diff options
| -rw-r--r-- | CMakeLists.txt | 1 | ||||
| -rw-r--r-- | src/expected.hpp | 227 |
2 files changed, 228 insertions, 0 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index 6326c05..86de9c9 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -34,6 +34,7 @@ set(WANDA_CORE_HEADERS "src/control_connection.hpp" "src/deferred_failure.hpp" "src/environment.hpp" + "src/expected.hpp" "src/keyed.hpp" "src/message.hpp" "src/optional.hpp" diff --git a/src/expected.hpp b/src/expected.hpp new file mode 100644 index 0000000..8cacefe --- /dev/null +++ b/src/expected.hpp @@ -0,0 +1,227 @@ +#ifndef WANDA_EXPECTED_HPP +#define WANDA_EXPECTED_HPP + +#include <initializer_list> +#include <type_traits> +#include <utility> + +namespace wanda +{ + +template <typename ErrorType> +struct unexpected +{ + static_assert(!std::is_same_v<ErrorType, void>, "ErrorType can not be 'void'!"); + static_assert(!std::is_array_v<ErrorType>, "ErrorType can not be an array type!"); + + /** + * @brief Copy construct a new @p unexpected from another @p unexpected + */ + constexpr unexpected(unexpected const &) = default; + + /** + * @brief Move construct a new @p unexpected from another @p unexpected + */ + constexpr unexpected(unexpected &&) = default; + + /** + * @brief Construct a new @p unexpected by direct initializing the error object from @p args + */ + template <typename... Args> + constexpr explicit unexpected(std::in_place_t, Args &&... args) : m_error(std::forward<Args>(args)...) {} + + /** + * @brief Construct a new @p unexpected by direct initializing the error object from @p il and @p args + */ + template < + typename U, + typename... Args, + std::enable_if_t<std::is_constructible_v<ErrorType, std::initializer_list<U>, Args...>> * = nullptr> + constexpr explicit unexpected(std::in_place_t, std::initializer_list<U> il, Args &&... args) : m_error(il, std::forward<Args>(args)...) {} + + /** + * @brief Construct a new @p unexpected by direct initializing the error object from @p error + */ + template < + typename Err = ErrorType, + std::enable_if_t<std::is_constructible_v<ErrorType, Err> && + !std::is_same_v<std::remove_cv_t<std::remove_reference_t<Err>>, std::in_place_t> && + !std::is_same_v<std::remove_cv_t<std::remove_reference_t<Err>>, unexpected>> * = nullptr> + constexpr explicit unexpected(Err &&error) : m_error(std::forward<Err>(error)) {} + + /** + * @brief Construct a new @p unexpected by copying the value of another @p unexpected of different error type + */ + template < + typename Err, + std::enable_if_t<!( + std::is_constructible_v<ErrorType, Err> && + !std::is_constructible_v<ErrorType, unexpected<Err> &> && + !std::is_constructible_v<ErrorType, unexpected<Err>> && + !std::is_constructible_v<ErrorType, unexpected<Err> const &> && + !std::is_constructible_v<ErrorType, unexpected<Err> const> && + !std::is_convertible_v<unexpected<Err> &, ErrorType> && + !std::is_convertible_v<unexpected<Err>, ErrorType> && + !std::is_convertible_v<unexpected<Err> const &, ErrorType> && + !std::is_convertible_v<unexpected<Err> const, ErrorType>)> * = nullptr, + std::enable_if_t<!std::is_convertible_v<Err, ErrorType>> * = nullptr> + constexpr explicit unexpected(unexpected<Err> const &error) : m_error(error.m_error) {} + + /** + * @brief Construct a new @p unexpected by copying the value of another @p unexpected of different error type + */ + template < + typename Err, + std::enable_if_t<!( + std::is_constructible_v<ErrorType, Err> && + !std::is_constructible_v<ErrorType, unexpected<Err> &> && + !std::is_constructible_v<ErrorType, unexpected<Err>> && + !std::is_constructible_v<ErrorType, unexpected<Err> const &> && + !std::is_constructible_v<ErrorType, unexpected<Err> const> && + !std::is_convertible_v<unexpected<Err> &, ErrorType> && + !std::is_convertible_v<unexpected<Err>, ErrorType> && + !std::is_convertible_v<unexpected<Err> const &, ErrorType> && + !std::is_convertible_v<unexpected<Err> const, ErrorType>)> * = nullptr, + std::enable_if_t<std::is_convertible_v<Err, ErrorType>> * = nullptr> + constexpr unexpected(unexpected<Err> const &error) : m_error(error.m_error) {} + + /** + * @brief Construct a new @p unexpected by moving the value of another @p unexpected of different error type + */ + template < + typename Err, + std::enable_if_t<!( + std::is_constructible_v<ErrorType, Err> && + !std::is_constructible_v<ErrorType, unexpected<Err> &> && + !std::is_constructible_v<ErrorType, unexpected<Err>> && + !std::is_constructible_v<ErrorType, unexpected<Err> const &> && + !std::is_constructible_v<ErrorType, unexpected<Err> const> && + !std::is_convertible_v<unexpected<Err> &, ErrorType> && + !std::is_convertible_v<unexpected<Err>, ErrorType> && + !std::is_convertible_v<unexpected<Err> const &, ErrorType> && + !std::is_convertible_v<unexpected<Err> const, ErrorType>)> * = nullptr, + std::enable_if_t<!std::is_convertible_v<Err, ErrorType>> * = nullptr> + constexpr explicit unexpected(unexpected<Err> &&error) : m_error(std::move(error.m_error)) {} + + /** + * @brief Construct a new @p unexpected by moving the value of another @p unexpected of different error type + */ + template < + typename Err, + std::enable_if_t<!( + std::is_constructible_v<ErrorType, Err> && + !std::is_constructible_v<ErrorType, unexpected<Err> &> && + !std::is_constructible_v<ErrorType, unexpected<Err>> && + !std::is_constructible_v<ErrorType, unexpected<Err> const &> && + !std::is_constructible_v<ErrorType, unexpected<Err> const> && + !std::is_convertible_v<unexpected<Err> &, ErrorType> && + !std::is_convertible_v<unexpected<Err>, ErrorType> && + !std::is_convertible_v<unexpected<Err> const &, ErrorType> && + !std::is_convertible_v<unexpected<Err> const, ErrorType>)> * = nullptr, + std::enable_if_t<std::is_convertible_v<Err, ErrorType>> * = nullptr> + constexpr unexpected(unexpected<Err> &&error) : m_error(std::move(error.m_error)) {} + + /** + * @brief Get the error value contained in this @p unexpected instance + */ + constexpr ErrorType const &value() const & + { + return m_error; + } + + /** + * @brief Get the error value contained in this @p unexpected instance + */ + constexpr ErrorType &value() & + { + return m_error; + } + + /** + * @brief Get the error value contained in this @p unexpected instance + */ + constexpr ErrorType &&value() && + { + return std::move(m_error); + } + + /** + * @brief Get the error value contained in this @p unexpected instance + */ + constexpr ErrorType const &&value() const && + { + return std::move(m_error); + } + + /** + * @brief Swap the error value of this @p unexpected instance with the one of @p other + */ + void swap(unexpected &other) noexcept(std::is_nothrow_swappable_v<ErrorType>) + { + using std::swap; + swap(m_error, other.m_error); + } + + template <typename ErrorType1, typename ErrorType2> + friend constexpr bool operator==(unexpected<ErrorType1> const &lhs, unexpected<ErrorType2> const &rhs); + + template <typename ErrorType1, typename ErrorType2> + friend constexpr bool operator!=(unexpected<ErrorType1> const &lhs, unexpected<ErrorType2> const &rhs); + + template < + typename Err, + std::enable_if_t<std::is_swappable_v<Err>> *> + friend void swap(unexpected<Err> &lhs, unexpected<Err> &rhs); + + private: + ErrorType m_error; +}; + +template <typename ErrorType> +unexpected(ErrorType)->unexpected<ErrorType>; + +/** + * @brief Compare two @p unexpected instances for equality + */ +template <typename ErrorType1, typename ErrorType2> +constexpr bool operator==(unexpected<ErrorType1> const &lhs, unexpected<ErrorType2> const &rhs) +{ + return lhs.m_error == rhs.m_error; +} + +/** + * @brief Compare two @p unexpected instances for inequality + */ +template <typename ErrorType1, typename ErrorType2> +constexpr bool operator!=(unexpected<ErrorType1> const &lhs, unexpected<ErrorType2> const &rhs) +{ + return lhs.m_error != rhs.m_error; +} + +/** + * @brief Swap the error values of two @p unexpected instances + */ +template < + typename Err, + std::enable_if_t<std::is_swappable_v<Err>> * = nullptr> +void swap(unexpected<Err> &lhs, unexpected<Err> &rhs) +{ + lhs.swap(rhs); +} + +/** + * @brief A tag type for @p unexpected + */ +struct unexpect_t +{ + explicit unexpect_t() = default; +}; + +/** + * @brief A tap for @p unexpected + */ +inline constexpr unexpect_t unexpect{}; + +} // namespace wanda + +#endif
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