Add PropertyDrawerCache

Author: mackysoft

Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/PropertyDrawerCache.cs

@@ -0,0 +1,52 @@
+#if UNITY_2019_3_OR_NEWER
+using System;
+using System.Collections.Generic;
+using UnityEditor;
+using System.Reflection;
+
+namespace MackySoft.SerializeReferenceExtensions.Editor
+{
+	public static class PropertyDrawerCache
+	{
+
+		static readonly Dictionary<Type, PropertyDrawer> s_Caches = new Dictionary<Type, PropertyDrawer>();
+
+		public static bool TryGetPropertyDrawer (Type type,out PropertyDrawer drawer)
+		{
+			if (!s_Caches.TryGetValue(type,out drawer))
+			{
+				Type drawerType = GetCustomPropertyDrawerType(type);
+				drawer = (drawerType != null) ? (PropertyDrawer)Activator.CreateInstance(drawerType) : null;
+
+				s_Caches.Add(type, drawer);
+			}
+			return (drawer != null);
+		}
+
+		static Type GetCustomPropertyDrawerType (Type type)
+		{
+			foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies())
+			{
+				foreach (Type drawerType in assembly.GetTypes())
+				{
+					var customPropertyDrawerAttributes = drawerType.GetCustomAttributes(typeof(CustomPropertyDrawer), true);
+					foreach (CustomPropertyDrawer customPropertyDrawer in customPropertyDrawerAttributes)
+					{
+						var field = customPropertyDrawer.GetType().GetField("m_Type", BindingFlags.NonPublic | BindingFlags.Instance);
+						if (field != null)
+						{
+							var fieldType = field.GetValue(customPropertyDrawer) as Type;
+							if (fieldType != null && fieldType == type)
+							{
+								return drawerType;
+							}
+						}
+					}
+				}
+			}
+			return null;
+		}
+
+	}
+}
+#endif