Large scale refactor to add class support!

Instance classes are now strongly typed with real property fields that
are derived from the JSON API Dump! This required a lot of reworking
across the board:

- Classes and Enums are auto-generated in the 'Generated' folder now.
This is done using a custom built-in plugin, which can be found in
the Plugins folder of this project.
- Property objects are now tied to .NET's reflection system. Reading
and writing from them will try to redirect into a field of the
Instance they are bound to.
- Property types that were loosely defined now have proper data types
(such as Color3uint8, Content, ProtectedString, SharedString, etc)
- Fixed an error with the CFrame directional vectors.
- The binary PRNT chunk now writes instances in child->parent order.
- Enums are now generated correctly, with up-to-date values.
- INST chunks are now referred to as 'Classes' instead of 'Types'.
- Unary operator added to Vector2 and Vector3.
- CollectionService tags can now be manipulated per-instance using
the Instance.Tags member.
- The Instance.Archivable property now works correctly.
- XML files now save/load metadata correctly.
- Cleaned up the property tokens directory.

I probably missed a few things, but that's a general overview of
everything that changed.

XmlFormat/IO/XmlFileReader.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Xml;
 
+using RobloxFiles.DataTypes;
+
 namespace RobloxFiles.XmlFormat
 {
     public static class XmlRobloxFileReader
@@ -35,11 +37,35 @@ namespace RobloxFiles.XmlFormat
                     string key = md5Node.InnerText;
                     string value = sharedString.InnerText.Replace("\n", "");
 
-                    file.SharedStrings.Add(key, value);
+                    byte[] buffer = Convert.FromBase64String(value);
+                    SharedString record = SharedString.FromBase64(value);
+
+                    if (record.MD5_Key != key)
+                        throw error("The provided md5 hash did not match with the md5 hash computed for the value!");
+
+                    file.SharedStrings.Add(key);
                 }
             }
         }
 
+        public static void ReadMetadata(XmlNode meta, XmlRobloxFile file)
+        {
+            var error = createErrorHandler("ReadMetadata");
+
+            if (meta.Name != "Meta")
+                throw error("Provided XmlNode's class should be 'Meta'!");
+
+            XmlNode propName = meta.Attributes.GetNamedItem("name");
+
+            if (propName == null)
+                throw error("Got a Meta node without a 'name' attribute!");
+
+            string key = propName.InnerText;
+            string value = meta.InnerText;
+
+            file.Metadata[key] = value;
+        }
+
         public static void ReadProperties(Instance instance, XmlNode propsNode)
         {
             var error = createErrorHandler("ReadProperties");
@@ -53,7 +79,12 @@ namespace RobloxFiles.XmlFormat
                 XmlNode propName = propNode.Attributes.GetNamedItem("name");
 
                 if (propName == null)
+                {
+                    if (propNode.Name == "Item")
+                        continue;
+
                     throw error("Got a property node without a 'name' attribute!");
+                }
 
                 IXmlPropertyToken tokenHandler = XmlPropertyTokens.GetHandler(propType);
 
@@ -90,8 +121,12 @@ namespace RobloxFiles.XmlFormat
             if (classToken == null)
                 throw error("Got an Item without a defined 'class' attribute!");
 
-            Instance inst = new Instance() { ClassName = classToken.InnerText };
 
+            string className = classToken.InnerText;
+
+            Type instType = Type.GetType($"RobloxFiles.{className}") ?? typeof(Instance);
+            Instance inst = Activator.CreateInstance(instType) as Instance;
+            
             // The 'referent' attribute is optional, but should be defined if a Ref property needs to link to this Instance.
             XmlNode refToken = instNode.Attributes.GetNamedItem("referent");
 

XmlFormat/IO/XmlFileWriter.cs

@@ -1,9 +1,8 @@
 using System;
-using System.Linq;
-using System.Security.Cryptography;
 using System.Text;
 using System.Xml;
 
+using RobloxFiles.DataTypes;
 using RobloxFiles.XmlFormat.PropertyTokens;
 
 namespace RobloxFiles.XmlFormat
@@ -40,7 +39,7 @@ namespace RobloxFiles.XmlFormat
             foreach (Instance child in inst.GetChildren())
                 RecordInstances(file, child);
 
-            if (inst.Referent.Length < 35)
+            if (inst.Referent == null || inst.Referent.Length < 35)
                 inst.Referent = CreateReferent();
 
             file.Instances.Add(inst.Referent, inst);
@@ -102,19 +101,8 @@ namespace RobloxFiles.XmlFormat
 
             if (prop.Type == PropertyType.SharedString)
             {
-                string data = prop.Value.ToString();
-                byte[] buffer = Convert.FromBase64String(data);
-
-                using (MD5 md5 = MD5.Create())
-                {
-                    byte[] hash = md5.ComputeHash(buffer);
-                    string key = Convert.ToBase64String(hash);
-
-                    if (!file.SharedStrings.ContainsKey(key))
-                        file.SharedStrings.Add(key, data);
-
-                    propNode.InnerText = key;
-                }
+                SharedString value = prop.CastValue<SharedString>();
+                file.SharedStrings.Add(value.MD5_Key);
             }
 
             return propNode;
@@ -122,6 +110,9 @@ namespace RobloxFiles.XmlFormat
 
         public static XmlNode WriteInstance(Instance instance, XmlDocument doc, XmlRobloxFile file)
         {
+            if (!instance.Archivable)
+                return null;
+
             XmlElement instNode = doc.CreateElement("Item");
             instNode.SetAttribute("class", instance.ClassName);
             instNode.SetAttribute("referent", instance.Referent);
@@ -129,7 +120,7 @@ namespace RobloxFiles.XmlFormat
             XmlElement propsNode = doc.CreateElement("Properties");
             instNode.AppendChild(propsNode);
 
-            var props = instance.Properties;
+            var props = instance.RefreshProperties();
             
             foreach (string propName in props.Keys)
             {
@@ -140,8 +131,11 @@ namespace RobloxFiles.XmlFormat
 
             foreach (Instance child in instance.GetChildren())
             {
-                XmlNode childNode = WriteInstance(child, doc, file);
-                instNode.AppendChild(childNode);
+                if (child.Archivable)
+                {
+                    XmlNode childNode = WriteInstance(child, doc, file);
+                    instNode.AppendChild(childNode);
+                }
             }
 
             return instNode;
@@ -152,18 +146,15 @@ namespace RobloxFiles.XmlFormat
             XmlElement sharedStrings = doc.CreateElement("SharedStrings");
 
             var binaryWriter = XmlPropertyTokens.GetHandler<BinaryStringToken>();
-            var bufferProp = new Property("SharedString", PropertyType.String);
+            var binaryBuffer = new Property("SharedString", PropertyType.String);
 
-            foreach (string md5 in file.SharedStrings.Keys)
+            foreach (string md5 in file.SharedStrings)
             {
                 XmlElement sharedString = doc.CreateElement("SharedString");
                 sharedString.SetAttribute("md5", md5);
 
-                string data = file.SharedStrings[md5];
-                byte[] buffer = Convert.FromBase64String(data);
-
-                bufferProp.RawBuffer = buffer;
-                binaryWriter.WriteProperty(bufferProp, doc, sharedString);
+                binaryBuffer.RawBuffer = SharedString.FindRecord(md5);
+                binaryWriter.WriteProperty(binaryBuffer, doc, sharedString);
 
                 sharedStrings.AppendChild(sharedString);
             }