188 lines
8.5 KiB
C++
188 lines
8.5 KiB
C++
/* Storage for a very simple basic_result type
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(C) 2017-2022 Niall Douglas <http://www.nedproductions.biz/> (6 commits)
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File Created: Oct 2017
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Boost Software License - Version 1.0 - August 17th, 2003
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Permission is hereby granted, free of charge, to any person or organization
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obtaining a copy of the software and accompanying documentation covered by
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this license (the "Software") to use, reproduce, display, distribute,
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execute, and transmit the Software, and to prepare derivative works of the
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Software, and to permit third-parties to whom the Software is furnished to
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do so, all subject to the following:
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The copyright notices in the Software and this entire statement, including
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the above license grant, this restriction and the following disclaimer,
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must be included in all copies of the Software, in whole or in part, and
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all derivative works of the Software, unless such copies or derivative
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works are solely in the form of machine-executable object code generated by
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a source language processor.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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*/
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#ifndef BOOST_OUTCOME_BASIC_RESULT_STORAGE_HPP
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#define BOOST_OUTCOME_BASIC_RESULT_STORAGE_HPP
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#include "../success_failure.hpp"
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#include "../trait.hpp"
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#include "value_storage.hpp"
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BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
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namespace detail
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{
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template <class R, class EC, class NoValuePolicy> class basic_result_storage;
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} // namespace detail
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namespace hooks
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{
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template <class R, class S, class NoValuePolicy> constexpr inline uint16_t spare_storage(const detail::basic_result_storage<R, S, NoValuePolicy> *r) noexcept;
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template <class R, class S, class NoValuePolicy>
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constexpr inline void set_spare_storage(detail::basic_result_storage<R, S, NoValuePolicy> *r, uint16_t v) noexcept;
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} // namespace hooks
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namespace policy
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{
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struct base;
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} // namespace policy
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namespace detail
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{
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template <class R, class EC, class NoValuePolicy> //
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class basic_result_storage
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{
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static_assert(trait::type_can_be_used_in_basic_result<R>, "The type R cannot be used in a basic_result");
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static_assert(trait::type_can_be_used_in_basic_result<EC>, "The type S cannot be used in a basic_result");
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friend struct policy::base;
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template <class T, class U, class V> //
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friend class basic_result_storage;
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template <class T, class U, class V> friend class basic_result_final;
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template <class T, class U, class V>
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friend constexpr inline uint16_t hooks::spare_storage(const detail::basic_result_storage<T, U, V> *r) noexcept; // NOLINT
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template <class T, class U, class V>
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friend constexpr inline void hooks::set_spare_storage(detail::basic_result_storage<T, U, V> *r, uint16_t v) noexcept; // NOLINT
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struct disable_in_place_value_type
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{
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};
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struct disable_in_place_error_type
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{
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};
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protected:
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using _value_type = std::conditional_t<std::is_same<R, EC>::value, disable_in_place_value_type, R>;
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using _error_type = std::conditional_t<std::is_same<R, EC>::value, disable_in_place_error_type, EC>;
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using _state_type = value_storage_select_impl<_value_type, _error_type>;
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#ifdef BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE
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value_storage_trivial<_value_type, _error_type> _state;
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#else
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_state_type _state;
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#endif
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public:
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// Used by iostream support to access state
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_state_type &_iostreams_state() { return _state; }
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const _state_type &_iostreams_state() const { return _state; }
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protected:
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basic_result_storage() = default;
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basic_result_storage(const basic_result_storage &) = default; // NOLINT
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basic_result_storage(basic_result_storage &&) = default; // NOLINT
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basic_result_storage &operator=(const basic_result_storage &) = default; // NOLINT
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basic_result_storage &operator=(basic_result_storage &&) = default; // NOLINT
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~basic_result_storage() = default;
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template <class... Args>
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constexpr explicit basic_result_storage(in_place_type_t<_value_type> _,
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Args &&... args) noexcept(detail::is_nothrow_constructible<_value_type, Args...>)
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: _state{_, static_cast<Args &&>(args)...}
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{
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}
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template <class U, class... Args>
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constexpr basic_result_storage(in_place_type_t<_value_type> _, std::initializer_list<U> il,
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Args &&... args) noexcept(detail::is_nothrow_constructible<_value_type, std::initializer_list<U>, Args...>)
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: _state{_, il, static_cast<Args &&>(args)...}
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{
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}
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template <class... Args>
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constexpr explicit basic_result_storage(in_place_type_t<_error_type> _,
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Args &&... args) noexcept(detail::is_nothrow_constructible<_error_type, Args...>)
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: _state{_, static_cast<Args &&>(args)...}
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{
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}
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template <class U, class... Args>
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constexpr basic_result_storage(in_place_type_t<_error_type> _, std::initializer_list<U> il,
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Args &&... args) noexcept(detail::is_nothrow_constructible<_error_type, std::initializer_list<U>, Args...>)
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: _state{_, il, static_cast<Args &&>(args)...}
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{
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}
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struct compatible_conversion_tag
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{
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};
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template <class T, class U, class V>
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constexpr basic_result_storage(compatible_conversion_tag /*unused*/, const basic_result_storage<T, U, V> &o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&detail::is_nothrow_constructible<_error_type, U>)
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: _state(o._state)
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{
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}
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template <class T, class U, class V>
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constexpr basic_result_storage(compatible_conversion_tag /*unused*/, basic_result_storage<T, U, V> &&o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&detail::is_nothrow_constructible<_error_type, U>)
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: _state(static_cast<decltype(o._state) &&>(o._state))
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{
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}
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struct make_error_code_compatible_conversion_tag
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{
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};
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template <class T, class U, class V>
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constexpr basic_result_storage(make_error_code_compatible_conversion_tag /*unused*/, const basic_result_storage<T, U, V> &o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&noexcept(make_error_code(std::declval<U>())))
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: _state(o._state._status.have_value() ? _state_type(in_place_type<_value_type>, o._state._value) :
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_state_type(in_place_type<_error_type>, make_error_code(o._state._error)))
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{
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}
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template <class T, class U, class V>
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constexpr basic_result_storage(make_error_code_compatible_conversion_tag /*unused*/, basic_result_storage<T, U, V> &&o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&noexcept(make_error_code(std::declval<U>())))
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: _state(o._state._status.have_value() ? _state_type(in_place_type<_value_type>, static_cast<T &&>(o._state._value)) :
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_state_type(in_place_type<_error_type>, make_error_code(static_cast<U &&>(o._state._error))))
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{
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}
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struct make_exception_ptr_compatible_conversion_tag
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{
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};
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template <class T, class U, class V>
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constexpr basic_result_storage(make_exception_ptr_compatible_conversion_tag /*unused*/, const basic_result_storage<T, U, V> &o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&noexcept(make_exception_ptr(std::declval<U>())))
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: _state(o._state._status.have_value() ? _state_type(in_place_type<_value_type>, o._state._value) :
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_state_type(in_place_type<_error_type>, make_exception_ptr(o._state._error)))
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{
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}
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template <class T, class U, class V>
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constexpr basic_result_storage(make_exception_ptr_compatible_conversion_tag /*unused*/, basic_result_storage<T, U, V> &&o) noexcept(
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detail::is_nothrow_constructible<_value_type, T> &&noexcept(make_exception_ptr(std::declval<U>())))
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: _state(o._state._status.have_value() ? _state_type(in_place_type<_value_type>, static_cast<T &&>(o._state._value)) :
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_state_type(in_place_type<_error_type>, make_exception_ptr(static_cast<U &&>(o._state._error))))
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{
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}
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};
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} // namespace detail
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BOOST_OUTCOME_V2_NAMESPACE_END
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#endif
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