chore: initial commit

Packages/com.kybernetik.animancer/Editor/GUI/Custom GUI/CustomGUIFactory.cs

@@ -0,0 +1,152 @@
+// Animancer // https://kybernetik.com.au/animancer // Copyright 2018-2026 Kybernetik //
+
+#if UNITY_EDITOR
+
+//#define LOG_CUSTOM_GUI_FACTORY
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using UnityEditor;
+using UnityEngine;
+
+namespace Animancer.Editor
+{
+    /// <summary>[Editor-Only] Draws a custom GUI for an object.</summary>
+    /// <remarks>
+    /// Every non-abstract type implementing this interface must have at least one <see cref="CustomGUIAttribute"/>.
+    /// </remarks>
+    /// https://kybernetik.com.au/animancer/api/Animancer.Editor/CustomGUIFactory
+    /// 
+    public static class CustomGUIFactory
+    {
+        /************************************************************************************************************************/
+
+        private static readonly Dictionary<Type, Type>
+            TargetTypeToGUIType = new();
+
+        static CustomGUIFactory()
+        {
+            foreach (var guiType in TypeCache.GetTypesWithAttribute(typeof(CustomGUIAttribute)))
+            {
+                if (guiType.IsAbstract ||
+                    guiType.IsInterface)
+                    continue;
+
+                if (!typeof(ICustomGUI).IsAssignableFrom(guiType))
+                {
+                    Debug.LogWarning(
+                        $"{guiType.FullName} has a {nameof(CustomGUIAttribute)}" +
+                        $" but doesn't implement {nameof(ICustomGUI)}.");
+                    continue;
+                }
+
+                var attribute = guiType.GetCustomAttribute<CustomGUIAttribute>();
+                if (attribute.TargetType != null)
+                {
+
+                    TargetTypeToGUIType.Add(attribute.TargetType, guiType);
+                }
+            }
+        }
+
+        /************************************************************************************************************************/
+
+        private static readonly ConditionalWeakTable<object, ICustomGUI>
+            TargetToGUI = new();
+
+        /// <summary>Returns an existing <see cref="ICustomGUI"/> for the `targetType` or creates one if necessary.</summary>
+        /// <remarks>Returns null if the `targetType` is null or no valid <see cref="ICustomGUI"/> type is found.</remarks>
+        public static ICustomGUI GetOrCreateForType(Type targetType)
+        {
+            if (targetType == null)
+                return null;
+
+            if (TargetToGUI.TryGetValue(targetType, out var gui))
+                return gui;
+
+            gui = Create(targetType);
+
+            TargetToGUI.Add(targetType, gui);
+
+            return gui;
+        }
+
+        /// <summary>Returns an existing <see cref="ICustomGUI"/> for the `value` or creates one if necessary.</summary>
+        /// <remarks>Returns null if the `value` is null or no valid <see cref="ICustomGUI"/> type is found.</remarks>
+        public static ICustomGUI GetOrCreateForObject(object value)
+        {
+            if (value == null)
+                return null;
+
+            if (TargetToGUI.TryGetValue(value, out var gui))
+                return gui;
+
+            gui = Create(value.GetType());
+            if (gui != null)
+                gui.Value = value;
+
+            TargetToGUI.Add(value, gui);
+            return gui;
+        }
+
+        /************************************************************************************************************************/
+
+        /// <summary>Creates an <see cref="ICustomGUI"/> for the `targetType`.</summary>
+        /// <remarks>Returns null if the `value` is null or no valid <see cref="ICustomGUI"/> type is found.</remarks>
+        public static ICustomGUI Create(Type targetType)
+        {
+            if (!TryGetGUIType(targetType, out var guiType))
+                return null;
+
+            try
+            {
+                if (guiType.IsGenericTypeDefinition)
+                    guiType = guiType.MakeGenericType(targetType);
+
+                var gui = (ICustomGUI)Activator.CreateInstance(guiType);
+
+                return gui;
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+                return null;
+            }
+        }
+
+        /************************************************************************************************************************/
+
+        /// <summary>Tries to determine the valid <see cref="ICustomGUI"/> type for drawing the `target`.</summary>
+        public static bool TryGetGUIType(Type target, out Type gui)
+        {
+            // Try the target and its base types.
+
+            var type = target;
+            while (type != null && type != typeof(object))
+            {
+                if (TargetTypeToGUIType.TryGetValue(type, out gui))
+                    return true;
+
+                type = type.BaseType;
+            }
+
+            // Try any interfaces.
+
+            var interfaces = target.GetInterfaces();
+            for (int i = 0; i < interfaces.Length; i++)
+                if (TargetTypeToGUIType.TryGetValue(interfaces[i], out gui))
+                    return true;
+
+            // Try base object.
+
+            return TargetTypeToGUIType.TryGetValue(typeof(object), out gui);
+        }
+
+        /************************************************************************************************************************/
+    }
+}
+
+#endif
+