/* Essentially an internal optional implementation :)
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(C) 2017-2020 Niall Douglas <http://www.nedproductions.biz/> (24 commits)
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File Created: June 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_VALUE_STORAGE_HPP
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#define BOOST_OUTCOME_VALUE_STORAGE_HPP
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#include "../config.hpp"
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#include <cassert>
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BOOST_OUTCOME_V2_NAMESPACE_BEGIN
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namespace detail
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{
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template <class T, bool nothrow> struct strong_swap_impl
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{
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constexpr strong_swap_impl(bool &allgood, T &a, T &b)
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{
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allgood = true;
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using std::swap;
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swap(a, b);
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}
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};
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#ifndef BOOST_NO_EXCEPTIONS
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template <class T> struct strong_swap_impl<T, false>
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{
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strong_swap_impl(bool &allgood, T &a, T &b)
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{
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allgood = true;
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T v(static_cast<T &&>(a));
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try
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{
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a = static_cast<T &&>(b);
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}
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catch(...)
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{
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// Try to put back a
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try
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{
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a = static_cast<T &&>(v);
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// fall through as all good
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}
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catch(...)
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{
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// failed to completely restore
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allgood = false;
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// throw away second exception
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}
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throw; // rethrow original exception
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}
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// b has been moved to a, try to move v to b
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try
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{
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b = static_cast<T &&>(v);
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}
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catch(...)
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{
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// Try to restore a to b, and v to a
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try
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{
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b = static_cast<T &&>(a);
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a = static_cast<T &&>(v);
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// fall through as all good
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}
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catch(...)
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{
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// failed to completely restore
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allgood = false;
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// throw away second exception
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}
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throw; // rethrow original exception
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}
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}
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};
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#endif
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} // namespace detail
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/*!
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*/
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BOOST_OUTCOME_TEMPLATE(class T)
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BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(std::is_move_constructible<T>::value &&std::is_move_assignable<T>::value))
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constexpr inline void strong_swap(bool &allgood, T &a, T &b) noexcept(detail::is_nothrow_swappable<T>::value)
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{
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detail::strong_swap_impl<T, detail::is_nothrow_swappable<T>::value>(allgood, a, b);
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}
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namespace detail
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{
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template <class T>
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constexpr
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#ifdef _MSC_VER
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__declspec(noreturn)
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#elif defined(__GNUC__) || defined(__clang__)
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__attribute__((noreturn))
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#endif
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void make_ub(T && /*unused*/)
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{
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assert(false); // NOLINT
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#if defined(__GNUC__) || defined(__clang__)
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__builtin_unreachable();
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#elif defined(_MSC_VER)
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__assume(0);
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#endif
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}
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/* Outcome v1 used a C bitfield whose values were tracked by compiler optimisers nicely,
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but that produces ICEs when used in constexpr.
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Outcome v2.0-v2.1 used a 32 bit integer and manually set and cleared bits. Unfortunately
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only GCC's optimiser tracks bit values during constant folding, and only per byte, and
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even then unreliably. https://wg21.link/P1886 "Error speed benchmarking" showed just how
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poorly clang and MSVC fails to optimise outcome-using code, if you manually set bits.
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Outcome v2.2 therefore uses an enum with fixed values, and constexpr manipulation functions
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to change the value to one of the enum's values. This is stupid to look at in source code,
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but it make clang's optimiser do the right thing, so it's worth it.
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*/
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#define BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS 0
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enum class status : uint16_t
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{
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// WARNING: These bits are not tracked by abi-dumper, but changing them will break ABI!
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none = 0,
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have_value = (1U << 0U),
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have_error = (1U << 1U),
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have_exception = (2U << 1U),
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have_error_exception = (3U << 1U),
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// failed to complete a strong swap
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have_lost_consistency = (1U << 3U),
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have_value_lost_consistency = (1U << 0U) | (1U << 3U),
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have_error_lost_consistency = (1U << 1U) | (1U << 3U),
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have_exception_lost_consistency = (2U << 1U) | (1U << 3U),
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have_error_exception_lost_consistency = (3U << 1U) | (1U << 3U),
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// can errno be set from this error?
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have_error_is_errno = (1U << 4U),
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have_error_error_is_errno = (1U << 1U) | (1U << 4U),
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have_error_exception_error_is_errno = (3U << 1U) | (1U << 4U),
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have_error_lost_consistency_error_is_errno = (1U << 1U) | (1U << 3U) | (1U << 4U),
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have_error_exception_lost_consistency_error_is_errno = (3U << 1U) | (1U << 3U) | (1U << 4U),
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// value has been moved from
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have_moved_from = (1U << 5U)
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};
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struct status_bitfield_type
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{
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status status_value{status::none};
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uint16_t spare_storage_value{0}; // hooks::spare_storage()
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constexpr status_bitfield_type() = default;
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constexpr status_bitfield_type(status v) noexcept
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: status_value(v)
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{
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} // NOLINT
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constexpr status_bitfield_type(status v, uint16_t s) noexcept
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: status_value(v)
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, spare_storage_value(s)
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{
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}
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constexpr status_bitfield_type(const status_bitfield_type &) = default;
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constexpr status_bitfield_type(status_bitfield_type &&) = default;
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constexpr status_bitfield_type &operator=(const status_bitfield_type &) = default;
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constexpr status_bitfield_type &operator=(status_bitfield_type &&) = default;
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//~status_bitfield_type() = default; // Do NOT uncomment this, it breaks older clangs!
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constexpr bool have_value() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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return (status_value == status::have_value) //
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|| (status_value == status::have_value_lost_consistency) //
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;
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_value)) != 0;
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#endif
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}
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constexpr bool have_error() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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return (status_value == status::have_error) //
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|| (status_value == status::have_error_exception) //
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|| (status_value == status::have_error_lost_consistency) //
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|| (status_value == status::have_error_exception_lost_consistency) //
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|| (status_value == status::have_error_error_is_errno) //
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|| (status_value == status::have_error_exception_error_is_errno) //
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|| (status_value == status::have_error_lost_consistency_error_is_errno) //
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|| (status_value == status::have_error_exception_lost_consistency_error_is_errno) //
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;
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_error)) != 0;
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#endif
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}
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constexpr bool have_exception() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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return (status_value == status::have_exception) //
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|| (status_value == status::have_error_exception) //
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|| (status_value == status::have_exception_lost_consistency) //
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|| (status_value == status::have_error_exception_lost_consistency) //
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|| (status_value == status::have_error_exception_error_is_errno) //
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|| (status_value == status::have_error_exception_lost_consistency_error_is_errno) //
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;
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_exception)) != 0;
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#endif
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}
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constexpr bool have_lost_consistency() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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return (status_value == status::have_value_lost_consistency) //
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|| (status_value == status::have_error_lost_consistency) //
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|| (status_value == status::have_exception_lost_consistency) //
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|| (status_value == status::have_error_lost_consistency_error_is_errno) //
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|| (status_value == status::have_error_exception_lost_consistency_error_is_errno) //
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;
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_lost_consistency)) != 0;
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#endif
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}
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constexpr bool have_error_is_errno() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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return (status_value == status::have_error_error_is_errno) //
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|| (status_value == status::have_error_exception_error_is_errno) //
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|| (status_value == status::have_error_lost_consistency_error_is_errno) //
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|| (status_value == status::have_error_exception_lost_consistency_error_is_errno) //
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;
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_error_is_errno)) != 0;
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#endif
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}
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constexpr bool have_moved_from() const noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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#error Fixme
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#else
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return (static_cast<uint16_t>(status_value) & static_cast<uint16_t>(status::have_moved_from)) != 0;
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#endif
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}
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constexpr status_bitfield_type &set_have_value(bool v) noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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switch(status_value)
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{
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case status::none:
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if(v)
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{
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status_value = status::have_value;
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}
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break;
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case status::have_value:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_exception:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_exception:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_value_lost_consistency:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error_lost_consistency:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_exception_lost_consistency:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_exception_lost_consistency:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_error_is_errno:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_exception_error_is_errno:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_lost_consistency_error_is_errno:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_exception_lost_consistency_error_is_errno:
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if(v)
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{
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make_ub(*this);
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}
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break;
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}
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#else
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status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_value)) :
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(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_value)));
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#endif
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return *this;
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}
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constexpr status_bitfield_type &set_have_error(bool v) noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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switch(status_value)
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{
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case status::none:
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if(v)
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{
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status_value = status::have_error;
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}
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break;
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case status::have_value:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_exception:
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if(v)
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{
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status_value = status::have_error_exception;
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}
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break;
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case status::have_error_exception:
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if(!v)
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{
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status_value = status::have_exception;
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}
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break;
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case status::have_value_lost_consistency:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_lost_consistency:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_exception_lost_consistency:
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if(v)
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{
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status_value = status::have_error_exception_lost_consistency;
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}
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break;
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case status::have_error_exception_lost_consistency:
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if(!v)
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{
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status_value = status::have_exception_lost_consistency;
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}
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break;
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case status::have_error_error_is_errno:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error_exception_error_is_errno:
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if(!v)
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{
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status_value = status::have_exception;
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}
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break;
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case status::have_error_lost_consistency_error_is_errno:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error_exception_lost_consistency_error_is_errno:
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if(!v)
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{
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status_value = status::have_exception_lost_consistency;
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}
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break;
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}
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#else
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status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_error)) :
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(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_error)));
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#endif
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return *this;
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}
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constexpr status_bitfield_type &set_have_exception(bool v) noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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switch(status_value)
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{
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case status::none:
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if(v)
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{
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status_value = status::have_exception;
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}
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break;
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case status::have_value:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error:
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if(v)
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{
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status_value = status::have_error_exception;
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}
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break;
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case status::have_exception:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error_exception:
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if(!v)
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{
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status_value = status::have_error;
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}
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break;
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case status::have_value_lost_consistency:
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if(v)
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{
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make_ub(*this);
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}
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break;
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case status::have_error_lost_consistency:
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if(v)
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{
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status_value = status::have_error_exception_lost_consistency;
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}
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break;
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case status::have_exception_lost_consistency:
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if(!v)
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{
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status_value = status::none;
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}
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break;
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case status::have_error_exception_lost_consistency:
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if(!v)
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{
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status_value = status::have_error_lost_consistency;
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}
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break;
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case status::have_error_error_is_errno:
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if(v)
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{
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status_value = status::have_error_exception_error_is_errno;
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}
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break;
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case status::have_error_exception_error_is_errno:
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if(!v)
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{
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status_value = status::have_error_error_is_errno;
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}
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break;
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case status::have_error_lost_consistency_error_is_errno:
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if(v)
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{
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status_value = status::have_error_exception_lost_consistency_error_is_errno;
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}
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break;
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case status::have_error_exception_lost_consistency_error_is_errno:
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if(!v)
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{
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status_value = status::have_error_lost_consistency_error_is_errno;
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}
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break;
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}
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#else
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status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_exception)) :
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(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_exception)));
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#endif
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return *this;
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}
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constexpr status_bitfield_type &set_have_error_is_errno(bool v) noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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switch(status_value)
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{
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case status::none:
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make_ub(*this);
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break;
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case status::have_value:
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make_ub(*this);
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break;
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case status::have_error:
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if(v)
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{
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status_value = status::have_error_error_is_errno;
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}
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break;
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case status::have_exception:
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make_ub(*this);
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break;
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case status::have_error_exception:
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if(v)
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{
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status_value = status::have_error_exception_error_is_errno;
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}
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break;
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case status::have_value_lost_consistency:
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make_ub(*this);
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break;
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case status::have_error_lost_consistency:
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if(v)
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{
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status_value = status::have_error_lost_consistency_error_is_errno;
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}
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break;
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case status::have_exception_lost_consistency:
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make_ub(*this);
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break;
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case status::have_error_exception_lost_consistency:
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if(v)
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{
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status_value = status::have_error_exception_lost_consistency_error_is_errno;
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}
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break;
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case status::have_error_error_is_errno:
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if(!v)
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{
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status_value = status::have_error;
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}
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break;
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case status::have_error_exception_error_is_errno:
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if(!v)
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{
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status_value = status::have_error_exception;
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}
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break;
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case status::have_error_lost_consistency_error_is_errno:
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if(!v)
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{
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status_value = status::have_error_lost_consistency;
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}
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break;
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case status::have_error_exception_lost_consistency_error_is_errno:
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if(!v)
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{
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status_value = status::have_error_exception_lost_consistency;
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}
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break;
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}
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#else
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status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_error_is_errno)) :
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(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_error_is_errno)));
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#endif
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return *this;
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}
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constexpr status_bitfield_type &set_have_lost_consistency(bool v) noexcept
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{
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#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
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switch(status_value)
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{
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case status::none:
|
if(v)
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{
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make_ub(*this);
|
}
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break;
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case status::have_value:
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if(v)
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{
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status_value = status::have_value_lost_consistency;
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}
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break;
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case status::have_error:
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if(v)
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{
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status_value = status::have_error_lost_consistency;
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}
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break;
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case status::have_exception:
|
if(v)
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{
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status_value = status::have_exception_lost_consistency;
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}
|
break;
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case status::have_error_exception:
|
if(v)
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{
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status_value = status::have_error_exception_lost_consistency;
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}
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break;
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case status::have_value_lost_consistency:
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if(!v)
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{
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status_value = status::have_value;
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}
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break;
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case status::have_error_lost_consistency:
|
if(!v)
|
{
|
status_value = status::have_error;
|
}
|
break;
|
case status::have_exception_lost_consistency:
|
if(!v)
|
{
|
status_value = status::have_exception;
|
}
|
break;
|
case status::have_error_exception_lost_consistency:
|
if(!v)
|
{
|
status_value = status::have_error_exception;
|
}
|
break;
|
case status::have_error_error_is_errno:
|
if(v)
|
{
|
status_value = status::have_error_lost_consistency_error_is_errno;
|
}
|
break;
|
case status::have_error_exception_error_is_errno:
|
if(v)
|
{
|
status_value = status::have_error_exception_lost_consistency_error_is_errno;
|
}
|
break;
|
case status::have_error_lost_consistency_error_is_errno:
|
if(!v)
|
{
|
status_value = status::have_error_exception_error_is_errno;
|
}
|
break;
|
case status::have_error_exception_lost_consistency_error_is_errno:
|
if(!v)
|
{
|
status_value = status::have_error_exception_error_is_errno;
|
}
|
break;
|
}
|
#else
|
status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_lost_consistency)) :
|
(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_lost_consistency)));
|
#endif
|
return *this;
|
}
|
constexpr status_bitfield_type &set_have_moved_from(bool v) noexcept
|
{
|
#if BOOST_OUTCOME_USE_CONSTEXPR_ENUM_STATUS
|
#error Fixme
|
#else
|
status_value = static_cast<status>(v ? (static_cast<uint16_t>(status_value) | static_cast<uint16_t>(status::have_moved_from)) :
|
(static_cast<uint16_t>(status_value) & ~static_cast<uint16_t>(status::have_moved_from)));
|
#endif
|
return *this;
|
}
|
};
|
#if !defined(NDEBUG)
|
// Check is trivial in all ways except default constructibility
|
static_assert(sizeof(status_bitfield_type) == 4, "status_bitfield_type is not sized 4 bytes!");
|
static_assert(std::is_trivially_copyable<status_bitfield_type>::value, "status_bitfield_type is not trivially copyable!");
|
static_assert(std::is_trivially_assignable<status_bitfield_type, status_bitfield_type>::value, "status_bitfield_type is not trivially assignable!");
|
static_assert(std::is_trivially_destructible<status_bitfield_type>::value, "status_bitfield_type is not trivially destructible!");
|
static_assert(std::is_trivially_copy_constructible<status_bitfield_type>::value, "status_bitfield_type is not trivially copy constructible!");
|
static_assert(std::is_trivially_move_constructible<status_bitfield_type>::value, "status_bitfield_type is not trivially move constructible!");
|
static_assert(std::is_trivially_copy_assignable<status_bitfield_type>::value, "status_bitfield_type is not trivially copy assignable!");
|
static_assert(std::is_trivially_move_assignable<status_bitfield_type>::value, "status_bitfield_type is not trivially move assignable!");
|
// Also check is standard layout
|
static_assert(std::is_standard_layout<status_bitfield_type>::value, "status_bitfield_type is not a standard layout type!");
|
#endif
|
|
// Used if T is trivial
|
template <class T> struct value_storage_trivial
|
{
|
using value_type = T;
|
union {
|
empty_type _empty;
|
devoid<T> _value;
|
};
|
status_bitfield_type _status;
|
constexpr value_storage_trivial() noexcept
|
: _empty{}
|
{
|
}
|
// Special from-void catchall constructor, always constructs default T irrespective of whether void is valued or not (can do no better if T cannot be
|
// copied)
|
struct disable_void_catchall
|
{
|
};
|
using void_value_storage_trivial = std::conditional_t<std::is_void<T>::value, disable_void_catchall, value_storage_trivial<void>>;
|
explicit constexpr value_storage_trivial(const void_value_storage_trivial &o) noexcept(std::is_nothrow_default_constructible<value_type>::value)
|
: _value()
|
, _status(o._status)
|
{
|
}
|
value_storage_trivial(const value_storage_trivial &) = default; // NOLINT
|
value_storage_trivial(value_storage_trivial &&) = default; // NOLINT
|
value_storage_trivial &operator=(const value_storage_trivial &) = default; // NOLINT
|
value_storage_trivial &operator=(value_storage_trivial &&) = default; // NOLINT
|
~value_storage_trivial() = default;
|
constexpr explicit value_storage_trivial(status_bitfield_type status)
|
: _empty()
|
, _status(status)
|
{
|
}
|
template <class... Args>
|
constexpr explicit value_storage_trivial(in_place_type_t<value_type> /*unused*/,
|
Args &&... args) noexcept(detail::is_nothrow_constructible<value_type, Args...>)
|
: _value(static_cast<Args &&>(args)...)
|
, _status(status::have_value)
|
{
|
}
|
template <class U, class... Args>
|
constexpr value_storage_trivial(in_place_type_t<value_type> /*unused*/, std::initializer_list<U> il,
|
Args &&... args) noexcept(detail::is_nothrow_constructible<value_type, std::initializer_list<U>, Args...>)
|
: _value(il, static_cast<Args &&>(args)...)
|
, _status(status::have_value)
|
{
|
}
|
template <class U>
|
static constexpr bool enable_converting_constructor = !std::is_same<std::decay_t<U>, value_type>::value && detail::is_constructible<value_type, U>;
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_trivial(const value_storage_trivial<U> &o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_trivial(o._status.have_value() ? value_storage_trivial(in_place_type<value_type>, o._value) : value_storage_trivial()) // NOLINT
|
{
|
_status = o._status;
|
}
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_trivial(value_storage_trivial<U> &&o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_trivial(o._status.have_value() ? value_storage_trivial(in_place_type<value_type>, static_cast<U &&>(o._value)) :
|
value_storage_trivial()) // NOLINT
|
{
|
_status = o._status;
|
}
|
constexpr void swap(value_storage_trivial &o) noexcept
|
{
|
// storage is trivial, so just use assignment
|
auto temp = static_cast<value_storage_trivial &&>(*this);
|
*this = static_cast<value_storage_trivial &&>(o);
|
o = static_cast<value_storage_trivial &&>(temp);
|
}
|
};
|
// Used if T is non-trivial
|
template <class T> struct value_storage_nontrivial
|
{
|
using value_type = T;
|
union {
|
empty_type _empty;
|
value_type _value;
|
};
|
status_bitfield_type _status;
|
value_storage_nontrivial() noexcept
|
: _empty{}
|
{
|
}
|
value_storage_nontrivial &operator=(const value_storage_nontrivial &) = default; // if reaches here, copy assignment is trivial
|
value_storage_nontrivial &operator=(value_storage_nontrivial &&) = default; // NOLINT if reaches here, move assignment is trivial
|
value_storage_nontrivial(value_storage_nontrivial &&o) noexcept(std::is_nothrow_move_constructible<value_type>::value) // NOLINT
|
: _status(o._status)
|
{
|
if(this->_status.have_value())
|
{
|
this->_status.set_have_value(false);
|
new(&_value) value_type(static_cast<value_type &&>(o._value)); // NOLINT
|
_status = o._status;
|
}
|
}
|
value_storage_nontrivial(const value_storage_nontrivial &o) noexcept(std::is_nothrow_copy_constructible<value_type>::value)
|
: _status(o._status)
|
{
|
if(this->_status.have_value())
|
{
|
this->_status.set_have_value(false);
|
new(&_value) value_type(o._value); // NOLINT
|
_status = o._status;
|
}
|
}
|
// Special from-void constructor, constructs default T if void valued
|
explicit value_storage_nontrivial(const value_storage_trivial<void> &o) noexcept(std::is_nothrow_default_constructible<value_type>::value)
|
: _status(o._status)
|
{
|
if(this->_status.have_value())
|
{
|
this->_status.set_have_value(false);
|
new(&_value) value_type; // NOLINT
|
_status = o._status;
|
}
|
}
|
explicit value_storage_nontrivial(status_bitfield_type status)
|
: _empty()
|
, _status(status)
|
{
|
}
|
template <class... Args>
|
explicit value_storage_nontrivial(in_place_type_t<value_type> /*unused*/,
|
Args &&... args) noexcept(detail::is_nothrow_constructible<value_type, Args...>)
|
: _value(static_cast<Args &&>(args)...) // NOLINT
|
, _status(status::have_value)
|
{
|
}
|
template <class U, class... Args>
|
value_storage_nontrivial(in_place_type_t<value_type> /*unused*/, std::initializer_list<U> il,
|
Args &&... args) noexcept(detail::is_nothrow_constructible<value_type, std::initializer_list<U>, Args...>)
|
: _value(il, static_cast<Args &&>(args)...)
|
, _status(status::have_value)
|
{
|
}
|
template <class U>
|
static constexpr bool enable_converting_constructor = !std::is_same<std::decay_t<U>, value_type>::value && detail::is_constructible<value_type, U>;
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_nontrivial(const value_storage_nontrivial<U> &o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_nontrivial(o._status.have_value() ? value_storage_nontrivial(in_place_type<value_type>, o._value) : value_storage_nontrivial())
|
{
|
_status = o._status;
|
}
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_nontrivial(const value_storage_trivial<U> &o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_nontrivial(o._status.have_value() ? value_storage_nontrivial(in_place_type<value_type>, o._value) : value_storage_nontrivial())
|
{
|
_status = o._status;
|
}
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_nontrivial(value_storage_nontrivial<U> &&o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_nontrivial(o._status.have_value() ? value_storage_nontrivial(in_place_type<value_type>, static_cast<U &&>(o._value)) :
|
value_storage_nontrivial())
|
{
|
_status = o._status;
|
}
|
BOOST_OUTCOME_TEMPLATE(class U)
|
BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(enable_converting_constructor<U>))
|
constexpr explicit value_storage_nontrivial(value_storage_trivial<U> &&o) noexcept(detail::is_nothrow_constructible<value_type, U>)
|
: value_storage_nontrivial(o._status.have_value() ? value_storage_nontrivial(in_place_type<value_type>, static_cast<U &&>(o._value)) :
|
value_storage_nontrivial())
|
{
|
_status = o._status;
|
}
|
~value_storage_nontrivial() noexcept(std::is_nothrow_destructible<T>::value)
|
{
|
if(this->_status.have_value())
|
{
|
this->_value.~value_type(); // NOLINT
|
this->_status.set_have_value(false);
|
}
|
}
|
constexpr void swap(value_storage_nontrivial &o) noexcept(detail::is_nothrow_swappable<value_type>::value)
|
{
|
using std::swap;
|
if(!_status.have_value() && !o._status.have_value())
|
{
|
swap(_status, o._status);
|
return;
|
}
|
if(_status.have_value() && o._status.have_value())
|
{
|
struct _
|
{
|
status_bitfield_type &a, &b;
|
bool all_good{false};
|
~_()
|
{
|
if(!all_good)
|
{
|
// We lost one of the values
|
a.set_have_lost_consistency(true);
|
b.set_have_lost_consistency(true);
|
}
|
}
|
} _{_status, o._status};
|
strong_swap(_.all_good, _value, o._value);
|
swap(_status, o._status);
|
return;
|
}
|
// One must be empty and the other non-empty, so use move construction
|
if(_status.have_value())
|
{
|
// Move construct me into other
|
new(&o._value) value_type(static_cast<value_type &&>(_value)); // NOLINT
|
this->_value.~value_type(); // NOLINT
|
swap(_status, o._status);
|
}
|
else
|
{
|
// Move construct other into me
|
new(&_value) value_type(static_cast<value_type &&>(o._value)); // NOLINT
|
o._value.~value_type(); // NOLINT
|
swap(_status, o._status);
|
}
|
}
|
};
|
template <class Base> struct value_storage_delete_copy_constructor : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_delete_copy_constructor() = default;
|
value_storage_delete_copy_constructor(const value_storage_delete_copy_constructor &) = delete;
|
value_storage_delete_copy_constructor(value_storage_delete_copy_constructor &&) = default; // NOLINT
|
};
|
template <class Base> struct value_storage_delete_copy_assignment : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_delete_copy_assignment() = default;
|
value_storage_delete_copy_assignment(const value_storage_delete_copy_assignment &) = default;
|
value_storage_delete_copy_assignment(value_storage_delete_copy_assignment &&) = default; // NOLINT
|
value_storage_delete_copy_assignment &operator=(const value_storage_delete_copy_assignment &o) = delete;
|
value_storage_delete_copy_assignment &operator=(value_storage_delete_copy_assignment &&o) = default; // NOLINT
|
};
|
template <class Base> struct value_storage_delete_move_assignment : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_delete_move_assignment() = default;
|
value_storage_delete_move_assignment(const value_storage_delete_move_assignment &) = default;
|
value_storage_delete_move_assignment(value_storage_delete_move_assignment &&) = default; // NOLINT
|
value_storage_delete_move_assignment &operator=(const value_storage_delete_move_assignment &o) = default;
|
value_storage_delete_move_assignment &operator=(value_storage_delete_move_assignment &&o) = delete;
|
};
|
template <class Base> struct value_storage_delete_move_constructor : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_delete_move_constructor() = default;
|
value_storage_delete_move_constructor(const value_storage_delete_move_constructor &) = default;
|
value_storage_delete_move_constructor(value_storage_delete_move_constructor &&) = delete;
|
};
|
template <class Base> struct value_storage_nontrivial_move_assignment : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_nontrivial_move_assignment() = default;
|
value_storage_nontrivial_move_assignment(const value_storage_nontrivial_move_assignment &) = default;
|
value_storage_nontrivial_move_assignment(value_storage_nontrivial_move_assignment &&) = default; // NOLINT
|
value_storage_nontrivial_move_assignment &operator=(const value_storage_nontrivial_move_assignment &o) = default;
|
value_storage_nontrivial_move_assignment &
|
operator=(value_storage_nontrivial_move_assignment &&o) noexcept(std::is_nothrow_move_assignable<value_type>::value) // NOLINT
|
{
|
if(this->_status.have_value() && o._status.have_value())
|
{
|
this->_value = static_cast<value_type &&>(o._value); // NOLINT
|
}
|
else if(this->_status.have_value() && !o._status.have_value())
|
{
|
this->_value.~value_type(); // NOLINT
|
}
|
else if(!this->_status.have_value() && o._status.have_value())
|
{
|
new(&this->_value) value_type(static_cast<value_type &&>(o._value)); // NOLINT
|
}
|
this->_status = o._status;
|
return *this;
|
}
|
};
|
template <class Base> struct value_storage_nontrivial_copy_assignment : Base // NOLINT
|
{
|
using Base::Base;
|
using value_type = typename Base::value_type;
|
value_storage_nontrivial_copy_assignment() = default;
|
value_storage_nontrivial_copy_assignment(const value_storage_nontrivial_copy_assignment &) = default;
|
value_storage_nontrivial_copy_assignment(value_storage_nontrivial_copy_assignment &&) = default; // NOLINT
|
value_storage_nontrivial_copy_assignment &operator=(value_storage_nontrivial_copy_assignment &&o) = default; // NOLINT
|
value_storage_nontrivial_copy_assignment &
|
operator=(const value_storage_nontrivial_copy_assignment &o) noexcept(std::is_nothrow_copy_assignable<value_type>::value)
|
{
|
if(this->_status.have_value() && o._status.have_value())
|
{
|
this->_value = o._value; // NOLINT
|
}
|
else if(this->_status.have_value() && !o._status.have_value())
|
{
|
this->_value.~value_type(); // NOLINT
|
}
|
else if(!this->_status.have_value() && o._status.have_value())
|
{
|
new(&this->_value) value_type(o._value); // NOLINT
|
}
|
this->_status = o._status;
|
return *this;
|
}
|
};
|
|
// We don't actually need all of std::is_trivial<>, std::is_trivially_copyable<> is sufficient
|
template <class T>
|
using value_storage_select_trivality =
|
std::conditional_t<std::is_trivially_copyable<devoid<T>>::value, value_storage_trivial<T>, value_storage_nontrivial<T>>;
|
template <class T>
|
using value_storage_select_move_constructor = std::conditional_t<std::is_move_constructible<devoid<T>>::value, value_storage_select_trivality<T>,
|
value_storage_delete_move_constructor<value_storage_select_trivality<T>>>;
|
template <class T>
|
using value_storage_select_copy_constructor = std::conditional_t<std::is_copy_constructible<devoid<T>>::value, value_storage_select_move_constructor<T>,
|
value_storage_delete_copy_constructor<value_storage_select_move_constructor<T>>>;
|
template <class T>
|
using value_storage_select_move_assignment = std::conditional_t<
|
std::is_trivially_move_assignable<devoid<T>>::value, value_storage_select_copy_constructor<T>,
|
std::conditional_t<std::is_move_assignable<devoid<T>>::value, value_storage_nontrivial_move_assignment<value_storage_select_copy_constructor<T>>,
|
value_storage_delete_copy_assignment<value_storage_select_copy_constructor<T>>>>;
|
template <class T>
|
using value_storage_select_copy_assignment = std::conditional_t<
|
std::is_trivially_copy_assignable<devoid<T>>::value, value_storage_select_move_assignment<T>,
|
std::conditional_t<std::is_copy_assignable<devoid<T>>::value, value_storage_nontrivial_copy_assignment<value_storage_select_move_assignment<T>>,
|
value_storage_delete_copy_assignment<value_storage_select_move_assignment<T>>>>;
|
template <class T> using value_storage_select_impl = value_storage_select_copy_assignment<T>;
|
#ifndef NDEBUG
|
// Check is trivial in all ways except default constructibility
|
// static_assert(std::is_trivial<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivial!");
|
// static_assert(std::is_trivially_default_constructible<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivially default
|
// constructible!");
|
static_assert(std::is_trivially_copyable<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivially copyable!");
|
static_assert(std::is_trivially_assignable<value_storage_select_impl<int>, value_storage_select_impl<int>>::value,
|
"value_storage_select_impl<int> is not trivially assignable!");
|
static_assert(std::is_trivially_destructible<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivially destructible!");
|
static_assert(std::is_trivially_copy_constructible<value_storage_select_impl<int>>::value,
|
"value_storage_select_impl<int> is not trivially copy constructible!");
|
static_assert(std::is_trivially_move_constructible<value_storage_select_impl<int>>::value,
|
"value_storage_select_impl<int> is not trivially move constructible!");
|
static_assert(std::is_trivially_copy_assignable<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivially copy assignable!");
|
static_assert(std::is_trivially_move_assignable<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not trivially move assignable!");
|
// Also check is standard layout
|
static_assert(std::is_standard_layout<value_storage_select_impl<int>>::value, "value_storage_select_impl<int> is not a standard layout type!");
|
#endif
|
} // namespace detail
|
|
BOOST_OUTCOME_V2_NAMESPACE_END
|
|
#endif
|
