[GUI] Add support for .lnk files via Drag&Drop. Close #13

AssetStudio/AssetsManager.cs

@@ -82,7 +82,7 @@ namespace AssetStudio
                     MergeSplitAssets(fullPath, true);
                     fileList.AddRange(Directory.GetFiles(fullPath, "*.*", SearchOption.AllDirectories));
                 }
-                else
+                else if (File.Exists(fullPath))
                 {
                     parentPath = Path.GetDirectoryName(fullPath);
                     fileList.Add(fullPath);

AssetStudio/Extensions/BinaryReaderExtensions.cs

@@ -35,10 +35,13 @@ namespace AssetStudio
             return "";
         }
 
-        public static string ReadStringToNull(this BinaryReader reader, int maxLength = 32767)
+        public static string ReadStringToNull(this BinaryReader reader, int maxLength = 32767, Encoding encoding = null)
         {
+            if (encoding?.CodePage == 1200) //Unicode (UTF-16LE)
+                return reader.ReadUnicodeStringToNull(maxLength * 2);
+
             var bytes = new List<byte>();
-            int count = 0;
+            var count = 0;
             while (reader.BaseStream.Position != reader.BaseStream.Length && count < maxLength)
             {
                 var b = reader.ReadByte();
@@ -49,7 +52,24 @@ namespace AssetStudio
                 bytes.Add(b);
                 count++;
             }
-            return Encoding.UTF8.GetString(bytes.ToArray());
+            return encoding?.GetString(bytes.ToArray()) ?? Encoding.UTF8.GetString(bytes.ToArray());
+        }
+
+        private static string ReadUnicodeStringToNull(this BinaryReader reader, int maxLength)
+        {
+            var bytes = new List<byte>();
+            var count = 0;
+            while (reader.BaseStream.Position != reader.BaseStream.Length && count < maxLength)
+            {
+                var b = reader.ReadBytes(2);
+                if (b.Length < 2 || (b[0] == 0 && b[1] == 0))
+                {
+                    break;
+                }
+                bytes.AddRange(b);
+                count += 2;
+            }
+            return Encoding.Unicode.GetString(bytes.ToArray());
         }
 
         public static Quaternion ReadQuaternion(this BinaryReader reader)

AssetStudioGUI/AssetStudioGUIForm.cs

@@ -146,14 +146,25 @@ namespace AssetStudioGUI
         private async void AssetStudioGUIForm_DragDrop(object sender, DragEventArgs e)
         {
             var paths = (string[])e.Data.GetData(DataFormats.FileDrop);
-            if (paths.Length > 0)
+            if (paths.Length == 0)
+                return;
+
+            ResetForm();
+            for (var i = 0; i < paths.Length; i++)
             {
-                ResetForm();
-                assetsManager.SpecifyUnityVersion = specifyUnityVersion.Text;
-                await Task.Run(() => assetsManager.LoadFilesAndFolders(out openDirectoryBackup, paths));
-                saveDirectoryBackup = openDirectoryBackup;
-                BuildAssetStructures();
+                if (paths[i].ToLower().EndsWith(".lnk"))
+                {
+                    var targetPath = LnkReader.GetLnkTarget(paths[i]);
+                    if (!string.IsNullOrEmpty(targetPath))
+                    {
+                        paths[i] = targetPath;
+                    }
+                }
             }
+            assetsManager.SpecifyUnityVersion = specifyUnityVersion.Text;
+            await Task.Run(() => assetsManager.LoadFilesAndFolders(out openDirectoryBackup, paths));
+            saveDirectoryBackup = openDirectoryBackup;
+            BuildAssetStructures();
         }
 
         private async void loadFile_Click(object sender, EventArgs e)

AssetStudioGUI/Components/LnkReader.cs

@@ -0,0 +1,164 @@
+// Shortcut (.lnk) file reader
+// by aelurum
+// Based on https://github.com/libyal/liblnk/blob/main/documentation/Windows%20Shortcut%20File%20(LNK)%20format.asciidoc
+
+using AssetStudio;
+using System;
+using System.IO;
+using System.Text;
+
+namespace AssetStudioGUI
+{
+    public static class LnkReader
+    {
+        [Flags]
+        private enum LnkDataFlags
+        {
+            //The LNK file contains a link target identifier
+            HasTargetIDList = 0x00000001,
+            //The LNK file contains location information
+            HasLinkInfo = 0x00000002,
+        }
+
+        [Flags]
+        private enum LnkLocFlags
+        {
+            //The linked file is on a volume
+            //If set the volume information and the local path contain data
+            VolumeIDAndLocalBasePath = 0x0001,
+            //The linked file is on a network share
+            //If set the network share information and common path contain data
+            CommonNetworkRelativeLinkAndPathSuffix = 0x0002
+        }
+
+        [Flags]
+        private enum PathTypeFlags
+        {
+            IsUnicodeLocalPath = 0x01,
+            IsUnicodeNetShareName = 0x02,
+            IsUnicodeCommonPath = 0x04
+        }
+
+        public static string GetLnkTarget(string filePath)
+        {
+            var targetPath = string.Empty;
+            var pathType = (PathTypeFlags)0;
+            Encoding sysEncoding;
+            try
+            {
+                sysEncoding = GetSysEncoding();
+                Logger.Debug($"System default text encoding: {sysEncoding.CodePage}");
+            }
+            catch (Exception ex)
+            {
+                Logger.Error("Text encoding error", ex);
+                return null;
+            }
+
+            using (var reader = new FileReader(filePath))
+            {
+                reader.Endian = EndianType.LittleEndian;
+
+                var headerSize = reader.ReadUInt32(); //76 bytes
+                reader.Position = 20; //skip LNK class identifier (GUID)
+                var dataFlags = (LnkDataFlags)reader.ReadUInt32();
+                if ((dataFlags & LnkDataFlags.HasLinkInfo) == 0)
+                {
+                    Logger.Warning("Unsupported type of .lnk file. Link info was not found.");
+                    return null;
+                }
+                reader.Position = headerSize;
+
+                //Skip the shell item ID list
+                if ((dataFlags & LnkDataFlags.HasTargetIDList) != 0)
+                {
+                    var itemIDListSize = reader.ReadUInt16();
+                    reader.Position += itemIDListSize;
+                }
+
+                //The offsets is relative to the start of the location information block
+                var locInfoPos = reader.Position;
+                var locInfoFullSize = reader.ReadUInt32();
+                if (locInfoFullSize == 0)
+                {
+                    Logger.Warning("Unsupported type of .lnk file. Link info was not found.");
+                    return null;
+                }
+                var locInfoHeaderSize = reader.ReadUInt32();
+                var locFlags = (LnkLocFlags)reader.ReadUInt32();
+                //Offset to the volume information block
+                var offsetVolumeInfo = reader.ReadUInt32();
+                //Offset to the ANSI local path
+                var offsetLocalPath = reader.ReadUInt32();
+                //Offset to the network share information block
+                var offsetNetInfo = reader.ReadUInt32();
+                //Offset to the ANSI common path. 0 if not available
+                var offsetCommonPath = reader.ReadUInt32();
+                if (locInfoHeaderSize > 28)
+                {
+                    //Offset to the Unicode local path
+                    offsetLocalPath = reader.ReadUInt32();
+                    pathType |= PathTypeFlags.IsUnicodeLocalPath;
+                }
+                if (locInfoHeaderSize > 32)
+                {
+                    //Offset to the Unicode common path
+                    offsetCommonPath = reader.ReadUInt32();
+                    pathType |= PathTypeFlags.IsUnicodeCommonPath;
+                }
+
+                //Read local path, if exist                
+                if (offsetLocalPath > 0)
+                {
+                    reader.Position = locInfoPos + offsetLocalPath;
+                    targetPath = (pathType & PathTypeFlags.IsUnicodeLocalPath) != 0
+                        ? reader.ReadStringToNull(encoding: Encoding.Unicode)
+                        : reader.ReadStringToNull(encoding: sysEncoding);
+                }
+
+                //Read network path, if exist
+                if (locFlags == LnkLocFlags.CommonNetworkRelativeLinkAndPathSuffix)
+                {
+                    reader.Position = locInfoPos + offsetNetInfo;
+                    var netInfoSize = reader.ReadUInt32();
+                    var netInfoFlags = reader.ReadUInt32();
+                    //Offset to the ANSI network share name. The offset is relative to the start of the network share information block
+                    var offsetNetShareName = reader.ReadUInt32();
+                    if (offsetNetShareName > 20)
+                    {
+                        reader.Position = locInfoPos + offsetNetInfo + 20;
+                        //Offset to the Unicode network share name
+                        offsetNetShareName = reader.ReadUInt32();
+                        pathType |= PathTypeFlags.IsUnicodeNetShareName;
+                    }
+                    if (offsetNetShareName > 0)
+                    {
+                        reader.Position = locInfoPos + offsetNetInfo + offsetNetShareName;
+                        targetPath = (pathType & PathTypeFlags.IsUnicodeNetShareName) != 0
+                            ? reader.ReadStringToNull(encoding: Encoding.Unicode)
+                            : reader.ReadStringToNull(encoding: sysEncoding);
+                    }
+                }
+
+                //Read common path, if exist
+                if (offsetCommonPath > 0)
+                {
+                    reader.Position = locInfoPos + offsetCommonPath;
+                    var commonPath = (pathType & PathTypeFlags.IsUnicodeCommonPath) != 0
+                        ? reader.ReadStringToNull(encoding: Encoding.Unicode)
+                        : reader.ReadStringToNull(encoding: sysEncoding);
+                    targetPath = Path.Combine(targetPath, commonPath);
+                }
+            }
+            return targetPath;
+        }
+
+        private static Encoding GetSysEncoding()
+        {
+#if !NETFRAMEWORK
+            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+#endif
+            return Encoding.GetEncoding(0);
+        }
+    }
+}