added component editor utility to upgrade/downgrade components

XRTK-Core/Packages/com.xrtk.core/Editor/Utilities/ComponentEditorUtility.cs

@@ -0,0 +1,151 @@
+using System;
+using UnityEditor;
+using UnityEngine;
+using Object = UnityEngine.Object;
+
+namespace XRTK.Editor.Utilities
+{
+    public static class ComponentEditorUtility
+    {
+        private class ComponentUpgradePopup : EditorWindow
+        {
+            private bool initializedPosition;
+
+            private TypeCache.TypeCollection types;
+
+            private Component component;
+
+            private void OnEnable()
+            {
+                GetWindow(typeof(ComponentUpgradePopup));
+            }
+
+            public void Init(Component component, TypeCache.TypeCollection types)
+            {
+                this.component = component;
+                this.types = types;
+            }
+
+            private void OnGUI()
+            {
+                if (!initializedPosition)
+                {
+                    Vector2 mousePos = GUIUtility.GUIToScreenPoint(Event.current.mousePosition);
+                    position = new Rect(mousePos.x - (position.width / 2), mousePos.y, position.width, position.height);
+                    initializedPosition = true;
+                }
+
+                GUILayout.Space(20);
+
+                foreach (var type in types)
+                {
+                    if (GUILayout.Button(new GUIContent(type.Name)))
+                    {
+                        ReplaceComponent(type, component);
+                        Close();
+                    }
+                }
+            }
+        }
+
+        [MenuItem("CONTEXT/Component/Upgrade Component", true, 9998)]
+        private static bool UpgradeValidate(MenuCommand command)
+        {
+            if (command.context is not Component component)
+            {
+                return false;
+            }
+
+            var types = TypeCache.GetTypesDerivedFrom(component.GetType());
+            return types.Count > 0;
+        }
+
+        [MenuItem("CONTEXT/Component/Upgrade Component", false, 9998)]
+        private static void Upgrade(MenuCommand command)
+        {
+            if (command.context is not Component component)
+            {
+                return;
+            }
+
+            var types = TypeCache.GetTypesDerivedFrom(command.context.GetType());
+
+            if (types.Count == 1)
+            {
+                ReplaceComponent(types[0], component);
+            }
+            else
+            {
+                Debug.Log(EditorWindow.focusedWindow.GetType().Name);
+                var typePicker = ScriptableObject.CreateInstance<ComponentUpgradePopup>();
+                typePicker.Init(component, types);
+                typePicker.ShowPopup();
+            }
+        }
+
+        [MenuItem("CONTEXT/Component/Downgrade Component", true, 9999)]
+        private static bool DowngradeValidate(MenuCommand command)
+        {
+            if (command.context is not Component component)
+            {
+                return false;
+            }
+
+            var baseType = component.GetType().BaseType;
+            return baseType != typeof(MonoBehaviour) &&
+                   baseType != typeof(Component) &&
+                   baseType != typeof(Behaviour) &&
+                   baseType != typeof(Transform) &&
+                   baseType!.IsClass && !baseType!.IsAbstract;
+        }
+
+        [MenuItem("CONTEXT/Component/Downgrade Component", false, 9999)]
+        private static void Downgrade(MenuCommand command)
+        {
+            if (command.context is not Component component)
+            {
+                return;
+            }
+
+            ReplaceComponent(component.GetType().BaseType, component);
+        }
+
+        private static void ReplaceComponent(Type type, Component @base)
+        {
+            var baseType = @base.GetType();
+            var serializedSource = new SerializedObject(@base);
+            var gameObject = @base.gameObject;
+            Object.DestroyImmediate(@base);
+            var component = gameObject.AddComponent(type);
+
+            // if something bad happened revert
+            if (component == null)
+            {
+                component = gameObject.AddComponent(baseType);
+            }
+
+            SerializedObject serializedTarget = new SerializedObject(component);
+            SerializedProperty iterator = serializedSource.GetIterator();
+
+            // jump into serialized object, this will skip script type so that we don't override the destination component's type
+            if (iterator.NextVisible(true))
+            {
+                // iterate through all serializedProperties
+                while (iterator.NextVisible(true))
+                {
+                    // try obtaining the property in destination component
+                    SerializedProperty element = serializedTarget.FindProperty(iterator.name);
+
+                    // validate that the properties are present in both components, and that they're the same type
+                    if (element != null && element.propertyType == iterator.propertyType)
+                    {
+                        // copy value from source to destination component
+                        serializedTarget.CopyFromSerializedProperty(iterator);
+                    }
+                }
+            }
+
+            serializedTarget.ApplyModifiedProperties();
+        }
+    }
+}