mirror of
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128 lines
3.9 KiB
C++
128 lines
3.9 KiB
C++
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/*
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/~` _ _ _|_. _ _ |_ | _
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\_,(_)| | | || ||_|(_||_)|(/_
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https://github.com/Naios/continuable
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v2.0.0
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Copyright(c) 2015 - 2017 Denis Blank <denis.blank at outlook dot com>
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files(the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions :
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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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 AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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**/
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#ifndef CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED__
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#define CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED__
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#include <algorithm>
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#include <memory>
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#include <continuable/continuable-api.hpp>
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#include <continuable/detail/types.hpp>
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#include <continuable/detail/util.hpp>
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namespace cti {
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namespace detail {
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namespace expected {
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namespace detail {
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template <bool IsCopyable, typename Base>
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struct expected_base {
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explicit expected_base(expected_base const& right) {
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static_cast<Base const*>(&right)->visit([&](auto&& value) {
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using type = std::decay_t<decltype(value)>;
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auto storage = &static_cast<Base*>(this)->storage_;
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new (storage) type(std::forward<decltype(value)>(value));
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});
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}
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expected_base& operator=(expected_base const& right) {
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static_cast<Base const*>(&right)->visit([&](auto&& value) {
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using type = std::decay_t<decltype(value)>;
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auto storage = &static_cast<Base*>(this)->storage_;
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new (storage) type(std::forward<decltype(value)>(value));
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});
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return *this;
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}
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};
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} // namespace detail
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/// A class similar to the one in the expected proposal,
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/// however it is capable of carrying an exception_ptr if
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/// exceptions are used.
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template <typename T, typename Storage = std::aligned_storage_t<std::max(
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sizeof(types::error_type), sizeof(T))>>
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class expected {
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friend class expected_base;
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enum class slot_t { empty, value, error };
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Storage storage_;
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slot_t slot_;
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public:
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explicit expected() : slot_(slot_t::empty) {
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}
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explicit expected(T value) : slot_(slot_t::value) {
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}
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explicit expected(types::error_type error) : slot_(slot_t::value) {
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}
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bool is_empty() const noexcept {
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return slot_ == slot_t::empty;
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}
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bool is_value() const noexcept {
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return slot_ == slot_t::value;
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}
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bool is_error() const noexcept {
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return slot_ == slot_t::error;
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}
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template <typename V>
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void visit(V&& visitor) {
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switch (slot_) {
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case slot_t::value:
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return std::forward<V>(visitor)(static_cast<T*>(&storage_));
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case slot_t::error:
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return std::forward<V>(visitor)(
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static_cast<types::error_type*>(&storage_));
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}
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util::unreachable();
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}
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template <typename V>
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void visit(V&& visitor) const {
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switch (slot_) {
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case slot_t::value:
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return std::forward<V>(visitor)(static_cast<T*>(&storage_));
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case slot_t::error:
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return std::forward<V>(visitor)(
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static_cast<types::error_type*>(&storage_));
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}
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util::unreachable();
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}
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};
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} // namespace expected
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} // namespace detail
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} // namespace cti
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#endif // CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED__
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