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meta: added is_key_only_meta_associative_container[_v] to type traits

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This commit is contained in:
Michele Caini
2020-06-22 10:19:06 +02:00
parent f3d0e3f4dd
commit ad3413d6ad
2 changed files with 27 additions and 13 deletions
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16
src/entt/meta/meta.hpp
View File

@@ -69,14 +69,6 @@ private:
/*! @brief Proxy object for associative containers. */
class meta_associative_container {
template<typename, typename = void>
struct has_mapped_type: std::false_type {};
template<typename Type>
struct has_mapped_type<Type, std::void_t<typename meta_associative_container_traits<Type>::mapped_type>>
: std::true_type
{};
template<typename>
struct meta_associative_container_proxy;
@@ -1788,14 +1780,12 @@ inline std::pair<meta_sequence_container::iterator, bool> meta_sequence_containe
template<typename Type>
struct meta_associative_container::meta_associative_container_proxy {
static constexpr auto has_mapped_type = meta_associative_container::has_mapped_type<Type>::value;
[[nodiscard]] static meta_type key_type() {
return internal::meta_info<typename meta_associative_container_traits<Type>::key_type>::resolve();
}
[[nodiscard]] static meta_type mapped_type() {
if constexpr(has_mapped_type) {
if constexpr(is_key_only_meta_associative_container_v<Type>) {
return internal::meta_info<typename meta_associative_container_traits<Type>::mapped_type>::resolve();
} else {
return meta_type{};
@@ -1826,7 +1816,7 @@ struct meta_associative_container::meta_associative_container_proxy {
bool ret = false;
if(const auto *k_ptr = key.try_cast<typename meta_associative_container_traits<Type>::key_type>(); k_ptr) {
if constexpr(has_mapped_type) {
if constexpr(is_key_only_meta_associative_container_v<Type>) {
if(auto *m_ptr = value.try_cast<typename meta_associative_container_traits<Type>::mapped_type>(); m_ptr) {
ret = meta_associative_container_traits<Type>::insert(*static_cast<Type *>(container), *k_ptr, *m_ptr);
}
@@ -1867,7 +1857,7 @@ struct meta_associative_container::meta_associative_container_proxy {
*/
template<typename Type>
meta_associative_container::meta_associative_container(Type &container)
: key_only_container{!meta_associative_container_proxy<Type>::has_mapped_type},
: key_only_container{!is_key_only_meta_associative_container_v<Type>},
key_type_fn{&meta_associative_container_proxy<Type>::key_type},
mapped_type_fn{&meta_associative_container_proxy<Type>::mapped_type},
value_type_fn{&meta_associative_container_proxy<Type>::value_type},

24
src/entt/meta/type_traits.hpp
View File

@@ -72,6 +72,30 @@ template<typename Type>
inline constexpr auto has_meta_associative_container_traits_v = has_meta_associative_container_traits<Type>::value;
/**
* @brief Provides the member constant `value` to true if a meta associative
* container claims to wrap a key-only type, false otherwise.
* @tparam Type Potentially key-only meta associative container type.
*/
template<typename, typename = void>
struct is_key_only_meta_associative_container: std::false_type {};
/*! @copydoc is_key_only_meta_associative_container */
template<typename Type>
struct is_key_only_meta_associative_container<Type, std::void_t<typename meta_associative_container_traits<Type>::mapped_type>>
: std::true_type
{};
/**
* @brief Helper variable template.
* @tparam Type Potentially key-only meta associative container type.
*/
template<typename Type>
inline constexpr auto is_key_only_meta_associative_container_v = is_key_only_meta_associative_container<Type>::value;
/**
* @brief Provides the member constant `value` to true if a given type is a
* pointer-like type from the point of view of the meta system, false otherwise.