Start of entity serialization

2026-09-05 13:01:52 +00:00 · 2023-12-15 14:53:31 +01:00
parent b884ee8303
commit 89e4e4ef17
2 changed files with 302 additions and 0 deletions
@@ -0,0 +1,290 @@
+using GlitchyEngine.Editor;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Reflection;
+using System.Text;
+using GlitchyEngine.Core;
+using GlitchyEngine.Extensions;
+using System.Xml.Linq;
+
+namespace GlitchyEngine.Serialization;
+
+public static class EntitySerializer
+{
+    public class SerializationContext
+    {
+        StringBuilder _builder = new();
+
+        public Dictionary<object, SerializationContext> SerializedClasses = new();
+
+        public UUID ID = UUID.CreateNew();
+
+        private int _indentLevel = 0;
+
+        private void BeginLine()
+        {
+            for (int i = 0; i < _indentLevel; i++)
+                _builder.Append('\t');
+        }
+
+        private void WriteLine(string line)
+        {
+            BeginLine();
+
+            _builder.AppendLine(line);
+        }
+
+        private void WriteField(string type, string name, string value)
+        {
+            BeginLine();
+
+            _builder.AppendFormat("{0} {1} = {2}", type, name, value);
+            _builder.Append('\n');
+        }
+
+        private void StartBlock()
+        {
+            WriteLine("{");
+            _indentLevel++;
+        }
+
+        private void EndBlock()
+        {
+            Debug.Assert(_indentLevel > 0);
+            _indentLevel--;
+            WriteLine("}");
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="o"></param>
+        /// <returns>A serialization context for the given object. And true, if the context was used before, false otherwise.</returns>
+        private (SerializationContext context, bool newContext) GetReferenceTypeContext(object o)
+        {
+            SerializationContext context;
+
+            if (SerializedClasses.TryGetValue(o, out context))
+                return (context, false);
+            
+            context = new SerializationContext
+            {
+                SerializedClasses = SerializedClasses,
+                // The indentation is arbitrary anyway, this is just for style
+                _indentLevel = 1
+            };
+
+            SerializedClasses.Add(o, context);
+
+            return (context, true);
+        }
+        
+        private void SerializeArray(string fieldName, Type fieldType, object o)
+        {
+            Type type = o.GetType();
+
+            Debug.Assert(type.IsArray);
+
+            Type elementType = type.GetElementType();
+            
+            Debug.Assert(elementType != null);
+            
+            WriteField(type.ToString(), fieldName, "");
+
+            StartBlock();
+
+            Array array = (Array)o;
+
+            foreach (var element in array)
+            {
+                Serialize("", elementType, element);
+            }
+
+            EndBlock();
+        }
+
+        public void SerializeList(string fieldName, Type fieldType, object o)
+        {
+            Type type = o.GetType();
+            
+            Debug.Assert(type.IsGenericType);
+
+            Type elementType = type.GetGenericArguments()[0];
+            
+            WriteField(type.ToString(), fieldName, "");
+
+            StartBlock();
+
+            IList list = (IList)o;
+
+            foreach (var element in list)
+            {
+                Serialize("", elementType, element);
+            }
+
+            EndBlock();
+        }
+        void SerializeFields(Type objectType, object instance)
+        {
+            foreach (FieldInfo fieldInfo in objectType.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+            {
+                if (!SerializeField(fieldInfo))
+                    continue;
+
+                object value = fieldInfo.GetValue(instance);
+                Serialize(fieldInfo.Name, fieldInfo.FieldType, value);
+            }
+        }
+
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="o"></param>
+        /// <param name="shallowEntities">If true, entities will only be serialized as their UUID</param>
+        public void Serialize(string fieldName, Type fieldType, object o, bool shallowEntities = true)
+        {
+            // TODO: is this shortcut valid?
+            if (o == null)
+            {
+                WriteField(fieldType.ToString(), fieldName, "null");
+                return;
+            }
+
+            Type type = o.GetType();
+
+            if (typeof(Entity).IsAssignableFrom(type))
+            {
+                if (shallowEntities)
+                    WriteField(type.ToString(), fieldName, ((Entity)o).UUID.ToString());
+                else
+                    SerializeClass(fieldName, type, o);
+                    //SerializeFields(type, o);
+            }
+            else if (typeof(Component).IsAssignableFrom(type))
+            {
+                WriteField(type.ToString(), fieldName, ((Component)o).UUID.ToString());
+            }
+            else if (type == typeof(string))
+            {
+                WriteField(type.ToString(), fieldName, $"\"{(string)o}\"");
+            }
+            else if (type.IsPrimitive)
+            {
+                WriteField(type.ToString(), fieldName, o.ToString());
+            }
+            else if (type.IsEnum)
+            {
+                WriteField(type.ToString(), fieldName, o.ToString());
+            }
+            else if (type.IsArray)
+            {
+                SerializeArray(fieldName, type, o);
+            }
+            else if (type.IsGenericType)
+            {
+                if (fieldType.GetGenericTypeDefinition() == typeof(List<>))
+                {
+                    SerializeList(fieldName, type, o);
+                }
+                //else if (fieldType.GetGenericTypeDefinition() == typeof(Dictionary<,>))
+                //{
+                //    ImGui.Text($"{fieldName} Dictionary");
+                //}
+                else
+                {
+                    // TODO: what to do?
+                }
+            }
+            else if (type.IsValueType)
+            {
+                SerializeStruct(fieldName, type, o);
+            }
+            else if (type.IsClass)
+            {
+                // TODO: Use custom serializer, if available
+                
+                SerializeClass(fieldName, type, o);
+            }
+            else
+            {
+                Log.Error($"Encountered unhandled type \"{type}\" while serializing.");
+            }
+        }
+        
+        private void SerializeStruct(string fieldName, Type type, object o)
+        {
+            WriteField(type.ToString(), fieldName, "{");
+            StartBlock();
+            
+            SerializeFields(type, o);
+
+            EndBlock();
+        }
+
+        private void SerializeClass(string fieldName, Type type, object o)
+        {
+            (SerializationContext context, bool newContext) = GetReferenceTypeContext(o);
+            
+            // Only serialize the class, if it wasn't serialized before, obviously...
+            if (newContext)
+                context.SerializeFields(type, o);
+
+            WriteField(type.ToString(), fieldName, context.ID.ToString());
+        }
+
+        public override string ToString()
+        {
+            StringBuilder finalBuilder = new();
+
+            foreach (var context in SerializedClasses)
+            {
+                finalBuilder.Append($"{context.Value.ID} = {{\n");
+                
+                finalBuilder.Append(context.Value._builder);
+                
+                finalBuilder.Append("}\n\n");
+            }
+            
+            finalBuilder.Append("Object:");
+
+            finalBuilder.Append(_builder);
+
+            return finalBuilder.ToString();
+
+        }
+    }
+
+    public static void Serialize(Entity entity, SerializationContext context)
+    {
+        context ??= new SerializationContext();
+        
+        context.Serialize($"Entity: {entity.UUID}", typeof(Entity), entity, false);
+    }
+
+    public static bool SerializeField(FieldInfo fieldInfo)
+    {
+        var serializeField = fieldInfo.HasCustomAttribute<SerializeFieldAttribute>();
+        var dontSerializeField = fieldInfo.HasCustomAttribute<DontSerializeFieldAttribute>();
+        //var hideField = fieldInfo.HasCustomAttribute<HideInEditorAttribute>();
+        var showField = fieldInfo.HasCustomAttribute<ShowInEditorAttribute>();
+
+        if (fieldInfo.IsPublic)
+        {
+            if (dontSerializeField)
+                return false;
+
+            return true;
+        }
+        
+        if (serializeField)
+            return true;
+        
+        if (showField && !dontSerializeField)
+            return true;
+
+        return false;
+    }
+}