suyu/externals/vcpkg/packages/boost-system_x64-windows/include/boost/system/result.hpp
2024-03-05 16:42:40 +08:00

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#ifndef BOOST_SYSTEM_RESULT_HPP_INCLUDED
#define BOOST_SYSTEM_RESULT_HPP_INCLUDED
// Copyright 2017, 2021, 2022 Peter Dimov.
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/system/errc.hpp>
#include <boost/system/system_error.hpp>
#include <boost/system/detail/error_code.hpp>
#include <boost/system/detail/error_category_impl.hpp>
#include <boost/variant2/variant.hpp>
#include <boost/throw_exception.hpp>
#include <boost/assert/source_location.hpp>
#include <boost/assert.hpp>
#include <boost/config.hpp>
#include <type_traits>
#include <utility>
#include <iosfwd>
#include <system_error>
#include <exception>
//
namespace boost
{
namespace system
{
// throw_exception_from_error
#if defined(__GNUC__) && __GNUC__ >= 7 && __GNUC__ <= 8
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wattributes"
#endif
BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( error_code const & e, boost::source_location const& loc )
{
boost::throw_with_location( system_error( e ), loc );
}
BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( errc::errc_t const & e, boost::source_location const& loc )
{
boost::throw_with_location( system_error( make_error_code( e ) ), loc );
}
BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::error_code const & e, boost::source_location const& loc )
{
boost::throw_with_location( std::system_error( e ), loc );
}
BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::errc const & e, boost::source_location const& loc )
{
boost::throw_with_location( std::system_error( make_error_code( e ) ), loc );
}
BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::exception_ptr const & p, boost::source_location const& loc )
{
if( p )
{
std::rethrow_exception( p );
}
else
{
boost::throw_with_location( std::bad_exception(), loc );
}
}
#if defined(__GNUC__) && __GNUC__ >= 7 && __GNUC__ <= 8
# pragma GCC diagnostic pop
#endif
// in_place_*
using in_place_value_t = variant2::in_place_index_t<0>;
constexpr in_place_value_t in_place_value{};
using in_place_error_t = variant2::in_place_index_t<1>;
constexpr in_place_error_t in_place_error{};
namespace detail
{
template<class T> using remove_cvref = typename std::remove_cv< typename std::remove_reference<T>::type >::type;
template<class... T> using is_errc_t = std::is_same<mp11::mp_list<remove_cvref<T>...>, mp11::mp_list<errc::errc_t>>;
} // namespace detail
// result
template<class T, class E = error_code> class result
{
private:
variant2::variant<T, E> v_;
public:
// constructors
// default
template<class En2 = void, class En = typename std::enable_if<
std::is_void<En2>::value &&
std::is_default_constructible<T>::value
>::type>
constexpr result()
noexcept( std::is_nothrow_default_constructible<T>::value )
: v_( in_place_value )
{
}
// implicit, value
template<class A = T, typename std::enable_if<
std::is_convertible<A, T>::value &&
!(detail::is_errc_t<A>::value && std::is_arithmetic<T>::value) &&
!std::is_constructible<E, A>::value, int>::type = 0>
constexpr result( A&& a )
noexcept( std::is_nothrow_constructible<T, A>::value )
: v_( in_place_value, std::forward<A>(a) )
{
}
// implicit, error
template<class A = E, class = void, typename std::enable_if<
std::is_convertible<A, E>::value &&
!std::is_constructible<T, A>::value, int>::type = 0>
constexpr result( A&& a )
noexcept( std::is_nothrow_constructible<E, A>::value )
: v_( in_place_error, std::forward<A>(a) )
{
}
// explicit, value
template<class... A, class En = typename std::enable_if<
std::is_constructible<T, A...>::value &&
!(detail::is_errc_t<A...>::value && std::is_arithmetic<T>::value) &&
!std::is_constructible<E, A...>::value
>::type>
explicit constexpr result( A&&... a )
noexcept( std::is_nothrow_constructible<T, A...>::value )
: v_( in_place_value, std::forward<A>(a)... )
{
}
// explicit, error
template<class... A, class En2 = void, class En = typename std::enable_if<
!std::is_constructible<T, A...>::value &&
std::is_constructible<E, A...>::value
>::type>
explicit constexpr result( A&&... a )
noexcept( std::is_nothrow_constructible<E, A...>::value )
: v_( in_place_error, std::forward<A>(a)... )
{
}
// tagged, value
template<class... A, class En = typename std::enable_if<
std::is_constructible<T, A...>::value
>::type>
constexpr result( in_place_value_t, A&&... a )
noexcept( std::is_nothrow_constructible<T, A...>::value )
: v_( in_place_value, std::forward<A>(a)... )
{
}
// tagged, error
template<class... A, class En = typename std::enable_if<
std::is_constructible<E, A...>::value
>::type>
constexpr result( in_place_error_t, A&&... a )
noexcept( std::is_nothrow_constructible<E, A...>::value )
: v_( in_place_error, std::forward<A>(a)... )
{
}
// queries
constexpr bool has_value() const noexcept
{
return v_.index() == 0;
}
constexpr bool has_error() const noexcept
{
return v_.index() != 0;
}
constexpr explicit operator bool() const noexcept
{
return v_.index() == 0;
}
// checked value access
#if defined( BOOST_NO_CXX11_REF_QUALIFIERS )
BOOST_CXX14_CONSTEXPR T value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) const
{
if( has_value() )
{
return variant2::unsafe_get<0>( v_ );
}
else
{
throw_exception_from_error( variant2::unsafe_get<1>( v_ ), loc );
}
}
#else
BOOST_CXX14_CONSTEXPR T& value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) &
{
if( has_value() )
{
return variant2::unsafe_get<0>( v_ );
}
else
{
throw_exception_from_error( variant2::unsafe_get<1>( v_ ), loc );
}
}
BOOST_CXX14_CONSTEXPR T const& value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) const&
{
if( has_value() )
{
return variant2::unsafe_get<0>( v_ );
}
else
{
throw_exception_from_error( variant2::unsafe_get<1>( v_ ), loc );
}
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<std::is_move_constructible<U>::value, T>::type
value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) &&
{
return std::move( value( loc ) );
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<!std::is_move_constructible<U>::value, T&&>::type
value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) &&
{
return std::move( value( loc ) );
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<std::is_move_constructible<U>::value, T>::type
value() const && = delete;
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<!std::is_move_constructible<U>::value, T const&&>::type
value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) const &&
{
return std::move( value( loc ) );
}
#endif
// unchecked value access
BOOST_CXX14_CONSTEXPR T* operator->() noexcept
{
return variant2::get_if<0>( &v_ );
}
BOOST_CXX14_CONSTEXPR T const* operator->() const noexcept
{
return variant2::get_if<0>( &v_ );
}
#if defined( BOOST_NO_CXX11_REF_QUALIFIERS )
BOOST_CXX14_CONSTEXPR T& operator*() noexcept
{
T* p = operator->();
BOOST_ASSERT( p != 0 );
return *p;
}
BOOST_CXX14_CONSTEXPR T const& operator*() const noexcept
{
T const* p = operator->();
BOOST_ASSERT( p != 0 );
return *p;
}
#else
BOOST_CXX14_CONSTEXPR T& operator*() & noexcept
{
T* p = operator->();
BOOST_ASSERT( p != 0 );
return *p;
}
BOOST_CXX14_CONSTEXPR T const& operator*() const & noexcept
{
T const* p = operator->();
BOOST_ASSERT( p != 0 );
return *p;
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<std::is_move_constructible<U>::value, T>::type
operator*() && noexcept(std::is_nothrow_move_constructible<T>::value)
{
return std::move(**this);
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<!std::is_move_constructible<U>::value, T&&>::type
operator*() && noexcept
{
return std::move(**this);
}
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<std::is_move_constructible<U>::value, T>::type
operator*() const && noexcept = delete;
template<class U = T>
BOOST_CXX14_CONSTEXPR
typename std::enable_if<!std::is_move_constructible<U>::value, T const&&>::type
operator*() const && noexcept
{
return std::move(**this);
}
#endif
// error access
constexpr E error() const
noexcept( std::is_nothrow_default_constructible<E>::value && std::is_nothrow_copy_constructible<E>::value )
{
return has_error()? variant2::unsafe_get<1>( v_ ): E();
}
// swap
BOOST_CXX14_CONSTEXPR void swap( result& r )
noexcept( noexcept( v_.swap( r.v_ ) ) )
{
v_.swap( r.v_ );
}
friend BOOST_CXX14_CONSTEXPR void swap( result & r1, result & r2 )
noexcept( noexcept( r1.swap( r2 ) ) )
{
r1.swap( r2 );
}
// equality
friend constexpr bool operator==( result const & r1, result const & r2 )
noexcept( noexcept( r1.v_ == r2.v_ ) )
{
return r1.v_ == r2.v_;
}
friend constexpr bool operator!=( result const & r1, result const & r2 )
noexcept( noexcept( !( r1 == r2 ) ) )
{
return !( r1 == r2 );
}
};
template<class Ch, class Tr, class T, class E> std::basic_ostream<Ch, Tr>& operator<<( std::basic_ostream<Ch, Tr>& os, result<T, E> const & r )
{
if( r.has_value() )
{
os << "value:" << *r;
}
else
{
os << "error:" << r.error();
}
return os;
}
// result<void>
template<class E> class result<void, E>
{
private:
variant2::variant<variant2::monostate, E> v_;
public:
// constructors
// default
constexpr result() noexcept
: v_( in_place_value )
{
}
// explicit, error
template<class A, class En = typename std::enable_if<
std::is_constructible<E, A>::value &&
!std::is_convertible<A, E>::value
>::type>
explicit constexpr result( A&& a )
noexcept( std::is_nothrow_constructible<E, A>::value )
: v_( in_place_error, std::forward<A>(a) )
{
}
// implicit, error
template<class A, class En2 = void, class En = typename std::enable_if<
std::is_convertible<A, E>::value
>::type>
constexpr result( A&& a )
noexcept( std::is_nothrow_constructible<E, A>::value )
: v_( in_place_error, std::forward<A>(a) )
{
}
// more than one arg, error
template<class... A, class En2 = void, class En3 = void, class En = typename std::enable_if<
std::is_constructible<E, A...>::value &&
sizeof...(A) >= 2
>::type>
constexpr result( A&&... a )
noexcept( std::is_nothrow_constructible<E, A...>::value )
: v_( in_place_error, std::forward<A>(a)... )
{
}
// tagged, value
constexpr result( in_place_value_t ) noexcept
: v_( in_place_value )
{
}
// tagged, error
template<class... A, class En = typename std::enable_if<
std::is_constructible<E, A...>::value
>::type>
constexpr result( in_place_error_t, A&&... a )
noexcept( std::is_nothrow_constructible<E, A...>::value )
: v_( in_place_error, std::forward<A>(a)... )
{
}
// queries
constexpr bool has_value() const noexcept
{
return v_.index() == 0;
}
constexpr bool has_error() const noexcept
{
return v_.index() != 0;
}
constexpr explicit operator bool() const noexcept
{
return v_.index() == 0;
}
// checked value access
BOOST_CXX14_CONSTEXPR void value( boost::source_location const& loc = BOOST_CURRENT_LOCATION ) const
{
if( has_value() )
{
}
else
{
throw_exception_from_error( variant2::unsafe_get<1>( v_ ), loc );
}
}
// unchecked value access
BOOST_CXX14_CONSTEXPR void* operator->() noexcept
{
return variant2::get_if<0>( &v_ );
}
BOOST_CXX14_CONSTEXPR void const* operator->() const noexcept
{
return variant2::get_if<0>( &v_ );
}
BOOST_CXX14_CONSTEXPR void operator*() const noexcept
{
BOOST_ASSERT( has_value() );
}
// error access
constexpr E error() const
noexcept( std::is_nothrow_default_constructible<E>::value && std::is_nothrow_copy_constructible<E>::value )
{
return has_error()? variant2::unsafe_get<1>( v_ ): E();
}
// swap
BOOST_CXX14_CONSTEXPR void swap( result& r )
noexcept( noexcept( v_.swap( r.v_ ) ) )
{
v_.swap( r.v_ );
}
friend BOOST_CXX14_CONSTEXPR void swap( result & r1, result & r2 )
noexcept( noexcept( r1.swap( r2 ) ) )
{
r1.swap( r2 );
}
// equality
friend constexpr bool operator==( result const & r1, result const & r2 )
noexcept( noexcept( r1.v_ == r2.v_ ) )
{
return r1.v_ == r2.v_;
}
friend constexpr bool operator!=( result const & r1, result const & r2 )
noexcept( noexcept( !( r1 == r2 ) ) )
{
return !( r1 == r2 );
}
};
template<class Ch, class Tr, class E> std::basic_ostream<Ch, Tr>& operator<<( std::basic_ostream<Ch, Tr>& os, result<void, E> const & r )
{
if( r.has_value() )
{
os << "value:void";
}
else
{
os << "error:" << r.error();
}
return os;
}
} // namespace system
} // namespace boost
#endif // #ifndef BOOST_SYSTEM_RESULT_HPP_INCLUDED