Scarfski/entt
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

meta: auto-detect meta containers, use traits to opt-out

Browse Source
This commit is contained in:
skypjack
2026-02-22 15:17:02 +01:00
parent e14033b215
commit 8d4597ead0
2 changed files with 57 additions and 101 deletions
Download Patch File Download Diff File Expand all files Collapse all files

136
src/entt/meta/container.hpp
View File

@@ -3,20 +3,11 @@
#ifndef ENTT_META_CONTAINER_HPP
#define ENTT_META_CONTAINER_HPP
#include <array>
#include <concepts>
#include <cstddef>
#include <deque>
#include <iterator>
#include <list>
#include <map>
#include <set>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "../container/dense_map.hpp"
#include "../container/dense_set.hpp"
#include <utility>
#include "../core/concepts.hpp"
#include "../core/type_traits.hpp"
#include "context.hpp"
@@ -39,15 +30,27 @@ struct sequence_container_extent<Type>: integral_constant<std::tuple_size_v<Type
template<typename Type>
inline constexpr std::size_t sequence_container_extent_v = sequence_container_extent<Type>::value;
template<typename>
struct key_only_associative_container: std::true_type {};
template<typename Type>
concept meta_sequence_container_like = requires(Type elem) {
typename Type::value_type;
typename Type::iterator;
requires std::forward_iterator<typename Type::iterator>;
{ elem.begin() } -> std::same_as<typename Type::iterator>;
{ elem.end() } -> std::same_as<typename Type::iterator>;
requires !requires { typename Type::key_type; };
requires !requires { elem.substr(); };
};
template<typename Type>
requires requires { typename Type::mapped_type; }
struct key_only_associative_container<Type>: std::false_type {};
template<typename Type>
inline constexpr bool key_only_associative_container_v = key_only_associative_container<Type>::value;
concept meta_associative_container_like = requires(Type value) {
typename Type::key_type;
typename Type::value_type;
typename Type::iterator;
requires std::forward_iterator<typename Type::iterator>;
{ value.begin() } -> std::same_as<typename Type::iterator>;
{ value.end() } -> std::same_as<typename Type::iterator>;
value.find(std::declval<typename Type::key_type>());
};
} // namespace internal
/*! @endcond */
@@ -81,7 +84,7 @@ struct basic_meta_sequence_container_traits {
* @return True in case of success, false otherwise.
*/
[[nodiscard]] static bool clear([[maybe_unused]] void *container) {
if constexpr(extent == meta_dynamic_extent) {
if constexpr(requires(Type elem) { elem.clear(); }) {
static_cast<Type *>(container)->clear();
return true;
} else {
@@ -96,7 +99,7 @@ struct basic_meta_sequence_container_traits {
* @return True in case of success, false otherwise.
*/
[[nodiscard]] static bool reserve([[maybe_unused]] void *container, [[maybe_unused]] const size_type sz) {
if constexpr(requires(Type elem) { { elem.reserve(sz) }; }) {
if constexpr(requires(Type elem) { elem.reserve(sz); }) {
static_cast<Type *>(container)->reserve(sz);
return true;
} else {
@@ -111,7 +114,7 @@ struct basic_meta_sequence_container_traits {
* @return True in case of success, false otherwise.
*/
[[nodiscard]] static bool resize([[maybe_unused]] void *container, [[maybe_unused]] const size_type sz) {
if constexpr((extent == meta_dynamic_extent) && std::is_default_constructible_v<typename Type::value_type>) {
if constexpr(std::is_default_constructible_v<typename Type::value_type> && requires(Type elem) { elem.resize(sz); }) {
static_cast<Type *>(container)->resize(sz);
return true;
} else {
@@ -147,7 +150,7 @@ struct basic_meta_sequence_container_traits {
* @return A possibly invalid iterator to the inserted element.
*/
[[nodiscard]] static iterator insert([[maybe_unused]] const meta_ctx &area, [[maybe_unused]] void *container, [[maybe_unused]] const void *value, [[maybe_unused]] const void *cref, [[maybe_unused]] const iterator &it) {
if constexpr(extent == meta_dynamic_extent) {
if constexpr(requires(Type elem, typename Type::const_iterator it, Type::value_type instance) { elem.insert(it, instance); }) {
auto *const non_const = any_cast<typename Type::iterator>(&it.base());
return {area, static_cast<Type *>(container)->insert(
non_const ? *non_const : any_cast<const typename Type::const_iterator &>(it.base()),
@@ -165,7 +168,7 @@ struct basic_meta_sequence_container_traits {
* @return A possibly invalid iterator following the last removed element.
*/
[[nodiscard]] static iterator erase([[maybe_unused]] const meta_ctx &area, [[maybe_unused]] void *container, [[maybe_unused]] const iterator &it) {
if constexpr(extent == meta_dynamic_extent) {
if constexpr(requires(Type elem, typename Type::const_iterator it) { elem.erase(it); }) {
auto *const non_const = any_cast<typename Type::iterator>(&it.base());
return {area, static_cast<Type *>(container)->erase(non_const ? *non_const : any_cast<const typename Type::const_iterator &>(it.base()))};
} else {
@@ -186,7 +189,7 @@ struct basic_meta_associative_container_traits {
using iterator = meta_associative_container::iterator;
/*! @brief True in case of key-only containers, false otherwise. */
static constexpr bool key_only = internal::key_only_associative_container_v<Type>;
static constexpr bool key_only = !requires { typename Type::mapped_type; };
/**
* @brief Returns the number of elements in a container.
@@ -214,7 +217,7 @@ struct basic_meta_associative_container_traits {
* @return True in case of success, false otherwise.
*/
[[nodiscard]] static bool reserve([[maybe_unused]] void *container, [[maybe_unused]] const size_type sz) {
if constexpr(requires(Type elem) { { elem.reserve(sz) }; }) {
if constexpr(requires(Type elem) { elem.reserve(sz); }) {
static_cast<Type *>(container)->reserve(sz);
return true;
} else {
@@ -277,87 +280,18 @@ struct basic_meta_associative_container_traits {
};
/**
* @brief Meta sequence container traits for `std::vector`s of any type.
* @tparam Args Template arguments for the container.
* @brief Traits meta sequence container like types.
* @tparam Type Container type to inspect.
*/
template<typename... Args>
struct meta_sequence_container_traits<std::vector<Args...>>
: basic_meta_sequence_container_traits<std::vector<Args...>> {};
template<internal::meta_sequence_container_like Type>
struct meta_sequence_container_traits<Type>: basic_meta_sequence_container_traits<Type> {};
/**
* @brief Meta sequence container traits for `std::array`s of any type.
* @tparam Type Template arguments for the container.
* @tparam N Template arguments for the container.
* @brief Traits for meta associative container like types.
* @tparam Type Container type to inspect.
*/
template<typename Type, auto N>
struct meta_sequence_container_traits<std::array<Type, N>>
: basic_meta_sequence_container_traits<std::array<Type, N>> {};
/**
* @brief Meta sequence container traits for `std::list`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_sequence_container_traits<std::list<Args...>>
: basic_meta_sequence_container_traits<std::list<Args...>> {};
/**
* @brief Meta sequence container traits for `std::deque`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_sequence_container_traits<std::deque<Args...>>
: basic_meta_sequence_container_traits<std::deque<Args...>> {};
/**
* @brief Meta associative container traits for `std::map`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<std::map<Args...>>
: basic_meta_associative_container_traits<std::map<Args...>> {};
/**
* @brief Meta associative container traits for `std::unordered_map`s of any
* type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<std::unordered_map<Args...>>
: basic_meta_associative_container_traits<std::unordered_map<Args...>> {};
/**
* @brief Meta associative container traits for `std::set`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<std::set<Args...>>
: basic_meta_associative_container_traits<std::set<Args...>> {};
/**
* @brief Meta associative container traits for `std::unordered_set`s of any
* type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<std::unordered_set<Args...>>
: basic_meta_associative_container_traits<std::unordered_set<Args...>> {};
/**
* @brief Meta associative container traits for `dense_map`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<dense_map<Args...>>
: basic_meta_associative_container_traits<dense_map<Args...>> {};
/**
* @brief Meta associative container traits for `dense_set`s of any type.
* @tparam Args Template arguments for the container.
*/
template<typename... Args>
struct meta_associative_container_traits<dense_set<Args...>>
: basic_meta_associative_container_traits<dense_set<Args...>> {};
template<internal::meta_associative_container_like Type>
struct meta_associative_container_traits<Type>: basic_meta_associative_container_traits<Type> {};
} // namespace entt

22
test/entt/meta/meta_container.cpp
View File

@@ -3,6 +3,8 @@
#include <list>
#include <map>
#include <set>
#include <string>
#include <string_view>
#include <utility>
#include <vector>
#include <gtest/gtest.h>
@@ -63,6 +65,26 @@ TEST(SequenceContainer, Iterator) {
ASSERT_EQ((--first)->cast<int>(), 2);
}
TEST(SequenceContainer, StdString) {
std::string str{};
auto any = entt::forward_as_meta(str);
auto view = any.as_sequence_container();
auto cview = std::as_const(any).as_sequence_container();
ASSERT_FALSE(view);
ASSERT_FALSE(cview);
}
TEST(SequenceContainer, StdStringView) {
std::string_view str{};
auto any = entt::forward_as_meta(str);
auto view = any.as_sequence_container();
auto cview = std::as_const(any).as_sequence_container();
ASSERT_FALSE(view);
ASSERT_FALSE(cview);
}
TEST(SequenceContainer, StdVector) {
std::vector<int> vec{};
auto any = entt::forward_as_meta(vec);