1 package org.stackoverflowusers.file;
3 import java.io.ByteArrayOutputStream;
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;
12 * Represents a Windows shortcut (typically visible to Java only as a '.lnk' file).
14 * Retrieved 2011-09-23 from http://stackoverflow.com/questions/309495/windows-shortcut-lnk-parser-in-java/672775#672775
15 * Originally called LnkParser
17 * Written by: (the stack overflow users, obviously!)
18 * Apache Commons VFS dependency removed by crysxd (why were we using that!?) https://github.com/crysxd
19 * Headerified, refactored and commented by Code Bling http://stackoverflow.com/users/675721/code-bling
20 * Network file support added by Stefan Cordes http://stackoverflow.com/users/81330/stefan-cordes
21 * Adapted by Sam Brightman http://stackoverflow.com/users/2492/sam-brightman
22 * Based on information in 'The Windows Shortcut File Format' by Jesse Hager <jessehager@iname.com>
23 * And somewhat based on code from the book 'Swing Hacks: Tips and Tools for Killer GUIs'
24 * by Joshua Marinacci and Chris Adamson
26 * http://www.oreilly.com/catalog/swinghks/
28 public class WindowsShortcut
30 private boolean isDirectory;
31 private boolean isLocal;
32 private String real_file;
35 * Provides a quick test to see if this could be a valid link !
36 * If you try to instantiate a new WindowShortcut and the link is not valid,
37 * Exceptions may be thrown and Exceptions are extremely slow to generate,
38 * therefore any code needing to loop through several files should first check this.
40 * @param file the potential link
41 * @return true if may be a link, false otherwise
42 * @throws IOException if an IOException is thrown while reading from the file
44 public static boolean isPotentialValidLink(File file) throws IOException {
45 final int minimum_length = 0x64;
46 InputStream fis = new FileInputStream(file);
47 boolean isPotentiallyValid = false;
49 isPotentiallyValid = file.isFile()
50 && file.getName().toLowerCase(Locale.ROOT).endsWith(".lnk")
51 && fis.available() >= minimum_length
52 && isMagicPresent(getBytes(fis, 32));
56 return isPotentiallyValid;
59 public WindowsShortcut(File file) throws IOException, ParseException {
60 InputStream in = new FileInputStream(file);
62 parseLink(getBytes(in));
69 * @return the name of the filesystem object pointed to by this shortcut
71 public String getRealFilename() {
76 * Tests if the shortcut points to a local resource.
77 * @return true if the 'local' bit is set in this shortcut, false otherwise
79 public boolean isLocal() {
84 * Tests if the shortcut points to a directory.
85 * @return true if the 'directory' bit is set in this shortcut, false otherwise
87 public boolean isDirectory() {
92 * Gets all the bytes from an InputStream
93 * @param in the InputStream from which to read bytes
94 * @return array of all the bytes contained in 'in'
95 * @throws IOException if an IOException is encountered while reading the data from the InputStream
97 private static byte[] getBytes(InputStream in) throws IOException {
98 return getBytes(in, null);
102 * Gets up to max bytes from an InputStream
103 * @param in the InputStream from which to read bytes
104 * @param max maximum number of bytes to read
105 * @return array of all the bytes contained in 'in'
106 * @throws IOException if an IOException is encountered while reading the data from the InputStream
108 private static byte[] getBytes(InputStream in, Integer max) throws IOException {
109 // read the entire file into a byte buffer
110 ByteArrayOutputStream bout = new ByteArrayOutputStream();
111 byte[] buff = new byte[256];
112 while (max == null || max > 0) {
113 int n = in.read(buff);
117 bout.write(buff, 0, n);
122 return bout.toByteArray();
125 private static boolean isMagicPresent(byte[] link) {
126 final int magic = 0x0000004C;
127 final int magic_offset = 0x00;
128 return link.length >= 32 && bytesToDword(link, magic_offset) == magic;
132 * Gobbles up link data by parsing it and storing info in member fields
133 * @param link all the bytes from the .lnk file
135 private void parseLink(byte[] link) throws ParseException {
137 if (!isMagicPresent(link))
138 throw new ParseException("Invalid shortcut; magic is missing", 0);
140 // get the flags byte
141 byte flags = link[0x14];
143 // get the file attributes byte
144 final int file_atts_offset = 0x18;
145 byte file_atts = link[file_atts_offset];
146 byte is_dir_mask = (byte)0x10;
147 if ((file_atts & is_dir_mask) > 0) {
153 // if the shell settings are present, skip them
154 final int shell_offset = 0x4c;
155 final byte has_shell_mask = (byte)0x01;
157 if ((flags & has_shell_mask) > 0) {
158 // the plus 2 accounts for the length marker itself
159 shell_len = bytesToWord(link, shell_offset) + 2;
162 // get to the file settings
163 int file_start = 0x4c + shell_len;
165 final int file_location_info_flag_offset_offset = 0x08;
166 int file_location_info_flag = link[file_start + file_location_info_flag_offset_offset];
167 isLocal = (file_location_info_flag & 2) == 0;
168 // get the local volume and local system values
169 //final int localVolumeTable_offset_offset = 0x0C;
170 final int basename_offset_offset = 0x10;
171 final int networkVolumeTable_offset_offset = 0x14;
172 final int finalname_offset_offset = 0x18;
173 int finalname_offset = link[file_start + finalname_offset_offset] + file_start;
174 String finalname = getNullDelimitedString(link, finalname_offset);
176 int basename_offset = link[file_start + basename_offset_offset] + file_start;
177 String basename = getNullDelimitedString(link, basename_offset);
178 real_file = basename + finalname;
180 int networkVolumeTable_offset = link[file_start + networkVolumeTable_offset_offset] + file_start;
181 int shareName_offset_offset = 0x08;
182 int shareName_offset = link[networkVolumeTable_offset + shareName_offset_offset]
183 + networkVolumeTable_offset;
184 String shareName = getNullDelimitedString(link, shareName_offset);
185 real_file = shareName + "\\" + finalname;
187 } catch (ArrayIndexOutOfBoundsException e) {
188 throw new ParseException("Could not be parsed, probably not a valid WindowsShortcut", 0);
192 private static String getNullDelimitedString(byte[] bytes, int off) {
194 // count bytes until the null character (0)
196 if (bytes[off + len] == 0) {
201 return new String(bytes, off, len);
205 * convert two bytes into a short note, this is little endian because it's
206 * for an Intel only OS.
208 private static int bytesToWord(byte[] bytes, int off) {
209 return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);
212 private static int bytesToDword(byte[] bytes, int off) {
213 return (bytesToWord(bytes, off + 2) << 16) | bytesToWord(bytes, off);