pybind11/include/pybind11/stl.h
Dean Moldovan 3c4933cb50 Fix STL casters for containers with proxies (regression)
To avoid an ODR violation in the test suite while testing
both `stl.h` and `std_bind.h` with `std::vector<bool>`,
the `py::bind_vector<std::vector<bool>>` test is moved to
the secondary module (which does not include `stl.h`).
2017-09-10 12:25:10 +02:00

370 lines
13 KiB
C++

/*
pybind11/stl.h: Transparent conversion for STL data types
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#pragma once
#include "pybind11.h"
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <iostream>
#include <list>
#include <valarray>
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
#endif
#ifdef __has_include
// std::optional (but including it in c++14 mode isn't allowed)
# if defined(PYBIND11_CPP17) && __has_include(<optional>)
# include <optional>
# define PYBIND11_HAS_OPTIONAL 1
# endif
// std::experimental::optional (but not allowed in c++11 mode)
# if defined(PYBIND11_CPP14) && __has_include(<experimental/optional>)
# include <experimental/optional>
# 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)
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>;
bool load(handle src, bool convert) {
if (!isinstance<pybind11::set>(src))
return false;
auto s = reinterpret_borrow<pybind11::set>(src);
value.clear();
for (auto entry : s) {
key_conv conv;
if (!conv.load(entry, convert))
return false;
value.insert(cast_op<Key &&>(std::move(conv)));
}
return true;
}
template <typename T>
static handle cast(T &&src, return_value_policy policy, handle parent) {
pybind11::set s;
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();
}
return s.release();
}
PYBIND11_TYPE_CASTER(type, _("Set[") + key_conv::name() + _("]"));
};
template <typename Type, typename Key, typename Value> struct map_caster {
using key_conv = make_caster<Key>;
using value_conv = make_caster<Value>;
bool load(handle src, bool convert) {
if (!isinstance<dict>(src))
return false;
auto d = reinterpret_borrow<dict>(src);
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 &&>(std::move(kconv)), cast_op<Value &&>(std::move(vconv)));
}
return true;
}
template <typename T>
static handle cast(T &&src, return_value_policy policy, handle parent) {
dict d;
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;
}
return d.release();
}
PYBIND11_TYPE_CASTER(Type, _("Dict[") + key_conv::name() + _(", ") + value_conv::name() + _("]"));
};
template <typename Type, typename Value> struct list_caster {
using value_conv = make_caster<Value>;
bool load(handle src, bool convert) {
if (!isinstance<sequence>(src))
return false;
auto s = reinterpret_borrow<sequence>(src);
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 &&>(std::move(conv)));
}
return true;
}
private:
template <typename T = Type,
enable_if_t<std::is_same<decltype(std::declval<T>().reserve(0)), void>::value, int> = 0>
void reserve_maybe(sequence s, Type *) { value.reserve(s.size()); }
void reserve_maybe(sequence, void *) { }
public:
template <typename T>
static handle cast(T &&src, return_value_policy policy, handle parent) {
list l(src.size());
size_t index = 0;
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
}
return l.release();
}
PYBIND11_TYPE_CASTER(Type, _("List[") + value_conv::name() + _("]"));
};
template <typename Type, typename Alloc> struct type_caster<std::vector<Type, Alloc>>
: list_caster<std::vector<Type, Alloc>, Type> { };
template <typename Type, typename Alloc> struct type_caster<std::list<Type, Alloc>>
: list_caster<std::list<Type, Alloc>, Type> { };
template <typename ArrayType, typename Value, bool Resizable, size_t Size = 0> struct array_caster {
using value_conv = make_caster<Value>;
private:
template <bool R = Resizable>
bool require_size(enable_if_t<R, size_t> size) {
if (value.size() != size)
value.resize(size);
return true;
}
template <bool R = Resizable>
bool require_size(enable_if_t<!R, size_t> size) {
return size == Size;
}
public:
bool load(handle src, bool convert) {
if (!isinstance<list>(src))
return false;
auto l = reinterpret_borrow<list>(src);
if (!require_size(l.size()))
return false;
size_t ctr = 0;
for (auto it : l) {
value_conv conv;
if (!conv.load(it, convert))
return false;
value[ctr++] = cast_op<Value &&>(std::move(conv));
}
return true;
}
template <typename T>
static handle cast(T &&src, return_value_policy policy, handle parent) {
list l(src.size());
size_t index = 0;
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
}
return l.release();
}
PYBIND11_TYPE_CASTER(ArrayType, _("List[") + value_conv::name() + _<Resizable>(_(""), _("[") + _<Size>() + _("]")) + _("]"));
};
template <typename Type, size_t Size> struct type_caster<std::array<Type, Size>>
: array_caster<std::array<Type, Size>, Type, false, Size> { };
template <typename Type> struct type_caster<std::valarray<Type>>
: array_caster<std::valarray<Type>, Type, true> { };
template <typename Key, typename Compare, typename Alloc> struct type_caster<std::set<Key, Compare, Alloc>>
: set_caster<std::set<Key, Compare, Alloc>, Key> { };
template <typename Key, typename Hash, typename Equal, typename Alloc> struct type_caster<std::unordered_set<Key, Hash, Equal, Alloc>>
: set_caster<std::unordered_set<Key, Hash, Equal, Alloc>, Key> { };
template <typename Key, typename Value, typename Compare, typename Alloc> struct type_caster<std::map<Key, Value, Compare, Alloc>>
: map_caster<std::map<Key, Value, Compare, Alloc>, Key, Value> { };
template <typename Key, typename Value, typename Hash, typename Equal, typename Alloc> struct type_caster<std::unordered_map<Key, Value, Hash, Equal, Alloc>>
: map_caster<std::unordered_map<Key, Value, Hash, Equal, Alloc>, Key, Value> { };
// This type caster is intended to be used for std::optional and std::experimental::optional
template<typename T> struct optional_caster {
using value_conv = make_caster<typename T::value_type>;
template <typename T_>
static handle cast(T_ &&src, return_value_policy policy, handle parent) {
if (!src)
return none().inc_ref();
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()) {
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 &&>(std::move(inner_caster)));
return true;
}
PYBIND11_TYPE_CASTER(T, _("Optional[") + value_conv::name() + _("]"));
};
#if PYBIND11_HAS_OPTIONAL
template<typename T> struct type_caster<std::optional<T>>
: public optional_caster<std::optional<T>> {};
template<> struct type_caster<std::nullopt_t>
: public void_caster<std::nullopt_t> {};
#endif
#if PYBIND11_HAS_EXP_OPTIONAL
template<typename T> struct type_caster<std::experimental::optional<T>>
: public optional_caster<std::experimental::optional<T>> {};
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()...) + _("]"));
};
#if 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) {
os << (std::string) str(obj);
return os;
}
NAMESPACE_END(PYBIND11_NAMESPACE)
#if defined(_MSC_VER)
#pragma warning(pop)
#endif