257 lines
10 KiB
C++
257 lines
10 KiB
C++
/* Pointer to a SG14 status_code
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(C) 2018 - 2023 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
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File Created: Sep 2018
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License in the accompanying file
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Licence.txt or at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file Licence.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_OUTCOME_SYSTEM_ERROR2_NESTED_STATUS_CODE_HPP
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#define BOOST_OUTCOME_SYSTEM_ERROR2_NESTED_STATUS_CODE_HPP
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#include "quick_status_code_from_enum.hpp"
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#include <memory> // for allocator
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BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
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namespace detail
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{
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template <class StatusCode, class Allocator> class indirecting_domain : public status_code_domain
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{
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template <class DomainType> friend class status_code;
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using _base = status_code_domain;
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public:
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struct payload_type
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{
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using allocator_traits = std::allocator_traits<Allocator>;
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union
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{
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char _uninit[sizeof(StatusCode)];
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StatusCode sc;
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};
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Allocator alloc;
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payload_type(StatusCode _sc, Allocator _alloc)
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: alloc(static_cast<Allocator &&>(_alloc))
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{
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allocator_traits::construct(alloc, &sc, static_cast<StatusCode &&>(_sc));
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}
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payload_type(const payload_type &) = delete;
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payload_type(payload_type &&) = delete;
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~payload_type() { allocator_traits::destroy(alloc, &sc); }
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};
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using value_type = payload_type *;
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using payload_allocator_traits = typename payload_type::allocator_traits::template rebind_traits<payload_type>;
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using _base::string_ref;
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constexpr indirecting_domain() noexcept
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: _base(0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id() /* unique-ish based on domain's unique id */)
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{
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}
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indirecting_domain(const indirecting_domain &) = default;
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indirecting_domain(indirecting_domain &&) = default; // NOLINT
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indirecting_domain &operator=(const indirecting_domain &) = default;
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indirecting_domain &operator=(indirecting_domain &&) = default; // NOLINT
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~indirecting_domain() = default;
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#if __cplusplus < 201402L && !defined(_MSC_VER)
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static inline const indirecting_domain &get()
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{
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static indirecting_domain v;
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return v;
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}
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#else
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static inline constexpr const indirecting_domain &get();
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#endif
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virtual string_ref name() const noexcept override { return typename StatusCode::domain_type().name(); } // NOLINT
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virtual payload_info_t payload_info() const noexcept override
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{
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return {sizeof(value_type), sizeof(status_code_domain *) + sizeof(value_type),
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(alignof(value_type) > alignof(status_code_domain *)) ? alignof(value_type) : alignof(status_code_domain *)};
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}
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protected:
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using _mycode = status_code<indirecting_domain>;
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virtual bool _do_failure(const status_code<void> &code) const noexcept override // NOLINT
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{
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assert(code.domain() == *this);
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const auto &c = static_cast<const _mycode &>(code); // NOLINT
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return static_cast<status_code_domain &&>(typename StatusCode::domain_type())._do_failure(c.value()->sc);
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}
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virtual bool _do_equivalent(const status_code<void> &code1, const status_code<void> &code2) const noexcept override // NOLINT
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{
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assert(code1.domain() == *this);
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const auto &c1 = static_cast<const _mycode &>(code1); // NOLINT
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return static_cast<status_code_domain &&>(typename StatusCode::domain_type())._do_equivalent(c1.value()->sc, code2);
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}
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virtual generic_code _generic_code(const status_code<void> &code) const noexcept override // NOLINT
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{
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assert(code.domain() == *this);
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const auto &c = static_cast<const _mycode &>(code); // NOLINT
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return static_cast<status_code_domain &&>(typename StatusCode::domain_type())._generic_code(c.value()->sc);
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}
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virtual string_ref _do_message(const status_code<void> &code) const noexcept override // NOLINT
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{
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assert(code.domain() == *this);
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const auto &c = static_cast<const _mycode &>(code); // NOLINT
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return static_cast<status_code_domain &&>(typename StatusCode::domain_type())._do_message(c.value()->sc);
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}
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#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
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BOOST_OUTCOME_SYSTEM_ERROR2_NORETURN virtual void _do_throw_exception(const status_code<void> &code) const override // NOLINT
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{
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assert(code.domain() == *this);
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const auto &c = static_cast<const _mycode &>(code); // NOLINT
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static_cast<status_code_domain &&>(typename StatusCode::domain_type())._do_throw_exception(c.value()->sc);
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abort(); // suppress buggy GCC warning
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}
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#endif
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virtual bool _do_erased_copy(status_code<void> &dst, const status_code<void> &src, payload_info_t dstinfo) const override // NOLINT
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{
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// Note that dst may not have its domain set
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const auto srcinfo = payload_info();
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assert(src.domain() == *this);
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if(dstinfo.total_size < srcinfo.total_size)
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{
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return false;
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}
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auto &d = static_cast<_mycode &>(dst); // NOLINT
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const auto &_s = static_cast<const _mycode &>(src); // NOLINT
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const payload_type &sp = *_s.value();
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typename payload_allocator_traits::template rebind_alloc<payload_type> payload_alloc(sp.alloc);
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auto *dp = payload_allocator_traits::allocate(payload_alloc, 1);
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#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
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try
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#endif
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{
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payload_allocator_traits::construct(payload_alloc, dp, sp.sc, sp.alloc);
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new(BOOST_OUTCOME_SYSTEM_ERROR2_ADDRESS_OF(d)) _mycode(in_place, dp);
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}
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#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
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catch(...)
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{
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payload_allocator_traits::deallocate(payload_alloc, dp, 1);
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throw;
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}
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#endif
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return true;
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}
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virtual void _do_erased_destroy(status_code<void> &code, payload_info_t /*unused*/) const noexcept override // NOLINT
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{
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assert(code.domain() == *this);
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auto &c = static_cast<_mycode &>(code); // NOLINT
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payload_type *p = c.value();
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typename payload_allocator_traits::template rebind_alloc<payload_type> payload_alloc(p->alloc);
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payload_allocator_traits::destroy(payload_alloc, p);
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payload_allocator_traits::deallocate(payload_alloc, p, 1);
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}
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};
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#if __cplusplus >= 201402L || defined(_MSC_VER)
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template <class StatusCode, class Allocator> constexpr indirecting_domain<StatusCode, Allocator> _indirecting_domain{};
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template <class StatusCode, class Allocator>
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inline constexpr const indirecting_domain<StatusCode, Allocator> &indirecting_domain<StatusCode, Allocator>::get()
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{
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return _indirecting_domain<StatusCode, Allocator>;
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}
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#endif
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} // namespace detail
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/*! Make an erased status code which indirects to a dynamically allocated status code,
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using the allocator `alloc`.
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This is useful for shoehorning a rich status code with large value type into a small
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erased status code like `system_code`, with which the status code generated by this
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function is compatible. Note that this function can throw if the allocator throws.
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*/
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BOOST_OUTCOME_SYSTEM_ERROR2_TEMPLATE(class T, class Alloc = std::allocator<typename std::decay<T>::type>)
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BOOST_OUTCOME_SYSTEM_ERROR2_TREQUIRES(BOOST_OUTCOME_SYSTEM_ERROR2_TPRED(is_status_code<T>::value)) //
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inline status_code<detail::erased<typename std::add_pointer<typename std::decay<T>::type>::type>> make_nested_status_code(T &&v, Alloc alloc = {})
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{
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using status_code_type = typename std::decay<T>::type;
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using domain_type = detail::indirecting_domain<status_code_type, typename std::decay<Alloc>::type>;
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using payload_allocator_traits = typename domain_type::payload_allocator_traits;
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typename payload_allocator_traits::template rebind_alloc<typename domain_type::payload_type> payload_alloc(alloc);
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auto *p = payload_allocator_traits::allocate(payload_alloc, 1);
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#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
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try
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#endif
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{
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payload_allocator_traits::construct(payload_alloc, p, static_cast<T &&>(v), static_cast<Alloc &&>(alloc));
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return status_code<domain_type>(in_place, p);
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}
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#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
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catch(...)
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{
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payload_allocator_traits::deallocate(payload_alloc, p, 1);
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throw;
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}
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#endif
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}
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/*! If a status code refers to a `nested_status_code` which indirects to a status
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code of type `StatusCode`, return a pointer to that `StatusCode`. Otherwise return null.
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*/
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BOOST_OUTCOME_SYSTEM_ERROR2_TEMPLATE(class StatusCode, class U)
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BOOST_OUTCOME_SYSTEM_ERROR2_TREQUIRES(BOOST_OUTCOME_SYSTEM_ERROR2_TPRED(is_status_code<StatusCode>::value)) inline StatusCode *get_if(status_code<detail::erased<U>> *v) noexcept
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{
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if((0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id()) != v->domain().id())
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{
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return nullptr;
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}
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union
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{
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U value;
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StatusCode *ret;
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};
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value = v->value();
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return ret;
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}
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//! \overload Const overload
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BOOST_OUTCOME_SYSTEM_ERROR2_TEMPLATE(class StatusCode, class U)
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BOOST_OUTCOME_SYSTEM_ERROR2_TREQUIRES(BOOST_OUTCOME_SYSTEM_ERROR2_TPRED(is_status_code<StatusCode>::value))
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inline const StatusCode *get_if(const status_code<detail::erased<U>> *v) noexcept
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{
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if((0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id()) != v->domain().id())
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{
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return nullptr;
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}
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union
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{
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U value;
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const StatusCode *ret;
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};
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value = v->value();
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return ret;
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}
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/*! If a status code refers to a `nested_status_code`, return the id of the erased
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status code's domain. Otherwise return a meaningless number.
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*/
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template <class U> inline typename status_code_domain::unique_id_type get_id(const status_code<detail::erased<U>> &v) noexcept
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{
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return 0xc44f7bdeb2cc50e9 ^ v.domain().id();
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}
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BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END
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#endif
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