From a87433515ee8e8edfd774fa4cca2fa863f88af7b Mon Sep 17 00:00:00 2001 From: Vsevolod Stakhov Date: Thu, 14 Jan 2021 15:25:55 +0000 Subject: [PATCH] [Project] Add expected library --- contrib/expected/expected.hpp | 2326 +++++++++++++++++++++++++++++++++ 1 file changed, 2326 insertions(+) create mode 100644 contrib/expected/expected.hpp diff --git a/contrib/expected/expected.hpp b/contrib/expected/expected.hpp new file mode 100644 index 000000000..31a519362 --- /dev/null +++ b/contrib/expected/expected.hpp @@ -0,0 +1,2326 @@ +/// +// expected - An implementation of std::expected with extensions +// Written in 2017 by Simon Brand (simonrbrand@gmail.com, @TartanLlama) +// +// Documentation available at http://tl.tartanllama.xyz/ +// +// To the extent possible under law, the author(s) have dedicated all +// copyright and related and neighboring rights to this software to the +// public domain worldwide. This software is distributed without any warranty. +// +// You should have received a copy of the CC0 Public Domain Dedication +// along with this software. If not, see +// . +/// + +#ifndef TL_EXPECTED_HPP +#define TL_EXPECTED_HPP + +#define TL_EXPECTED_VERSION_MAJOR 1 +#define TL_EXPECTED_VERSION_MINOR 0 +#define TL_EXPECTED_VERSION_PATCH 1 + +#include +#include +#include +#include + +#if defined(__EXCEPTIONS) || defined(_CPPUNWIND) +#define TL_EXPECTED_EXCEPTIONS_ENABLED +#endif + +#if (defined(_MSC_VER) && _MSC_VER == 1900) +#define TL_EXPECTED_MSVC2015 +#define TL_EXPECTED_MSVC2015_CONSTEXPR +#else +#define TL_EXPECTED_MSVC2015_CONSTEXPR constexpr +#endif + +#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \ + !defined(__clang__)) +#define TL_EXPECTED_GCC49 +#endif + +#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 4 && \ + !defined(__clang__)) +#define TL_EXPECTED_GCC54 +#endif + +#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 5 && \ + !defined(__clang__)) +#define TL_EXPECTED_GCC55 +#endif + +#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 && \ + !defined(__clang__)) +// GCC < 5 doesn't support overloading on const&& for member functions + +#define TL_EXPECTED_NO_CONSTRR +// GCC < 5 doesn't support some standard C++11 type traits +#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \ + std::has_trivial_copy_constructor +#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \ + std::has_trivial_copy_assign + +// This one will be different for GCC 5.7 if it's ever supported +#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \ + std::is_trivially_destructible + +// GCC 5 < v < 8 has a bug in is_trivially_copy_constructible which breaks std::vector +// for non-copyable types +#elif (defined(__GNUC__) && __GNUC__ < 8 && \ + !defined(__clang__)) +#ifndef TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX +#define TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX +namespace tl { + namespace detail { + template + struct is_trivially_copy_constructible : std::is_trivially_copy_constructible{}; +#ifdef _GLIBCXX_VECTOR + template + struct is_trivially_copy_constructible> + : std::false_type{}; +#endif + } +} +#endif + +#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \ + tl::detail::is_trivially_copy_constructible +#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \ + std::is_trivially_copy_assignable +#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) std::is_trivially_destructible +#else +#define TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) \ + std::is_trivially_copy_constructible +#define TL_EXPECTED_IS_TRIVIALLY_COPY_ASSIGNABLE(T) \ + std::is_trivially_copy_assignable +#define TL_EXPECTED_IS_TRIVIALLY_DESTRUCTIBLE(T) \ + std::is_trivially_destructible +#endif + +#if __cplusplus > 201103L +#define TL_EXPECTED_CXX14 +#endif + +#ifdef TL_EXPECTED_GCC49 +#define TL_EXPECTED_GCC49_CONSTEXPR +#else +#define TL_EXPECTED_GCC49_CONSTEXPR constexpr +#endif + +#if (__cplusplus == 201103L || defined(TL_EXPECTED_MSVC2015) || \ + defined(TL_EXPECTED_GCC49)) +#define TL_EXPECTED_11_CONSTEXPR +#else +#define TL_EXPECTED_11_CONSTEXPR constexpr +#endif + +namespace tl { +template class expected; + +#ifndef TL_MONOSTATE_INPLACE_MUTEX +#define TL_MONOSTATE_INPLACE_MUTEX +class monostate {}; + +struct in_place_t { + explicit in_place_t() = default; +}; +static constexpr in_place_t in_place{}; +#endif + +template class unexpected { +public: + static_assert(!std::is_same::value, "E must not be void"); + + unexpected() = delete; + constexpr explicit unexpected(const E &e) : m_val(e) {} + + constexpr explicit unexpected(E &&e) : m_val(std::move(e)) {} + + constexpr const E &value() const & { return m_val; } + TL_EXPECTED_11_CONSTEXPR E &value() & { return m_val; } + TL_EXPECTED_11_CONSTEXPR E &&value() && { return std::move(m_val); } + constexpr const E &&value() const && { return std::move(m_val); } + +private: + E m_val; +}; + +template +constexpr bool operator==(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() == rhs.value(); +} +template +constexpr bool operator!=(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() != rhs.value(); +} +template +constexpr bool operator<(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() < rhs.value(); +} +template +constexpr bool operator<=(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() <= rhs.value(); +} +template +constexpr bool operator>(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() > rhs.value(); +} +template +constexpr bool operator>=(const unexpected &lhs, const unexpected &rhs) { + return lhs.value() >= rhs.value(); +} + +template +unexpected::type> make_unexpected(E &&e) { + return unexpected::type>(std::forward(e)); +} + +struct unexpect_t { + unexpect_t() = default; +}; +static constexpr unexpect_t unexpect{}; + +namespace detail { +template +[[noreturn]] TL_EXPECTED_11_CONSTEXPR void throw_exception(E &&e) { +#ifdef TL_EXPECTED_EXCEPTIONS_ENABLED + throw std::forward(e); +#else + #ifdef _MSC_VER + __assume(0); + #else + __builtin_unreachable(); + #endif +#endif +} + +#ifndef TL_TRAITS_MUTEX +#define TL_TRAITS_MUTEX +// C++14-style aliases for brevity +template using remove_const_t = typename std::remove_const::type; +template +using remove_reference_t = typename std::remove_reference::type; +template using decay_t = typename std::decay::type; +template +using enable_if_t = typename std::enable_if::type; +template +using conditional_t = typename std::conditional::type; + +// std::conjunction from C++17 +template struct conjunction : std::true_type {}; +template struct conjunction : B {}; +template +struct conjunction + : std::conditional, B>::type {}; + +#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L +#define TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND +#endif + +// In C++11 mode, there's an issue in libc++'s std::mem_fn +// which results in a hard-error when using it in a noexcept expression +// in some cases. This is a check to workaround the common failing case. +#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND +template struct is_pointer_to_non_const_member_func : std::false_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; +template +struct is_pointer_to_non_const_member_func : std::true_type {}; + +template struct is_const_or_const_ref : std::false_type {}; +template struct is_const_or_const_ref : std::true_type {}; +template struct is_const_or_const_ref : std::true_type {}; +#endif + +// std::invoke from C++17 +// https://stackoverflow.com/questions/38288042/c11-14-invoke-workaround +template ::value + && is_const_or_const_ref::value)>, +#endif + typename = enable_if_t>::value>, + int = 0> + constexpr auto invoke(Fn && f, Args && ... args) noexcept( + noexcept(std::mem_fn(f)(std::forward(args)...))) + -> decltype(std::mem_fn(f)(std::forward(args)...)) { + return std::mem_fn(f)(std::forward(args)...); +} + +template >::value>> + constexpr auto invoke(Fn && f, Args && ... args) noexcept( + noexcept(std::forward(f)(std::forward(args)...))) + -> decltype(std::forward(f)(std::forward(args)...)) { + return std::forward(f)(std::forward(args)...); +} + +// std::invoke_result from C++17 +template struct invoke_result_impl; + +template +struct invoke_result_impl< + F, decltype(detail::invoke(std::declval(), std::declval()...), void()), + Us...> { + using type = decltype(detail::invoke(std::declval(), std::declval()...)); +}; + +template +using invoke_result = invoke_result_impl; + +template +using invoke_result_t = typename invoke_result::type; + +#if defined(_MSC_VER) && _MSC_VER <= 1900 +// TODO make a version which works with MSVC 2015 +template struct is_swappable : std::true_type {}; + +template struct is_nothrow_swappable : std::true_type {}; +#else +// https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept +namespace swap_adl_tests { + // if swap ADL finds this then it would call std::swap otherwise (same + // signature) + struct tag {}; + + template tag swap(T&, T&); + template tag swap(T(&a)[N], T(&b)[N]); + + // helper functions to test if an unqualified swap is possible, and if it + // becomes std::swap + template std::false_type can_swap(...) noexcept(false); + template (), std::declval()))> + std::true_type can_swap(int) noexcept(noexcept(swap(std::declval(), + std::declval()))); + + template std::false_type uses_std(...); + template + std::is_same(), std::declval())), tag> + uses_std(int); + + template + struct is_std_swap_noexcept + : std::integral_constant::value&& + std::is_nothrow_move_assignable::value> {}; + + template + struct is_std_swap_noexcept : is_std_swap_noexcept {}; + + template + struct is_adl_swap_noexcept + : std::integral_constant(0))> {}; +} // namespace swap_adl_tests + +template +struct is_swappable + : std::integral_constant< + bool, + decltype(detail::swap_adl_tests::can_swap(0))::value && + (!decltype(detail::swap_adl_tests::uses_std(0))::value || + (std::is_move_assignable::value && + std::is_move_constructible::value))> {}; + +template +struct is_swappable + : std::integral_constant< + bool, + decltype(detail::swap_adl_tests::can_swap(0))::value && + (!decltype( + detail::swap_adl_tests::uses_std(0))::value || + is_swappable::value)> {}; + +template +struct is_nothrow_swappable + : std::integral_constant< + bool, + is_swappable::value && + ((decltype(detail::swap_adl_tests::uses_std(0))::value + && detail::swap_adl_tests::is_std_swap_noexcept::value) || + (!decltype(detail::swap_adl_tests::uses_std(0))::value && + detail::swap_adl_tests::is_adl_swap_noexcept::value))> { +}; +#endif +#endif + +// Trait for checking if a type is a tl::expected +template struct is_expected_impl : std::false_type {}; +template +struct is_expected_impl> : std::true_type {}; +template using is_expected = is_expected_impl>; + +template +using expected_enable_forward_value = detail::enable_if_t< + std::is_constructible::value && + !std::is_same, in_place_t>::value && + !std::is_same, detail::decay_t>::value && + !std::is_same, detail::decay_t>::value>; + +template +using expected_enable_from_other = detail::enable_if_t< + std::is_constructible::value && + std::is_constructible::value && + !std::is_constructible &>::value && + !std::is_constructible &&>::value && + !std::is_constructible &>::value && + !std::is_constructible &&>::value && + !std::is_convertible &, T>::value && + !std::is_convertible &&, T>::value && + !std::is_convertible &, T>::value && + !std::is_convertible &&, T>::value>; + +template +using is_void_or = conditional_t::value, std::true_type, U>; + +template +using is_copy_constructible_or_void = + is_void_or>; + +template +using is_move_constructible_or_void = + is_void_or>; + +template +using is_copy_assignable_or_void = + is_void_or>; + + +template +using is_move_assignable_or_void = + is_void_or>; + + +} // namespace detail + +namespace detail { +struct no_init_t {}; +static constexpr no_init_t no_init{}; + +// Implements the storage of the values, and ensures that the destructor is +// trivial if it can be. +// +// This specialization is for where neither `T` or `E` is trivially +// destructible, so the destructors must be called on destruction of the +// `expected` +template ::value, + bool = std::is_trivially_destructible::value> +struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr expected_storage_base(in_place_t, Args &&... args) + : m_val(std::forward(args)...), m_has_val(true) {} + + template &, Args &&...>::value> * = nullptr> + constexpr expected_storage_base(in_place_t, std::initializer_list il, + Args &&... args) + : m_val(il, std::forward(args)...), m_has_val(true) {} + template ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() { + if (m_has_val) { + m_val.~T(); + } else { + m_unexpect.~unexpected(); + } + } + union { + T m_val; + unexpected 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 struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr expected_storage_base(in_place_t, Args &&... args) + : m_val(std::forward(args)...), m_has_val(true) {} + + template &, Args &&...>::value> * = nullptr> + constexpr expected_storage_base(in_place_t, std::initializer_list il, + Args &&... args) + : m_val(il, std::forward(args)...), m_has_val(true) {} + template ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() = default; + union { + T m_val; + unexpected m_unexpect; + char m_no_init; + }; + bool m_has_val; +}; + +// T is trivial, E is not. +template struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr expected_storage_base(in_place_t, Args &&... args) + : m_val(std::forward(args)...), m_has_val(true) {} + + template &, Args &&...>::value> * = nullptr> + constexpr expected_storage_base(in_place_t, std::initializer_list il, + Args &&... args) + : m_val(il, std::forward(args)...), m_has_val(true) {} + template ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() { + if (!m_has_val) { + m_unexpect.~unexpected(); + } + } + + union { + T m_val; + unexpected m_unexpect; + char m_no_init; + }; + bool m_has_val; +}; + +// E is trivial, T is not. +template struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr expected_storage_base(in_place_t, Args &&... args) + : m_val(std::forward(args)...), m_has_val(true) {} + + template &, Args &&...>::value> * = nullptr> + constexpr expected_storage_base(in_place_t, std::initializer_list il, + Args &&... args) + : m_val(il, std::forward(args)...), m_has_val(true) {} + template ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() { + if (m_has_val) { + m_val.~T(); + } + } + union { + T m_val; + unexpected m_unexpect; + char m_no_init; + }; + bool m_has_val; +}; + +// `T` is `void`, `E` is trivially-destructible +template struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() = default; + struct dummy {}; + union { + unexpected m_unexpect; + dummy m_val; + }; + bool m_has_val; +}; + +// `T` is `void`, `E` is not trivially-destructible +template struct expected_storage_base { + 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 ::value> * = + nullptr> + constexpr explicit expected_storage_base(unexpect_t, Args &&... args) + : m_unexpect(std::forward(args)...), m_has_val(false) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected_storage_base(unexpect_t, + std::initializer_list il, + Args &&... args) + : m_unexpect(il, std::forward(args)...), m_has_val(false) {} + + ~expected_storage_base() { + if (!m_has_val) { + m_unexpect.~unexpected(); + } + } + + union { + unexpected 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 +struct expected_operations_base : expected_storage_base { + using expected_storage_base::expected_storage_base; + + template void construct(Args &&... args) noexcept { + new (std::addressof(this->m_val)) T(std::forward(args)...); + this->m_has_val = true; + } + + template void construct_with(Rhs &&rhs) noexcept { + new (std::addressof(this->m_val)) T(std::forward(rhs).get()); + this->m_has_val = true; + } + + template void construct_error(Args &&... args) noexcept { + new (std::addressof(this->m_unexpect)) + unexpected(std::forward(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 ::value> + * = nullptr> + void assign(const expected_operations_base &rhs) noexcept { + if (!this->m_has_val && rhs.m_has_val) { + geterr().~unexpected(); + 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 ::value && + std::is_nothrow_move_constructible::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(); + 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 ::value && + !std::is_nothrow_move_constructible::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(); + +#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 ::value> + * = nullptr> + void assign(expected_operations_base &&rhs) noexcept { + if (!this->m_has_val && rhs.m_has_val) { + geterr().~unexpected(); + construct(std::move(rhs).get()); + } else { + assign_common(std::move(rhs)); + } + } + + template ::value> + * = nullptr> + void assign(expected_operations_base &&rhs) { + if (!this->m_has_val && rhs.m_has_val) { + auto tmp = std::move(geterr()); + geterr().~unexpected(); +#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(); + 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(); + construct(std::move(rhs).get()); + } else { + assign_common(rhs); + } + } + + #endif + + // The common part of move/copy assigning + template void assign_common(Rhs &&rhs) { + if (this->m_has_val) { + if (rhs.m_has_val) { + get() = std::forward(rhs).get(); + } else { + destroy_val(); + construct_error(std::forward(rhs).geterr()); + } + } else { + if (!rhs.m_has_val) { + geterr() = std::forward(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 &geterr() & { + return this->m_unexpect; + } + constexpr const unexpected &geterr() const & { return this->m_unexpect; } + TL_EXPECTED_11_CONSTEXPR unexpected &&geterr() && { + return std::move(this->m_unexpect); + } +#ifndef TL_EXPECTED_NO_CONSTRR + constexpr const unexpected &&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 +struct expected_operations_base : expected_storage_base { + using expected_storage_base::expected_storage_base; + + template 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 void construct_with(Rhs &&) noexcept { + this->m_has_val = true; + } + + template void construct_error(Args &&... args) noexcept { + new (std::addressof(this->m_unexpect)) + unexpected(std::forward(args)...); + this->m_has_val = false; + } + + template void assign(Rhs &&rhs) noexcept { + if (!this->m_has_val) { + if (rhs.m_has_val) { + geterr().~unexpected(); + construct(); + } else { + geterr() = std::forward(rhs).geterr(); + } + } else { + if (!rhs.m_has_val) { + construct_error(std::forward(rhs).geterr()); + } + } + } + + bool has_value() const { return this->m_has_val; } + + TL_EXPECTED_11_CONSTEXPR unexpected &geterr() & { + return this->m_unexpect; + } + constexpr const unexpected &geterr() const & { return this->m_unexpect; } + TL_EXPECTED_11_CONSTEXPR unexpected &&geterr() && { + return std::move(this->m_unexpect); + } +#ifndef TL_EXPECTED_NO_CONSTRR + constexpr const unexpected &&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 :: + value &&TL_EXPECTED_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(E)::value> +struct expected_copy_base : expected_operations_base { + using expected_operations_base::expected_operations_base; +}; + +// This specialization is for when T or E are not trivially copy constructible +template +struct expected_copy_base : expected_operations_base { + using expected_operations_base::expected_operations_base; + + expected_copy_base() = default; + expected_copy_base(const expected_copy_base &rhs) + : expected_operations_base(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 >::value + &&std::is_trivially_move_constructible::value> +struct expected_move_base : expected_copy_base { + using expected_copy_base::expected_copy_base; +}; +#else +template struct expected_move_base; +#endif +template +struct expected_move_base : expected_copy_base { + using expected_copy_base::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::value) + : expected_copy_base(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 >::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 { + using expected_move_base::expected_move_base; +}; + +template +struct expected_copy_assign_base : expected_move_base { + using expected_move_base::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 , + std::is_trivially_move_constructible, + std::is_trivially_move_assignable>>:: + value &&std::is_trivially_destructible::value + &&std::is_trivially_move_constructible::value + &&std::is_trivially_move_assignable::value> +struct expected_move_assign_base : expected_copy_assign_base { + using expected_copy_assign_base::expected_copy_assign_base; +}; +#else +template struct expected_move_assign_base; +#endif + +template +struct expected_move_assign_base + : expected_copy_assign_base { + using expected_copy_assign_base::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::value + &&std::is_nothrow_move_assignable::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 ::value && + std::is_copy_constructible::value), + bool EnableMove = (is_move_constructible_or_void::value && + std::is_move_constructible::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 +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 = delete; + expected_delete_ctor_base & + operator=(const expected_delete_ctor_base &) = default; + expected_delete_ctor_base & + operator=(expected_delete_ctor_base &&) noexcept = default; +}; + +template +struct expected_delete_ctor_base { + 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 +struct expected_delete_ctor_base { + 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 ::value && + std::is_copy_constructible::value && + is_copy_assignable_or_void::value && + std::is_copy_assignable::value), + bool EnableMove = (is_move_constructible_or_void::value && + std::is_move_constructible::value && + is_move_assignable_or_void::value && + std::is_move_assignable::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 +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 = delete; +}; + +template +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 &) = delete; + expected_delete_assign_base & + operator=(expected_delete_assign_base &&) noexcept = default; +}; + +template +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 &) = 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 ::value || std::is_void::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 struct expected_default_ctor_base { + 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 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` 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 expected : private detail::expected_move_assign_base, + private detail::expected_delete_ctor_base, + private detail::expected_delete_assign_base, + private detail::expected_default_ctor_base { + static_assert(!std::is_reference::value, "T must not be a reference"); + static_assert(!std::is_same>::value, + "T must not be in_place_t"); + static_assert(!std::is_same>::value, + "T must not be unexpect_t"); + static_assert(!std::is_same>>::value, + "T must not be unexpected"); + static_assert(!std::is_reference::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 *errptr() { return std::addressof(this->m_unexpect); } + const unexpected *errptr() const { return std::addressof(this->m_unexpect); } + + template ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR U &val() { + return this->m_val; + } + TL_EXPECTED_11_CONSTEXPR unexpected &err() { return this->m_unexpect; } + + template ::value> * = nullptr> + constexpr const U &val() const { + return this->m_val; + } + constexpr const unexpected &err() const { return this->m_unexpect; } + + using impl_base = detail::expected_move_assign_base; + using ctor_base = detail::expected_default_ctor_base; + +public: + typedef T value_type; + typedef E error_type; + typedef unexpected unexpected_type; + +#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \ + !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55) + template TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) & { + return and_then_impl(*this, std::forward(f)); + } + template TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) && { + return and_then_impl(std::move(*this), std::forward(f)); + } + template constexpr auto and_then(F &&f) const & { + return and_then_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template constexpr auto and_then(F &&f) const && { + return and_then_impl(std::move(*this), std::forward(f)); + } +#endif + +#else + template + TL_EXPECTED_11_CONSTEXPR auto + and_then(F &&f) & -> decltype(and_then_impl(std::declval(), std::forward(f))) { + return and_then_impl(*this, std::forward(f)); + } + template + TL_EXPECTED_11_CONSTEXPR auto and_then(F &&f) && -> decltype( + and_then_impl(std::declval(), std::forward(f))) { + return and_then_impl(std::move(*this), std::forward(f)); + } + template + constexpr auto and_then(F &&f) const & -> decltype( + and_then_impl(std::declval(), std::forward(f))) { + return and_then_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template + constexpr auto and_then(F &&f) const && -> decltype( + and_then_impl(std::declval(), std::forward(f))) { + return and_then_impl(std::move(*this), std::forward(f)); + } +#endif +#endif + +#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \ + !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55) + template TL_EXPECTED_11_CONSTEXPR auto map(F &&f) & { + return expected_map_impl(*this, std::forward(f)); + } + template TL_EXPECTED_11_CONSTEXPR auto map(F &&f) && { + return expected_map_impl(std::move(*this), std::forward(f)); + } + template constexpr auto map(F &&f) const & { + return expected_map_impl(*this, std::forward(f)); + } + template constexpr auto map(F &&f) const && { + return expected_map_impl(std::move(*this), std::forward(f)); + } +#else + template + TL_EXPECTED_11_CONSTEXPR decltype( + expected_map_impl(std::declval(), std::declval())) + map(F &&f) & { + return expected_map_impl(*this, std::forward(f)); + } + template + TL_EXPECTED_11_CONSTEXPR decltype( + expected_map_impl(std::declval(), std::declval())) + map(F &&f) && { + return expected_map_impl(std::move(*this), std::forward(f)); + } + template + constexpr decltype(expected_map_impl(std::declval(), + std::declval())) + map(F &&f) const & { + return expected_map_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template + constexpr decltype(expected_map_impl(std::declval(), + std::declval())) + map(F &&f) const && { + return expected_map_impl(std::move(*this), std::forward(f)); + } +#endif +#endif + +#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \ + !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55) + template TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) & { + return expected_map_impl(*this, std::forward(f)); + } + template TL_EXPECTED_11_CONSTEXPR auto transform(F &&f) && { + return expected_map_impl(std::move(*this), std::forward(f)); + } + template constexpr auto transform(F &&f) const & { + return expected_map_impl(*this, std::forward(f)); + } + template constexpr auto transform(F &&f) const && { + return expected_map_impl(std::move(*this), std::forward(f)); + } +#else + template + TL_EXPECTED_11_CONSTEXPR decltype( + expected_map_impl(std::declval(), std::declval())) + transform(F &&f) & { + return expected_map_impl(*this, std::forward(f)); + } + template + TL_EXPECTED_11_CONSTEXPR decltype( + expected_map_impl(std::declval(), std::declval())) + transform(F &&f) && { + return expected_map_impl(std::move(*this), std::forward(f)); + } + template + constexpr decltype(expected_map_impl(std::declval(), + std::declval())) + transform(F &&f) const & { + return expected_map_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template + constexpr decltype(expected_map_impl(std::declval(), + std::declval())) + transform(F &&f) const && { + return expected_map_impl(std::move(*this), std::forward(f)); + } +#endif +#endif + +#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \ + !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55) + template TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) & { + return map_error_impl(*this, std::forward(f)); + } + template TL_EXPECTED_11_CONSTEXPR auto map_error(F &&f) && { + return map_error_impl(std::move(*this), std::forward(f)); + } + template constexpr auto map_error(F &&f) const & { + return map_error_impl(*this, std::forward(f)); + } + template constexpr auto map_error(F &&f) const && { + return map_error_impl(std::move(*this), std::forward(f)); + } +#else + template + TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval(), + std::declval())) + map_error(F &&f) & { + return map_error_impl(*this, std::forward(f)); + } + template + TL_EXPECTED_11_CONSTEXPR decltype(map_error_impl(std::declval(), + std::declval())) + map_error(F &&f) && { + return map_error_impl(std::move(*this), std::forward(f)); + } + template + constexpr decltype(map_error_impl(std::declval(), + std::declval())) + map_error(F &&f) const & { + return map_error_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template + constexpr decltype(map_error_impl(std::declval(), + std::declval())) + map_error(F &&f) const && { + return map_error_impl(std::move(*this), std::forward(f)); + } +#endif +#endif + template expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) & { + return or_else_impl(*this, std::forward(f)); + } + + template expected TL_EXPECTED_11_CONSTEXPR or_else(F &&f) && { + return or_else_impl(std::move(*this), std::forward(f)); + } + + template expected constexpr or_else(F &&f) const & { + return or_else_impl(*this, std::forward(f)); + } + +#ifndef TL_EXPECTED_NO_CONSTRR + template expected constexpr or_else(F &&f) const && { + return or_else_impl(std::move(*this), std::forward(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 ::value> * = + nullptr> + constexpr expected(in_place_t, Args &&... args) + : impl_base(in_place, std::forward(args)...), + ctor_base(detail::default_constructor_tag{}) {} + + template &, Args &&...>::value> * = nullptr> + constexpr expected(in_place_t, std::initializer_list il, Args &&... args) + : impl_base(in_place, il, std::forward(args)...), + ctor_base(detail::default_constructor_tag{}) {} + + template ::value> * = + nullptr, + detail::enable_if_t::value> * = + nullptr> + explicit constexpr expected(const unexpected &e) + : impl_base(unexpect, e.value()), + ctor_base(detail::default_constructor_tag{}) {} + + template < + class G = E, + detail::enable_if_t::value> * = + nullptr, + detail::enable_if_t::value> * = nullptr> + constexpr expected(unexpected const &e) + : impl_base(unexpect, e.value()), + ctor_base(detail::default_constructor_tag{}) {} + + template < + class G = E, + detail::enable_if_t::value> * = nullptr, + detail::enable_if_t::value> * = nullptr> + explicit constexpr expected(unexpected &&e) noexcept( + std::is_nothrow_constructible::value) + : impl_base(unexpect, std::move(e.value())), + ctor_base(detail::default_constructor_tag{}) {} + + template < + class G = E, + detail::enable_if_t::value> * = nullptr, + detail::enable_if_t::value> * = nullptr> + constexpr expected(unexpected &&e) noexcept( + std::is_nothrow_constructible::value) + : impl_base(unexpect, std::move(e.value())), + ctor_base(detail::default_constructor_tag{}) {} + + template ::value> * = + nullptr> + constexpr explicit expected(unexpect_t, Args &&... args) + : impl_base(unexpect, std::forward(args)...), + ctor_base(detail::default_constructor_tag{}) {} + + template &, Args &&...>::value> * = nullptr> + constexpr explicit expected(unexpect_t, std::initializer_list il, + Args &&... args) + : impl_base(unexpect, il, std::forward(args)...), + ctor_base(detail::default_constructor_tag{}) {} + + template ::value && + std::is_convertible::value)> * = + nullptr, + detail::expected_enable_from_other + * = nullptr> + explicit TL_EXPECTED_11_CONSTEXPR expected(const expected &rhs) + : ctor_base(detail::default_constructor_tag{}) { + if (rhs.has_value()) { + this->construct(*rhs); + } else { + this->construct_error(rhs.error()); + } + } + + template ::value && + std::is_convertible::value)> * = + nullptr, + detail::expected_enable_from_other + * = nullptr> + TL_EXPECTED_11_CONSTEXPR expected(const expected &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::value && + std::is_convertible::value)> * = nullptr, + detail::expected_enable_from_other * = nullptr> + explicit TL_EXPECTED_11_CONSTEXPR expected(expected &&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::value && + std::is_convertible::value)> * = nullptr, + detail::expected_enable_from_other * = nullptr> + TL_EXPECTED_11_CONSTEXPR expected(expected &&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::value> * = nullptr, + detail::expected_enable_forward_value * = nullptr> + explicit TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v) + : expected(in_place, std::forward(v)) {} + + template < + class U = T, + detail::enable_if_t::value> * = nullptr, + detail::expected_enable_forward_value * = nullptr> + TL_EXPECTED_MSVC2015_CONSTEXPR expected(U &&v) + : expected(in_place, std::forward(v)) {} + + template < + class U = T, class G = T, + detail::enable_if_t::value> * = + nullptr, + detail::enable_if_t::value> * = nullptr, + detail::enable_if_t< + (!std::is_same, detail::decay_t>::value && + !detail::conjunction, + std::is_same>>::value && + std::is_constructible::value && + std::is_assignable::value && + std::is_nothrow_move_constructible::value)> * = nullptr> + expected &operator=(U &&v) { + if (has_value()) { + val() = std::forward(v); + } else { + err().~unexpected(); + ::new (valptr()) T(std::forward(v)); + this->m_has_val = true; + } + + return *this; + } + + template < + class U = T, class G = T, + detail::enable_if_t::value> * = + nullptr, + detail::enable_if_t::value> * = nullptr, + detail::enable_if_t< + (!std::is_same, detail::decay_t>::value && + !detail::conjunction, + std::is_same>>::value && + std::is_constructible::value && + std::is_assignable::value && + std::is_nothrow_move_constructible::value)> * = nullptr> + expected &operator=(U &&v) { + if (has_value()) { + val() = std::forward(v); + } else { + auto tmp = std::move(err()); + err().~unexpected(); + + #ifdef TL_EXPECTED_EXCEPTIONS_ENABLED + try { + ::new (valptr()) T(std::forward(v)); + this->m_has_val = true; + } catch (...) { + err() = std::move(tmp); + throw; + } + #else + ::new (valptr()) T(std::forward(v)); + this->m_has_val = true; + #endif + } + + return *this; + } + + template ::value && + std::is_assignable::value> * = nullptr> + expected &operator=(const unexpected &rhs) { + if (!has_value()) { + err() = rhs; + } else { + this->destroy_val(); + ::new (errptr()) unexpected(rhs); + this->m_has_val = false; + } + + return *this; + } + + template ::value && + std::is_move_assignable::value> * = nullptr> + expected &operator=(unexpected &&rhs) noexcept { + if (!has_value()) { + err() = std::move(rhs); + } else { + this->destroy_val(); + ::new (errptr()) unexpected(std::move(rhs)); + this->m_has_val = false; + } + + return *this; + } + + template ::value> * = nullptr> + void emplace(Args &&... args) { + if (has_value()) { + val() = T(std::forward(args)...); + } else { + err().~unexpected(); + ::new (valptr()) T(std::forward(args)...); + this->m_has_val = true; + } + } + + template ::value> * = nullptr> + void emplace(Args &&... args) { + if (has_value()) { + val() = T(std::forward(args)...); + } else { + auto tmp = std::move(err()); + err().~unexpected(); + + #ifdef TL_EXPECTED_EXCEPTIONS_ENABLED + try { + ::new (valptr()) T(std::forward(args)...); + this->m_has_val = true; + } catch (...) { + err() = std::move(tmp); + throw; + } + #else + ::new (valptr()) T(std::forward(args)...); + this->m_has_val = true; + #endif + } + } + + template &, Args &&...>::value> * = nullptr> + void emplace(std::initializer_list il, Args &&... args) { + if (has_value()) { + T t(il, std::forward(args)...); + val() = std::move(t); + } else { + err().~unexpected(); + ::new (valptr()) T(il, std::forward(args)...); + this->m_has_val = true; + } + } + + template &, Args &&...>::value> * = nullptr> + void emplace(std::initializer_list il, Args &&... args) { + if (has_value()) { + T t(il, std::forward(args)...); + val() = std::move(t); + } else { + auto tmp = std::move(err()); + err().~unexpected(); + + #ifdef TL_EXPECTED_EXCEPTIONS_ENABLED + try { + ::new (valptr()) T(il, std::forward(args)...); + this->m_has_val = true; + } catch (...) { + err() = std::move(tmp); + throw; + } + #else + ::new (valptr()) T(il, std::forward(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::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::type{}, + typename std::is_nothrow_move_constructible::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 + detail::enable_if_t::value && + detail::is_swappable::value && + (std::is_nothrow_move_constructible::value || + std::is_nothrow_move_constructible::value)> + swap(expected &rhs) noexcept( + std::is_nothrow_move_constructible::value + &&detail::is_nothrow_swappable::value + &&std::is_nothrow_move_constructible::value + &&detail::is_nothrow_swappable::value) { + if (has_value() && rhs.has_value()) { + swap_where_both_have_value(rhs, typename std::is_void::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::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 ::value> * = nullptr> + constexpr const U &operator*() const & { + return val(); + } + template ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR U &operator*() & { + return val(); + } + template ::value> * = nullptr> + constexpr const U &&operator*() const && { + return std::move(val()); + } + template ::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 ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR const U &value() const & { + if (!has_value()) + detail::throw_exception(bad_expected_access(err().value())); + return val(); + } + template ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR U &value() & { + if (!has_value()) + detail::throw_exception(bad_expected_access(err().value())); + return val(); + } + template ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR const U &&value() const && { + if (!has_value()) + detail::throw_exception(bad_expected_access(std::move(err()).value())); + return std::move(val()); + } + template ::value> * = nullptr> + TL_EXPECTED_11_CONSTEXPR U &&value() && { + if (!has_value()) + detail::throw_exception(bad_expected_access(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 constexpr T value_or(U &&v) const & { + static_assert(std::is_copy_constructible::value && + std::is_convertible::value, + "T must be copy-constructible and convertible to from U&&"); + return bool(*this) ? **this : static_cast(std::forward(v)); + } + template TL_EXPECTED_11_CONSTEXPR T value_or(U &&v) && { + static_assert(std::is_move_constructible::value && + std::is_convertible::value, + "T must be move-constructible and convertible to from U&&"); + return bool(*this) ? std::move(**this) : static_cast(std::forward(v)); + } +}; + +namespace detail { +template using exp_t = typename detail::decay_t::value_type; +template using err_t = typename detail::decay_t::error_type; +template using ret_t = expected>; + +#ifdef TL_EXPECTED_CXX14 +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + *std::declval()))> +constexpr auto and_then_impl(Exp &&exp, F &&f) { + static_assert(detail::is_expected::value, "F must return an expected"); + + return exp.has_value() + ? detail::invoke(std::forward(f), *std::forward(exp)) + : Ret(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval()))> +constexpr auto and_then_impl(Exp &&exp, F &&f) { + static_assert(detail::is_expected::value, "F must return an expected"); + + return exp.has_value() ? detail::invoke(std::forward(f)) + : Ret(unexpect, std::forward(exp).error()); +} +#else +template struct TC; +template (), + *std::declval())), + detail::enable_if_t>::value> * = nullptr> +auto and_then_impl(Exp &&exp, F &&f) -> Ret { + static_assert(detail::is_expected::value, "F must return an expected"); + + return exp.has_value() + ? detail::invoke(std::forward(f), *std::forward(exp)) + : Ret(unexpect, std::forward(exp).error()); +} + +template ())), + detail::enable_if_t>::value> * = nullptr> +constexpr auto and_then_impl(Exp &&exp, F &&f) -> Ret { + static_assert(detail::is_expected::value, "F must return an expected"); + + return exp.has_value() ? detail::invoke(std::forward(f)) + : Ret(unexpect, std::forward(exp).error()); +} +#endif + +#ifdef TL_EXPECTED_CXX14 +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + *std::declval())), + detail::enable_if_t::value> * = nullptr> +constexpr auto expected_map_impl(Exp &&exp, F &&f) { + using result = ret_t>; + return exp.has_value() ? result(detail::invoke(std::forward(f), + *std::forward(exp))) + : result(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + *std::declval())), + detail::enable_if_t::value> * = nullptr> +auto expected_map_impl(Exp &&exp, F &&f) { + using result = expected>; + if (exp.has_value()) { + detail::invoke(std::forward(f), *std::forward(exp)); + return result(); + } + + return result(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval())), + detail::enable_if_t::value> * = nullptr> +constexpr auto expected_map_impl(Exp &&exp, F &&f) { + using result = ret_t>; + return exp.has_value() ? result(detail::invoke(std::forward(f))) + : result(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval())), + detail::enable_if_t::value> * = nullptr> +auto expected_map_impl(Exp &&exp, F &&f) { + using result = expected>; + if (exp.has_value()) { + detail::invoke(std::forward(f)); + return result(); + } + + return result(unexpect, std::forward(exp).error()); +} +#else +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + *std::declval())), + detail::enable_if_t::value> * = nullptr> + +constexpr auto expected_map_impl(Exp &&exp, F &&f) + -> ret_t> { + using result = ret_t>; + + return exp.has_value() ? result(detail::invoke(std::forward(f), + *std::forward(exp))) + : result(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + *std::declval())), + detail::enable_if_t::value> * = nullptr> + +auto expected_map_impl(Exp &&exp, F &&f) -> expected> { + if (exp.has_value()) { + detail::invoke(std::forward(f), *std::forward(exp)); + return {}; + } + + return unexpected>(std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval())), + detail::enable_if_t::value> * = nullptr> + +constexpr auto expected_map_impl(Exp &&exp, F &&f) + -> ret_t> { + using result = ret_t>; + + return exp.has_value() ? result(detail::invoke(std::forward(f))) + : result(unexpect, std::forward(exp).error()); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval())), + detail::enable_if_t::value> * = nullptr> + +auto expected_map_impl(Exp &&exp, F &&f) -> expected> { + if (exp.has_value()) { + detail::invoke(std::forward(f)); + return {}; + } + + return unexpected>(std::forward(exp).error()); +} +#endif + +#if defined(TL_EXPECTED_CXX14) && !defined(TL_EXPECTED_GCC49) && \ + !defined(TL_EXPECTED_GCC54) && !defined(TL_EXPECTED_GCC55) +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +constexpr auto map_error_impl(Exp &&exp, F &&f) { + using result = expected, detail::decay_t>; + return exp.has_value() + ? result(*std::forward(exp)) + : result(unexpect, detail::invoke(std::forward(f), + std::forward(exp).error())); +} +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +auto map_error_impl(Exp &&exp, F &&f) { + using result = expected, monostate>; + if (exp.has_value()) { + return result(*std::forward(exp)); + } + + detail::invoke(std::forward(f), std::forward(exp).error()); + return result(unexpect, monostate{}); +} +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +constexpr auto map_error_impl(Exp &&exp, F &&f) { + using result = expected, detail::decay_t>; + return exp.has_value() + ? result() + : result(unexpect, detail::invoke(std::forward(f), + std::forward(exp).error())); +} +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +auto map_error_impl(Exp &&exp, F &&f) { + using result = expected, monostate>; + if (exp.has_value()) { + return result(); + } + + detail::invoke(std::forward(f), std::forward(exp).error()); + return result(unexpect, monostate{}); +} +#else +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +constexpr auto map_error_impl(Exp &&exp, F &&f) + -> expected, detail::decay_t> { + using result = expected, detail::decay_t>; + + return exp.has_value() + ? result(*std::forward(exp)) + : result(unexpect, detail::invoke(std::forward(f), + std::forward(exp).error())); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +auto map_error_impl(Exp &&exp, F &&f) -> expected, monostate> { + using result = expected, monostate>; + if (exp.has_value()) { + return result(*std::forward(exp)); + } + + detail::invoke(std::forward(f), std::forward(exp).error()); + return result(unexpect, monostate{}); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +constexpr auto map_error_impl(Exp &&exp, F &&f) + -> expected, detail::decay_t> { + using result = expected, detail::decay_t>; + + return exp.has_value() + ? result() + : result(unexpect, detail::invoke(std::forward(f), + std::forward(exp).error())); +} + +template >::value> * = nullptr, + class Ret = decltype(detail::invoke(std::declval(), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +auto map_error_impl(Exp &&exp, F &&f) -> expected, monostate> { + using result = expected, monostate>; + if (exp.has_value()) { + return result(); + } + + detail::invoke(std::forward(f), std::forward(exp).error()); + return result(unexpect, monostate{}); +} +#endif + +#ifdef TL_EXPECTED_CXX14 +template (), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +constexpr auto or_else_impl(Exp &&exp, F &&f) { + static_assert(detail::is_expected::value, "F must return an expected"); + return exp.has_value() + ? std::forward(exp) + : detail::invoke(std::forward(f), std::forward(exp).error()); +} + +template (), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +detail::decay_t or_else_impl(Exp &&exp, F &&f) { + return exp.has_value() + ? std::forward(exp) + : (detail::invoke(std::forward(f), std::forward(exp).error()), + std::forward(exp)); +} +#else +template (), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +auto or_else_impl(Exp &&exp, F &&f) -> Ret { + static_assert(detail::is_expected::value, "F must return an expected"); + return exp.has_value() + ? std::forward(exp) + : detail::invoke(std::forward(f), std::forward(exp).error()); +} + +template (), + std::declval().error())), + detail::enable_if_t::value> * = nullptr> +detail::decay_t or_else_impl(Exp &&exp, F &&f) { + return exp.has_value() + ? std::forward(exp) + : (detail::invoke(std::forward(f), std::forward(exp).error()), + std::forward(exp)); +} +#endif +} // namespace detail + +template +constexpr bool operator==(const expected &lhs, + const expected &rhs) { + return (lhs.has_value() != rhs.has_value()) + ? false + : (!lhs.has_value() ? lhs.error() == rhs.error() : *lhs == *rhs); +} +template +constexpr bool operator!=(const expected &lhs, + const expected &rhs) { + return (lhs.has_value() != rhs.has_value()) + ? true + : (!lhs.has_value() ? lhs.error() != rhs.error() : *lhs != *rhs); +} + +template +constexpr bool operator==(const expected &x, const U &v) { + return x.has_value() ? *x == v : false; +} +template +constexpr bool operator==(const U &v, const expected &x) { + return x.has_value() ? *x == v : false; +} +template +constexpr bool operator!=(const expected &x, const U &v) { + return x.has_value() ? *x != v : true; +} +template +constexpr bool operator!=(const U &v, const expected &x) { + return x.has_value() ? *x != v : true; +} + +template +constexpr bool operator==(const expected &x, const unexpected &e) { + return x.has_value() ? false : x.error() == e.value(); +} +template +constexpr bool operator==(const unexpected &e, const expected &x) { + return x.has_value() ? false : x.error() == e.value(); +} +template +constexpr bool operator!=(const expected &x, const unexpected &e) { + return x.has_value() ? true : x.error() != e.value(); +} +template +constexpr bool operator!=(const unexpected &e, const expected &x) { + return x.has_value() ? true : x.error() != e.value(); +} + +template ::value || + std::is_move_constructible::value) && + detail::is_swappable::value && + std::is_move_constructible::value && + detail::is_swappable::value> * = nullptr> +void swap(expected &lhs, + expected &rhs) noexcept(noexcept(lhs.swap(rhs))) { + lhs.swap(rhs); +} +} // namespace tl + +#endif -- 2.39.5