101 lines
3.9 KiB
C++
101 lines
3.9 KiB
C++
/* Failure observers for outcome type
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(C) 2017-2022 Niall Douglas <http://www.nedproductions.biz/> (7 commits)
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File Created: Oct 2017
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Boost Software License - Version 1.0 - August 17th, 2003
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Permission is hereby granted, free of charge, to any person or organization
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obtaining a copy of the software and accompanying documentation covered by
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this license (the "Software") to use, reproduce, display, distribute,
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execute, and transmit the Software, and to prepare derivative works of the
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Software, and to permit third-parties to whom the Software is furnished to
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do so, all subject to the following:
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The copyright notices in the Software and this entire statement, including
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the above license grant, this restriction and the following disclaimer,
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must be included in all copies of the Software, in whole or in part, and
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all derivative works of the Software, unless such copies or derivative
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works are solely in the form of machine-executable object code generated by
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a source language processor.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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*/
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#ifndef BOOST_OUTCOME_BASIC_OUTCOME_FAILURE_OBSERVERS_HPP
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#define BOOST_OUTCOME_BASIC_OUTCOME_FAILURE_OBSERVERS_HPP
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#include "basic_result_storage.hpp"
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BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
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namespace detail
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{
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namespace adl
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{
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struct search_detail_adl
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{
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};
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// Do NOT use template requirements here!
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template <class S, typename = decltype(basic_outcome_failure_exception_from_error(std::declval<S>()))>
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inline auto _delayed_lookup_basic_outcome_failure_exception_from_error(const S &ec, search_detail_adl /*unused*/)
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{
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// ADL discovered
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return basic_outcome_failure_exception_from_error(ec);
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}
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} // namespace adl
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#if defined(_MSC_VER) && _MSC_VER <= 1923 // VS2019
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// VS2017 and VS2019 with /permissive- chokes on the correct form due to over eager early instantiation.
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template <class S, class P> inline void _delayed_lookup_basic_outcome_failure_exception_from_error(...) { static_assert(sizeof(S) == 0, "No specialisation for these error and exception types available!"); }
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#else
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template <class S, class P> inline void _delayed_lookup_basic_outcome_failure_exception_from_error(...) = delete; // NOLINT No specialisation for these error and exception types available!
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#endif
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template <class exception_type> inline exception_type current_exception_or_fatal(std::exception_ptr e) { std::rethrow_exception(e); }
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template <> inline std::exception_ptr current_exception_or_fatal<std::exception_ptr>(std::exception_ptr e) { return e; }
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template <class Base, class R, class S, class P, class NoValuePolicy> class basic_outcome_failure_observers : public Base
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{
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public:
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using exception_type = P;
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using Base::Base;
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exception_type failure() const noexcept
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{
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#ifndef BOOST_NO_EXCEPTIONS
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try
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#endif
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{
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if(this->_state._status.have_exception())
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{
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return this->assume_exception();
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}
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if(this->_state._status.have_error())
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{
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return _delayed_lookup_basic_outcome_failure_exception_from_error(this->assume_error(), adl::search_detail_adl());
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}
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return exception_type();
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}
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#ifndef BOOST_NO_EXCEPTIONS
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catch(...)
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{
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// Return the failure if exception_type is std::exception_ptr,
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// otherwise terminate same as throwing an exception inside noexcept
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return current_exception_or_fatal<exception_type>(std::current_exception());
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}
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#endif
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}
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};
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} // namespace detail
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BOOST_OUTCOME_V2_NAMESPACE_END
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#endif
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