chore: initial commit

Packages/com.kybernetik.animancer/Editor/GUI/PropertyDrawers.cs

@@ -0,0 +1,179 @@
+// Animancer // https://kybernetik.com.au/animancer // Copyright 2018-2026 Kybernetik //
+
+#if UNITY_EDITOR
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using UnityEditor;
+using UnityEngine;
+
+#if UNITY_6000_0_OR_NEWER
+using GetDrawerTypeForTypeDelegate = System.Func<System.Type, System.Type[], bool, System.Type>;
+#elif UNITY_2022_3_OR_NEWER
+using GetDrawerTypeForTypeDelegate = System.Func<System.Type, bool, System.Type>;
+#else
+using GetDrawerTypeForTypeDelegate = System.Func<System.Type, System.Type>;
+#endif
+
+namespace Animancer.Editor
+{
+    /// <summary>[Editor-Only] A cache of <see cref="PropertyDrawer"/>s mapped to their target type.</summary>
+    /// https://kybernetik.com.au/animancer/api/Animancer.Editor/PropertyDrawers
+    public static class PropertyDrawers
+    {
+        /************************************************************************************************************************/
+
+        private const string
+            ScriptAttributeUtility = "UnityEditor.ScriptAttributeUtility",
+            FieldFieldName = "m_FieldInfo",
+            AttributeFieldName = "m_Attribute";
+
+        private static readonly GetDrawerTypeForTypeDelegate
+            GetDrawerTypeForType;
+
+        private static readonly FieldInfo
+            FieldField,
+            AttributeField;
+
+        /************************************************************************************************************************/
+
+        static PropertyDrawers()
+        {
+            var editorAssembly = typeof(CustomPropertyDrawer).Assembly;
+            var scriptAttributeUtility = editorAssembly.GetType(ScriptAttributeUtility);
+            if (scriptAttributeUtility == null)
+                return;
+
+            var getDrawerTypeForType = scriptAttributeUtility.GetMethod(
+                nameof(GetDrawerTypeForType),
+                AnimancerReflection.StaticBindings,
+                null,
+#if UNITY_6000_0_OR_NEWER
+                new Type[] { typeof(Type), typeof(Type[]), typeof(bool) },
+#elif UNITY_2022_3_OR_NEWER
+                new Type[] { typeof(Type), typeof(bool) },
+#else
+                new Type[] { typeof(Type) },
+#endif
+                null);
+            if (getDrawerTypeForType == null)
+                return;
+
+            GetDrawerTypeForType = (GetDrawerTypeForTypeDelegate)Delegate.CreateDelegate(
+                typeof(GetDrawerTypeForTypeDelegate),
+                getDrawerTypeForType);
+
+            var propertyDrawer = typeof(PropertyDrawer);
+            FieldField = propertyDrawer.GetField(FieldFieldName, AnimancerReflection.InstanceBindings);
+            AttributeField = propertyDrawer.GetField(AttributeFieldName, AnimancerReflection.InstanceBindings);
+
+            Selection.selectionChanged += OnSelectionChanged;
+        }
+
+        /************************************************************************************************************************/
+
+        private static readonly Dictionary<Type, PropertyDrawer>
+            ObjectTypeToDrawer = new();
+
+        private static readonly Dictionary<Type, PropertyDrawer>
+            DrawerTypeToInstance = new();
+
+        /// <summary>Tries to get a <see cref="PropertyDrawer"/> for the given `objectType`.</summary>
+        public static bool TryGetDrawer(
+            Type objectType,
+            FieldInfo field,
+            Attribute attribute,
+            out PropertyDrawer drawer)
+        {
+            if (GetDrawerTypeForType == null)
+            {
+                drawer = null;
+                return false;
+            }
+
+            if (ObjectTypeToDrawer.TryGetValue(objectType, out drawer))
+                return true;
+
+            Type drawerType;
+            try
+            {
+#if UNITY_6000_0_OR_NEWER
+                drawerType = GetDrawerTypeForType(objectType, Type.EmptyTypes, true);
+#elif UNITY_2022_3_OR_NEWER
+                drawerType = GetDrawerTypeForType(objectType, true);
+#else
+                drawerType = GetDrawerTypeForType(objectType);
+#endif
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+                ObjectTypeToDrawer.Add(objectType, null);
+                return false;
+            }
+
+            if (DrawerTypeToInstance.TryGetValue(drawerType, out drawer))
+            {
+                ObjectTypeToDrawer.Add(objectType, drawer);
+                return true;
+            }
+
+            try
+            {
+                drawer = (PropertyDrawer)Activator.CreateInstance(drawerType);
+
+                FieldField?.SetValue(drawer, field);
+                AttributeField?.SetValue(drawer, attribute);
+            }
+            catch (Exception exception)
+            {
+                Debug.LogException(exception);
+            }
+
+            ObjectTypeToDrawer.Add(objectType, drawer);
+            DrawerTypeToInstance.Add(drawerType, drawer);
+            return drawer != null;
+        }
+
+        /************************************************************************************************************************/
+
+        /// <summary>[Editor-Only]
+        /// Indicates that a cached <see cref="PropertyDrawer"/>
+        /// should not be kept in the cache after the selection changes.
+        /// </summary>
+        /// https://kybernetik.com.au/animancer/api/Animancer.Editor/IDiscardOnSelectionChange
+        public interface IDiscardOnSelectionChange { }
+
+        /************************************************************************************************************************/
+
+        /// <summary>Discards any cached <see cref="IDiscardOnSelectionChange"/> drawers.</summary>
+        private static void OnSelectionChanged()
+        {
+            DiscardOnSelectionChanged(ObjectTypeToDrawer);
+            DiscardOnSelectionChanged(DrawerTypeToInstance);
+        }
+
+        /************************************************************************************************************************/
+
+        /// <summary>Discards any cached <see cref="IDiscardOnSelectionChange"/> drawers.</summary>
+        private static void DiscardOnSelectionChanged(Dictionary<Type, PropertyDrawer> drawers)
+        {
+            var discard = ListPool<Type>.Instance.Acquire();
+
+            foreach (var drawer in drawers)
+                if (drawer.Value is IDiscardOnSelectionChange)
+                    discard.Add(drawer.Key);
+
+            for (int i = discard.Count - 1; i >= 0; i--)
+                drawers.Remove(discard[i]);
+
+            ListPool<Type>.Instance.Release(discard);
+        }
+
+        /************************************************************************************************************************/
+    }
+}
+
+#endif
+