meta: make instances meta handles all around the codebase

src/entt/meta/factory.hpp

@@ -76,14 +76,14 @@ template<typename Type, typename... Args, std::size_t... Indexes>
 
 
 template<typename Type, auto Data>
-[[nodiscard]] bool setter([[maybe_unused]] meta_any instance, [[maybe_unused]] meta_any value) {
+[[nodiscard]] bool setter([[maybe_unused]] meta_handle instance, [[maybe_unused]] meta_any value) {
     bool accepted = false;
 
     if constexpr(std::is_function_v<std::remove_reference_t<std::remove_pointer_t<decltype(Data)>>> || std::is_member_function_pointer_v<decltype(Data)>) {
         using helper_type = meta_function_helper_t<decltype(Data)>;
         using data_type = std::tuple_element_t<!std::is_member_function_pointer_v<decltype(Data)>, typename helper_type::args_type>;
 
-        if(auto * const clazz = instance.try_cast<Type>(); clazz) {
+        if(auto * const clazz = (*instance).try_cast<Type>(); clazz) {
             if(auto * const direct = value.try_cast<data_type>(); direct || value.convert<data_type>()) {
                 std::invoke(Data, *clazz, direct ? *direct : value.cast<data_type>());
                 accepted = true;
@@ -93,7 +93,7 @@ template<typename Type, auto Data>
         using data_type = std::remove_cv_t<std::remove_reference_t<decltype(std::declval<Type>().*Data)>>;
 
         if constexpr(!std::is_array_v<data_type>) {
-            if(auto * const clazz = instance.try_cast<Type>(); clazz) {
+            if(auto * const clazz = (*instance).try_cast<Type>(); clazz) {
                 if(auto * const direct = value.try_cast<data_type>(); direct || value.convert<data_type>()) {
                     std::invoke(Data, clazz) = (direct ? *direct : value.cast<data_type>());
                     accepted = true;
@@ -116,7 +116,7 @@ template<typename Type, auto Data>
 
 
 template<typename Type, auto Data, typename Policy>
-[[nodiscard]] meta_any getter([[maybe_unused]] meta_any instance) {
+[[nodiscard]] meta_any getter([[maybe_unused]] meta_handle instance) {
     auto dispatch = [](auto &&value) {
         if constexpr(std::is_same_v<Policy, as_void_t>) {
             return meta_any{std::in_place_type<void>, std::forward<decltype(value)>(value)};
@@ -129,13 +129,13 @@ template<typename Type, auto Data, typename Policy>
     };
 
     if constexpr(std::is_function_v<std::remove_reference_t<std::remove_pointer_t<decltype(Data)>>> || std::is_member_function_pointer_v<decltype(Data)>) {
-        auto * const clazz = instance.try_cast<Type>();
+        auto * const clazz = (*instance).try_cast<Type>();
         return clazz ? dispatch(std::invoke(Data, *clazz)) : meta_any{};
     } else if constexpr(std::is_member_object_pointer_v<decltype(Data)>) {
         if constexpr(std::is_array_v<std::remove_cv_t<std::remove_reference_t<decltype(std::declval<Type>().*Data)>>>) {
             return meta_any{};
         } else {
-            auto * const clazz = instance.try_cast<Type>();
+            auto * const clazz = (*instance).try_cast<Type>();
             return clazz ? dispatch(std::invoke(Data, clazz)) : meta_any{};
         }
     } else if constexpr(std::is_pointer_v<std::decay_t<decltype(Data)>>) {
@@ -151,7 +151,7 @@ template<typename Type, auto Data, typename Policy>
 
 
 template<typename Type, auto Candidate, typename Policy, std::size_t... Indexes>
-[[nodiscard]] meta_any invoke([[maybe_unused]] meta_any instance, meta_any *args, std::index_sequence<Indexes...>) {
+[[nodiscard]] meta_any invoke([[maybe_unused]] meta_handle instance, meta_any *args, std::index_sequence<Indexes...>) {
     using helper_type = meta_function_helper_t<decltype(Candidate)>;
 
     auto dispatch = [](auto *... params) {
@@ -179,7 +179,7 @@ template<typename Type, auto Candidate, typename Policy, std::size_t... Indexes>
     if constexpr(std::is_function_v<std::remove_reference_t<std::remove_pointer_t<decltype(Candidate)>>>) {
         return (std::get<Indexes>(direct) && ...) ? dispatch(std::get<Indexes>(direct)...) : meta_any{};
     } else {
-        auto * const clazz = instance.try_cast<Type>();
+        auto * const clazz = (*instance).try_cast<Type>();
         return (clazz && (std::get<Indexes>(direct) && ...)) ? dispatch(clazz, std::get<Indexes>(direct)...) : meta_any{};
     }
 }
@@ -682,7 +682,7 @@ public:
             !std::is_member_function_pointer_v<decltype(Candidate)>,
             &internal::meta_info<std::conditional_t<std::is_same_v<Policy, as_void_t>, void, typename helper_type::return_type>>::resolve,
             &helper_type::arg,
-            [](meta_any instance, meta_any *args) {
+            [](meta_handle instance, meta_any *args) {
                 return internal::invoke<Type, Candidate, Policy>(std::move(instance), args, std::make_index_sequence<std::tuple_size_v<typename helper_type::args_type>>{});
             }
         };

src/entt/meta/internal.hpp

@@ -17,6 +17,7 @@ namespace entt {
 
 
 class meta_any;
+struct meta_handle;
 
 
 /**
@@ -78,8 +79,8 @@ struct meta_data_node {
     meta_prop_node * prop;
     const bool is_static;
     meta_type_node *(* const type)() ENTT_NOEXCEPT;
-    bool(* const set)(meta_any, meta_any);
-    meta_any(* const get)(meta_any);
+    bool(* const set)(meta_handle, meta_any);
+    meta_any(* const get)(meta_handle);
 };
 
 
@@ -94,7 +95,7 @@ struct meta_func_node {
     const bool is_static;
     meta_type_node *(* const ret)() ENTT_NOEXCEPT;
     meta_type_node *(* const arg)(size_type) ENTT_NOEXCEPT;
-    meta_any(* const invoke)(meta_any, meta_any *);
+    meta_any(* const invoke)(meta_handle, meta_any *);
 };
 
 

src/entt/meta/meta.hpp

@@ -333,7 +333,7 @@ public:
      * @brief Indirection operator for aliasing construction.
      * @return A meta any that shares a reference to an unmanaged object.
      */
-    [[nodiscard]] meta_any operator *() const ENTT_NOEXCEPT {
+    [[nodiscard]] meta_any operator*() const ENTT_NOEXCEPT {
         return ref();
     }
 
@@ -432,8 +432,8 @@ struct meta_handle {
     }
 
     /*! @copydoc meta_any::operator* */
-    [[nodiscard]] meta_any operator *() const {
-        return *any;
+    [[nodiscard]] meta_any operator*() const {
+        return any;
     }
 
 private:
@@ -711,7 +711,7 @@ struct meta_data {
      */
     template<typename Type>
     bool set(meta_handle instance, Type &&value) const {
-        return node->set && node->set(*instance, std::forward<Type>(value));
+        return node->set && node->set(std::move(instance), std::forward<Type>(value));
     }
 
     /**
@@ -724,7 +724,7 @@ struct meta_data {
      * @return A meta any containing the value of the underlying variable.
      */
     [[nodiscard]] meta_any get(meta_handle instance) const {
-        return node->get(*instance);
+        return node->get(std::move(instance));
     }
 
     /*! @copydoc meta_ctor::prop */
@@ -843,8 +843,18 @@ struct meta_func {
      */
     template<typename... Args>
     meta_any invoke(meta_handle instance, Args &&... args) const {
-        meta_any arguments[]{*instance, std::forward<Args>(args)...};
-        return sizeof...(Args) == size() ? node->invoke(arguments[0], &arguments[sizeof...(Args) != 0]) : meta_any{};
+        meta_any any{};
+
+        if(sizeof...(Args) == size()) {
+            if constexpr(sizeof...(Args) == 0) {
+                any = node->invoke(std::move(instance), nullptr);
+            } else {
+                meta_any arguments[]{std::forward<Args>(args)...};
+                any = node->invoke(std::move(instance), arguments);
+            }
+        }
+
+        return any;
     }
 
     /*! @copydoc meta_ctor::prop */