diff options
Diffstat (limited to 'ext/pybind11/include/pybind11/stl.h')
-rw-r--r-- | ext/pybind11/include/pybind11/stl.h | 157 |
1 files changed, 125 insertions, 32 deletions
diff --git a/ext/pybind11/include/pybind11/stl.h b/ext/pybind11/include/pybind11/stl.h index 37b6bcde3..44abb8c6c 100644 --- a/ext/pybind11/include/pybind11/stl.h +++ b/ext/pybind11/include/pybind11/stl.h @@ -32,15 +32,36 @@ // std::experimental::optional (but not allowed in c++11 mode) # if defined(PYBIND11_CPP14) && __has_include(<experimental/optional>) # include <experimental/optional> -# if __cpp_lib_experimental_optional // just in case -# define PYBIND11_HAS_EXP_OPTIONAL 1 -# endif +# define PYBIND11_HAS_EXP_OPTIONAL 1 # endif +// std::variant +# if defined(PYBIND11_CPP17) && __has_include(<variant>) +# include <variant> +# define PYBIND11_HAS_VARIANT 1 +# endif +#elif defined(_MSC_VER) && defined(PYBIND11_CPP17) +# include <optional> +# include <variant> +# define PYBIND11_HAS_OPTIONAL 1 +# define PYBIND11_HAS_VARIANT 1 #endif -NAMESPACE_BEGIN(pybind11) +NAMESPACE_BEGIN(PYBIND11_NAMESPACE) NAMESPACE_BEGIN(detail) +/// Extracts an const lvalue reference or rvalue reference for U based on the type of T (e.g. for +/// forwarding a container element). Typically used indirect via forwarded_type(), below. +template <typename T, typename U> +using forwarded_type = conditional_t< + std::is_lvalue_reference<T>::value, remove_reference_t<U> &, remove_reference_t<U> &&>; + +/// Forwards a value U as rvalue or lvalue according to whether T is rvalue or lvalue; typically +/// used for forwarding a container's elements. +template <typename T, typename U> +forwarded_type<T, U> forward_like(U &&u) { + return std::forward<detail::forwarded_type<T, U>>(std::forward<U>(u)); +} + template <typename Type, typename Key> struct set_caster { using type = Type; using key_conv = make_caster<Key>; @@ -50,19 +71,20 @@ template <typename Type, typename Key> struct set_caster { return false; auto s = reinterpret_borrow<pybind11::set>(src); value.clear(); - key_conv conv; for (auto entry : s) { + key_conv conv; if (!conv.load(entry, convert)) return false; - value.insert(cast_op<Key>(conv)); + value.insert(cast_op<Key &&>(std::move(conv))); } return true; } - static handle cast(const type &src, return_value_policy policy, handle parent) { + template <typename T> + static handle cast(T &&src, return_value_policy policy, handle parent) { pybind11::set s; - for (auto const &value: src) { - auto value_ = reinterpret_steal<object>(key_conv::cast(value, policy, parent)); + for (auto &&value : src) { + auto value_ = reinterpret_steal<object>(key_conv::cast(forward_like<T>(value), policy, parent)); if (!value_ || !s.add(value_)) return handle(); } @@ -80,23 +102,24 @@ template <typename Type, typename Key, typename Value> struct map_caster { if (!isinstance<dict>(src)) return false; auto d = reinterpret_borrow<dict>(src); - key_conv kconv; - value_conv vconv; value.clear(); for (auto it : d) { + key_conv kconv; + value_conv vconv; if (!kconv.load(it.first.ptr(), convert) || !vconv.load(it.second.ptr(), convert)) return false; - value.emplace(cast_op<Key>(kconv), cast_op<Value>(vconv)); + value.emplace(cast_op<Key &&>(std::move(kconv)), cast_op<Value &&>(std::move(vconv))); } return true; } - static handle cast(const Type &src, return_value_policy policy, handle parent) { + template <typename T> + static handle cast(T &&src, return_value_policy policy, handle parent) { dict d; - for (auto const &kv: src) { - auto key = reinterpret_steal<object>(key_conv::cast(kv.first, policy, parent)); - auto value = reinterpret_steal<object>(value_conv::cast(kv.second, policy, parent)); + for (auto &&kv : src) { + auto key = reinterpret_steal<object>(key_conv::cast(forward_like<T>(kv.first), policy, parent)); + auto value = reinterpret_steal<object>(value_conv::cast(forward_like<T>(kv.second), policy, parent)); if (!key || !value) return handle(); d[key] = value; @@ -114,13 +137,13 @@ template <typename Type, typename Value> struct list_caster { if (!isinstance<sequence>(src)) return false; auto s = reinterpret_borrow<sequence>(src); - value_conv conv; value.clear(); reserve_maybe(s, &value); for (auto it : s) { + value_conv conv; if (!conv.load(it, convert)) return false; - value.push_back(cast_op<Value>(conv)); + value.push_back(cast_op<Value &&>(std::move(conv))); } return true; } @@ -132,11 +155,12 @@ private: void reserve_maybe(sequence, void *) { } public: - static handle cast(const Type &src, return_value_policy policy, handle parent) { + template <typename T> + static handle cast(T &&src, return_value_policy policy, handle parent) { list l(src.size()); size_t index = 0; - for (auto const &value: src) { - auto value_ = reinterpret_steal<object>(value_conv::cast(value, policy, parent)); + for (auto &&value : src) { + auto value_ = reinterpret_steal<object>(value_conv::cast(forward_like<T>(value), policy, parent)); if (!value_) return handle(); PyList_SET_ITEM(l.ptr(), (ssize_t) index++, value_.release().ptr()); // steals a reference @@ -175,21 +199,22 @@ public: auto l = reinterpret_borrow<list>(src); if (!require_size(l.size())) return false; - value_conv conv; size_t ctr = 0; for (auto it : l) { + value_conv conv; if (!conv.load(it, convert)) return false; - value[ctr++] = cast_op<Value>(conv); + value[ctr++] = cast_op<Value &&>(std::move(conv)); } return true; } - static handle cast(const ArrayType &src, return_value_policy policy, handle parent) { + template <typename T> + static handle cast(T &&src, return_value_policy policy, handle parent) { list l(src.size()); size_t index = 0; - for (auto const &value: src) { - auto value_ = reinterpret_steal<object>(value_conv::cast(value, policy, parent)); + for (auto &&value : src) { + auto value_ = reinterpret_steal<object>(value_conv::cast(forward_like<T>(value), policy, parent)); if (!value_) return handle(); PyList_SET_ITEM(l.ptr(), (ssize_t) index++, value_.release().ptr()); // steals a reference @@ -222,24 +247,24 @@ template <typename Key, typename Value, typename Hash, typename Equal, typename template<typename T> struct optional_caster { using value_conv = make_caster<typename T::value_type>; - static handle cast(const T& src, return_value_policy policy, handle parent) { + template <typename T_> + static handle cast(T_ &&src, return_value_policy policy, handle parent) { if (!src) return none().inc_ref(); - return value_conv::cast(*src, policy, parent); + return value_conv::cast(*std::forward<T_>(src), policy, parent); } bool load(handle src, bool convert) { if (!src) { return false; } else if (src.is_none()) { - value = {}; // nullopt - return true; + return true; // default-constructed value is already empty } value_conv inner_caster; if (!inner_caster.load(src, convert)) return false; - value.emplace(cast_op<typename T::value_type>(inner_caster)); + value.emplace(cast_op<typename T::value_type &&>(std::move(inner_caster))); return true; } @@ -262,6 +287,74 @@ template<> struct type_caster<std::experimental::nullopt_t> : public void_caster<std::experimental::nullopt_t> {}; #endif +/// Visit a variant and cast any found type to Python +struct variant_caster_visitor { + return_value_policy policy; + handle parent; + + using result_type = handle; // required by boost::variant in C++11 + + template <typename T> + result_type operator()(T &&src) const { + return make_caster<T>::cast(std::forward<T>(src), policy, parent); + } +}; + +/// Helper class which abstracts away variant's `visit` function. `std::variant` and similar +/// `namespace::variant` types which provide a `namespace::visit()` function are handled here +/// automatically using argument-dependent lookup. Users can provide specializations for other +/// variant-like classes, e.g. `boost::variant` and `boost::apply_visitor`. +template <template<typename...> class Variant> +struct visit_helper { + template <typename... Args> + static auto call(Args &&...args) -> decltype(visit(std::forward<Args>(args)...)) { + return visit(std::forward<Args>(args)...); + } +}; + +/// Generic variant caster +template <typename Variant> struct variant_caster; + +template <template<typename...> class V, typename... Ts> +struct variant_caster<V<Ts...>> { + static_assert(sizeof...(Ts) > 0, "Variant must consist of at least one alternative."); + + template <typename U, typename... Us> + bool load_alternative(handle src, bool convert, type_list<U, Us...>) { + auto caster = make_caster<U>(); + if (caster.load(src, convert)) { + value = cast_op<U>(caster); + return true; + } + return load_alternative(src, convert, type_list<Us...>{}); + } + + bool load_alternative(handle, bool, type_list<>) { return false; } + + bool load(handle src, bool convert) { + // Do a first pass without conversions to improve constructor resolution. + // E.g. `py::int_(1).cast<variant<double, int>>()` needs to fill the `int` + // slot of the variant. Without two-pass loading `double` would be filled + // because it appears first and a conversion is possible. + if (convert && load_alternative(src, false, type_list<Ts...>{})) + return true; + return load_alternative(src, convert, type_list<Ts...>{}); + } + + template <typename Variant> + static handle cast(Variant &&src, return_value_policy policy, handle parent) { + return visit_helper<V>::call(variant_caster_visitor{policy, parent}, + std::forward<Variant>(src)); + } + + using Type = V<Ts...>; + PYBIND11_TYPE_CASTER(Type, _("Union[") + detail::concat(make_caster<Ts>::name()...) + _("]")); +}; + +#ifdef PYBIND11_HAS_VARIANT +template <typename... Ts> +struct type_caster<std::variant<Ts...>> : variant_caster<std::variant<Ts...>> { }; +#endif NAMESPACE_END(detail) inline std::ostream &operator<<(std::ostream &os, const handle &obj) { @@ -269,7 +362,7 @@ inline std::ostream &operator<<(std::ostream &os, const handle &obj) { return os; } -NAMESPACE_END(pybind11) +NAMESPACE_END(PYBIND11_NAMESPACE) #if defined(_MSC_VER) #pragma warning(pop) |