// <any> -*- C++ -*-
-// Copyright (C) 2014-2016 Free Software Foundation, Inc.
+// Copyright (C) 2014-2020 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
#pragma GCC system_header
-#if __cplusplus <= 201402L
-# include <bits/c++17_warning.h>
-#else
+#if __cplusplus >= 201703L
#include <typeinfo>
#include <new>
#endif
}
+#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
* of CopyConstructible type.
*/
template<typename _Tp, typename _Decayed = decay_t<_Tp>>
using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>;
+ /// Emplace with an object created from @p __args as the contained object.
+ template <typename _Tp, typename... _Args,
+ typename _Mgr = _Manager<_Tp>>
+ void __do_emplace(_Args&&... __args)
+ {
+ reset();
+ _Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
+ _M_manager = &_Mgr::_S_manage;
+ }
+
+ /// Emplace with an object created from @p __il and @p __args as
+ /// the contained object.
+ template <typename _Tp, typename _Up, typename... _Args,
+ typename _Mgr = _Manager<_Tp>>
+ void __do_emplace(initializer_list<_Up> __il, _Args&&... __args)
+ {
+ reset();
+ _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
+ _M_manager = &_Mgr::_S_manage;
+ }
+
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 =
- enable_if_t<__and_<is_copy_constructible<_Tp>,
- is_constructible<_Tp, _Args...>>::value,
- bool>;
+ 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>
+ __any_constructible_t<_Tp, _ValueType&&> = true,
+ enable_if_t<!__is_in_place_type<_Tp>::value, bool> = true>
any(_ValueType&& __value)
: _M_manager(&_Mgr::_S_manage)
{
/// 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&&>>>::value,
+ enable_if_t<__and_v<is_copy_constructible<_Tp>,
+ __not_<is_constructible<_Tp, _ValueType&&>>,
+ __not_<__is_in_place_type<_Tp>>>,
bool> = false>
any(_ValueType&& __value)
: _M_manager(&_Mgr::_S_manage)
}
/// Construct with an object created from @p __args as the contained object.
- template <typename _Tp, typename... _Args,
+ template <typename _ValueType, typename... _Args,
+ typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
__any_constructible_t<_Tp, _Args&&...> = false>
- any(in_place_type_t<_Tp>, _Args&&... __args)
+ explicit
+ any(in_place_type_t<_ValueType>, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
_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 _Tp, typename _Up, typename... _Args,
+ template <typename _ValueType, typename _Up, typename... _Args,
+ typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>,
__any_constructible_t<_Tp, initializer_list<_Up>,
_Args&&...> = false>
- any(in_place_type_t<_Tp>, initializer_list<_Up> __il, _Args&&... __args)
+ explicit
+ any(in_place_type_t<_ValueType>,
+ initializer_list<_Up> __il, _Args&&... __args)
: _M_manager(&_Mgr::_S_manage)
{
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
/// Copy the state of another object.
any& operator=(const any& __rhs)
{
- if (!__rhs.has_value())
- reset();
- else if (this != &__rhs)
- {
- if (has_value())
- _M_manager(_Op_destroy, this, nullptr);
- _Arg __arg;
- __arg._M_any = this;
- __rhs._M_manager(_Op_clone, &__rhs, &__arg);
- }
+ *this = any(__rhs);
return *this;
}
reset();
else if (this != &__rhs)
{
- if (has_value())
- _M_manager(_Op_destroy, this, nullptr);
+ reset();
_Arg __arg;
__arg._M_any = this;
__rhs._M_manager(_Op_xfer, &__rhs, &__arg);
/// Store a copy of @p __rhs as the contained object.
template<typename _ValueType>
- enable_if_t<__and_<__not_<is_same<any, decay_t<_ValueType>>>,
- is_copy_constructible<_ValueType>>::value, any&>
+ enable_if_t<is_copy_constructible<_Decay<_ValueType>>::value, any&>
operator=(_ValueType&& __rhs)
{
*this = any(std::forward<_ValueType>(__rhs));
}
/// Emplace with an object created from @p __args as the contained object.
- template <typename _Tp, typename... _Args,
- typename _Mgr = _Manager<_Tp>,
- __any_constructible_t<_Tp, _Args&&...> = false>
- void emplace(_Args&&... __args)
+ template <typename _ValueType, typename... _Args>
+ typename __any_constructible<_Decay<_ValueType>&,
+ _Decay<_ValueType>, _Args&&...>::type
+ emplace(_Args&&... __args)
{
- reset();
- _M_manager = &_Mgr::_S_manage;
- _Mgr::_S_create(_M_storage, std::forward<_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);
}
/// Emplace with an object created from @p __il and @p __args as
/// the contained object.
- template <typename _Tp, typename _Up, typename... _Args,
- typename _Mgr = _Manager<_Tp>,
- __any_constructible_t<_Tp, initializer_list<_Up>,
- _Args&&...> = false>
- void emplace(initializer_list<_Up> __il, _Args&&... __args)
+ template <typename _ValueType, typename _Up, typename... _Args>
+ typename __any_constructible<_Decay<_ValueType>&,
+ _Decay<_ValueType>,
+ initializer_list<_Up>,
+ _Args&&...>::type
+ emplace(initializer_list<_Up> __il, _Args&&... __args)
{
- reset();
- _M_manager = &_Mgr::_S_manage;
- _Mgr::_S_create(_M_storage, __il, std::forward<_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);
}
// modifiers
template <typename _Tp, typename... _Args>
any make_any(_Args&&... __args)
{
- return any(in_place<_Tp>, std::forward<_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.
template <typename _Tp, typename _Up, typename... _Args>
any make_any(initializer_list<_Up> __il, _Args&&... __args)
{
- return any(in_place<_Tp>, __il, std::forward<_Args>(__args)...);
+ return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...);
}
/**
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<add_const_t<remove_reference_t<_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 *__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<remove_reference_t<_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 *__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<remove_reference_t<_ValueType>>(&__any);
- if (__p)
- return *__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<remove_reference_t<_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 std::move(*__p);
+ return static_cast<_ValueType>(std::move(*__p));
__throw_bad_any_cast();
}
// @}
+ /// @cond undocumented
template<typename _Tp>
void* __any_caster(const any* __any)
{
- if (__any->_M_manager != &any::_Manager<decay_t<_Tp>>::_S_manage)
+ // 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;
- any::_Arg __arg;
- __any->_M_manager(any::_Op_access, __any, &__arg);
- return __arg._M_obj;
+ // 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
+ )
+ {
+ any::_Arg __arg;
+ __any->_M_manager(any::_Op_access, __any, &__arg);
+ return __arg._M_obj;
+ }
+ 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;
}
// @}
__ptr->~_Tp();
break;
case _Op_xfer:
- ::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr);
+ ::new(&__arg->_M_any->_M_storage._M_buffer) _Tp
+ (std::move(*const_cast<_Tp*>(__ptr)));
__ptr->~_Tp();
__arg->_M_any->_M_manager = __any->_M_manager;
const_cast<any*>(__any)->_M_manager = nullptr;
}
/// @}
-
+
+ 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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