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#include "pybind11_tests.h"
#include <cstddef>
#include <memory>
#include <vector>
namespace test_class_sh_mi_thunks {
// For general background: https://shaharmike.com/cpp/vtable-part2/
// C++ vtables - Part 2 - Multiple Inheritance
// ... the compiler creates a 'thunk' method that corrects `this` ...
struct Base0 {
virtual ~Base0() = default;
Base0() = default;
Base0(const Base0 &) = delete;
};
struct Base1 {
virtual ~Base1() = default;
// Using `vector` here because it is known to make this test very sensitive to bugs.
std::vector<int> vec = {1, 2, 3, 4, 5};
Base1() = default;
Base1(const Base1 &) = delete;
};
struct Derived : Base1, Base0 {
~Derived() override = default;
Derived() = default;
Derived(const Derived &) = delete;
};
} // namespace test_class_sh_mi_thunks
TEST_SUBMODULE(class_sh_mi_thunks, m) {
using namespace test_class_sh_mi_thunks;
m.def("ptrdiff_drvd_base0", []() {
auto drvd = std::unique_ptr<Derived>(new Derived);
auto *base0 = dynamic_cast<Base0 *>(drvd.get());
return std::ptrdiff_t(reinterpret_cast<char *>(drvd.get())
- reinterpret_cast<char *>(base0));
});
py::classh<Base0>(m, "Base0");
py::classh<Base1>(m, "Base1");
py::classh<Derived, Base1, Base0>(m, "Derived");
m.def(
"get_drvd_as_base0_raw_ptr",
[]() {
auto *drvd = new Derived;
auto *base0 = dynamic_cast<Base0 *>(drvd);
return base0;
},
py::return_value_policy::take_ownership);
m.def("get_drvd_as_base0_shared_ptr", []() {
auto drvd = std::make_shared<Derived>();
auto base0 = std::dynamic_pointer_cast<Base0>(drvd);
return base0;
});
m.def("get_drvd_as_base0_unique_ptr", []() {
auto drvd = std::unique_ptr<Derived>(new Derived);
auto base0 = std::unique_ptr<Base0>(std::move(drvd));
return base0;
});
m.def("vec_size_base0_raw_ptr", [](const Base0 *obj) {
const auto *obj_der = dynamic_cast<const Derived *>(obj);
if (obj_der == nullptr) {
return std::size_t(0);
}
return obj_der->vec.size();
});
m.def("vec_size_base0_shared_ptr", [](const std::shared_ptr<Base0> &obj) -> std::size_t {
const auto obj_der = std::dynamic_pointer_cast<Derived>(obj);
if (!obj_der) {
return std::size_t(0);
}
return obj_der->vec.size();
});
m.def("vec_size_base0_unique_ptr", [](std::unique_ptr<Base0> obj) -> std::size_t {
const auto *obj_der = dynamic_cast<const Derived *>(obj.get());
if (obj_der == nullptr) {
return std::size_t(0);
}
return obj_der->vec.size();
});
}
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