Win32Lnk.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.io;
import java.io.*;
import java.util.Arrays;
/**
* A {@code File} implementation that resolves the Windows {@code .lnk} files as symbolic links.
* <p>
* This class is based on example code from
* <a href="http://www.oreilly.com/catalog/swinghks/index.html">Swing Hacks</a>,
* By Joshua Marinacci, Chris Adamson (O'Reilly, ISBN: 0-596-00907-0), Hack 30.
* </p>
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/io/Win32Lnk.java#2 $
*/
final class Win32Lnk extends File {
private final static byte[] LNK_MAGIC = {
'L', 0x00, 0x00, 0x00, // Magic
};
private final static byte[] LNK_GUID = {
0x01, 0x14, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, // Shell Link GUID
(byte) 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 'F'
};
private final File target;
private static final int FLAG_ITEM_ID_LIST = 0x01;
private static final int FLAG_FILE_LOC_INFO = 0x02;
private static final int FLAG_DESC_STRING = 0x04;
private static final int FLAG_REL_PATH_STRING = 0x08;
private static final int FLAG_WORKING_DIRECTORY = 0x10;
private static final int FLAG_COMMAND_LINE_ARGS = 0x20;
private static final int FLAG_ICON_FILENAME = 0x40;
private static final int FLAG_ADDITIONAL_INFO = 0x80;
private Win32Lnk(final String pPath) throws IOException {
super(pPath);
File target = parse(this);
if (target == this) {
// NOTE: This is a workaround
// target = this causes infinite loops in some methods
target = new File(pPath);
}
this.target = target;
}
Win32Lnk(final File pPath) throws IOException {
this(pPath.getPath());
}
/**
* Parses a {@code .lnk} file to find the real file.
*
* @param pPath the path to the {@code .lnk} file
* @return a new file object that
* @throws java.io.IOException if the {@code .lnk} cannot be parsed
*/
static File parse(final File pPath) throws IOException {
if (!pPath.getName().endsWith(".lnk")) {
return pPath;
}
File result = pPath;
LittleEndianDataInputStream in = new LittleEndianDataInputStream(new BufferedInputStream(new FileInputStream(pPath)));
try {
byte[] magic = new byte[4];
in.readFully(magic);
byte[] guid = new byte[16];
in.readFully(guid);
if (!(Arrays.equals(LNK_MAGIC, magic) && Arrays.equals(LNK_GUID, guid))) {
//System.out.println("Not a symlink");
// Not a symlink
return pPath;
}
// Get the flags
int flags = in.readInt();
//System.out.println("flags: " + Integer.toBinaryString(flags & 0xff));
// Get to the file settings
/*int attributes = */in.readInt();
// File attributes
// 0 Target is read only.
// 1 Target is hidden.
// 2 Target is a system file.
// 3 Target is a volume label. (Not possible)
// 4 Target is a directory.
// 5 Target has been modified since last backup. (archive)
// 6 Target is encrypted (NTFS EFS)
// 7 Target is Normal??
// 8 Target is temporary.
// 9 Target is a sparse file.
// 10 Target has reparse point data.
// 11 Target is compressed.
// 12 Target is offline.
//System.out.println("attributes: " + Integer.toBinaryString(attributes));
// NOTE: Cygwin .lnks are not directory links, can't rely on this.. :-/
in.skipBytes(48); // TODO: Make sense of this data...
// Skipped data:
// long time 1 (creation)
// long time 2 (modification)
// long time 3 (last access)
// int file length
// int icon number
// int ShowVnd value
// int hotkey
// int, int - unknown: 0,0
// If the shell settings are present, skip them
if ((flags & FLAG_ITEM_ID_LIST) != 0) {
// Shell Item Id List present
//System.out.println("Shell Item Id List present");
int shellLen = in.readShort(); // Short
//System.out.println("shellLen: " + shellLen);
// TODO: Probably need to parse this data, to determine
// Cygwin folders...
/*
int read = 2;
int itemLen = in.readShort();
while (itemLen > 0) {
System.out.println("--> ITEM: " + itemLen);
BufferedReader reader = new BufferedReader(new InputStreamReader(new SubStream(in, itemLen - 2)));
//byte[] itemBytes = new byte[itemLen - 2]; // NOTE: Lenght included
//in.readFully(itemBytes);
String item = reader.readLine();
System.out.println("item: \"" + item + "\"");
itemLen = in.readShort();
read += itemLen;
}
System.out.println("read: " + read);
*/
in.skipBytes(shellLen);
}
if ((flags & FLAG_FILE_LOC_INFO) != 0) {
// File Location Info Table present
//System.out.println("File Location Info Table present");
// 0h 1 dword This is the total length of this structure and all following data
// 4h 1 dword This is a pointer to first offset after this structure. 1Ch
// 8h 1 dword Flags
// Ch 1 dword Offset of local volume info
// 10h 1 dword Offset of base pathname on local system
// 14h 1 dword Offset of network volume info
// 18h 1 dword Offset of remaining pathname
// Flags:
// Bit Meaning
// 0 Available on a local volume
// 1 Available on a network share
// TODO: Make sure the path is on a local disk, etc..
int tableLen = in.readInt(); // Int
//System.out.println("tableLen: " + tableLen);
in.readInt(); // Skip
int locFlags = in.readInt();
//System.out.println("locFlags: " + Integer.toBinaryString(locFlags));
if ((locFlags & 0x01) != 0) {
//System.out.println("Available local");
}
if ((locFlags & 0x02) != 0) {
//System.err.println("Available on network path");
}
// Get the local volume and local system values
in.skipBytes(4); // TODO: see above for structure
int localSysOff = in.readInt();
//System.out.println("localSysOff: " + localSysOff);
in.skipBytes(localSysOff - 20); // Relative to start of chunk
byte[] pathBytes = new byte[tableLen - localSysOff - 1];
in.readFully(pathBytes, 0, pathBytes.length);
String path = new String(pathBytes, 0, pathBytes.length - 1);
/*
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
byte read;
// Read bytes until the null (0) character
while (true) {
read = in.readByte();
if (read == 0) {
break;
}
bytes.write(read & 0xff);
}
String path = new String(bytes.toByteArray(), 0, bytes.size());
//*/
// Recurse to end of link chain
// TODO: This may cause endless loop if cyclic chain...
//System.out.println("path: \"" + path + "\"");
try {
result = parse(new File(path));
}
catch (StackOverflowError e) {
throw new IOException("Cannot resolve cyclic link: " + e.getMessage());
}
}
if ((flags & FLAG_DESC_STRING) != 0) {
// Description String present, skip it.
//System.out.println("Description String present");
// The string length is the first word which must also be skipped.
int descLen = in.readShort();
//System.out.println("descLen: " + descLen);
byte[] descBytes = new byte[descLen];
in.readFully(descBytes, 0, descLen);
//String desc = new String(descBytes, 0, descLen);
//System.out.println("desc: " + desc);
}
if ((flags & FLAG_REL_PATH_STRING) != 0) {
// Relative Path String present
//System.out.println("Relative Path String present");
// The string length is the first word which must also be skipped.
int pathLen = in.readShort();
//System.out.println("pathLen: " + pathLen);
byte[] pathBytes = new byte[pathLen];
in.readFully(pathBytes, 0, pathLen);
String path = new String(pathBytes, 0, pathLen);
// TODO: This may cause endless loop if cyclic chain...
//System.out.println("path: \"" + path + "\"");
if (result == pPath) {
try {
result = parse(new File(pPath.getParentFile(), path));
}
catch (StackOverflowError e) {
throw new IOException("Cannot resolve cyclic link: " + e.getMessage());
}
}
}
if ((flags & FLAG_WORKING_DIRECTORY) != 0) {
//System.out.println("Working Directory present");
}
if ((flags & FLAG_COMMAND_LINE_ARGS) != 0) {
//System.out.println("Command Line Arguments present");
// NOTE: This means this .lnk is not a folder, don't follow
result = pPath;
}
if ((flags & FLAG_ICON_FILENAME) != 0) {
//System.out.println("Icon Filename present");
}
if ((flags & FLAG_ADDITIONAL_INFO) != 0) {
//System.out.println("Additional Info present");
}
}
finally {
in.close();
}
return result;
}
/*
private static String getNullDelimitedString(byte[] bytes, int off) {
int len = 0;
// Count bytes until the null (0) character
while (true) {
if (bytes[off + len] == 0) {
break;
}
len++;
}
System.err.println("--> " + len);
return new String(bytes, off, len);
}
*/
/**
* Converts two bytes into a short.
* <p>
* NOTE: this is little endian because it's for an
* Intel only OS
* </p>
*
* @ param bytes
* @ param off
* @return the bytes as a short.
*/
/*
private static int bytes2short(byte[] bytes, int off) {
return ((bytes[off + 1] & 0xff) << 8) | (bytes[off] & 0xff);
}
*/
public File getTarget() {
return target;
}
// java.io.File overrides below
@Override
public boolean isDirectory() {
return target.isDirectory();
}
@Override
public boolean canRead() {
return target.canRead();
}
@Override
public boolean canWrite() {
return target.canWrite();
}
// NOTE: equals is implemented using compareto == 0
/*
public int compareTo(File pathname) {
// TODO: Verify this
// Probably not a good idea, as it IS NOT THE SAME file
// It's probably better to not override
return target.compareTo(pathname);
}
*/
// Should probably never allow creating a new .lnk
// public boolean createNewFile() throws IOException
// Deletes only the .lnk
// public boolean delete() {
//public void deleteOnExit() {
@Override
public boolean exists() {
return target.exists();
}
// A .lnk may be absolute
//public File getAbsoluteFile() {
//public String getAbsolutePath() {
// Theses should be resolved according to the API (for Unix).
@Override
public File getCanonicalFile() throws IOException {
return target.getCanonicalFile();
}
@Override
public String getCanonicalPath() throws IOException {
return target.getCanonicalPath();
}
//public String getName() {
// I guess the parent should be the parent of the .lnk, not the target
//public String getParent() {
//public File getParentFile() {
// public boolean isAbsolute() {
@Override
public boolean isFile() {
return target.isFile();
}
@Override
public boolean isHidden() {
return target.isHidden();
}
@Override
public long lastModified() {
return target.lastModified();
}
@Override
public long length() {
return target.length();
}
@Override
public String[] list() {
return target.list();
}
@Override
public String[] list(final FilenameFilter filter) {
return target.list(filter);
}
@Override
public File[] listFiles() {
return Win32File.wrap(target.listFiles());
}
@Override
public File[] listFiles(final FileFilter filter) {
return Win32File.wrap(target.listFiles(filter));
}
@Override
public File[] listFiles(final FilenameFilter filter) {
return Win32File.wrap(target.listFiles(filter));
}
// Makes no sense, does it?
//public boolean mkdir() {
//public boolean mkdirs() {
// Only rename the lnk
//public boolean renameTo(File dest) {
@Override
public boolean setLastModified(long time) {
return target.setLastModified(time);
}
@Override
public boolean setReadOnly() {
return target.setReadOnly();
}
@Override
public String toString() {
if (target.equals(this)) {
return super.toString();
}
return super.toString() + " -> " + target.toString();
}
}