// <any> -*- C++ -*-
-// Copyright (C) 2014-2018 Free Software Foundation, Inc.
+// Copyright (C) 2014-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
#if __cplusplus >= 201703L
+#include <initializer_list>
#include <typeinfo>
#include <new>
-#include <utility>
#include <type_traits>
+#include <bits/utility.h> // in_place_type_t
namespace std _GLIBCXX_VISIBILITY(default)
{
#endif
}
-#define __cpp_lib_any 201603
+#define __cpp_lib_any 201606L
/**
* @brief A type-safe container of any type.
*
- * An @c any object's state is either empty or it stores a contained object
+ * An `any` object's state is either empty or it stores a contained object
* of CopyConstructible type.
+ *
+ * @since C++17
*/
class any
{
struct _Manager_external; // creates contained object on the heap
template<typename _Tp>
- using _Manager = conditional_t<_Internal<_Tp>::value,
- _Manager_internal<_Tp>,
- _Manager_external<_Tp>>;
+ using _Manager = __conditional_t<_Internal<_Tp>::value,
+ _Manager_internal<_Tp>,
+ _Manager_external<_Tp>>;
- template<typename _Tp, typename _Decayed = decay_t<_Tp>>
- using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>;
+ template<typename _Tp, typename _VTp = decay_t<_Tp>>
+ using _Decay_if_not_any = enable_if_t<!is_same_v<_VTp, any>, _VTp>;
/// Emplace with an object created from @p __args as the contained object.
template <typename _Tp, typename... _Args,
void __do_emplace(initializer_list<_Up> __il, _Args&&... __args)
{
reset();
- _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
+ _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
_M_manager = &_Mgr::_S_manage;
}
+ template <typename _Res, typename _Tp, typename... _Args>
+ using __any_constructible
+ = enable_if<__and_<is_copy_constructible<_Tp>,
+ is_constructible<_Tp, _Args...>>::value,
+ _Res>;
+
+ template <typename _Tp, typename... _Args>
+ using __any_constructible_t
+ = typename __any_constructible<bool, _Tp, _Args...>::type;
+
+ template<typename _VTp, typename... _Args>
+ using __emplace_t
+ = typename __any_constructible<_VTp&, _VTp, _Args...>::type;
+
public:
// construct/destruct
}
}
- template <typename _Res, typename _Tp, typename... _Args>
- using __any_constructible =
- enable_if<__and_<is_copy_constructible<_Tp>,
- is_constructible<_Tp, _Args...>>::value,
- _Res>;
-
- template <typename _Tp, typename... _Args>
- using __any_constructible_t =
- typename __any_constructible<bool, _Tp, _Args...>::type;
-
/// Construct with a copy of @p __value as the contained object.
- template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
- typename _Mgr = _Manager<_Tp>,
- __any_constructible_t<_Tp, _ValueType&&> = true,
- enable_if_t<!__is_in_place_type<_Tp>::value, bool> = true>
- any(_ValueType&& __value)
+ template <typename _Tp, typename _VTp = _Decay_if_not_any<_Tp>,
+ typename _Mgr = _Manager<_VTp>,
+ typename = _Require<__not_<__is_in_place_type<_VTp>>,
+ is_copy_constructible<_VTp>>>
+ any(_Tp&& __value)
: _M_manager(&_Mgr::_S_manage)
{
- _Mgr::_S_create(_M_storage, std::forward<_ValueType>(__value));
- }
-
- /// Construct with a copy of @p __value as the contained object.
- template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
- typename _Mgr = _Manager<_Tp>,
- enable_if_t<__and_<is_copy_constructible<_Tp>,
- __not_<is_constructible<_Tp, _ValueType&&>>,
- __not_<__is_in_place_type<_Tp>>>::value,
- bool> = false>
- any(_ValueType&& __value)
- : _M_manager(&_Mgr::_S_manage)
- {
- _Mgr::_S_create(_M_storage, __value);
+ _Mgr::_S_create(_M_storage, std::forward<_Tp>(__value));
}
/// Construct with an object created from @p __args as the contained object.
- template <typename _ValueType, typename... _Args,
- typename _Tp = _Decay<_ValueType>,
- typename _Mgr = _Manager<_Tp>,
- __any_constructible_t<_Tp, _Args&&...> = false>
+ template <typename _Tp, typename... _Args, typename _VTp = decay_t<_Tp>,
+ typename _Mgr = _Manager<_VTp>,
+ __any_constructible_t<_VTp, _Args&&...> = false>
explicit
- any(in_place_type_t<_ValueType>, _Args&&... __args)
+ any(in_place_type_t<_Tp>, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
- _Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
+ _Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
}
/// Construct with an object created from @p __il and @p __args as
/// the contained object.
- template <typename _ValueType, typename _Up, typename... _Args,
- typename _Tp = _Decay<_ValueType>,
- typename _Mgr = _Manager<_Tp>,
- __any_constructible_t<_Tp, initializer_list<_Up>,
+ template <typename _Tp, typename _Up, typename... _Args,
+ typename _VTp = decay_t<_Tp>, typename _Mgr = _Manager<_VTp>,
+ __any_constructible_t<_VTp, initializer_list<_Up>&,
_Args&&...> = false>
explicit
- any(in_place_type_t<_ValueType>,
- initializer_list<_Up> __il, _Args&&... __args)
+ any(in_place_type_t<_Tp>, initializer_list<_Up> __il, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
- _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
+ _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
}
/// Destructor, calls @c reset()
// assignments
/// Copy the state of another object.
- any& operator=(const any& __rhs)
+ any&
+ operator=(const any& __rhs)
{
*this = any(__rhs);
return *this;
*
* @post @c !__rhs.has_value() (not guaranteed for other implementations)
*/
- any& operator=(any&& __rhs) noexcept
+ any&
+ operator=(any&& __rhs) noexcept
{
if (!__rhs.has_value())
reset();
}
/// Store a copy of @p __rhs as the contained object.
- template<typename _ValueType>
- enable_if_t<is_copy_constructible<_Decay<_ValueType>>::value, any&>
- operator=(_ValueType&& __rhs)
+ template<typename _Tp>
+ enable_if_t<is_copy_constructible<_Decay_if_not_any<_Tp>>::value, any&>
+ operator=(_Tp&& __rhs)
{
- *this = any(std::forward<_ValueType>(__rhs));
+ *this = any(std::forward<_Tp>(__rhs));
return *this;
}
/// Emplace with an object created from @p __args as the contained object.
- template <typename _ValueType, typename... _Args>
- typename __any_constructible<_Decay<_ValueType>&,
- _Decay<_ValueType>, _Args&&...>::type
+ template <typename _Tp, typename... _Args>
+ __emplace_t<decay_t<_Tp>, _Args...>
emplace(_Args&&... __args)
{
- __do_emplace<_Decay<_ValueType>>(std::forward<_Args>(__args)...);
- any::_Arg __arg;
- this->_M_manager(any::_Op_access, this, &__arg);
- return *static_cast<_Decay<_ValueType>*>(__arg._M_obj);
+ using _VTp = decay_t<_Tp>;
+ __do_emplace<_VTp>(std::forward<_Args>(__args)...);
+ return *any::_Manager<_VTp>::_S_access(_M_storage);
}
/// Emplace with an object created from @p __il and @p __args as
/// the contained object.
- template <typename _ValueType, typename _Up, typename... _Args>
- typename __any_constructible<_Decay<_ValueType>&,
- _Decay<_ValueType>,
- initializer_list<_Up>,
- _Args&&...>::type
+ template <typename _Tp, typename _Up, typename... _Args>
+ __emplace_t<decay_t<_Tp>, initializer_list<_Up>&, _Args&&...>
emplace(initializer_list<_Up> __il, _Args&&... __args)
{
- __do_emplace<_Decay<_ValueType>, _Up>(__il,
- std::forward<_Args>(__args)...);
- any::_Arg __arg;
- this->_M_manager(any::_Op_access, this, &__arg);
- return *static_cast<_Decay<_ValueType>*>(__arg._M_obj);
+ using _VTp = decay_t<_Tp>;
+ __do_emplace<_VTp, _Up>(__il, std::forward<_Args>(__args)...);
+ return *any::_Manager<_VTp>::_S_access(_M_storage);
}
// modifiers
}
#endif
+ /// @cond undocumented
template<typename _Tp>
static constexpr bool __is_valid_cast()
{ return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; }
+ /// @endcond
private:
enum _Op {
void (*_M_manager)(_Op, const any*, _Arg*);
_Storage _M_storage;
+ /// @cond undocumented
template<typename _Tp>
friend void* __any_caster(const any* __any);
+ /// @endcond
// Manage in-place contained object.
template<typename _Tp>
void* __addr = &__storage._M_buffer;
::new (__addr) _Tp(std::forward<_Args>(__args)...);
}
+
+ static _Tp*
+ _S_access(const _Storage& __storage)
+ {
+ // The contained object is in __storage._M_buffer
+ const void* __addr = &__storage._M_buffer;
+ return static_cast<_Tp*>(const_cast<void*>(__addr));
+ }
};
// Manage external contained object.
{
__storage._M_ptr = new _Tp(std::forward<_Args>(__args)...);
}
+ static _Tp*
+ _S_access(const _Storage& __storage)
+ {
+ // The contained object is in *__storage._M_ptr
+ return static_cast<_Tp*>(__storage._M_ptr);
+ }
};
};
/// Exchange the states of two @c any objects.
inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); }
- /// Create an any holding a @c _Tp constructed from @c __args.
+ /// Create an `any` holding a `_Tp` constructed from `__args...`.
template <typename _Tp, typename... _Args>
- any make_any(_Args&&... __args)
+ inline
+ enable_if_t<is_constructible_v<any, in_place_type_t<_Tp>, _Args...>, any>
+ make_any(_Args&&... __args)
{
return any(in_place_type<_Tp>, std::forward<_Args>(__args)...);
}
- /// Create an any holding a @c _Tp constructed from @c __il and @c __args.
+ /// Create an `any` holding a `_Tp` constructed from `__il` and `__args...`.
template <typename _Tp, typename _Up, typename... _Args>
- any make_any(initializer_list<_Up> __il, _Args&&... __args)
+ inline
+ enable_if_t<is_constructible_v<any, in_place_type_t<_Tp>,
+ initializer_list<_Up>&, _Args...>, any>
+ make_any(initializer_list<_Up> __il, _Args&&... __args)
{
return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...);
}
- template <typename _Tp>
- using _AnyCast = remove_cv_t<remove_reference_t<_Tp>>;
/**
* @brief Access the contained object.
*
template<typename _ValueType>
inline _ValueType any_cast(const any& __any)
{
+ using _Up = __remove_cvref_t<_ValueType>;
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
- auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
+ static_assert(is_constructible_v<_ValueType, const _Up&>,
+ "Template argument must be constructible from a const value.");
+ auto __p = any_cast<_Up>(&__any);
if (__p)
return static_cast<_ValueType>(*__p);
__throw_bad_any_cast();
template<typename _ValueType>
inline _ValueType any_cast(any& __any)
{
+ using _Up = __remove_cvref_t<_ValueType>;
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
- auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
+ static_assert(is_constructible_v<_ValueType, _Up&>,
+ "Template argument must be constructible from an lvalue.");
+ auto __p = any_cast<_Up>(&__any);
if (__p)
return static_cast<_ValueType>(*__p);
__throw_bad_any_cast();
}
- template<typename _ValueType,
- typename enable_if<!is_move_constructible<_ValueType>::value
- || is_lvalue_reference<_ValueType>::value,
- bool>::type = true>
- inline _ValueType any_cast(any&& __any)
- {
- static_assert(any::__is_valid_cast<_ValueType>(),
- "Template argument must be a reference or CopyConstructible type");
- auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
- if (__p)
- return static_cast<_ValueType>(*__p);
- __throw_bad_any_cast();
- }
-
- template<typename _ValueType,
- typename enable_if<is_move_constructible<_ValueType>::value
- && !is_lvalue_reference<_ValueType>::value,
- bool>::type = false>
+ template<typename _ValueType>
inline _ValueType any_cast(any&& __any)
{
+ using _Up = __remove_cvref_t<_ValueType>;
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
- auto __p = any_cast<_AnyCast<_ValueType>>(&__any);
+ static_assert(is_constructible_v<_ValueType, _Up>,
+ "Template argument must be constructible from an rvalue.");
+ auto __p = any_cast<_Up>(&__any);
if (__p)
return static_cast<_ValueType>(std::move(*__p));
__throw_bad_any_cast();
}
- // @}
+ /// @}
+ /// @cond undocumented
template<typename _Tp>
void* __any_caster(const any* __any)
{
- if constexpr (is_copy_constructible_v<decay_t<_Tp>>)
+ // any_cast<T> returns non-null if __any->type() == typeid(T) and
+ // typeid(T) ignores cv-qualifiers so remove them:
+ using _Up = remove_cv_t<_Tp>;
+ // The contained value has a decayed type, so if decay_t<U> is not U,
+ // then it's not possible to have a contained value of type U:
+ if constexpr (!is_same_v<decay_t<_Up>, _Up>)
+ return nullptr;
+ // Only copy constructible types can be used for contained values:
+ else if constexpr (!is_copy_constructible_v<_Up>)
+ return nullptr;
+ // First try comparing function addresses, which works without RTTI
+ else if (__any->_M_manager == &any::_Manager<_Up>::_S_manage
+#if __cpp_rtti
+ || __any->type() == typeid(_Tp)
+#endif
+ )
{
- if (__any->_M_manager == &any::_Manager<decay_t<_Tp>>::_S_manage)
- {
- any::_Arg __arg;
- __any->_M_manager(any::_Op_access, __any, &__arg);
- return __arg._M_obj;
- }
+ return any::_Manager<_Up>::_S_access(__any->_M_storage);
}
return nullptr;
}
+ /// @endcond
/**
* @brief Access the contained object.
template<typename _ValueType>
inline const _ValueType* any_cast(const any* __any) noexcept
{
- if (__any)
- return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
+ if constexpr (is_object_v<_ValueType>)
+ if (__any)
+ return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
return nullptr;
}
template<typename _ValueType>
inline _ValueType* any_cast(any* __any) noexcept
{
- if (__any)
- return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
+ if constexpr (is_object_v<_ValueType>)
+ if (__any)
+ return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
return nullptr;
}
- // @}
+ /// @}
template<typename _Tp>
void
/// @}
+ namespace __detail::__variant
+ {
+ template<typename> struct _Never_valueless_alt; // see <variant>
+
+ // Provide the strong exception-safety guarantee when emplacing an
+ // any into a variant.
+ template<>
+ struct _Never_valueless_alt<std::any>
+ : std::true_type
+ { };
+ } // namespace __detail::__variant
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
-#endif // C++14
-
+#endif // C++17
#endif // _GLIBCXX_ANY
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