Merge branch 'minimal_element_leak' into 'master'

Minimal solution to UI Element leak

See merge request OpenMW/openmw!2770

components/lua_ui/element.cpp

@@ -189,8 +189,8 @@ namespace LuaUi
         assert(!mRoot);
         if (!mRoot)
         {
-            mRoot = createWidget(mLayout, 0);
-            mLayer = setLayer(mRoot, mLayout);
+            mRoot = createWidget(layout(), 0);
+            mLayer = setLayer(mRoot, layout());
             updateAttachment();
         }
     }
@@ -199,16 +199,16 @@ namespace LuaUi
     {
         if (mRoot && mUpdate)
         {
-            if (mRoot->widget()->getTypeName() != widgetType(mLayout))
+            if (mRoot->widget()->getTypeName() != widgetType(layout()))
             {
                 destroyWidget(mRoot);
-                mRoot = createWidget(mLayout, 0);
+                mRoot = createWidget(layout(), 0);
             }
             else
             {
-                updateWidget(mRoot, mLayout, 0);
+                updateWidget(mRoot, layout(), 0);
             }
-            mLayer = setLayer(mRoot, mLayout);
+            mLayer = setLayer(mRoot, layout());
             updateAttachment();
         }
         mUpdate = false;
@@ -216,9 +216,11 @@ namespace LuaUi
 
     void Element::destroy()
     {
-        if (mRoot)
-            destroyWidget(mRoot);
+        if (!mRoot)
+            return;
+        destroyWidget(mRoot);
         mRoot = nullptr;
+        mLayout = sol::make_object(mLayout.lua_state(), sol::nil);
         sAllElements.erase(this);
     }
 

components/lua_ui/element.hpp

@@ -18,7 +18,7 @@ namespace LuaUi
 
         WidgetExtension* mRoot;
         WidgetExtension* mAttachedTo;
-        sol::table mLayout;
+        sol::object mLayout;
         std::string mLayer;
         bool mUpdate;
         bool mDestroy;
@@ -36,6 +36,7 @@ namespace LuaUi
 
     private:
         Element(sol::table layout);
+        sol::table layout() { return mLayout.as<sol::table>(); }
         static std::map<Element*, std::shared_ptr<Element>> sAllElements;
         void updateAttachment();
     };

files/lua_api/openmw/ui.lua

@@ -239,6 +239,7 @@
 
 ---
 -- Access or replace the element's layout
+--   Note: Is reset to `nil` on `destroy`
 -- @field [parent=#Element] #Layout layout
 
 ---