2327 lines
87 KiB
C++
2327 lines
87 KiB
C++
///
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// expected - An implementation of std::expected with extensions
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// Written in 2017 by Simon Brand (simonrbrand@gmail.com, @TartanLlama)
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//
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// Documentation available at http://tl.tartanllama.xyz/
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//
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// To the extent possible under law, the author(s) have dedicated all
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// copyright and related and neighboring rights to this software to the
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// public domain worldwide. This software is distributed without any warranty.
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//
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// You should have received a copy of the CC0 Public Domain Dedication
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// along with this software. If not, see
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// <http://creativecommons.org/publicdomain/zero/1.0/>.
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///
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#ifndef TL_EXPECTED_HPP
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#define TL_EXPECTED_HPP
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#define TL_EXPECTED_VERSION_MAJOR 1
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#define TL_EXPECTED_VERSION_MINOR 0
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#define TL_EXPECTED_VERSION_PATCH 1
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#include <exception>
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#include <functional>
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#include <type_traits>
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#include <utility>
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#if defined(__EXCEPTIONS) || defined(_CPPUNWIND)
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#define TL_EXPECTED_EXCEPTIONS_ENABLED
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#endif
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#if (defined(_MSC_VER) && _MSC_VER == 1900)
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#define TL_EXPECTED_MSVC2015
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#define TL_EXPECTED_MSVC2015_CONSTEXPR
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#else
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#define TL_EXPECTED_MSVC2015_CONSTEXPR constexpr
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#endif
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#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \
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!defined(__clang__))
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#define TL_EXPECTED_GCC49
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#endif
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#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 4 && \
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!defined(__clang__))
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#define TL_EXPECTED_GCC54
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#endif
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#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 5 && \
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!defined(__clang__))
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#define TL_EXPECTED_GCC55
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#endif
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#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \
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!defined(__clang__))
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// GCC < 5 doesn't support overloading on const&& for member functions
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#define TL_EXPECTED_NO_CONSTRR
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// GCC < 5 doesn't support some standard C++11 type traits
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
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std::has_trivial_copy_constructor<T>
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
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std::has_trivial_copy_assign<T>
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// This one will be different for GCC 5.7 if it's ever supported
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#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \
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std::is_trivially_destructible<T>
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// GCC 5 < v < 8 has a bug in is_trivially_copy_constructible which breaks std::vector
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// for non-copyable types
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#elif (defined(__GNUC__) && __GNUC__ < 8 && \
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!defined(__clang__))
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#ifndef TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
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#define TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
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namespace tl {
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namespace detail {
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template<class T>
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struct is_trivially_copy_constructible : std::is_trivially_copy_constructible<T>{};
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#ifdef _GLIBCXX_VECTOR
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template<class T, class A>
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struct is_trivially_copy_constructible<std::vector<T,A>>
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: std::false_type{};
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#endif
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}
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}
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#endif
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
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tl::detail::is_trivially_copy_constructible<T>
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
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std::is_trivially_copy_assignable<T>
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#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) std::is_trivially_destructible<T>
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#else
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \
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std::is_trivially_copy_constructible<T>
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#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \
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std::is_trivially_copy_assignable<T>
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#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \
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std::is_trivially_destructible<T>
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#endif
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#if __cplusplus > 201103L
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#define TL_EXPECTED_CXX14
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#endif
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#ifdef TL_EXPECTED_GCC49
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#define TL_EXPECTED_GCC49_CONSTEXPR
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#else
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#define TL_EXPECTED_GCC49_CONSTEXPR constexpr
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#endif
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#if (__cplusplus == 201103L || defined(TL_EXPECTED_MSVC2015) || \
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defined(TL_EXPECTED_GCC49))
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#define TL_EXPECTED_11_CONSTEXPR
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#else
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#define TL_EXPECTED_11_CONSTEXPR constexpr
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#endif
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namespace tl {
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template <class T, class E> class expected;
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#ifndef TL_MONOSTATE_INPLACE_MUTEX
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#define TL_MONOSTATE_INPLACE_MUTEX
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class monostate {};
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struct in_place_t {
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explicit in_place_t() = default;
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};
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static constexpr in_place_t in_place{};
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#endif
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template <class E> class unexpected {
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public:
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static_assert(!std::is_same<E, void>::value, "E must not be void");
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unexpected() = delete;
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constexpr explicit unexpected(const E &e) : m_val(e) {}
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constexpr explicit unexpected(E &&e) : m_val(std::move(e)) {}
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constexpr const E &value() const & { return m_val; }
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TL_EXPECTED_11_CONSTEXPR E &value() & { return m_val; }
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TL_EXPECTED_11_CONSTEXPR E &&value() && { return std::move(m_val); }
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constexpr const E &&value() const && { return std::move(m_val); }
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private:
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E m_val;
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};
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template <class E>
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constexpr bool operator==(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() == rhs.value();
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}
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template <class E>
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constexpr bool operator!=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() != rhs.value();
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}
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template <class E>
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constexpr bool operator<(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() < rhs.value();
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}
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template <class E>
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constexpr bool operator<=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() <= rhs.value();
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}
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template <class E>
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constexpr bool operator>(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() > rhs.value();
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}
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template <class E>
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constexpr bool operator>=(const unexpected<E> &lhs, const unexpected<E> &rhs) {
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return lhs.value() >= rhs.value();
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}
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template <class E>
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unexpected<typename std::decay<E>::type> make_unexpected(E &&e) {
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return unexpected<typename std::decay<E>::type>(std::forward<E>(e));
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}
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struct unexpect_t {
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unexpect_t() = default;
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};
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static constexpr unexpect_t unexpect{};
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namespace detail {
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template<typename E>
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[[noreturn]] TL_EXPECTED_11_CONSTEXPR void throw_exception(E &&e) {
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#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
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throw std::forward<E>(e);
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#else
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#ifdef _MSC_VER
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__assume(0);
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#else
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__builtin_unreachable();
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#endif
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#endif
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}
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#ifndef TL_TRAITS_MUTEX
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#define TL_TRAITS_MUTEX
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// C++14-style aliases for brevity
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template <class T> using remove_const_t = typename std::remove_const<T>::type;
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template <class T>
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using remove_reference_t = typename std::remove_reference<T>::type;
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template <class T> using decay_t = typename std::decay<T>::type;
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template <bool E, class T = void>
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using enable_if_t = typename std::enable_if<E, T>::type;
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template <bool B, class T, class F>
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using conditional_t = typename std::conditional<B, T, F>::type;
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// std::conjunction from C++17
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template <class...> struct conjunction : std::true_type {};
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template <class B> struct conjunction<B> : B {};
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template <class B, class... Bs>
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struct conjunction<B, Bs...>
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: std::conditional<bool(B::value), conjunction<Bs...>, B>::type {};
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#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L
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#define TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
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#endif
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// In C++11 mode, there's an issue in libc++'s std::mem_fn
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// which results in a hard-error when using it in a noexcept expression
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// in some cases. This is a check to workaround the common failing case.
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#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
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template <class T> struct is_pointer_to_non_const_member_func : std::false_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...)> : std::true_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...)&> : std::true_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) &&> : std::true_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile> : std::true_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile &> : std::true_type {};
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template <class T, class Ret, class... Args>
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struct is_pointer_to_non_const_member_func<Ret(T::*) (Args...) volatile &&> : std::true_type {};
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template <class T> struct is_const_or_const_ref : std::false_type {};
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template <class T> struct is_const_or_const_ref<T const&> : std::true_type {};
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template <class T> struct is_const_or_const_ref<T const> : std::true_type {};
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#endif
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// std::invoke from C++17
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// https://stackoverflow.com/questions/38288042/c11-14-invoke-workaround
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template <typename Fn, typename... Args,
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#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
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typename = enable_if_t<!(is_pointer_to_non_const_member_func<Fn>::value
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&& is_const_or_const_ref<Args...>::value)>,
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#endif
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typename = enable_if_t<std::is_member_pointer<decay_t<Fn>>::value>,
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int = 0>
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constexpr auto invoke(Fn && f, Args && ... args) noexcept(
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noexcept(std::mem_fn(f)(std::forward<Args>(args)...)))
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-> decltype(std::mem_fn(f)(std::forward<Args>(args)...)) {
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return std::mem_fn(f)(std::forward<Args>(args)...);
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}
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template <typename Fn, typename... Args,
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typename = enable_if_t<!std::is_member_pointer<decay_t<Fn>>::value>>
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constexpr auto invoke(Fn && f, Args && ... args) noexcept(
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noexcept(std::forward<Fn>(f)(std::forward<Args>(args)...)))
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-> decltype(std::forward<Fn>(f)(std::forward<Args>(args)...)) {
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return std::forward<Fn>(f)(std::forward<Args>(args)...);
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}
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// std::invoke_result from C++17
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template <class F, class, class... Us> struct invoke_result_impl;
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template <class F, class... Us>
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struct invoke_result_impl<
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F, decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...), void()),
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Us...> {
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using type = decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...));
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};
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template <class F, class... Us>
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using invoke_result = invoke_result_impl<F, void, Us...>;
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template <class F, class... Us>
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using invoke_result_t = typename invoke_result<F, Us...>::type;
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#if defined(_MSC_VER) && _MSC_VER <= 1900
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// TODO make a version which works with MSVC 2015
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template <class T, class U = T> struct is_swappable : std::true_type {};
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template <class T, class U = T> struct is_nothrow_swappable : std::true_type {};
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#else
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// https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept
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namespace swap_adl_tests {
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// if swap ADL finds this then it would call std::swap otherwise (same
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// signature)
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struct tag {};
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template <class T> tag swap(T&, T&);
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template <class T, std::size_t N> tag swap(T(&a)[N], T(&b)[N]);
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// helper functions to test if an unqualified swap is possible, and if it
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// becomes std::swap
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template <class, class> std::false_type can_swap(...) noexcept(false);
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template <class T, class U,
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class = decltype(swap(std::declval<T&>(), std::declval<U&>()))>
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std::true_type can_swap(int) noexcept(noexcept(swap(std::declval<T&>(),
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std::declval<U&>())));
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template <class, class> std::false_type uses_std(...);
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template <class T, class U>
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std::is_same<decltype(swap(std::declval<T&>(), std::declval<U&>())), tag>
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uses_std(int);
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template <class T>
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struct is_std_swap_noexcept
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: std::integral_constant<bool,
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std::is_nothrow_move_constructible<T>::value&&
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std::is_nothrow_move_assignable<T>::value> {};
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template <class T, std::size_t N>
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struct is_std_swap_noexcept<T[N]> : is_std_swap_noexcept<T> {};
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template <class T, class U>
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struct is_adl_swap_noexcept
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: std::integral_constant<bool, noexcept(can_swap<T, U>(0))> {};
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} // namespace swap_adl_tests
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template <class T, class U = T>
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struct is_swappable
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: std::integral_constant<
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bool,
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decltype(detail::swap_adl_tests::can_swap<T, U>(0))::value &&
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(!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value ||
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(std::is_move_assignable<T>::value &&
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std::is_move_constructible<T>::value))> {};
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template <class T, std::size_t N>
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struct is_swappable<T[N], T[N]>
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: std::integral_constant<
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bool,
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decltype(detail::swap_adl_tests::can_swap<T[N], T[N]>(0))::value &&
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(!decltype(
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detail::swap_adl_tests::uses_std<T[N], T[N]>(0))::value ||
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is_swappable<T, T>::value)> {};
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template <class T, class U = T>
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struct is_nothrow_swappable
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: std::integral_constant<
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bool,
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is_swappable<T, U>::value &&
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((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value
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&& detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
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(!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
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detail::swap_adl_tests::is_adl_swap_noexcept<T,
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U>::value))> {
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};
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#endif
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#endif
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// Trait for checking if a type is a tl::expected
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template <class T> struct is_expected_impl : std::false_type {};
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template <class T, class E>
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struct is_expected_impl<expected<T, E>> : std::true_type {};
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template <class T> using is_expected = is_expected_impl<decay_t<T>>;
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template <class T, class E, class U>
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using expected_enable_forward_value = detail::enable_if_t<
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std::is_constructible<T, U &&>::value &&
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!std::is_same<detail::decay_t<U>, in_place_t>::value &&
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!std::is_same<expected<T, E>, detail::decay_t<U>>::value &&
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!std::is_same<unexpected<E>, detail::decay_t<U>>::value>;
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template <class T, class E, class U, class G, class UR, class GR>
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using expected_enable_from_other = detail::enable_if_t<
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std::is_constructible<T, UR>::value &&
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std::is_constructible<E, GR>::value &&
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!std::is_constructible<T, expected<U, G> &>::value &&
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!std::is_constructible<T, expected<U, G> &&>::value &&
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!std::is_constructible<T, const expected<U, G> &>::value &&
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!std::is_constructible<T, const expected<U, G> &&>::value &&
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!std::is_convertible<expected<U, G> &, T>::value &&
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!std::is_convertible<expected<U, G> &&, T>::value &&
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!std::is_convertible<const expected<U, G> &, T>::value &&
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!std::is_convertible<const expected<U, G> &&, T>::value>;
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template <class T, class U>
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using is_void_or = conditional_t<std::is_void<T>::value, std::true_type, U>;
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template <class T>
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using is_copy_constructible_or_void =
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is_void_or<T, std::is_copy_constructible<T>>;
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template <class T>
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using is_move_constructible_or_void =
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is_void_or<T, std::is_move_constructible<T>>;
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template <class T>
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using is_copy_assignable_or_void =
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is_void_or<T, std::is_copy_assignable<T>>;
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template <class T>
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using is_move_assignable_or_void =
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is_void_or<T, std::is_move_assignable<T>>;
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} // namespace detail
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namespace detail {
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struct no_init_t {};
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static constexpr no_init_t no_init{};
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// Implements the storage of the values, and ensures that the destructor is
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// trivial if it can be.
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//
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// This specialization is for where neither `T` or `E` is trivially
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// destructible, so the destructors must be called on destruction of the
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// `expected`
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template <class T, class E, bool = std::is_trivially_destructible<T>::value,
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bool = std::is_trivially_destructible<E>::value>
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struct expected_storage_base {
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constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
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constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}
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template <class... Args,
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detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
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nullptr>
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constexpr expected_storage_base(in_place_t, Args &&... args)
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: m_val(std::forward<Args>(args)...), m_has_val(true) {}
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|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() {
|
|
if (m_has_val) {
|
|
m_val.~T();
|
|
} else {
|
|
m_unexpect.~unexpected<E>();
|
|
}
|
|
}
|
|
union {
|
|
T m_val;
|
|
unexpected<E> m_unexpect;
|
|
char m_no_init;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// This specialization is for when both `T` and `E` are trivially-destructible,
|
|
// so the destructor of the `expected` can be trivial.
|
|
template <class T, class E> struct expected_storage_base<T, E, true, true> {
|
|
constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
|
|
constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr expected_storage_base(in_place_t, Args &&... args)
|
|
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() = default;
|
|
union {
|
|
T m_val;
|
|
unexpected<E> m_unexpect;
|
|
char m_no_init;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// T is trivial, E is not.
|
|
template <class T, class E> struct expected_storage_base<T, E, true, false> {
|
|
constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
|
|
TL_EXPECTED_MSVC2015_CONSTEXPR expected_storage_base(no_init_t)
|
|
: m_no_init(), m_has_val(false) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr expected_storage_base(in_place_t, Args &&... args)
|
|
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() {
|
|
if (!m_has_val) {
|
|
m_unexpect.~unexpected<E>();
|
|
}
|
|
}
|
|
|
|
union {
|
|
T m_val;
|
|
unexpected<E> m_unexpect;
|
|
char m_no_init;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// E is trivial, T is not.
|
|
template <class T, class E> struct expected_storage_base<T, E, false, true> {
|
|
constexpr expected_storage_base() : m_val(T{}), m_has_val(true) {}
|
|
constexpr expected_storage_base(no_init_t) : m_no_init(), m_has_val(false) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr expected_storage_base(in_place_t, Args &&... args)
|
|
: m_val(std::forward<Args>(args)...), m_has_val(true) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr expected_storage_base(in_place_t, std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_val(il, std::forward<Args>(args)...), m_has_val(true) {}
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() {
|
|
if (m_has_val) {
|
|
m_val.~T();
|
|
}
|
|
}
|
|
union {
|
|
T m_val;
|
|
unexpected<E> m_unexpect;
|
|
char m_no_init;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// `T` is `void`, `E` is trivially-destructible
|
|
template <class E> struct expected_storage_base<void, E, false, true> {
|
|
TL_EXPECTED_MSVC2015_CONSTEXPR expected_storage_base() : m_has_val(true) {}
|
|
constexpr expected_storage_base(no_init_t) : m_val(), m_has_val(false) {}
|
|
|
|
constexpr expected_storage_base(in_place_t) : m_has_val(true) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() = default;
|
|
struct dummy {};
|
|
union {
|
|
unexpected<E> m_unexpect;
|
|
dummy m_val;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// `T` is `void`, `E` is not trivially-destructible
|
|
template <class E> struct expected_storage_base<void, E, false, false> {
|
|
constexpr expected_storage_base() : m_dummy(), m_has_val(true) {}
|
|
constexpr expected_storage_base(no_init_t) : m_dummy(), m_has_val(false) {}
|
|
|
|
constexpr expected_storage_base(in_place_t) : m_dummy(), m_has_val(true) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t, Args &&... args)
|
|
: m_unexpect(std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected_storage_base(unexpect_t,
|
|
std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: m_unexpect(il, std::forward<Args>(args)...), m_has_val(false) {}
|
|
|
|
~expected_storage_base() {
|
|
if (!m_has_val) {
|
|
m_unexpect.~unexpected<E>();
|
|
}
|
|
}
|
|
|
|
union {
|
|
unexpected<E> m_unexpect;
|
|
char m_dummy;
|
|
};
|
|
bool m_has_val;
|
|
};
|
|
|
|
// This base class provides some handy member functions which can be used in
|
|
// further derived classes
|
|
template <class T, class E>
|
|
struct expected_operations_base : expected_storage_base<T, E> {
|
|
using expected_storage_base<T, E>::expected_storage_base;
|
|
|
|
template <class... Args> void construct(Args &&... args) noexcept {
|
|
new (std::addressof(this->m_val)) T(std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
}
|
|
|
|
template <class Rhs> void construct_with(Rhs &&rhs) noexcept {
|
|
new (std::addressof(this->m_val)) T(std::forward<Rhs>(rhs).get());
|
|
this->m_has_val = true;
|
|
}
|
|
|
|
template <class... Args> void construct_error(Args &&... args) noexcept {
|
|
new (std::addressof(this->m_unexpect))
|
|
unexpected<E>(std::forward<Args>(args)...);
|
|
this->m_has_val = false;
|
|
}
|
|
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
|
|
// These assign overloads ensure that the most efficient assignment
|
|
// implementation is used while maintaining the strong exception guarantee.
|
|
// The problematic case is where rhs has a value, but *this does not.
|
|
//
|
|
// This overload handles the case where we can just copy-construct `T`
|
|
// directly into place without throwing.
|
|
template <class U = T,
|
|
detail::enable_if_t<std::is_nothrow_copy_constructible<U>::value>
|
|
* = nullptr>
|
|
void assign(const expected_operations_base &rhs) noexcept {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
geterr().~unexpected<E>();
|
|
construct(rhs.get());
|
|
} else {
|
|
assign_common(rhs);
|
|
}
|
|
}
|
|
|
|
// This overload handles the case where we can attempt to create a copy of
|
|
// `T`, then no-throw move it into place if the copy was successful.
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_nothrow_copy_constructible<U>::value &&
|
|
std::is_nothrow_move_constructible<U>::value>
|
|
* = nullptr>
|
|
void assign(const expected_operations_base &rhs) noexcept {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
T tmp = rhs.get();
|
|
geterr().~unexpected<E>();
|
|
construct(std::move(tmp));
|
|
} else {
|
|
assign_common(rhs);
|
|
}
|
|
}
|
|
|
|
// This overload is the worst-case, where we have to move-construct the
|
|
// unexpected value into temporary storage, then try to copy the T into place.
|
|
// If the construction succeeds, then everything is fine, but if it throws,
|
|
// then we move the old unexpected value back into place before rethrowing the
|
|
// exception.
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_nothrow_copy_constructible<U>::value &&
|
|
!std::is_nothrow_move_constructible<U>::value>
|
|
* = nullptr>
|
|
void assign(const expected_operations_base &rhs) {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
auto tmp = std::move(geterr());
|
|
geterr().~unexpected<E>();
|
|
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
construct(rhs.get());
|
|
} catch (...) {
|
|
geterr() = std::move(tmp);
|
|
throw;
|
|
}
|
|
#else
|
|
construct(rhs.get());
|
|
#endif
|
|
} else {
|
|
assign_common(rhs);
|
|
}
|
|
}
|
|
|
|
// These overloads do the same as above, but for rvalues
|
|
template <class U = T,
|
|
detail::enable_if_t<std::is_nothrow_move_constructible<U>::value>
|
|
* = nullptr>
|
|
void assign(expected_operations_base &&rhs) noexcept {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
geterr().~unexpected<E>();
|
|
construct(std::move(rhs).get());
|
|
} else {
|
|
assign_common(std::move(rhs));
|
|
}
|
|
}
|
|
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_nothrow_move_constructible<U>::value>
|
|
* = nullptr>
|
|
void assign(expected_operations_base &&rhs) {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
auto tmp = std::move(geterr());
|
|
geterr().~unexpected<E>();
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
construct(std::move(rhs).get());
|
|
} catch (...) {
|
|
geterr() = std::move(tmp);
|
|
throw;
|
|
}
|
|
#else
|
|
construct(std::move(rhs).get());
|
|
#endif
|
|
} else {
|
|
assign_common(std::move(rhs));
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
// If exceptions are disabled then we can just copy-construct
|
|
void assign(const expected_operations_base &rhs) noexcept {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
geterr().~unexpected<E>();
|
|
construct(rhs.get());
|
|
} else {
|
|
assign_common(rhs);
|
|
}
|
|
}
|
|
|
|
void assign(expected_operations_base &&rhs) noexcept {
|
|
if (!this->m_has_val && rhs.m_has_val) {
|
|
geterr().~unexpected<E>();
|
|
construct(std::move(rhs).get());
|
|
} else {
|
|
assign_common(rhs);
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
// The common part of move/copy assigning
|
|
template <class Rhs> void assign_common(Rhs &&rhs) {
|
|
if (this->m_has_val) {
|
|
if (rhs.m_has_val) {
|
|
get() = std::forward<Rhs>(rhs).get();
|
|
} else {
|
|
destroy_val();
|
|
construct_error(std::forward<Rhs>(rhs).geterr());
|
|
}
|
|
} else {
|
|
if (!rhs.m_has_val) {
|
|
geterr() = std::forward<Rhs>(rhs).geterr();
|
|
}
|
|
}
|
|
}
|
|
|
|
bool has_value() const { return this->m_has_val; }
|
|
|
|
TL_EXPECTED_11_CONSTEXPR T &get() & { return this->m_val; }
|
|
constexpr const T &get() const & { return this->m_val; }
|
|
TL_EXPECTED_11_CONSTEXPR T &&get() && { return std::move(this->m_val); }
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
constexpr const T &&get() const && { return std::move(this->m_val); }
|
|
#endif
|
|
|
|
TL_EXPECTED_11_CONSTEXPR unexpected<E> &geterr() & {
|
|
return this->m_unexpect;
|
|
}
|
|
constexpr const unexpected<E> &geterr() const & { return this->m_unexpect; }
|
|
TL_EXPECTED_11_CONSTEXPR unexpected<E> &&geterr() && {
|
|
return std::move(this->m_unexpect);
|
|
}
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
constexpr const unexpected<E> &&geterr() const && {
|
|
return std::move(this->m_unexpect);
|
|
}
|
|
#endif
|
|
|
|
TL_EXPECTED_11_CONSTEXPR void destroy_val() {
|
|
get().~T();
|
|
}
|
|
};
|
|
|
|
// This base class provides some handy member functions which can be used in
|
|
// further derived classes
|
|
template <class E>
|
|
struct expected_operations_base<void, E> : expected_storage_base<void, E> {
|
|
using expected_storage_base<void, E>::expected_storage_base;
|
|
|
|
template <class... Args> void construct() noexcept { this->m_has_val = true; }
|
|
|
|
// This function doesn't use its argument, but needs it so that code in
|
|
// levels above this can work independently of whether T is void
|
|
template <class Rhs> void construct_with(Rhs &&) noexcept {
|
|
this->m_has_val = true;
|
|
}
|
|
|
|
template <class... Args> void construct_error(Args &&... args) noexcept {
|
|
new (std::addressof(this->m_unexpect))
|
|
unexpected<E>(std::forward<Args>(args)...);
|
|
this->m_has_val = false;
|
|
}
|
|
|
|
template <class Rhs> void assign(Rhs &&rhs) noexcept {
|
|
if (!this->m_has_val) {
|
|
if (rhs.m_has_val) {
|
|
geterr().~unexpected<E>();
|
|
construct();
|
|
} else {
|
|
geterr() = std::forward<Rhs>(rhs).geterr();
|
|
}
|
|
} else {
|
|
if (!rhs.m_has_val) {
|
|
construct_error(std::forward<Rhs>(rhs).geterr());
|
|
}
|
|
}
|
|
}
|
|
|
|
bool has_value() const { return this->m_has_val; }
|
|
|
|
TL_EXPECTED_11_CONSTEXPR unexpected<E> &geterr() & {
|
|
return this->m_unexpect;
|
|
}
|
|
constexpr const unexpected<E> &geterr() const & { return this->m_unexpect; }
|
|
TL_EXPECTED_11_CONSTEXPR unexpected<E> &&geterr() && {
|
|
return std::move(this->m_unexpect);
|
|
}
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
constexpr const unexpected<E> &&geterr() const && {
|
|
return std::move(this->m_unexpect);
|
|
}
|
|
#endif
|
|
|
|
TL_EXPECTED_11_CONSTEXPR void destroy_val() {
|
|
//no-op
|
|
}
|
|
};
|
|
|
|
// This class manages conditionally having a trivial copy constructor
|
|
// This specialization is for when T and E are trivially copy constructible
|
|
template <class T, class E,
|
|
bool = is_void_or<T, TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)>::
|
|
value &&TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(E)::value>
|
|
struct expected_copy_base : expected_operations_base<T, E> {
|
|
using expected_operations_base<T, E>::expected_operations_base;
|
|
};
|
|
|
|
// This specialization is for when T or E are not trivially copy constructible
|
|
template <class T, class E>
|
|
struct expected_copy_base<T, E, false> : expected_operations_base<T, E> {
|
|
using expected_operations_base<T, E>::expected_operations_base;
|
|
|
|
expected_copy_base() = default;
|
|
expected_copy_base(const expected_copy_base &rhs)
|
|
: expected_operations_base<T, E>(no_init) {
|
|
if (rhs.has_value()) {
|
|
this->construct_with(rhs);
|
|
} else {
|
|
this->construct_error(rhs.geterr());
|
|
}
|
|
}
|
|
|
|
expected_copy_base(expected_copy_base &&rhs) = default;
|
|
expected_copy_base &operator=(const expected_copy_base &rhs) = default;
|
|
expected_copy_base &operator=(expected_copy_base &&rhs) = default;
|
|
};
|
|
|
|
// This class manages conditionally having a trivial move constructor
|
|
// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
|
|
// doesn't implement an analogue to std::is_trivially_move_constructible. We
|
|
// have to make do with a non-trivial move constructor even if T is trivially
|
|
// move constructible
|
|
#ifndef TL_EXPECTED_GCC49
|
|
template <class T, class E,
|
|
bool = is_void_or<T, std::is_trivially_move_constructible<T>>::value
|
|
&&std::is_trivially_move_constructible<E>::value>
|
|
struct expected_move_base : expected_copy_base<T, E> {
|
|
using expected_copy_base<T, E>::expected_copy_base;
|
|
};
|
|
#else
|
|
template <class T, class E, bool = false> struct expected_move_base;
|
|
#endif
|
|
template <class T, class E>
|
|
struct expected_move_base<T, E, false> : expected_copy_base<T, E> {
|
|
using expected_copy_base<T, E>::expected_copy_base;
|
|
|
|
expected_move_base() = default;
|
|
expected_move_base(const expected_move_base &rhs) = default;
|
|
|
|
expected_move_base(expected_move_base &&rhs) noexcept(
|
|
std::is_nothrow_move_constructible<T>::value)
|
|
: expected_copy_base<T, E>(no_init) {
|
|
if (rhs.has_value()) {
|
|
this->construct_with(std::move(rhs));
|
|
} else {
|
|
this->construct_error(std::move(rhs.geterr()));
|
|
}
|
|
}
|
|
expected_move_base &operator=(const expected_move_base &rhs) = default;
|
|
expected_move_base &operator=(expected_move_base &&rhs) = default;
|
|
};
|
|
|
|
// This class manages conditionally having a trivial copy assignment operator
|
|
template <class T, class E,
|
|
bool = is_void_or<
|
|
T, conjunction<TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T),
|
|
TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T),
|
|
TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T)>>::value
|
|
&&TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(E)::value
|
|
&&TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(E)::value
|
|
&&TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(E)::value>
|
|
struct expected_copy_assign_base : expected_move_base<T, E> {
|
|
using expected_move_base<T, E>::expected_move_base;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_copy_assign_base<T, E, false> : expected_move_base<T, E> {
|
|
using expected_move_base<T, E>::expected_move_base;
|
|
|
|
expected_copy_assign_base() = default;
|
|
expected_copy_assign_base(const expected_copy_assign_base &rhs) = default;
|
|
|
|
expected_copy_assign_base(expected_copy_assign_base &&rhs) = default;
|
|
expected_copy_assign_base &operator=(const expected_copy_assign_base &rhs) {
|
|
this->assign(rhs);
|
|
return *this;
|
|
}
|
|
expected_copy_assign_base &
|
|
operator=(expected_copy_assign_base &&rhs) = default;
|
|
};
|
|
|
|
// This class manages conditionally having a trivial move assignment operator
|
|
// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
|
|
// doesn't implement an analogue to std::is_trivially_move_assignable. We have
|
|
// to make do with a non-trivial move assignment operator even if T is trivially
|
|
// move assignable
|
|
#ifndef TL_EXPECTED_GCC49
|
|
template <class T, class E,
|
|
bool =
|
|
is_void_or<T, conjunction<std::is_trivially_destructible<T>,
|
|
std::is_trivially_move_constructible<T>,
|
|
std::is_trivially_move_assignable<T>>>::
|
|
value &&std::is_trivially_destructible<E>::value
|
|
&&std::is_trivially_move_constructible<E>::value
|
|
&&std::is_trivially_move_assignable<E>::value>
|
|
struct expected_move_assign_base : expected_copy_assign_base<T, E> {
|
|
using expected_copy_assign_base<T, E>::expected_copy_assign_base;
|
|
};
|
|
#else
|
|
template <class T, class E, bool = false> struct expected_move_assign_base;
|
|
#endif
|
|
|
|
template <class T, class E>
|
|
struct expected_move_assign_base<T, E, false>
|
|
: expected_copy_assign_base<T, E> {
|
|
using expected_copy_assign_base<T, E>::expected_copy_assign_base;
|
|
|
|
expected_move_assign_base() = default;
|
|
expected_move_assign_base(const expected_move_assign_base &rhs) = default;
|
|
|
|
expected_move_assign_base(expected_move_assign_base &&rhs) = default;
|
|
|
|
expected_move_assign_base &
|
|
operator=(const expected_move_assign_base &rhs) = default;
|
|
|
|
expected_move_assign_base &
|
|
operator=(expected_move_assign_base &&rhs) noexcept(
|
|
std::is_nothrow_move_constructible<T>::value
|
|
&&std::is_nothrow_move_assignable<T>::value) {
|
|
this->assign(std::move(rhs));
|
|
return *this;
|
|
}
|
|
};
|
|
|
|
// expected_delete_ctor_base will conditionally delete copy and move
|
|
// constructors depending on whether T is copy/move constructible
|
|
template <class T, class E,
|
|
bool EnableCopy = (is_copy_constructible_or_void<T>::value &&
|
|
std::is_copy_constructible<E>::value),
|
|
bool EnableMove = (is_move_constructible_or_void<T>::value &&
|
|
std::is_move_constructible<E>::value)>
|
|
struct expected_delete_ctor_base {
|
|
expected_delete_ctor_base() = default;
|
|
expected_delete_ctor_base(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = default;
|
|
expected_delete_ctor_base &
|
|
operator=(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base &
|
|
operator=(expected_delete_ctor_base &&) noexcept = default;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_ctor_base<T, E, true, false> {
|
|
expected_delete_ctor_base() = default;
|
|
expected_delete_ctor_base(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = delete;
|
|
expected_delete_ctor_base &
|
|
operator=(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base &
|
|
operator=(expected_delete_ctor_base &&) noexcept = default;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_ctor_base<T, E, false, true> {
|
|
expected_delete_ctor_base() = default;
|
|
expected_delete_ctor_base(const expected_delete_ctor_base &) = delete;
|
|
expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = default;
|
|
expected_delete_ctor_base &
|
|
operator=(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base &
|
|
operator=(expected_delete_ctor_base &&) noexcept = default;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_ctor_base<T, E, false, false> {
|
|
expected_delete_ctor_base() = default;
|
|
expected_delete_ctor_base(const expected_delete_ctor_base &) = delete;
|
|
expected_delete_ctor_base(expected_delete_ctor_base &&) noexcept = delete;
|
|
expected_delete_ctor_base &
|
|
operator=(const expected_delete_ctor_base &) = default;
|
|
expected_delete_ctor_base &
|
|
operator=(expected_delete_ctor_base &&) noexcept = default;
|
|
};
|
|
|
|
// expected_delete_assign_base will conditionally delete copy and move
|
|
// constructors depending on whether T and E are copy/move constructible +
|
|
// assignable
|
|
template <class T, class E,
|
|
bool EnableCopy = (is_copy_constructible_or_void<T>::value &&
|
|
std::is_copy_constructible<E>::value &&
|
|
is_copy_assignable_or_void<T>::value &&
|
|
std::is_copy_assignable<E>::value),
|
|
bool EnableMove = (is_move_constructible_or_void<T>::value &&
|
|
std::is_move_constructible<E>::value &&
|
|
is_move_assignable_or_void<T>::value &&
|
|
std::is_move_assignable<E>::value)>
|
|
struct expected_delete_assign_base {
|
|
expected_delete_assign_base() = default;
|
|
expected_delete_assign_base(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
|
|
default;
|
|
expected_delete_assign_base &
|
|
operator=(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base &
|
|
operator=(expected_delete_assign_base &&) noexcept = default;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_assign_base<T, E, true, false> {
|
|
expected_delete_assign_base() = default;
|
|
expected_delete_assign_base(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
|
|
default;
|
|
expected_delete_assign_base &
|
|
operator=(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base &
|
|
operator=(expected_delete_assign_base &&) noexcept = delete;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_assign_base<T, E, false, true> {
|
|
expected_delete_assign_base() = default;
|
|
expected_delete_assign_base(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
|
|
default;
|
|
expected_delete_assign_base &
|
|
operator=(const expected_delete_assign_base &) = delete;
|
|
expected_delete_assign_base &
|
|
operator=(expected_delete_assign_base &&) noexcept = default;
|
|
};
|
|
|
|
template <class T, class E>
|
|
struct expected_delete_assign_base<T, E, false, false> {
|
|
expected_delete_assign_base() = default;
|
|
expected_delete_assign_base(const expected_delete_assign_base &) = default;
|
|
expected_delete_assign_base(expected_delete_assign_base &&) noexcept =
|
|
default;
|
|
expected_delete_assign_base &
|
|
operator=(const expected_delete_assign_base &) = delete;
|
|
expected_delete_assign_base &
|
|
operator=(expected_delete_assign_base &&) noexcept = delete;
|
|
};
|
|
|
|
// This is needed to be able to construct the expected_default_ctor_base which
|
|
// follows, while still conditionally deleting the default constructor.
|
|
struct default_constructor_tag {
|
|
explicit constexpr default_constructor_tag() = default;
|
|
};
|
|
|
|
// expected_default_ctor_base will ensure that expected has a deleted default
|
|
// consturctor if T is not default constructible.
|
|
// This specialization is for when T is default constructible
|
|
template <class T, class E,
|
|
bool Enable =
|
|
std::is_default_constructible<T>::value || std::is_void<T>::value>
|
|
struct expected_default_ctor_base {
|
|
constexpr expected_default_ctor_base() noexcept = default;
|
|
constexpr expected_default_ctor_base(
|
|
expected_default_ctor_base const &) noexcept = default;
|
|
constexpr expected_default_ctor_base(expected_default_ctor_base &&) noexcept =
|
|
default;
|
|
expected_default_ctor_base &
|
|
operator=(expected_default_ctor_base const &) noexcept = default;
|
|
expected_default_ctor_base &
|
|
operator=(expected_default_ctor_base &&) noexcept = default;
|
|
|
|
constexpr explicit expected_default_ctor_base(default_constructor_tag) {}
|
|
};
|
|
|
|
// This specialization is for when T is not default constructible
|
|
template <class T, class E> struct expected_default_ctor_base<T, E, false> {
|
|
constexpr expected_default_ctor_base() noexcept = delete;
|
|
constexpr expected_default_ctor_base(
|
|
expected_default_ctor_base const &) noexcept = default;
|
|
constexpr expected_default_ctor_base(expected_default_ctor_base &&) noexcept =
|
|
default;
|
|
expected_default_ctor_base &
|
|
operator=(expected_default_ctor_base const &) noexcept = default;
|
|
expected_default_ctor_base &
|
|
operator=(expected_default_ctor_base &&) noexcept = default;
|
|
|
|
constexpr explicit expected_default_ctor_base(default_constructor_tag) {}
|
|
};
|
|
} // namespace detail
|
|
|
|
template <class E> class bad_expected_access : public std::exception {
|
|
public:
|
|
explicit bad_expected_access(E e) : m_val(std::move(e)) {}
|
|
|
|
virtual const char *what() const noexcept override {
|
|
return "Bad expected access";
|
|
}
|
|
|
|
const E &error() const & { return m_val; }
|
|
E &error() & { return m_val; }
|
|
const E &&error() const && { return std::move(m_val); }
|
|
E &&error() && { return std::move(m_val); }
|
|
|
|
private:
|
|
E m_val;
|
|
};
|
|
|
|
/// An `expected<T, E>` object is an object that contains the storage for
|
|
/// another object and manages the lifetime of this contained object `T`.
|
|
/// Alternatively it could contain the storage for another unexpected object
|
|
/// `E`. The contained object may not be initialized after the expected object
|
|
/// has been initialized, and may not be destroyed before the expected object
|
|
/// has been destroyed. The initialization state of the contained object is
|
|
/// tracked by the expected object.
|
|
template <class T, class E>
|
|
class expected : private detail::expected_move_assign_base<T, E>,
|
|
private detail::expected_delete_ctor_base<T, E>,
|
|
private detail::expected_delete_assign_base<T, E>,
|
|
private detail::expected_default_ctor_base<T, E> {
|
|
static_assert(!std::is_reference<T>::value, "T must not be a reference");
|
|
static_assert(!std::is_same<T, std::remove_cv<in_place_t>::type>::value,
|
|
"T must not be in_place_t");
|
|
static_assert(!std::is_same<T, std::remove_cv<unexpect_t>::type>::value,
|
|
"T must not be unexpect_t");
|
|
static_assert(!std::is_same<T, typename std::remove_cv<unexpected<E>>::type>::value,
|
|
"T must not be unexpected<E>");
|
|
static_assert(!std::is_reference<E>::value, "E must not be a reference");
|
|
|
|
T *valptr() { return std::addressof(this->m_val); }
|
|
const T *valptr() const { return std::addressof(this->m_val); }
|
|
unexpected<E> *errptr() { return std::addressof(this->m_unexpect); }
|
|
const unexpected<E> *errptr() const { return std::addressof(this->m_unexpect); }
|
|
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR U &val() {
|
|
return this->m_val;
|
|
}
|
|
TL_EXPECTED_11_CONSTEXPR unexpected<E> &err() { return this->m_unexpect; }
|
|
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
constexpr const U &val() const {
|
|
return this->m_val;
|
|
}
|
|
constexpr const unexpected<E> &err() const { return this->m_unexpect; }
|
|
|
|
using impl_base = detail::expected_move_assign_base<T, E>;
|
|
using ctor_base = detail::expected_default_ctor_base<T, E>;
|
|
|
|
public:
|
|
typedef T value_type;
|
|
typedef E error_type;
|
|
typedef unexpected<E> unexpected_type;
|
|
|
|
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
|
|
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) & {
|
|
return and_then_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) && {
|
|
return and_then_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto and_then(F &&f) const & {
|
|
return and_then_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F> constexpr auto and_then(F &&f) const && {
|
|
return and_then_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
|
|
#else
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR auto
|
|
and_then(F &&f) & -> decltype(and_then_impl(std::declval<expected&>(), std::forward<F>(f))) {
|
|
return and_then_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) && -> decltype(
|
|
and_then_impl(std::declval<expected&&>(), std::forward<F>(f))) {
|
|
return and_then_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
constexpr auto and_then(F &&f) const & -> decltype(
|
|
and_then_impl(std::declval<expected const&>(), std::forward<F>(f))) {
|
|
return and_then_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F>
|
|
constexpr auto and_then(F &&f) const && -> decltype(
|
|
and_then_impl(std::declval<expected const&&>(), std::forward<F>(f))) {
|
|
return and_then_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
|
|
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto map(F &&f) & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto map(F &&f) && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto map(F &&f) const & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto map(F &&f) const && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#else
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(
|
|
expected_map_impl(std::declval<expected &>(), std::declval<F &&>()))
|
|
map(F &&f) & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(
|
|
expected_map_impl(std::declval<expected>(), std::declval<F &&>()))
|
|
map(F &&f) && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
constexpr decltype(expected_map_impl(std::declval<const expected &>(),
|
|
std::declval<F &&>()))
|
|
map(F &&f) const & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F>
|
|
constexpr decltype(expected_map_impl(std::declval<const expected &&>(),
|
|
std::declval<F &&>()))
|
|
map(F &&f) const && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
|
|
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto transform(F &&f) const & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto transform(F &&f) const && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#else
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(
|
|
expected_map_impl(std::declval<expected &>(), std::declval<F &&>()))
|
|
transform(F &&f) & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(
|
|
expected_map_impl(std::declval<expected>(), std::declval<F &&>()))
|
|
transform(F &&f) && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
constexpr decltype(expected_map_impl(std::declval<const expected &>(),
|
|
std::declval<F &&>()))
|
|
transform(F &&f) const & {
|
|
return expected_map_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F>
|
|
constexpr decltype(expected_map_impl(std::declval<const expected &&>(),
|
|
std::declval<F &&>()))
|
|
transform(F &&f) const && {
|
|
return expected_map_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
|
|
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) & {
|
|
return map_error_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) && {
|
|
return map_error_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto map_error(F &&f) const & {
|
|
return map_error_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F> constexpr auto map_error(F &&f) const && {
|
|
return map_error_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#else
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &>(),
|
|
std::declval<F &&>()))
|
|
map_error(F &&f) & {
|
|
return map_error_impl(*this, std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval<expected &&>(),
|
|
std::declval<F &&>()))
|
|
map_error(F &&f) && {
|
|
return map_error_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
template <class F>
|
|
constexpr decltype(map_error_impl(std::declval<const expected &>(),
|
|
std::declval<F &&>()))
|
|
map_error(F &&f) const & {
|
|
return map_error_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F>
|
|
constexpr decltype(map_error_impl(std::declval<const expected &&>(),
|
|
std::declval<F &&>()))
|
|
map_error(F &&f) const && {
|
|
return map_error_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
#endif
|
|
template <class F> expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) & {
|
|
return or_else_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
template <class F> expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) && {
|
|
return or_else_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
|
|
template <class F> expected constexpr or_else(F &&f) const & {
|
|
return or_else_impl(*this, std::forward<F>(f));
|
|
}
|
|
|
|
#ifndef TL_EXPECTED_NO_CONSTRR
|
|
template <class F> expected constexpr or_else(F &&f) const && {
|
|
return or_else_impl(std::move(*this), std::forward<F>(f));
|
|
}
|
|
#endif
|
|
constexpr expected() = default;
|
|
constexpr expected(const expected &rhs) = default;
|
|
constexpr expected(expected &&rhs) = default;
|
|
expected &operator=(const expected &rhs) = default;
|
|
expected &operator=(expected &&rhs) = default;
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<T, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr expected(in_place_t, Args &&... args)
|
|
: impl_base(in_place, std::forward<Args>(args)...),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr expected(in_place_t, std::initializer_list<U> il, Args &&... args)
|
|
: impl_base(in_place, il, std::forward<Args>(args)...),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <class G = E,
|
|
detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
|
|
nullptr,
|
|
detail::enable_if_t<!std::is_convertible<const G &, E>::value> * =
|
|
nullptr>
|
|
explicit constexpr expected(const unexpected<G> &e)
|
|
: impl_base(unexpect, e.value()),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <
|
|
class G = E,
|
|
detail::enable_if_t<std::is_constructible<E, const G &>::value> * =
|
|
nullptr,
|
|
detail::enable_if_t<std::is_convertible<const G &, E>::value> * = nullptr>
|
|
constexpr expected(unexpected<G> const &e)
|
|
: impl_base(unexpect, e.value()),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <
|
|
class G = E,
|
|
detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
|
|
detail::enable_if_t<!std::is_convertible<G &&, E>::value> * = nullptr>
|
|
explicit constexpr expected(unexpected<G> &&e) noexcept(
|
|
std::is_nothrow_constructible<E, G &&>::value)
|
|
: impl_base(unexpect, std::move(e.value())),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <
|
|
class G = E,
|
|
detail::enable_if_t<std::is_constructible<E, G &&>::value> * = nullptr,
|
|
detail::enable_if_t<std::is_convertible<G &&, E>::value> * = nullptr>
|
|
constexpr expected(unexpected<G> &&e) noexcept(
|
|
std::is_nothrow_constructible<E, G &&>::value)
|
|
: impl_base(unexpect, std::move(e.value())),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <class... Args,
|
|
detail::enable_if_t<std::is_constructible<E, Args &&...>::value> * =
|
|
nullptr>
|
|
constexpr explicit expected(unexpect_t, Args &&... args)
|
|
: impl_base(unexpect, std::forward<Args>(args)...),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_constructible<
|
|
E, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
constexpr explicit expected(unexpect_t, std::initializer_list<U> il,
|
|
Args &&... args)
|
|
: impl_base(unexpect, il, std::forward<Args>(args)...),
|
|
ctor_base(detail::default_constructor_tag{}) {}
|
|
|
|
template <class U, class G,
|
|
detail::enable_if_t<!(std::is_convertible<U const &, T>::value &&
|
|
std::is_convertible<G const &, E>::value)> * =
|
|
nullptr,
|
|
detail::expected_enable_from_other<T, E, U, G, const U &, const G &>
|
|
* = nullptr>
|
|
explicit TL_EXPECTED_11_CONSTEXPR expected(const expected<U, G> &rhs)
|
|
: ctor_base(detail::default_constructor_tag{}) {
|
|
if (rhs.has_value()) {
|
|
this->construct(*rhs);
|
|
} else {
|
|
this->construct_error(rhs.error());
|
|
}
|
|
}
|
|
|
|
template <class U, class G,
|
|
detail::enable_if_t<(std::is_convertible<U const &, T>::value &&
|
|
std::is_convertible<G const &, E>::value)> * =
|
|
nullptr,
|
|
detail::expected_enable_from_other<T, E, U, G, const U &, const G &>
|
|
* = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR expected(const expected<U, G> &rhs)
|
|
: ctor_base(detail::default_constructor_tag{}) {
|
|
if (rhs.has_value()) {
|
|
this->construct(*rhs);
|
|
} else {
|
|
this->construct_error(rhs.error());
|
|
}
|
|
}
|
|
|
|
template <
|
|
class U, class G,
|
|
detail::enable_if_t<!(std::is_convertible<U &&, T>::value &&
|
|
std::is_convertible<G &&, E>::value)> * = nullptr,
|
|
detail::expected_enable_from_other<T, E, U, G, U &&, G &&> * = nullptr>
|
|
explicit TL_EXPECTED_11_CONSTEXPR expected(expected<U, G> &&rhs)
|
|
: ctor_base(detail::default_constructor_tag{}) {
|
|
if (rhs.has_value()) {
|
|
this->construct(std::move(*rhs));
|
|
} else {
|
|
this->construct_error(std::move(rhs.error()));
|
|
}
|
|
}
|
|
|
|
template <
|
|
class U, class G,
|
|
detail::enable_if_t<(std::is_convertible<U &&, T>::value &&
|
|
std::is_convertible<G &&, E>::value)> * = nullptr,
|
|
detail::expected_enable_from_other<T, E, U, G, U &&, G &&> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR expected(expected<U, G> &&rhs)
|
|
: ctor_base(detail::default_constructor_tag{}) {
|
|
if (rhs.has_value()) {
|
|
this->construct(std::move(*rhs));
|
|
} else {
|
|
this->construct_error(std::move(rhs.error()));
|
|
}
|
|
}
|
|
|
|
template <
|
|
class U = T,
|
|
detail::enable_if_t<!std::is_convertible<U &&, T>::value> * = nullptr,
|
|
detail::expected_enable_forward_value<T, E, U> * = nullptr>
|
|
explicit TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v)
|
|
: expected(in_place, std::forward<U>(v)) {}
|
|
|
|
template <
|
|
class U = T,
|
|
detail::enable_if_t<std::is_convertible<U &&, T>::value> * = nullptr,
|
|
detail::expected_enable_forward_value<T, E, U> * = nullptr>
|
|
TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v)
|
|
: expected(in_place, std::forward<U>(v)) {}
|
|
|
|
template <
|
|
class U = T, class G = T,
|
|
detail::enable_if_t<std::is_nothrow_constructible<T, U &&>::value> * =
|
|
nullptr,
|
|
detail::enable_if_t<!std::is_void<G>::value> * = nullptr,
|
|
detail::enable_if_t<
|
|
(!std::is_same<expected<T, E>, detail::decay_t<U>>::value &&
|
|
!detail::conjunction<std::is_scalar<T>,
|
|
std::is_same<T, detail::decay_t<U>>>::value &&
|
|
std::is_constructible<T, U>::value &&
|
|
std::is_assignable<G &, U>::value &&
|
|
std::is_nothrow_move_constructible<E>::value)> * = nullptr>
|
|
expected &operator=(U &&v) {
|
|
if (has_value()) {
|
|
val() = std::forward<U>(v);
|
|
} else {
|
|
err().~unexpected<E>();
|
|
::new (valptr()) T(std::forward<U>(v));
|
|
this->m_has_val = true;
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
template <
|
|
class U = T, class G = T,
|
|
detail::enable_if_t<!std::is_nothrow_constructible<T, U &&>::value> * =
|
|
nullptr,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr,
|
|
detail::enable_if_t<
|
|
(!std::is_same<expected<T, E>, detail::decay_t<U>>::value &&
|
|
!detail::conjunction<std::is_scalar<T>,
|
|
std::is_same<T, detail::decay_t<U>>>::value &&
|
|
std::is_constructible<T, U>::value &&
|
|
std::is_assignable<G &, U>::value &&
|
|
std::is_nothrow_move_constructible<E>::value)> * = nullptr>
|
|
expected &operator=(U &&v) {
|
|
if (has_value()) {
|
|
val() = std::forward<U>(v);
|
|
} else {
|
|
auto tmp = std::move(err());
|
|
err().~unexpected<E>();
|
|
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
::new (valptr()) T(std::forward<U>(v));
|
|
this->m_has_val = true;
|
|
} catch (...) {
|
|
err() = std::move(tmp);
|
|
throw;
|
|
}
|
|
#else
|
|
::new (valptr()) T(std::forward<U>(v));
|
|
this->m_has_val = true;
|
|
#endif
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
template <class G = E,
|
|
detail::enable_if_t<std::is_nothrow_copy_constructible<G>::value &&
|
|
std::is_assignable<G &, G>::value> * = nullptr>
|
|
expected &operator=(const unexpected<G> &rhs) {
|
|
if (!has_value()) {
|
|
err() = rhs;
|
|
} else {
|
|
this->destroy_val();
|
|
::new (errptr()) unexpected<E>(rhs);
|
|
this->m_has_val = false;
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
template <class G = E,
|
|
detail::enable_if_t<std::is_nothrow_move_constructible<G>::value &&
|
|
std::is_move_assignable<G>::value> * = nullptr>
|
|
expected &operator=(unexpected<G> &&rhs) noexcept {
|
|
if (!has_value()) {
|
|
err() = std::move(rhs);
|
|
} else {
|
|
this->destroy_val();
|
|
::new (errptr()) unexpected<E>(std::move(rhs));
|
|
this->m_has_val = false;
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
template <class... Args, detail::enable_if_t<std::is_nothrow_constructible<
|
|
T, Args &&...>::value> * = nullptr>
|
|
void emplace(Args &&... args) {
|
|
if (has_value()) {
|
|
val() = T(std::forward<Args>(args)...);
|
|
} else {
|
|
err().~unexpected<E>();
|
|
::new (valptr()) T(std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
}
|
|
}
|
|
|
|
template <class... Args, detail::enable_if_t<!std::is_nothrow_constructible<
|
|
T, Args &&...>::value> * = nullptr>
|
|
void emplace(Args &&... args) {
|
|
if (has_value()) {
|
|
val() = T(std::forward<Args>(args)...);
|
|
} else {
|
|
auto tmp = std::move(err());
|
|
err().~unexpected<E>();
|
|
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
::new (valptr()) T(std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
} catch (...) {
|
|
err() = std::move(tmp);
|
|
throw;
|
|
}
|
|
#else
|
|
::new (valptr()) T(std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<std::is_nothrow_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
void emplace(std::initializer_list<U> il, Args &&... args) {
|
|
if (has_value()) {
|
|
T t(il, std::forward<Args>(args)...);
|
|
val() = std::move(t);
|
|
} else {
|
|
err().~unexpected<E>();
|
|
::new (valptr()) T(il, std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
}
|
|
}
|
|
|
|
template <class U, class... Args,
|
|
detail::enable_if_t<!std::is_nothrow_constructible<
|
|
T, std::initializer_list<U> &, Args &&...>::value> * = nullptr>
|
|
void emplace(std::initializer_list<U> il, Args &&... args) {
|
|
if (has_value()) {
|
|
T t(il, std::forward<Args>(args)...);
|
|
val() = std::move(t);
|
|
} else {
|
|
auto tmp = std::move(err());
|
|
err().~unexpected<E>();
|
|
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
::new (valptr()) T(il, std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
} catch (...) {
|
|
err() = std::move(tmp);
|
|
throw;
|
|
}
|
|
#else
|
|
::new (valptr()) T(il, std::forward<Args>(args)...);
|
|
this->m_has_val = true;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
private:
|
|
using t_is_void = std::true_type;
|
|
using t_is_not_void = std::false_type;
|
|
using t_is_nothrow_move_constructible = std::true_type;
|
|
using move_constructing_t_can_throw = std::false_type;
|
|
using e_is_nothrow_move_constructible = std::true_type;
|
|
using move_constructing_e_can_throw = std::false_type;
|
|
|
|
void swap_where_both_have_value(expected &/*rhs*/ , t_is_void) noexcept {
|
|
// swapping void is a no-op
|
|
}
|
|
|
|
void swap_where_both_have_value(expected &rhs, t_is_not_void) {
|
|
using std::swap;
|
|
swap(val(), rhs.val());
|
|
}
|
|
|
|
void swap_where_only_one_has_value(expected &rhs, t_is_void) noexcept(
|
|
std::is_nothrow_move_constructible<E>::value) {
|
|
::new (errptr()) unexpected_type(std::move(rhs.err()));
|
|
rhs.err().~unexpected_type();
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
}
|
|
|
|
void swap_where_only_one_has_value(expected &rhs, t_is_not_void) {
|
|
swap_where_only_one_has_value_and_t_is_not_void(
|
|
rhs, typename std::is_nothrow_move_constructible<T>::type{},
|
|
typename std::is_nothrow_move_constructible<E>::type{});
|
|
}
|
|
|
|
void swap_where_only_one_has_value_and_t_is_not_void(
|
|
expected &rhs, t_is_nothrow_move_constructible,
|
|
e_is_nothrow_move_constructible) noexcept {
|
|
auto temp = std::move(val());
|
|
val().~T();
|
|
::new (errptr()) unexpected_type(std::move(rhs.err()));
|
|
rhs.err().~unexpected_type();
|
|
::new (rhs.valptr()) T(std::move(temp));
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
}
|
|
|
|
void swap_where_only_one_has_value_and_t_is_not_void(
|
|
expected &rhs, t_is_nothrow_move_constructible,
|
|
move_constructing_e_can_throw) {
|
|
auto temp = std::move(val());
|
|
val().~T();
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
::new (errptr()) unexpected_type(std::move(rhs.err()));
|
|
rhs.err().~unexpected_type();
|
|
::new (rhs.valptr()) T(std::move(temp));
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
} catch (...) {
|
|
val() = std::move(temp);
|
|
throw;
|
|
}
|
|
#else
|
|
::new (errptr()) unexpected_type(std::move(rhs.err()));
|
|
rhs.err().~unexpected_type();
|
|
::new (rhs.valptr()) T(std::move(temp));
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
#endif
|
|
}
|
|
|
|
void swap_where_only_one_has_value_and_t_is_not_void(
|
|
expected &rhs, move_constructing_t_can_throw,
|
|
t_is_nothrow_move_constructible) {
|
|
auto temp = std::move(rhs.err());
|
|
rhs.err().~unexpected_type();
|
|
#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED
|
|
try {
|
|
::new (rhs.valptr()) T(val());
|
|
val().~T();
|
|
::new (errptr()) unexpected_type(std::move(temp));
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
} catch (...) {
|
|
rhs.err() = std::move(temp);
|
|
throw;
|
|
}
|
|
#else
|
|
::new (rhs.valptr()) T(val());
|
|
val().~T();
|
|
::new (errptr()) unexpected_type(std::move(temp));
|
|
std::swap(this->m_has_val, rhs.m_has_val);
|
|
#endif
|
|
}
|
|
|
|
public:
|
|
template <class OT = T, class OE = E>
|
|
detail::enable_if_t<detail::is_swappable<OT>::value &&
|
|
detail::is_swappable<OE>::value &&
|
|
(std::is_nothrow_move_constructible<OT>::value ||
|
|
std::is_nothrow_move_constructible<OE>::value)>
|
|
swap(expected &rhs) noexcept(
|
|
std::is_nothrow_move_constructible<T>::value
|
|
&&detail::is_nothrow_swappable<T>::value
|
|
&&std::is_nothrow_move_constructible<E>::value
|
|
&&detail::is_nothrow_swappable<E>::value) {
|
|
if (has_value() && rhs.has_value()) {
|
|
swap_where_both_have_value(rhs, typename std::is_void<T>::type{});
|
|
} else if (!has_value() && rhs.has_value()) {
|
|
rhs.swap(*this);
|
|
} else if (has_value()) {
|
|
swap_where_only_one_has_value(rhs, typename std::is_void<T>::type{});
|
|
} else {
|
|
using std::swap;
|
|
swap(err(), rhs.err());
|
|
}
|
|
}
|
|
|
|
constexpr const T *operator->() const { return valptr(); }
|
|
TL_EXPECTED_11_CONSTEXPR T *operator->() { return valptr(); }
|
|
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
constexpr const U &operator*() const & {
|
|
return val();
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR U &operator*() & {
|
|
return val();
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
constexpr const U &&operator*() const && {
|
|
return std::move(val());
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR U &&operator*() && {
|
|
return std::move(val());
|
|
}
|
|
|
|
constexpr bool has_value() const noexcept { return this->m_has_val; }
|
|
constexpr explicit operator bool() const noexcept { return this->m_has_val; }
|
|
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR const U &value() const & {
|
|
if (!has_value())
|
|
detail::throw_exception(bad_expected_access<E>(err().value()));
|
|
return val();
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR U &value() & {
|
|
if (!has_value())
|
|
detail::throw_exception(bad_expected_access<E>(err().value()));
|
|
return val();
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR const U &&value() const && {
|
|
if (!has_value())
|
|
detail::throw_exception(bad_expected_access<E>(std::move(err()).value()));
|
|
return std::move(val());
|
|
}
|
|
template <class U = T,
|
|
detail::enable_if_t<!std::is_void<U>::value> * = nullptr>
|
|
TL_EXPECTED_11_CONSTEXPR U &&value() && {
|
|
if (!has_value())
|
|
detail::throw_exception(bad_expected_access<E>(std::move(err()).value()));
|
|
return std::move(val());
|
|
}
|
|
|
|
constexpr const E &error() const & { return err().value(); }
|
|
TL_EXPECTED_11_CONSTEXPR E &error() & { return err().value(); }
|
|
constexpr const E &&error() const && { return std::move(err().value()); }
|
|
TL_EXPECTED_11_CONSTEXPR E &&error() && { return std::move(err().value()); }
|
|
|
|
template <class U> constexpr T value_or(U &&v) const & {
|
|
static_assert(std::is_copy_constructible<T>::value &&
|
|
std::is_convertible<U &&, T>::value,
|
|
"T must be copy-constructible and convertible to from U&&");
|
|
return bool(*this) ? **this : static_cast<T>(std::forward<U>(v));
|
|
}
|
|
template <class U> TL_EXPECTED_11_CONSTEXPR T value_or(U &&v) && {
|
|
static_assert(std::is_move_constructible<T>::value &&
|
|
std::is_convertible<U &&, T>::value,
|
|
"T must be move-constructible and convertible to from U&&");
|
|
return bool(*this) ? std::move(**this) : static_cast<T>(std::forward<U>(v));
|
|
}
|
|
};
|
|
|
|
namespace detail {
|
|
template <class Exp> using exp_t = typename detail::decay_t<Exp>::value_type;
|
|
template <class Exp> using err_t = typename detail::decay_t<Exp>::error_type;
|
|
template <class Exp, class Ret> using ret_t = expected<Ret, err_t<Exp>>;
|
|
|
|
#ifdef TL_EXPECTED_CXX14
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>()))>
|
|
constexpr auto and_then_impl(Exp &&exp, F &&f) {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
|
|
return exp.has_value()
|
|
? detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp))
|
|
: Ret(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>()))>
|
|
constexpr auto and_then_impl(Exp &&exp, F &&f) {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
|
|
return exp.has_value() ? detail::invoke(std::forward<F>(f))
|
|
: Ret(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
#else
|
|
template <class> struct TC;
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>())),
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr>
|
|
auto and_then_impl(Exp &&exp, F &&f) -> Ret {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
|
|
return exp.has_value()
|
|
? detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp))
|
|
: Ret(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>())),
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr>
|
|
constexpr auto and_then_impl(Exp &&exp, F &&f) -> Ret {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
|
|
return exp.has_value() ? detail::invoke(std::forward<F>(f))
|
|
: Ret(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
#endif
|
|
|
|
#ifdef TL_EXPECTED_CXX14
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto expected_map_impl(Exp &&exp, F &&f) {
|
|
using result = ret_t<Exp, detail::decay_t<Ret>>;
|
|
return exp.has_value() ? result(detail::invoke(std::forward<F>(f),
|
|
*std::forward<Exp>(exp)))
|
|
: result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto expected_map_impl(Exp &&exp, F &&f) {
|
|
using result = expected<void, err_t<Exp>>;
|
|
if (exp.has_value()) {
|
|
detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp));
|
|
return result();
|
|
}
|
|
|
|
return result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto expected_map_impl(Exp &&exp, F &&f) {
|
|
using result = ret_t<Exp, detail::decay_t<Ret>>;
|
|
return exp.has_value() ? result(detail::invoke(std::forward<F>(f)))
|
|
: result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto expected_map_impl(Exp &&exp, F &&f) {
|
|
using result = expected<void, err_t<Exp>>;
|
|
if (exp.has_value()) {
|
|
detail::invoke(std::forward<F>(f));
|
|
return result();
|
|
}
|
|
|
|
return result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
#else
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
|
|
constexpr auto expected_map_impl(Exp &&exp, F &&f)
|
|
-> ret_t<Exp, detail::decay_t<Ret>> {
|
|
using result = ret_t<Exp, detail::decay_t<Ret>>;
|
|
|
|
return exp.has_value() ? result(detail::invoke(std::forward<F>(f),
|
|
*std::forward<Exp>(exp)))
|
|
: result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
*std::declval<Exp>())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
|
|
auto expected_map_impl(Exp &&exp, F &&f) -> expected<void, err_t<Exp>> {
|
|
if (exp.has_value()) {
|
|
detail::invoke(std::forward<F>(f), *std::forward<Exp>(exp));
|
|
return {};
|
|
}
|
|
|
|
return unexpected<err_t<Exp>>(std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
|
|
constexpr auto expected_map_impl(Exp &&exp, F &&f)
|
|
-> ret_t<Exp, detail::decay_t<Ret>> {
|
|
using result = ret_t<Exp, detail::decay_t<Ret>>;
|
|
|
|
return exp.has_value() ? result(detail::invoke(std::forward<F>(f)))
|
|
: result(unexpect, std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
|
|
auto expected_map_impl(Exp &&exp, F &&f) -> expected<void, err_t<Exp>> {
|
|
if (exp.has_value()) {
|
|
detail::invoke(std::forward<F>(f));
|
|
return {};
|
|
}
|
|
|
|
return unexpected<err_t<Exp>>(std::forward<Exp>(exp).error());
|
|
}
|
|
#endif
|
|
|
|
#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \
|
|
!defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55)
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto map_error_impl(Exp &&exp, F &&f) {
|
|
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
|
|
return exp.has_value()
|
|
? result(*std::forward<Exp>(exp))
|
|
: result(unexpect, detail::invoke(std::forward<F>(f),
|
|
std::forward<Exp>(exp).error()));
|
|
}
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto map_error_impl(Exp &&exp, F &&f) {
|
|
using result = expected<exp_t<Exp>, monostate>;
|
|
if (exp.has_value()) {
|
|
return result(*std::forward<Exp>(exp));
|
|
}
|
|
|
|
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
return result(unexpect, monostate{});
|
|
}
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto map_error_impl(Exp &&exp, F &&f) {
|
|
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
|
|
return exp.has_value()
|
|
? result()
|
|
: result(unexpect, detail::invoke(std::forward<F>(f),
|
|
std::forward<Exp>(exp).error()));
|
|
}
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto map_error_impl(Exp &&exp, F &&f) {
|
|
using result = expected<exp_t<Exp>, monostate>;
|
|
if (exp.has_value()) {
|
|
return result();
|
|
}
|
|
|
|
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
return result(unexpect, monostate{});
|
|
}
|
|
#else
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto map_error_impl(Exp &&exp, F &&f)
|
|
-> expected<exp_t<Exp>, detail::decay_t<Ret>> {
|
|
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
|
|
|
|
return exp.has_value()
|
|
? result(*std::forward<Exp>(exp))
|
|
: result(unexpect, detail::invoke(std::forward<F>(f),
|
|
std::forward<Exp>(exp).error()));
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<!std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
|
|
using result = expected<exp_t<Exp>, monostate>;
|
|
if (exp.has_value()) {
|
|
return result(*std::forward<Exp>(exp));
|
|
}
|
|
|
|
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
return result(unexpect, monostate{});
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto map_error_impl(Exp &&exp, F &&f)
|
|
-> expected<exp_t<Exp>, detail::decay_t<Ret>> {
|
|
using result = expected<exp_t<Exp>, detail::decay_t<Ret>>;
|
|
|
|
return exp.has_value()
|
|
? result()
|
|
: result(unexpect, detail::invoke(std::forward<F>(f),
|
|
std::forward<Exp>(exp).error()));
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
detail::enable_if_t<std::is_void<exp_t<Exp>>::value> * = nullptr,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
|
|
using result = expected<exp_t<Exp>, monostate>;
|
|
if (exp.has_value()) {
|
|
return result();
|
|
}
|
|
|
|
detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
return result(unexpect, monostate{});
|
|
}
|
|
#endif
|
|
|
|
#ifdef TL_EXPECTED_CXX14
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
constexpr auto or_else_impl(Exp &&exp, F &&f) {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
return exp.has_value()
|
|
? std::forward<Exp>(exp)
|
|
: detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
|
|
return exp.has_value()
|
|
? std::forward<Exp>(exp)
|
|
: (detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error()),
|
|
std::forward<Exp>(exp));
|
|
}
|
|
#else
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
|
|
auto or_else_impl(Exp &&exp, F &&f) -> Ret {
|
|
static_assert(detail::is_expected<Ret>::value, "F must return an expected");
|
|
return exp.has_value()
|
|
? std::forward<Exp>(exp)
|
|
: detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error());
|
|
}
|
|
|
|
template <class Exp, class F,
|
|
class Ret = decltype(detail::invoke(std::declval<F>(),
|
|
std::declval<Exp>().error())),
|
|
detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
|
|
detail::decay_t<Exp> or_else_impl(Exp &&exp, F &&f) {
|
|
return exp.has_value()
|
|
? std::forward<Exp>(exp)
|
|
: (detail::invoke(std::forward<F>(f), std::forward<Exp>(exp).error()),
|
|
std::forward<Exp>(exp));
|
|
}
|
|
#endif
|
|
} // namespace detail
|
|
|
|
template <class T, class E, class U, class F>
|
|
constexpr bool operator==(const expected<T, E> &lhs,
|
|
const expected<U, F> &rhs) {
|
|
return (lhs.has_value() != rhs.has_value())
|
|
? false
|
|
: (!lhs.has_value() ? lhs.error() == rhs.error() : *lhs == *rhs);
|
|
}
|
|
template <class T, class E, class U, class F>
|
|
constexpr bool operator!=(const expected<T, E> &lhs,
|
|
const expected<U, F> &rhs) {
|
|
return (lhs.has_value() != rhs.has_value())
|
|
? true
|
|
: (!lhs.has_value() ? lhs.error() != rhs.error() : *lhs != *rhs);
|
|
}
|
|
|
|
template <class T, class E, class U>
|
|
constexpr bool operator==(const expected<T, E> &x, const U &v) {
|
|
return x.has_value() ? *x == v : false;
|
|
}
|
|
template <class T, class E, class U>
|
|
constexpr bool operator==(const U &v, const expected<T, E> &x) {
|
|
return x.has_value() ? *x == v : false;
|
|
}
|
|
template <class T, class E, class U>
|
|
constexpr bool operator!=(const expected<T, E> &x, const U &v) {
|
|
return x.has_value() ? *x != v : true;
|
|
}
|
|
template <class T, class E, class U>
|
|
constexpr bool operator!=(const U &v, const expected<T, E> &x) {
|
|
return x.has_value() ? *x != v : true;
|
|
}
|
|
|
|
template <class T, class E>
|
|
constexpr bool operator==(const expected<T, E> &x, const unexpected<E> &e) {
|
|
return x.has_value() ? false : x.error() == e.value();
|
|
}
|
|
template <class T, class E>
|
|
constexpr bool operator==(const unexpected<E> &e, const expected<T, E> &x) {
|
|
return x.has_value() ? false : x.error() == e.value();
|
|
}
|
|
template <class T, class E>
|
|
constexpr bool operator!=(const expected<T, E> &x, const unexpected<E> &e) {
|
|
return x.has_value() ? true : x.error() != e.value();
|
|
}
|
|
template <class T, class E>
|
|
constexpr bool operator!=(const unexpected<E> &e, const expected<T, E> &x) {
|
|
return x.has_value() ? true : x.error() != e.value();
|
|
}
|
|
|
|
template <class T, class E,
|
|
detail::enable_if_t<(std::is_void<T>::value ||
|
|
std::is_move_constructible<T>::value) &&
|
|
detail::is_swappable<T>::value &&
|
|
std::is_move_constructible<E>::value &&
|
|
detail::is_swappable<E>::value> * = nullptr>
|
|
void swap(expected<T, E> &lhs,
|
|
expected<T, E> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
|
|
lhs.swap(rhs);
|
|
}
|
|
} // namespace tl
|
|
|
|
#endif
|