Custom Serializers

- Dictionary serializer

ScriptCore/Editor/EntityEditor.cs

@@ -296,7 +296,7 @@ internal class EntityEditor
 
                     if (ImGui.BeginCombo("Create", "Create", ImGuiComboFlags.HeightSmall | ImGuiComboFlags.NoArrowButton))
                     {
-                        foreach (Type t in FindDerivedTypes(fieldType))
+                        foreach (Type t in TypeExtension.FindDerivedTypes(fieldType))
                         {
                             if (ImGui.Selectable(t.Name))
                             {
@@ -818,20 +818,6 @@ internal class EntityEditor
         return newList;
     }
 
-    /// <summary>
-    /// Enumerates all types that derive from the given type.
-    /// </summary>
-    /// <param name="baseType"></param>
-    /// <returns></returns>
-    public static IEnumerable<Type> FindDerivedTypes(Type baseType)
-    {
-        foreach (Assembly domainAssembly in AppDomain.CurrentDomain.GetAssemblies())
-        foreach (Type type in domainAssembly.GetTypes())
-        {
-            if (baseType.IsAssignableFrom(type) && !type.IsAbstract) yield return type;
-        }
-    }
-
     private static T ReadStaticField<T>(string name)
     {
         FieldInfo field = typeof(T).GetField(name, BindingFlags.Public | BindingFlags.Static);

ScriptCore/Extensions/KeyValuePairExtension.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace GlitchyEngine.Extensions;
+
+public static class KeyValuePairExtension
+{
+    public static void Deconstruct<T1, T2>(this KeyValuePair<T1, T2> tuple, out T1 key, out T2 value)
+    {
+        key = tuple.Key;
+        value = tuple.Value;
+    }
+}

ScriptCore/Extensions/TypeExtension.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Reflection;
 using System.Text;
 
 namespace GlitchyEngine.Extensions;
@@ -15,4 +16,53 @@ public static class TypeExtension
     {
         return targetType.IsAssignableFrom(type);
     }
+
+    /// <summary>
+    /// Enumerates all types in all assemblies.
+    /// </summary>
+    public static IEnumerable<Type> EnumerateAllTypes()
+    {
+        foreach (Assembly domainAssembly in AppDomain.CurrentDomain.GetAssemblies())
+        foreach (Type type in domainAssembly.GetTypes())
+        {
+            yield return type;
+        }
+    }
+
+    /// <summary>
+    /// Enumerates all types that derive from the given type.
+    /// </summary>
+    /// <param name="baseType"></param>
+    /// <returns></returns>
+    public static IEnumerable<Type> FindDerivedTypes(Type baseType)
+    {
+        foreach (Assembly domainAssembly in AppDomain.CurrentDomain.GetAssemblies())
+        foreach (Type type in domainAssembly.GetTypes())
+        {
+            if (baseType.IsAssignableFrom(type) && !type.IsAbstract) yield return type;
+        }
+    }
+
+    /// <summary>
+    /// Returns whether or not the type has an <see cref="Attribute"/> of the specified <see cref="Type"/> <see cref="T"/>.
+    /// </summary>
+    /// <typeparam name="T">The type of the attribute</typeparam>
+    /// <returns><see langword="true"/> if the type has the specified <see cref="Attribute"/>; <see langword="true"/> otherwise.</returns>
+    public static bool HasCustomAttribute<T>(this Type type) where T: Attribute
+    {
+        return type.GetCustomAttribute<T>() != null;
+    }
+
+    /// <summary>
+    /// Returns whether or not the type has an <see cref="Attribute"/> of the specified <see cref="Type"/> <see cref="T"/>.
+    /// </summary>
+    /// <typeparam name="T">The type of the attribute</typeparam>
+    /// <param name="attribute">The attribute, or <seealso langword="null"/>, if the type hasn't got the attribute specified.</param>
+    /// <returns><see langword="true"/> if the type has the specified <see cref="Attribute"/>; <see langword="true"/> otherwise.</returns>
+    public static bool TryGetCustomAttribute<T>(this Type type, out T attribute) where T: Attribute
+    {
+        attribute = type.GetCustomAttribute<T>();
+
+        return attribute != null;
+    }
 }

ScriptCore/Serialization/CustomSerializerAttribute.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace GlitchyEngine.Serialization;
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct)]
+public sealed class CustomSerializerAttribute : Attribute
+{
+    public Type Type { get; private set; }
+
+    public CustomSerializerAttribute(Type type)
+    {
+        Type = type;
+    }
+}

ScriptCore/Serialization/DeserializationObject.cs

@@ -10,12 +10,13 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
+using GlitchyEngine.Editor;
 
 namespace GlitchyEngine.Serialization;
 
-internal class DeserializationObject
+public class DeserializationObject
 {
-    private class NoObject
+    public class NoObject
     {
 
     }
@@ -23,7 +24,7 @@ internal class DeserializationObject
     /// <summary>
     /// Object used to specify, that no particular value was deserialized for the field and thus the value currently stored shall not be changed.
     /// </summary>
-    private static readonly NoObject NoValueDeserialized = new ();
+    public static readonly NoObject NoValueDeserialized = new ();
 
     private IntPtr _internalContext;
 
@@ -37,6 +38,24 @@ internal class DeserializationObject
 
     private object _instance;
     
+    private Dictionary<string, Type> _fullNameToType = new();
+    
+    private static Dictionary<Type, MethodInfo> _customDeserializers = new();
+
+
+    /// <summary>
+    /// Gets the type that was originally stored in the container, or null, if the type doesn't exist.
+    /// </summary>
+    public Type StoredType
+    {
+        get
+        {
+            ScriptGlue.Serialization_GetObjectTypeName(_internalContext, out string fullTypeName);
+
+            return GetTypeFromName(fullTypeName);
+        }
+    }
+
     public DeserializationObject(IntPtr internalContext, UUID id, Dictionary<UUID, DeserializationObject> deserializedClasses)
     {
         _internalContext = internalContext;
@@ -44,9 +63,29 @@ internal class DeserializationObject
         DeserializedClasses = deserializedClasses;
     }
     
-    private Dictionary<string, Type> _fullNameToType = new();
+    static DeserializationObject()
+    {
+        foreach (Type type in TypeExtension.EnumerateAllTypes())
+        {
+            if (type.TryGetCustomAttribute<CustomSerializerAttribute>(out var attribute))
+            {
+                MethodInfo deserializeMethod = type.GetMethod("Deserialize", BindingFlags.Static | BindingFlags.Public,
+                    null,
+                    new []{ typeof(DeserializationObject), typeof(string), typeof(Type) }, null);
 
-    private Type FindType(string fullName)
+                if (deserializeMethod == null)
+                {
+                    Log.Error($"No Deserialize-method found for type {type}");
+                }
+                else
+                {
+                    _customDeserializers.Add(attribute.Type, deserializeMethod);
+                }
+            }
+        }
+    }
+
+    public Type FindType(string fullName)
     {
         foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies().Reverse())
         {
@@ -59,7 +98,7 @@ internal class DeserializationObject
         return null;
     }
 
-    private Type GetTypeFromName(string fullName)
+    public Type GetTypeFromName(string fullName)
     {
         if (_fullNameToType.TryGetValue(fullName, out Type storedType))
             return storedType;
@@ -71,7 +110,7 @@ internal class DeserializationObject
         return type;
     }
 
-    private DeserializationObject GetDeserializedObject(UUID id)
+    public DeserializationObject GetDeserializedObject(UUID id)
     {
         DeserializationObject context;
         
@@ -87,14 +126,14 @@ internal class DeserializationObject
         return context;
     }
     
-    private void PushScope(string name)
+    public void PushScope(string name)
     {
         _structScope.Push(name);
 
         _structScopeName += $"{name}.";
     }
 
-    private void PopScope()
+    public void PopScope()
     {
         string scopeToRemove = _structScope.Pop();
         _structScopeName = _structScopeName.Remove(_structScopeName.Length - scopeToRemove.Length - 1);
@@ -115,12 +154,12 @@ internal class DeserializationObject
         public EngineObjectReferenceHelper EngineObjectReference;
     }
 
-    private T GetFieldValue<T>(string fieldName, SerializationType serializationType)
+    public T GetFieldValue<T>(string fieldName, SerializationType serializationType)
     {
         return (T)GetFieldValue(fieldName, serializationType);
     }
 
-    private unsafe object GetFieldValue(string fieldName, SerializationType serializationType)
+    public unsafe object GetFieldValue(string fieldName, SerializationType serializationType)
     {
         string completeFieldName = $"{_structScopeName}{fieldName}";
 
@@ -200,7 +239,7 @@ internal class DeserializationObject
         DeserializeFields(entity);
     }
     
-    private bool DeserializeFields(object obj)
+    public bool DeserializeFields(object obj)
     {
         Type type = obj.GetType();
 
@@ -225,7 +264,34 @@ internal class DeserializationObject
         return changed;
     }
     
-    private object DeserializeField(object fieldValue, Type fieldType, string fieldName)
+    private bool TryCustomDeserializer(string fieldName, Type fieldType, out object deserializedValue)
+    {
+        deserializedValue = NoValueDeserialized;
+
+        try
+        {
+            // Try to match the concrete type first (e.g. Foo -> Foo and Foo<Bar> -> List<Bar>)
+            // Note: Foo<Bar> wont match a serializer for Foo<>
+            if (_customDeserializers.TryGetValue(fieldType, out MethodInfo deserializeMethod))
+            {
+                deserializedValue = deserializeMethod.Invoke(null, new object[] { this, fieldName, fieldType });
+                return true;
+            }
+            
+            if (fieldType.IsGenericType && _customDeserializers.TryGetValue(fieldType.GetGenericTypeDefinition(), out deserializeMethod))
+            {
+                deserializedValue = deserializeMethod.Invoke(null, new object[] { this, fieldName, fieldType });
+            }   return true;
+        }
+        catch (Exception e)
+        {
+            Log.Error(e);
+        }
+
+        return false;
+    }
+
+    public object DeserializeField(object fieldValue, Type fieldType, string fieldName)
     {
         if (fieldType.IsPrimitive)
         {
@@ -245,6 +311,11 @@ internal class DeserializationObject
         }
         else if (fieldType.IsGenericType)
         {
+            if (TryCustomDeserializer(fieldName, fieldType, out object deserializedValue))
+            {
+                return deserializedValue;
+            }
+            
             if (fieldType.GetGenericTypeDefinition() == typeof(List<>))
             {
                 return DeserializeList(fieldName, fieldType, fieldType.GetGenericArguments()[0]);
@@ -261,10 +332,20 @@ internal class DeserializationObject
         }
         else if (fieldType.IsValueType)
         {
+            if (TryCustomDeserializer(fieldName, fieldType, out object deserializedValue))
+            {
+                return deserializedValue;
+            }
+
             return DeserializeStruct(fieldName, fieldValue);
         }
         else if (fieldType.IsClass)
         { 
+            if (TryCustomDeserializer(fieldName, fieldType, out object deserializedValue))
+            {
+                return deserializedValue;
+            }
+
             return DeserializeClass(fieldName, fieldType);
         }
         else
@@ -275,7 +356,7 @@ internal class DeserializationObject
         return NoValueDeserialized;
     }
 
-    private object DeserializePrimitive(string fieldName, Type fieldType)
+    public object DeserializePrimitive(string fieldName, Type fieldType)
     {
         Debug.Assert(fieldType.IsPrimitive, $"{fieldType} is not a primitive type.");
 
@@ -315,20 +396,7 @@ internal class DeserializationObject
         return GetFieldValue(fieldName, expectedType);
     }
 
-    /// <summary>
-    /// Gets the type that was originally stored in the container, or null, if the type doesn't exist.
-    /// </summary>
-    public Type StoredType
-    {
-        get
-        {
-            ScriptGlue.Serialization_GetObjectTypeName(_internalContext, out string fullTypeName);
-
-            return GetTypeFromName(fullTypeName);
-        }
-    }
-
-    private object DeserializeList(string fieldName, Type fieldType, Type elementType)
+    public object DeserializeList(string fieldName, Type fieldType, Type elementType)
     {
         UUID id = (UUID)GetFieldValue(fieldName, SerializationType.ObjectReference);
 
@@ -398,7 +466,7 @@ internal class DeserializationObject
         return deserializedObject._instance;
     }
 
-    private object DeserializeEnum(string fieldName, Type enumType)
+    public object DeserializeEnum(string fieldName, Type enumType)
     {
         if (GetFieldValue(fieldName, SerializationType.Enum) is not string valueName)
             return NoValueDeserialized;
@@ -415,7 +483,7 @@ internal class DeserializationObject
         return NoValueDeserialized;
     }
 
-    private object DeserializeStruct(string fieldName, object targetInstance)
+    public object DeserializeStruct(string fieldName, object targetInstance)
     {
         PushScope(fieldName);
 
@@ -426,7 +494,7 @@ internal class DeserializationObject
         return changed ? targetInstance : NoValueDeserialized;
     }
 
-    private unsafe object DeserializeClass(string fieldName, Type fieldType)
+    public unsafe object DeserializeClass(string fieldName, Type fieldType)
     {
         bool isEntity = typeof(Entity).IsAssignableFrom(fieldType);
         bool isComponent = fieldType.IsSubclassOf(typeof(Component));

ScriptCore/Serialization/DictionarySerializer.cs

@@ -0,0 +1,118 @@
+#nullable enable
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using GlitchyEngine.Core;
+using GlitchyEngine.Extensions;
+
+namespace GlitchyEngine.Serialization;
+
+/// <summary>
+/// Provides Serialization and Deserialization for Dictionaries.
+/// </summary>
+[CustomSerializer(typeof(Dictionary<,>))]
+public static class DictionarySerializer
+{
+    /// <summary>
+    /// Serializes a given Dictionary as a field of <see cref="container"/>.
+    /// </summary>
+    /// <param name="container">The parent object.</param>
+    /// <param name="fieldName">Name of the field in <see cref="container"/></param>
+    /// <param name="fieldValue">The dictionary</param>
+    /// <param name="fieldType">Type of <see cref="fieldValue"/> or the type of the field if <see cref="fieldValue"/> is <see langword="null"/></param>
+    public static void Serialize(SerializedObject container, string fieldName, object? fieldValue, Type fieldType)
+    {
+        if (fieldValue == null)
+        {
+            // Write a null pointer early out
+            container.AddField(fieldName, SerializationType.ObjectReference, UUID.Zero);
+            return;
+        }
+        
+        // Get a container for our dictionary (Note: container is our parent object).
+        // isNewContext is true, if our dictionary wasn't serialized so far.
+        var (context, isNewContext) = container.GetSerializedObject(fieldValue);
+
+        if (isNewContext)
+        {
+            Type keyType = fieldType.GetGenericArguments()[0];
+            Type valueType = fieldType.GetGenericArguments()[1];
+
+            IDictionary dictionary = (IDictionary)fieldValue;
+            ICollection collection = (ICollection)fieldValue;
+            
+            context.AddField("Count", SerializationType.Int32, collection.Count);
+
+            int index = 0;
+
+            foreach (DictionaryEntry entry in dictionary)
+            {
+                context.PushScope(index.ToString());
+
+                context.SerializeField("Key", entry.Key, keyType);
+                context.SerializeField("Value", entry.Value, valueType);
+
+                context.PopScope();
+
+                index++;
+            }
+        }
+        
+        // Write the reference to our dictionary into the field of the parent.
+        container.AddField(fieldName, SerializationType.ObjectReference, context.Id);
+    }
+
+    /// <summary>
+    /// Deserializes a dictionary that is a field of the given <see cref="container"/>.
+    /// </summary>
+    /// <param name="container">The parent object whose field with <see cref="fieldName"/> is a dictionary.</param>
+    /// <param name="fieldName">The name of the field.</param>
+    /// <param name="fieldType">The type of the field.</param>
+    /// <returns></returns>
+    public static object? Deserialize(DeserializationObject container, string fieldName, Type fieldType)
+    {
+        UUID id = container.GetFieldValue<UUID>(fieldName, SerializationType.ObjectReference);
+
+        if (id == UUID.Zero)
+            return null;
+        
+        // Get serialization container for the instance
+        DeserializationObject deserializedObject = container.GetDeserializedObject(id);
+
+        Type type = deserializedObject.StoredType;
+
+        if (type?.IsAssignableTo(fieldType) != true)
+            return DeserializationObject.NoValueDeserialized;
+
+        Type keyType = fieldType.GetGenericArguments()[0];
+        Type valueType = fieldType.GetGenericArguments()[1];
+
+        int count = deserializedObject.GetFieldValue<int>("Count", SerializationType.Int32);
+        
+        // Create instance, pass in capacity
+        object? instance = ActivatorExtension.CreateInstanceSafe(type, count);
+        
+        Debug.Assert(instance != null);
+
+        IDictionary dictionary = (IDictionary)instance!;
+
+        for (int i = 0; i < count; i++)
+        {
+            deserializedObject.PushScope(i.ToString());
+
+            object? key = deserializedObject.DeserializeField(null, keyType, "Key");
+            object value = deserializedObject.DeserializeField(null, valueType, "Value");
+
+            if (key != null)
+            {
+                dictionary.Add(key, value);
+            }
+
+            deserializedObject.PopScope();
+        }
+
+        return instance;
+    }
+}

ScriptCore/Serialization/EntitySerializer.cs

@@ -7,7 +7,7 @@ using GlitchyEngine.Extensions;
 
 namespace GlitchyEngine.Serialization;
 
-internal enum SerializationType : int
+public enum SerializationType : int
 {
     None,
 

ScriptCore/Serialization/SerializedObject.cs

@@ -4,10 +4,11 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
+using GlitchyEngine.Extensions;
 
 namespace GlitchyEngine.Serialization;
 
-internal class SerializedObject
+public class SerializedObject
 {
     private IntPtr _internalContext;
 
@@ -19,6 +20,10 @@ internal class SerializedObject
 
     private string _structScopeName;
 
+    private static Dictionary<Type, MethodInfo> _customSerializers = new();
+
+    public UUID Id => _id;
+    
     public SerializedObject(IntPtr internalContext, UUID id, Dictionary<object, SerializedObject> serializedClasses)
     {
         _internalContext = internalContext;
@@ -26,7 +31,7 @@ internal class SerializedObject
         _serializedClasses = serializedClasses;
     }
     
-    private (SerializedObject context, bool newContext) GetSerializedObject(object o)
+    public (SerializedObject context, bool newContext) GetSerializedObject(object o)
     {
         SerializedObject context;
 
@@ -42,20 +47,42 @@ internal class SerializedObject
         return (context, true);
     }
 
-    private void PushScope(string name)
+    static SerializedObject()
+    {
+        foreach (Type type in TypeExtension.EnumerateAllTypes())
+        {
+            if (type.TryGetCustomAttribute<CustomSerializerAttribute>(out var attribute))
+            {
+                MethodInfo serializeMethod = type.GetMethod("Serialize", BindingFlags.Static | BindingFlags.Public,
+                    null,
+                    new[] { typeof(SerializedObject), typeof(string), typeof(object), typeof(Type) }, null);
+
+                if (serializeMethod == null)
+                {
+                    Log.Error($"No Serialize-method found for type {type}");
+                }
+                else
+                {
+                    _customSerializers.Add(attribute.Type, serializeMethod);
+                }
+            }
+        }
+    }
+
+    public void PushScope(string name)
     {
         _structScope.Push(name);
 
         _structScopeName += $"{name}.";
     }
 
-    private void PopScope()
+    public void PopScope()
     {
         string scopeToRemove = _structScope.Pop();
         _structScopeName = _structScopeName.Remove(_structScopeName.Length - scopeToRemove.Length - 1);
     }
 
-    private void AddField(string fieldName, SerializationType serializationType, object value, string fullTypeName = null)
+    public void AddField(string fieldName, SerializationType serializationType, object value, string fullTypeName = null)
     {
         string completeFieldName = $"{_structScopeName}{fieldName}";
 
@@ -67,7 +94,7 @@ internal class SerializedObject
         SerializeFields(entity);
     }
     
-    private void SerializeFields(object obj)
+    public void SerializeFields(object obj)
     {
         Type type = obj.GetType();
 
@@ -83,7 +110,35 @@ internal class SerializedObject
         }
     }
 
-    private void SerializeField(string fieldName, object fieldValue, Type fieldType)
+    private bool TryCustomSerializer(string fieldName, object fieldValue, Type fieldType)
+    {
+        try
+        {
+            // Try to match the concrete type first (e.g. Foo -> Foo and Foo<Bar> -> List<Bar>)
+            // Note: Foo<Bar> wont match a serializer for Foo<>
+            if (_customSerializers.TryGetValue(fieldType, out MethodInfo serializeMethod))
+            {
+                serializeMethod.Invoke(null, new[] { this, fieldName, fieldValue, fieldType });
+                return true;
+            }
+            
+            if (fieldType.IsGenericType && _customSerializers.TryGetValue(fieldType.GetGenericTypeDefinition(), out serializeMethod))
+            {
+                serializeMethod.Invoke(null, new[] { this, fieldName, fieldValue, fieldType });
+                return true;
+            }
+        }
+        catch (Exception e)
+        {
+            Log.Error(e);
+            // Don't attempt to use any other serializer after this error...
+            return true;
+        }
+
+        return false;
+    }
+
+    public void SerializeField(string fieldName, object fieldValue, Type fieldType)
     {
         if (fieldType.IsPrimitive)
         {
@@ -110,6 +165,9 @@ internal class SerializedObject
         }
         else if (fieldType.IsGenericType)
         {
+            if (TryCustomSerializer(fieldName, fieldValue, fieldType))
+                return;
+
             if (fieldType.GetGenericTypeDefinition() == typeof(List<>))
             {
                 SerializeList(fieldName, fieldValue, fieldType, fieldType.GetGenericArguments()[0]);
@@ -126,10 +184,16 @@ internal class SerializedObject
         }
         else if (fieldType.IsValueType)
         {
+            if (TryCustomSerializer(fieldName, fieldValue, fieldType))
+                return;
+
             SerializeStruct(fieldName, fieldValue, fieldType);
         }
         else if (fieldType.IsClass)
         {
+            if (TryCustomSerializer(fieldName, fieldValue, fieldType))
+                return;
+
             SerializeClass(fieldName, fieldValue, fieldType);
         }
         else
@@ -138,7 +202,7 @@ internal class SerializedObject
         }
     }
 
-    private void SerializeList(string fieldName, object listObject, Type fieldType, Type elementType)
+    public void SerializeList(string fieldName, object listObject, Type fieldType, Type elementType)
     {
         if (listObject == null)
         {
@@ -168,7 +232,7 @@ internal class SerializedObject
         }
     }
 
-    private void SerializePrimitive(string fieldName, object fieldValue, Type fieldType)
+    public void SerializePrimitive(string fieldName, object fieldValue, Type fieldType)
     {
         Debug.Assert(fieldType.IsPrimitive, $"{fieldType} is not a primitive type.");
 
@@ -208,12 +272,12 @@ internal class SerializedObject
         AddField(fieldName, type, fieldValue);
     }
 
-    private void SerializeEnum(string fieldName, object fieldValue, Type fieldType)
+    public void SerializeEnum(string fieldName, object fieldValue, Type fieldType)
     {
         AddField(fieldName, SerializationType.Enum, fieldValue.ToString());
     }
 
-    private void SerializeStruct(string fieldName, object fieldValue, Type fieldType)
+    public void SerializeStruct(string fieldName, object fieldValue, Type fieldType)
     {
         PushScope(fieldName);
 
@@ -222,7 +286,7 @@ internal class SerializedObject
         PopScope();
     }
 
-    private void SerializeClass(string fieldName, object fieldValue, Type fieldType)
+    public void SerializeClass(string fieldName, object fieldValue, Type fieldType)
     {
         if (typeof(Entity).IsAssignableFrom(fieldType))
         {