package com.wilutions.fx.util;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
/**
* Represents a Windows shortcut (typically visible to Java only as a '.lnk' file).
*
* Retrieved 2011-09-23 from http://stackoverflow.com/questions/309495/windows-shortcut-lnk-parser-in-java/672775#672775
* Originally called LnkParser
*
* Written by: (the stack overflow users, obviously!)
* Apache Commons VFS dependency removed by crysxd (why were we using that!?) https://github.com/crysxd
* Headerified, refactored and commented by Code Bling http://stackoverflow.com/users/675721/code-bling
* Network file support added by Stefan Cordes http://stackoverflow.com/users/81330/stefan-cordes
* Adapted by Sam Brightman http://stackoverflow.com/users/2492/sam-brightman
* Based on information in 'The Windows Shortcut File Format' by Jesse Hager <jessehager@iname.com>
* And somewhat based on code from the book 'Swing Hacks: Tips and Tools for Killer GUIs'
* by Joshua Marinacci and Chris Adamson
* ISBN: 0-596-00907-0
* http://www.oreilly.com/catalog/swinghks/
*/
public class WindowsShortcut
{
private boolean isDirectory;
private boolean isLocal;
private String real_file;
/**
* Provides a quick test to see if this could be a valid link !
* If you try to instantiate a new WindowShortcut and the link is not valid,
* Exceptions may be thrown and Exceptions are extremely slow to generate,
* therefore any code needing to loop through several files should first check this.
*
* @param file the potential link
* @return true if may be a link, false otherwise
* @throws IOException if an IOException is thrown while reading from the file
*/
public static boolean isPotentialValidLink(File file) throws IOException {
final int minimum_length = 0x64;
InputStream fis = new FileInputStream(file);
boolean isPotentiallyValid = false;
try {
isPotentiallyValid = file.isFile()
&& file.getName().toLowerCase().endsWith(".lnk")
&& fis.available() >= minimum_length
&& isMagicPresent(getBytes(fis, 32));
} finally {
fis.close();
}
return isPotentiallyValid;
}
public WindowsShortcut(File file) throws IOException, ParseException {
InputStream in = new FileInputStream(file);
try {
parseLink(getBytes(in));
} finally {
in.close();
}
}
/**
* @return the name of the filesystem object pointed to by this shortcut
*/
public String getRealFilename() {
return real_file;
}
/**
* Tests if the shortcut points to a local resource.
* @return true if the 'local' bit is set in this shortcut, false otherwise
*/
public boolean isLocal() {
return isLocal;
}
/**
* Tests if the shortcut points to a directory.
* @return true if the 'directory' bit is set in this shortcut, false otherwise
*/
public boolean isDirectory() {
return isDirectory;
}
/**
* Gets all the bytes from an InputStream
* @param in the InputStream from which to read bytes
* @return array of all the bytes contained in 'in'
* @throws IOException if an IOException is encountered while reading the data from the InputStream
*/
private static byte[] getBytes(InputStream in) throws IOException {
return getBytes(in, null);
}
/**
* Gets up to max bytes from an InputStream
* @param in the InputStream from which to read bytes
* @param max maximum number of bytes to read
* @return array of all the bytes contained in 'in'
* @throws IOException if an IOException is encountered while reading the data from the InputStream
*/
private static byte[] getBytes(InputStream in, Integer max) throws IOException {
// read the entire file into a byte buffer
ByteArrayOutputStream bout = new ByteArrayOutputStream();
byte[] buff = new byte[256];
while (max == null || max > 0) {
int n = in.read(buff);
if (n == -1) {
break;
}
bout.write(buff, 0, n);
if (max != null)
max -= n;
}
in.close();
return bout.toByteArray();
}
private static boolean isMagicPresent(byte[] link) {
final int magic = 0x0000004C;
final int magic_offset = 0x00;
return link.length >= 32 && bytesToDword(link, magic_offset) == magic;
}
/**
* Gobbles up link data by parsing it and storing info in member fields
* @param link all the bytes from the .lnk file
*/
private void parseLink(byte[] link) throws ParseException {
try {
if (!isMagicPresent(link))
throw new ParseException("Invalid shortcut; magic is missing", 0);
// get the flags byte
byte flags = link[0x14];
// get the file attributes byte
final int file_atts_offset = 0x18;
byte file_atts = link[file_atts_offset];
byte is_dir_mask = (byte)0x10;
if ((file_atts & is_dir_mask) > 0) {
isDirectory = true;
} else {
isDirectory = false;
}
// if the shell settings are present, skip them
final int shell_offset = 0x4c;
final byte has_shell_mask = (byte)0x01;
int shell_len = 0;
if ((flags & has_shell_mask) > 0) {
// the plus 2 accounts for the length marker itself
shell_len = bytesToWord(link, shell_offset) + 2;
}
// get to the file settings
int file_start = 0x4c + shell_len;
final int file_location_info_flag_offset_offset = 0x08;
int file_location_info_flag = link[file_start + file_location_info_flag_offset_offset];
isLocal = (file_location_info_flag & 2) == 0;
// get the local volume and local system values
//final int localVolumeTable_offset_offset = 0x0C;
final int basename_offset_offset = 0x10;
final int networkVolumeTable_offset_offset = 0x14;
final int finalname_offset_offset = 0x18;
int finalname_offset = link[file_start + finalname_offset_offset] + file_start;
String finalname = getNullDelimitedString(link, finalname_offset);
if (isLocal) {
int basename_offset = link[file_start + basename_offset_offset] + file_start;
String basename = getNullDelimitedString(link, basename_offset);
real_file = basename + finalname;
} else {
int networkVolumeTable_offset = link[file_start + networkVolumeTable_offset_offset] + file_start;
int shareName_offset_offset = 0x08;
int shareName_offset = link[networkVolumeTable_offset + shareName_offset_offset]
+ networkVolumeTable_offset;
String shareName = getNullDelimitedString(link, shareName_offset);
real_file = shareName + "\\" + finalname;
}
} catch (ArrayIndexOutOfBoundsException e) {
throw new ParseException("Could not be parsed, probably not a valid WindowsShortcut", 0);
}
}
private static String getNullDelimitedString(byte[] bytes, int off) {
int len = 0;
// count bytes until the null character (0)
while (true) {
if (bytes[off + len] == 0) {
break;
}
len++;
}
return new String(bytes, off, len);
}
/*
* convert two bytes into a short note, this is little endian because it's
* for an Intel only OS.
*/
private static int bytesToWord(byte[] bytes, int off) {
return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);
}
private static int bytesToDword(byte[] bytes, int off) {
return (bytesToWord(bytes, off + 2) << 16) | bytesToWord(bytes, off);
}
}