows shortcut (typically visible to Java only as a '.lnk'
13    * file).
14    *
15    * Retrieved 2011-09-23 from
16    * http://stackoverflow.com/questions/309495/windows-shortcut-lnk-parser-in-java/672775#672775
17    * Originally called LnkParser
18    *
19    * Written by: (the stack overflow users, obviously!) Apache Commons VFS
20    * dependency removed by crysxd (why were we using that!?)
21    * https://github.com/crysxd Headerified, refactored and commented by Code Bling
22    * http://stackoverflow.com/users/675721/code-bling Network file support added
23    * by Stefan Cordes http://stackoverflow.com/users/81330/stefan-cordes Adapted
24    * by Sam Brightman http://stackoverflow.com/users/2492/sam-brightman Based on
25    * information in 'The Windows Shortcut File Format' by Jesse Hager
26    * <jessehager@iname.com> And somewhat based on code from the book 'Swing
27    * Hacks: Tips and Tools for Killer GUIs' by Joshua Marinacci and Chris Adamson
28    * ISBN: 0-596-00907-0 http://www.oreilly.com/catalog/swinghks/
29    */
 
30    public class WindowsShortcut
31    {
32    private boolean isDirectory;
33   
34    private boolean isLocal;
35   
36    private String real_file;
37   
38    /**
39    * Provides a quick test to see if this could be a valid link ! If you try to
40    * instantiate a new WindowShortcut and the link is not valid, Exceptions may
41    * be thrown and Exceptions are extremely slow to generate, therefore any code
42    * needing to loop through several files should first check this.
43    *
44    * @param file
45    * the potential link
46    * @return true if may be a link, false otherwise
47    * @throws IOException
48    * if an IOException is thrown while reading from the file
49    */
 
50  0 toggle public static boolean isPotentialValidLink(File file) throws IOException
51    {
52  0 final int minimum_length = 0x64;
53  0 InputStream fis = new FileInputStream(file);
54  0 boolean isPotentiallyValid = false;
55  0 try
56    {
57  0 isPotentiallyValid = file.isFile()
58    && file.getName().toLowerCase(Locale.ROOT).endsWith(".lnk")
59    && fis.available() >= minimum_length
60    && isMagicPresent(getBytes(fis, 32));
61    } finally
62    {
63  0 fis.close();
64    }
65  0 return isPotentiallyValid;
66    }
67   
 
68  0 toggle public WindowsShortcut(File file) throws IOException, ParseException
69    {
70  0 InputStream in = new FileInputStream(file);
71  0 try
72    {
73  0 parseLink(getBytes(in));
74    } finally
75    {
76  0 in.close();
77    }
78    }
79   
80    /**
81    * @return the name of the filesystem object pointed to by this shortcut
82    */
 
83  0 toggle public String getRealFilename()
84    {
85  0 return real_file;
86    }
87   
88    /**
89    * Tests if the shortcut points to a local resource.
90    *
91    * @return true if the 'local' bit is set in this shortcut, false otherwise
92    */
 
93  0 toggle public boolean isLocal()
94    {
95  0 return isLocal;
96    }
97   
98    /**
99    * Tests if the shortcut points to a directory.
100    *
101    * @return true if the 'directory' bit is set in this shortcut, false
102    * otherwise
103    */
 
104  0 toggle public boolean isDirectory()
105    {
106  0 return isDirectory;
107    }
108   
109    /**
110    * Gets all the bytes from an InputStream
111    *
112    * @param in
113    * the InputStream from which to read bytes
114    * @return array of all the bytes contained in 'in'
115    * @throws IOException
116    * if an IOException is encountered while reading the data from the
117    * InputStream
118    */
 
119  0 toggle private static byte[] getBytes(InputStream in) throws IOException
120    {
121  0 return getBytes(in, null);
122    }
123   
124    /**
125    * Gets up to max bytes from an InputStream
126    *
127    * @param in
128    * the InputStream from which to read bytes
129    * @param max
130    * maximum number of bytes to read
131    * @return array of all the bytes contained in 'in'
132    * @throws IOException
133    * if an IOException is encountered while reading the data from the
134    * InputStream
135    */
 
136  0 toggle private static byte[] getBytes(InputStream in, Integer max)
137    throws IOException
138    {
139    // read the entire file into a byte buffer
140  0 ByteArrayOutputStream bout = new ByteArrayOutputStream();
141  0 byte[] buff = new byte[256];
142  0 while (max == null || max > 0)
143    {
144  0 int n = in.read(buff);
145  0 if (n == -1)
146    {
147  0 break;
148    }
149  0 bout.write(buff, 0, n);
150  0 if (max != null)
151  0 max -= n;
152    }
153  0 in.close();
154  0 return bout.toByteArray();
155    }
156   
 
157  0 toggle private static boolean isMagicPresent(byte[] link)
158    {
159  0 final int magic = 0x0000004C;
160  0 final int magic_offset = 0x00;
161  0 return link.length >= 32 && bytesToDword(link, magic_offset) == magic;
162    }
163   
164    /**
165    * Gobbles up link data by parsing it and storing info in member fields
166    *
167    * @param link
168    * all the bytes from the .lnk file
169    */
 
170  0 toggle private void parseLink(byte[] link) throws ParseException
171    {
172  0 try
173    {
174  0 if (!isMagicPresent(link))
175  0 throw new ParseException("Invalid shortcut; magic is missing", 0);
176   
177    // get the flags byte
178  0 byte flags = link[0x14];
179   
180    // get the file attributes byte
181  0 final int file_atts_offset = 0x18;
182  0 byte file_atts = link[file_atts_offset];
183  0 byte is_dir_mask = (byte) 0x10;
184  0 if ((file_atts & is_dir_mask) > 0)
185    {
186  0 isDirectory = true;
187    }
188    else
189    {
190  0 isDirectory = false;
191    }
192   
193    // if the shell settings are present, skip them
194  0 final int shell_offset = 0x4c;
195  0 final byte has_shell_mask = (byte) 0x01;
196  0 int shell_len = 0;
197  0 if ((flags & has_shell_mask) > 0)
198    {
199    // the plus 2 accounts for the length marker itself
200  0 shell_len = bytesToWord(link, shell_offset) + 2;
201    }
202   
203    // get to the file settings
204  0 int file_start = 0x4c + shell_len;
205   
206  0 final int file_location_info_flag_offset_offset = 0x08;
207  0 int file_location_info_flag = link[file_start
208    + file_location_info_flag_offset_offset];
209  0 isLocal = (file_location_info_flag & 2) == 0;
210    // get the local volume and local system values
211    // final int localVolumeTable_offset_offset = 0x0C;
212  0 final int basename_offset_offset = 0x10;
213  0 final int networkVolumeTable_offset_offset = 0x14;
214  0 final int finalname_offset_offset = 0x18;
215  0 int finalname_offset = link[file_start + finalname_offset_offset]
216    + file_start;
217  0 String finalname = getNullDelimitedString(link, finalname_offset);
218  0 if (isLocal)
219    {
220  0 int basename_offset = link[file_start + basename_offset_offset]
221    + file_start;
222  0 String basename = getNullDelimitedString(link, basename_offset);
223  0 real_file = basename + finalname;
224    }
225    else
226    {
227  0 int networkVolumeTable_offset = link[file_start
228    + networkVolumeTable_offset_offset] + file_start;
229  0 int shareName_offset_offset = 0x08;
230  0 int shareName_offset = link[networkVolumeTable_offset
231    + shareName_offset_offset] + networkVolumeTable_offset;
232  0 String shareName = getNullDelimitedString(link, shareName_offset);
233  0 real_file = shareName + "\\" + finalname;
234    }
235    } catch (ArrayIndexOutOfBoundsException e)
236    {
237  0 throw new ParseException(
238    "Could not be parsed, probably not a valid WindowsShortcut",
239    0);
240    }
241    }
242   
 
243  0 toggle private static String getNullDelimitedString(byte[] bytes, int off)
244    {
245  0 int len = 0;
246    // count bytes until the null character (0)
247  0 while (true)
248    {
249  0 if (bytes[off + len] == 0)
250    {
251  0 break;
252    }
253  0 len++;
254    }
255  0 return new String(bytes, off, len);
256    }
257   
258    /*
259    * convert two bytes into a short note, this is little endian because it's
260    * for an Intel only OS.
261    */
 
262  0 toggle private static int bytesToWord(byte[] bytes, int off)
263    {
264  0 return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);
265    }
266   
 
267  0 toggle private static int bytesToDword(byte[] bytes, int off)
268    {
269  0 return (bytesToWord(bytes, off + 2) << 16) | bytesToWord(bytes, off);
270    }
271   
272    }