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Denis Blank
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@ -31,8 +31,9 @@
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#ifndef CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED__
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#define CONTINUABLE_DETAIL_EXPECTED_HPP_INCLUDED__
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#include <algorithm>
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#include <memory>
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#include <type_traits>
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#include <utility>
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#include <continuable/continuable-api.hpp>
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#include <continuable/detail/types.hpp>
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@ -40,85 +41,86 @@
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namespace cti {
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namespace detail {
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namespace expected {
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namespace util {
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namespace detail {
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enum class slot_t { empty, value, error };
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template <typename Base>
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struct expected_base_util {
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slot_t slot_;
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template <typename T>
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using storage_of_t = //
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std::aligned_storage_t<(sizeof(types::error_type) > sizeof(T)
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? sizeof(types::error_type)
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: sizeof(T))>;
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protected:
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template <typename T>
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void init(T&& value, slot_t slot) {
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set(slot);
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using type = std::decay_t<decltype(value)>;
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auto storage = &base()->storage_;
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new (storage) type(std::forward<decltype(value)>(value));
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}
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void destroy() {
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weak_destroy();
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set(slot_t::empty);
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}
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void weak_destroy() {
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base()->visit([&](auto&& value) {
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using type = std::decay_t<decltype(value)>;
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value.~type();
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});
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}
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slot_t get() const noexcept {
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return slot_;
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}
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bool is(slot_t slot) const noexcept {
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return get() == slot;
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}
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void set(slot_t slot) {
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slot_ = slot;
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}
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slot_t consume(slot_t slot) {
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auto current = get();
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destroy();
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return current;
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}
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Base* base() noexcept {
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return static_cast<Base*>(this);
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}
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Base const* base() const noexcept {
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return static_cast<Base*>(this);
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}
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};
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template <typename Base, bool IsCopyable /*= true*/>
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struct expected_copy_base {
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constexpr expected_copy_base() = default;
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template <bool IsCopyable /*= true */, typename Base>
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struct expected_base : expected_base_util<Base> {
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explicit expected_base(expected_base const& right) {
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right.visit([&](auto&& value) {
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this->init(std::forward<decltype(value)>(value));
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expected_copy_base(expected_copy_base const&) = default;
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explicit expected_copy_base(expected_copy_base&& right)
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// TODO noexcept(Base::is_nothrow_move_constructible)
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{
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Base& me = *static_cast<Base*>(this);
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Base& other = *static_cast<Base*>(&right);
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other.visit([&](auto&& value) {
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// ...
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me.init(std::move(value));
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});
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set(right.consume());
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set(other.get());
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}
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expected_base& operator=(expected_base const& right) {
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this->weak_destroy();
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right.visit([&](auto&& value) {
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this->init(std::forward<decltype(value)>(value));
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expected_copy_base& operator=(expected_copy_base const&) = default;
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expected_copy_base& operator=(expected_copy_base&& right)
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// TODO noexcept(Base::is_nothrow_move_constructible)
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{
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Base& me = *static_cast<Base*>(this);
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Base& other = *static_cast<Base*>(&right);
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me.weak_destroy();
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other.visit([&](auto&& value) {
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// ...
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me.init(std::move(value));
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});
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set(right.consume());
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set(other.get());
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return *this;
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}
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};
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template <bool IsCopyable /*= true */, typename Base>
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struct expected_base : expected_base_util<Base> {
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explicit expected_base(expected_base const& right) {
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right.visit([&](auto&& value) {
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this->init(std::forward<decltype(value)>(value));
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template <typename Base /*, bool IsCopyable = false*/>
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struct expected_copy_base<Base, false> {
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constexpr expected_copy_base() = default;
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expected_copy_base(expected_copy_base const&) = default;
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explicit expected_copy_base(expected_copy_base&& right) = delete;
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expected_copy_base& operator=(expected_copy_base const&) = default;
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expected_copy_base& operator=(expected_copy_base&& right) = delete;
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};
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template <typename Base>
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struct expected_move_base {
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constexpr expected_move_base() = default;
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expected_move_base(expected_move_base&&) = default;
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explicit expected_move_base(expected_move_base const& right) {
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Base& me = *static_cast<Base*>(this);
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Base const& other = *static_cast<Base const*>(&right);
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other.visit([&](auto&& value) {
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// ...
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me.init(std::move(value));
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});
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set(right.consume());
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set(other.consume());
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}
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expected_base& operator=(expected_base const& right) {
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this->weak_destroy();
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right.visit([&](auto&& value) {
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this->init(std::forward<decltype(value)>(value));
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expected_move_base& operator=(expected_move_base&&) = default;
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expected_move_base& operator=(expected_move_base const& right) {
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Base& me = *static_cast<Base*>(this);
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Base const& other = *static_cast<Base*>(&right);
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me.weak_destroy();
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other.visit([&](auto&& value) {
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// ...
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me.init(std::move(value));
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});
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set(right.consume());
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set(other.consume());
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return *this;
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}
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};
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@ -127,59 +129,121 @@ struct expected_base : expected_base_util<Base> {
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/// A class similar to the one in the expected proposal,
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/// however it is capable of carrying an exception_ptr if
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/// exceptions are used.
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template <typename T, typename Storage = std::aligned_storage_t<std::max(
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sizeof(types::error_type), sizeof(T))>>
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class expected {
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friend class expected_base;
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template <typename T>
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class expected
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: detail::expected_move_base<expected<T>>,
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detail::expected_copy_base<
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expected<T>, std::is_copy_constructible<types::error_type>::value &&
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std::is_copy_constructible<T>::value> {
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Storage storage_;
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template <typename>
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friend class expected_move_base;
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template <typename, bool>
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friend class expected_copy_base;
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detail::storage_of_t<T> storage_;
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detail::slot_t slot_ = detail::slot_t::empty;
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template <typename V>
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expected(V&& value, detail::slot_t const slot) {
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using type = std::decay_t<decltype(value)>;
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new (&storage_) type(std::forward<V>(value));
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set(slot);
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}
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public:
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explicit expected() : slot_(slot_t::empty) {
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explicit expected(T value) //
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: expected(std::move(value), detail::slot_t::value) {
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}
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explicit expected(types::error_type error) //
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: expected(std::move(error), detail::slot_t::error) {
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}
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explicit expected(T value) : slot_(slot_t::value) {
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}
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expected(expected const&) = default;
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expected(expected&& right) = default;
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expected& operator=(expected const&) = default;
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expected& operator=(expected&& right) = default;
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explicit expected(types::error_type error) : slot_(slot_t::value) {
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}
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bool is_empty() const noexcept {
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return slot_ == slot_t::empty;
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}
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bool is_value() const noexcept {
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return slot_ == slot_t::value;
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return slot_ == detail::slot_t::value;
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}
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bool is_error() const noexcept {
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return slot_ == slot_t::error;
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return slot_ == detail::slot_t::error;
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}
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protected:
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bool is_empty() const noexcept {
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return slot_ == detail::slot_t::empty;
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}
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template <typename V>
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void visit(V&& visitor) {
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switch (slot_) {
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case slot_t::value:
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case detail::slot_t::value:
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return std::forward<V>(visitor)(static_cast<T*>(&storage_));
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case slot_t::error:
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case detail::slot_t::error:
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return std::forward<V>(visitor)(
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static_cast<types::error_type*>(&storage_));
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default:
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// We don't visit when there is no value
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break;
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}
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util::unreachable();
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}
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template <typename V>
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void visit(V&& visitor) const {
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switch (slot_) {
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case slot_t::value:
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case detail::slot_t::value:
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return std::forward<V>(visitor)(static_cast<T*>(&storage_));
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case slot_t::error:
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case detail::slot_t::error:
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return std::forward<V>(visitor)(
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static_cast<types::error_type*>(&storage_));
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default:
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// We don't visit when there is no value
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break;
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}
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}
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util::unreachable();
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template <typename V>
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void init(V&& value, detail::slot_t const slot) {
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assert(is(slot_t::empty));
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set(slot);
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using type = std::decay_t<decltype(value)>;
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auto storage = &storage_;
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new (storage) type(std::forward<V>(value));
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}
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void destroy() {
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weak_destroy();
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#ifdef NDEBUG
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set(detail::slot_t::empty);
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#endif
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}
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void weak_destroy() {
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visit([&](auto&& value) {
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using type = std::decay_t<decltype(value)>;
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value.~type();
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});
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#ifndef NDEBUG
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set(detail::slot_t::empty);
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#endif
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}
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detail::slot_t get() const noexcept {
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return slot_;
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}
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bool is(detail::slot_t const slot) const noexcept {
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return get() == slot;
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}
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void set(detail::slot_t const slot) {
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slot_ = slot;
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}
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detail::slot_t consume(detail::slot_t slot) {
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auto const current = get();
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destroy();
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return current;
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}
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};
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} // namespace expected
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} // namespace util
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} // namespace detail
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} // namespace cti
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@ -13,6 +13,7 @@ foreach(STEP RANGE 4)
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-connection-all.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-connection-any.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-connection-seq.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-expected.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-erasure.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-regression.cpp
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${CMAKE_CURRENT_LIST_DIR}/test-continuable-transforms.cpp)
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33
test/unit-test/test-continuable-expected.cpp
Normal file
33
test/unit-test/test-continuable-expected.cpp
Normal file
@ -0,0 +1,33 @@
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/*
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Copyright(c) 2015 - 2017 Denis Blank <denis.blank at outlook dot com>
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files(the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions :
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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**/
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#include "test-continuable.hpp"
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using cti::detail::util::expected;
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using cti::detail::types::error_type;
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TEST(expected_tests, can_carry_errors) {
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expected<int> e(1);
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auto i = e;
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}
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