meta: prepare for further changes

src/entt/meta/factory.hpp

@@ -30,13 +30,14 @@ namespace internal {
 class basic_meta_factory {
     using invoke_type = std::remove_pointer_t<decltype(meta_func_node::invoke)>;
 
-    auto *find_overload() {
-        auto *curr = &details->func[bucket];
-
-        while(curr->invoke != invoke) {
-            curr = curr->next.get();
-        }
+    template<typename Type>
+    auto *find_member(Type &from) {
+        return &from[bucket];
+    }
 
+    auto *find_overload() {
+        auto *curr = find_member(details->func);
+        for(; curr->invoke != invoke; curr = curr->next.get()) {}
         return curr;
     }
 
@@ -49,20 +50,17 @@ protected:
         elem.id = id;
     }
 
-    void base(const id_type id, meta_base_node node) {
-        details->base.insert_or_assign(id, node);
-        invoke = nullptr;
-        bucket = parent;
-    }
-
-    void conv(const id_type id, meta_conv_node node) {
-        details->conv.insert_or_assign(id, node);
-        invoke = nullptr;
-        bucket = parent;
-    }
+    template<typename Type>
+    void insert_or_assign(const id_type id, Type node) {
+        if constexpr(std::is_same_v<Type, meta_base_node>) {
+            details->base.insert_or_assign(id, node);
+        } else if constexpr(std::is_same_v<Type, meta_conv_node>) {
+            details->conv.insert_or_assign(id, node);
+        } else {
+            static_assert(std::is_same_v<Type, meta_ctor_node>, "Unexpected type");
+            details->ctor.insert_or_assign(id, node);
+        }
 
-    void ctor(const id_type id, meta_ctor_node node) {
-        details->ctor.insert_or_assign(id, node);
         invoke = nullptr;
         bucket = parent;
     }
@@ -112,7 +110,7 @@ protected:
         if(bucket == parent) {
             details->prop[key] = std::move(value);
         } else if(invoke == nullptr) {
-            details->data[bucket].prop[key] = std::move(value);
+            find_member(details->data)->prop[key] = std::move(value);
         } else {
             find_overload()->prop[key] = std::move(value);
         }
@@ -122,7 +120,7 @@ protected:
         if(bucket == parent) {
             meta_context::from(*ctx).value[bucket].traits |= value;
         } else if(invoke == nullptr) {
-            details->data[bucket].traits |= value;
+            find_member(details->data)->traits |= value;
         } else {
             find_overload()->traits |= value;
         }
@@ -132,7 +130,7 @@ protected:
         if(bucket == parent) {
             meta_context::from(*ctx).value[bucket].custom = std::move(node);
         } else if(invoke == nullptr) {
-            details->data[bucket].custom = std::move(node);
+            find_member(details->data)->custom = std::move(node);
         } else {
             find_overload()->custom = std::move(node);
         }
@@ -223,7 +221,7 @@ public:
     meta_factory base() noexcept {
         static_assert(!std::is_same_v<Type, Base> && std::is_base_of_v<Base, Type>, "Invalid base type");
         auto *const op = +[](const void *instance) noexcept { return static_cast<const void *>(static_cast<const Base *>(static_cast<const Type *>(instance))); };
-        base_type::base(type_id<Base>().hash(), internal::meta_base_node{&internal::resolve<Base>, op});
+        base_type::insert_or_assign(type_id<Base>().hash(), internal::meta_base_node{&internal::resolve<Base>, op});
         return *this;
     }
 
@@ -243,7 +241,7 @@ public:
     auto conv() noexcept {
         using conv_type = std::remove_cv_t<std::remove_reference_t<std::invoke_result_t<decltype(Candidate), Type &>>>;
         auto *const op = +[](const meta_ctx &area, const void *instance) { return forward_as_meta(area, std::invoke(Candidate, *static_cast<const Type *>(instance))); };
-        base_type::conv(type_id<conv_type>().hash(), internal::meta_conv_node{op});
+        base_type::insert_or_assign(type_id<conv_type>().hash(), internal::meta_conv_node{op});
         return *this;
     }
 
@@ -260,7 +258,7 @@ public:
     meta_factory conv() noexcept {
         using conv_type = std::remove_cv_t<std::remove_reference_t<To>>;
         auto *const op = +[](const meta_ctx &area, const void *instance) { return forward_as_meta(area, static_cast<To>(*static_cast<const Type *>(instance))); };
-        base_type::conv(type_id<conv_type>().hash(), internal::meta_conv_node{op});
+        base_type::insert_or_assign(type_id<conv_type>().hash(), internal::meta_conv_node{op});
         return *this;
     }
 
@@ -282,7 +280,7 @@ public:
         using descriptor = meta_function_helper_t<Type, decltype(Candidate)>;
         static_assert(Policy::template value<typename descriptor::return_type>, "Invalid return type for the given policy");
         static_assert(std::is_same_v<std::remove_cv_t<std::remove_reference_t<typename descriptor::return_type>>, Type>, "The function doesn't return an object of the required type");
-        base_type::ctor(type_id<typename descriptor::args_type>().hash(), internal::meta_ctor_node{descriptor::args_type::size, &meta_arg<typename descriptor::args_type>, &meta_construct<Type, Candidate, Policy>});
+        base_type::insert_or_assign(type_id<typename descriptor::args_type>().hash(), internal::meta_ctor_node{descriptor::args_type::size, &meta_arg<typename descriptor::args_type>, &meta_construct<Type, Candidate, Policy>});
         return *this;
     }
 
@@ -301,7 +299,7 @@ public:
         // default constructor is already implicitly generated, no need for redundancy
         if constexpr(sizeof...(Args) != 0u) {
             using descriptor = meta_function_helper_t<Type, Type (*)(Args...)>;
-            base_type::ctor(type_id<typename descriptor::args_type>().hash(), internal::meta_ctor_node{descriptor::args_type::size, &meta_arg<typename descriptor::args_type>, &meta_construct<Type, Args...>});
+            base_type::insert_or_assign(type_id<typename descriptor::args_type>().hash(), internal::meta_ctor_node{descriptor::args_type::size, &meta_arg<typename descriptor::args_type>, &meta_construct<Type, Args...>});
         }
 
         return *this;