xref: /xnu-11417.121.6/tests/intrusive_shared_ptr_src/cast.reinterpret.cpp (revision a1e26a70f38d1d7daa7b49b258e2f8538ad81650)

//
// Tests for
//  template<typename To, typename From, typename R>
//  intrusive_shared_ptr<To, R> reinterpret_pointer_cast(intrusive_shared_ptr<From, R> const& ptr) noexcept;
//
//  template<typename To, typename From, typename R>
//  intrusive_shared_ptr<To, R> reinterpret_pointer_cast(intrusive_shared_ptr<From, R>&& ptr) noexcept
//

#include <libkern/c++/intrusive_shared_ptr.h>
#include <utility>
#include <darwintest.h>
#include "test_policy.h"

struct Base { int i; };
struct Derived : Base { };

// Layout compatible with Derived
struct Unrelated { int i; };

template <typename Stored, typename From, typename To>
static void
tests()
{
	Stored obj{3};

	{
		tracked_shared_ptr<From> const from(&obj, libkern::no_retain);
		tracking_policy::reset();
		tracked_shared_ptr<To> to = libkern::reinterpret_pointer_cast<To>(from);
		CHECK(tracking_policy::retains == 1);
		CHECK(tracking_policy::releases == 0);
		CHECK(to.get() == reinterpret_cast<To const*>(&obj));
		CHECK(from.get() == &obj);
	}
	{
		tracked_shared_ptr<From> from(&obj, libkern::no_retain);
		tracking_policy::reset();
		tracked_shared_ptr<To> to = libkern::reinterpret_pointer_cast<To>(std::move(from));
		CHECK(tracking_policy::retains == 0);
		CHECK(tracking_policy::releases == 0);
		CHECK(to.get() == reinterpret_cast<To const*>(&obj));
		CHECK(from.get() == nullptr);
	}

	// Test `reinterpret_pointer_cast`ing a null pointer
	{
		tracked_shared_ptr<From> const from = nullptr;
		tracking_policy::reset();
		tracked_shared_ptr<To> to = libkern::reinterpret_pointer_cast<To>(from);
		CHECK(tracking_policy::retains == 0);
		CHECK(tracking_policy::releases == 0);
		CHECK(to.get() == nullptr);
		CHECK(from.get() == nullptr);
	}
	{
		tracked_shared_ptr<From> from = nullptr;
		tracking_policy::reset();
		tracked_shared_ptr<To> to = libkern::reinterpret_pointer_cast<To>(std::move(from));
		CHECK(tracking_policy::retains == 0);
		CHECK(tracking_policy::releases == 0);
		CHECK(to.get() == nullptr);
		CHECK(from.get() == nullptr);
	}
}

T_DECL(cast_reinterpret, "intrusive_shared_ptr.cast.reinterpret", T_META_TAG_VM_PREFERRED) {
	tests</*stored*/ Derived, /*from*/ Derived, /*to*/ Base>();
	tests</*stored*/ Derived, /*from*/ Derived const, /*to*/ Base const>();

	tests</*stored*/ Derived, /*from*/ Derived, /*to*/ char>();
	tests</*stored*/ Derived, /*from*/ Derived const, /*to*/ char const>();

	tests</*stored*/ Derived, /*from*/ Derived, /*to*/ Unrelated>();
	tests</*stored*/ Derived, /*from*/ Derived const, /*to*/ Unrelated const>();
}