Add a QMetaAssociation

This requires refactoring of QMetaSequence, as they share a lot of
common functionality. QMetaAssociation provides a low level interface to
an associative container.

Task-number: QTBUG-81716
Change-Id: I273e00abd82f1549ba8803c323d82aa3a2d12ded
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 114 insertions, 8 deletions

diff --git a/src/corelib/global/qcontainerinfo.h b/src/corelib/global/qcontainerinfo.h
index c6ee9328ec..e0025fcef0 100644
--- a/src/corelib/global/qcontainerinfo.h
+++ b/src/corelib/global/qcontainerinfo.h
@@ -52,6 +52,12 @@ template<typename C>
 using value_type = typename C::value_type;
 
 template<typename C>
+using key_type = typename C::key_type;
+
+template<typename C>
+using mapped_type = typename C::mapped_type;
+
+template<typename C>
 using iterator = typename C::iterator;
 
 template<typename C>
@@ -62,6 +68,21 @@ QT_WARNING_PUSH
 QT_WARNING_DISABLE_CLANG("-Wunused-const-variable")
 
 template<typename C, typename = void>
+constexpr bool has_value_type_v = false;
+template<typename C>
+constexpr bool has_value_type_v<C, std::void_t<value_type<C>>> = true;
+
+template<typename C, typename = void>
+constexpr bool has_key_type_v = false;
+template<typename C>
+constexpr bool has_key_type_v<C, std::void_t<key_type<C>>> = true;
+
+template<typename C, typename = void>
+constexpr bool has_mapped_type_v = false;
+template<typename C>
+constexpr bool has_mapped_type_v<C, std::void_t<mapped_type<C>>> = true;
+
+template<typename C, typename = void>
 constexpr bool has_size_v = false;
 template<typename C>
 constexpr bool has_size_v<C, std::void_t<decltype(C().size())>> = true;
@@ -72,9 +93,14 @@ template<typename C>
 constexpr bool has_clear_v<C, std::void_t<decltype(C().clear())>> = true;
 
 template<typename, typename = void>
-constexpr bool has_at_v = false;
+constexpr bool has_at_index_v = false;
+template<typename C>
+constexpr bool has_at_index_v<C, std::void_t<decltype(C().at(0))>> = true;
+
+template<typename, typename = void>
+constexpr bool has_at_key_v = false;
 template<typename C>
-constexpr bool has_at_v<C, std::void_t<decltype(C().at(0))>> = true;
+constexpr bool has_at_key_v<C, std::void_t<decltype(C().at(key_type<C>()))>> = true;
 
 template<typename, typename = void>
 constexpr bool can_get_at_index_v = false;
@@ -122,19 +148,19 @@ template<typename C>
 constexpr bool has_const_iterator_v<C, std::void_t<const_iterator<C>>> = true;
 
 template<typename, typename = void>
-constexpr bool can_get_at_iterator_v = false;
+constexpr bool can_set_value_at_iterator_v = false;
 template<typename C>
-constexpr bool can_get_at_iterator_v<C, std::void_t<value_type<C>(decltype(*C().begin()))>> = true;
+constexpr bool can_set_value_at_iterator_v<C, std::void_t<decltype(*C().begin() = value_type<C>())>> = true;
 
 template<typename, typename = void>
-constexpr bool can_set_at_iterator_v = false;
+constexpr bool can_set_mapped_at_iterator_v = false;
 template<typename C>
-constexpr bool can_set_at_iterator_v<C, std::void_t<decltype(*C().begin() = value_type<C>())>> = true;
+constexpr bool can_set_mapped_at_iterator_v<C, std::void_t<decltype(*C().begin() = mapped_type<C>())>> = true;
 
 template<typename, typename = void>
-constexpr bool can_insert_at_iterator_v = false;
+constexpr bool can_insert_value_at_iterator_v = false;
 template<typename C>
-constexpr bool can_insert_at_iterator_v<C, std::void_t<decltype(C().insert(C().begin(), value_type<C>()))>> = true;
+constexpr bool can_insert_value_at_iterator_v<C, std::void_t<decltype(C().insert(C().begin(), value_type<C>()))>> = true;
 
 template<typename, typename = void>
 constexpr bool can_erase_at_iterator_v = false;
@@ -146,6 +172,86 @@ constexpr bool can_erase_range_at_iterator_v = false;
 template<typename C>
 constexpr bool can_erase_range_at_iterator_v<C, std::void_t<decltype(C().erase(C().begin(), C().end()))>> = true;
 
+template<typename, typename = void>
+constexpr bool can_get_at_key_v = false;
+template<typename C>
+constexpr bool can_get_at_key_v<C, std::void_t<mapped_type<C>(decltype(C()[key_type<C>()]))>> = true;
+
+template<typename, typename = void>
+constexpr bool can_set_at_key_v = false;
+template<typename C>
+constexpr bool can_set_at_key_v<C, std::void_t<decltype(C()[key_type<C>()] = mapped_type<C>())>> = true;
+
+template<typename, typename = void>
+constexpr bool can_erase_at_key_v = false;
+template<typename C>
+constexpr bool can_erase_at_key_v<C, std::void_t<decltype(C().erase(key_type<C>()))>> = true;
+
+template<typename, typename = void>
+constexpr bool can_remove_at_key_v = false;
+template<typename C>
+constexpr bool can_remove_at_key_v<C, std::void_t<decltype(C().remove(key_type<C>()))>> = true;
+
+template<typename, typename = void>
+constexpr bool can_insert_key_v = false;
+template<typename C>
+constexpr bool can_insert_key_v<C, std::void_t<decltype(C().insert(key_type<C>()))>> = true;
+
+template<typename, typename = void>
+constexpr bool can_insert_pair_v = false;
+template<typename C>
+constexpr bool can_insert_pair_v<C, std::void_t<decltype(C().insert({key_type<C>(), mapped_type<C>()}))>> = true;
+
+template<typename, typename = void>
+constexpr bool can_insert_key_mapped_v = false;
+template<typename C>
+constexpr bool can_insert_key_mapped_v<C, std::void_t<decltype(C().insert(key_type<C>(), mapped_type<C>()))>> = true;
+
+template<typename, typename = void>
+constexpr bool has_contains_v = false;
+template<typename C>
+constexpr bool has_contains_v<C, std::void_t<decltype(bool(C().contains(key_type<C>())))>> = true;
+
+template<typename, typename = void>
+constexpr bool has_find_v = false;
+template<typename C>
+constexpr bool has_find_v<C, std::void_t<decltype(C().find(key_type<C>()))>> = true;
+
+template<typename, typename = void>
+constexpr bool iterator_dereferences_to_value_v = false;
+template<typename C>
+constexpr bool iterator_dereferences_to_value_v<C, std::void_t<decltype(value_type<C>(*C().begin()))>> = true;
+
+template<typename, typename = void>
+constexpr bool iterator_has_key_v = false;
+template<typename C>
+constexpr bool iterator_has_key_v<C, std::void_t<decltype(key_type<C>(C().begin().key()))>> = true;
+
+template<typename, typename = void>
+constexpr bool value_type_has_first_v = false;
+template<typename C>
+constexpr bool value_type_has_first_v<C, std::void_t<decltype(key_type<C>(value_type<C>().first))>> = true;
+
+template<typename, typename = void>
+constexpr bool iterator_dereferences_to_key_v = false;
+template<typename C>
+constexpr bool iterator_dereferences_to_key_v<C, std::void_t<decltype(key_type<C>(*C().begin()))>> = true;
+
+template<typename, typename = void>
+constexpr bool iterator_has_value_v = false;
+template<typename C>
+constexpr bool iterator_has_value_v<C, std::void_t<decltype(mapped_type<C>(C().begin().value()))>> = true;
+
+template<typename, typename = void>
+constexpr bool value_type_has_second_v = false;
+template<typename C>
+constexpr bool value_type_has_second_v<C, std::void_t<decltype(mapped_type<C>(value_type<C>().second))>> = true;
+
+template<typename, typename = void>
+constexpr bool iterator_dereferences_to_mapped_v = false;
+template<typename C>
+constexpr bool iterator_dereferences_to_mapped_v<C, std::void_t<decltype(mapped_type<C>(*C().begin()))>> = true;
+
 QT_WARNING_POP
 
 }