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#include <library/cpp/testing/gtest/gtest.h>
#include <library/cpp/yt/memory/exact_ref_counted_cast.h>
#include <library/cpp/yt/memory/new.h>
#include <library/cpp/yt/memory/ref_counted.h>
#include <type_traits>
#include <typeinfo>
namespace NYT {
namespace {
////////////////////////////////////////////////////////////////////////////////
struct TBase
: public TRefCounted
{ };
struct TDerived
: public TBase
{
int Tag = 42;
};
struct TMoreDerived
: public TDerived
{ };
////////////////////////////////////////////////////////////////////////////////
// Pointer form.
TEST(TExactRefCountedCastTest, ExactMatch)
{
auto object = New<TDerived>();
TBase* base = object.Get();
EXPECT_EQ(ExactRefCountedCast<TDerived>(base), object.Get());
EXPECT_EQ(ExactRefCountedCast<TDerived>(base)->Tag, 42);
}
TEST(TExactRefCountedCastTest, SubclassDoesNotMatch)
{
auto object = New<TMoreDerived>();
TBase* base = object.Get();
// Object was New<TMoreDerived>(); an exact probe for TDerived must miss.
EXPECT_EQ(ExactRefCountedCast<TDerived>(base), nullptr);
// ...but the exact type matches.
EXPECT_EQ(ExactRefCountedCast<TMoreDerived>(base), object.Get());
}
TEST(TExactRefCountedCastTest, BaseDoesNotMatch)
{
auto object = New<TDerived>();
TBase* base = object.Get();
// It is exactly a TDerived, not a TBase.
EXPECT_EQ(ExactRefCountedCast<TBase>(base), nullptr);
}
TEST(TExactRefCountedCastTest, Null)
{
TBase* base = nullptr;
EXPECT_EQ(ExactRefCountedCast<TDerived>(base), nullptr);
}
TEST(TExactRefCountedCastTest, ConstnessPreserved)
{
auto object = New<TDerived>();
const TBase* base = object.Get();
auto* result = ExactRefCountedCast<TDerived>(base);
static_assert(std::is_same_v<decltype(result), const TDerived*>);
EXPECT_EQ(result, object.Get());
}
////////////////////////////////////////////////////////////////////////////////
// Reference form.
TEST(TExactRefCountedCastTest, RefExactMatch)
{
auto object = New<TDerived>();
TBase& base = *object;
EXPECT_EQ(&ExactRefCountedCast<TDerived>(base), object.Get());
}
TEST(TExactRefCountedCastTest, RefSubclassThrows)
{
auto object = New<TMoreDerived>();
TBase& base = *object;
EXPECT_THROW((void)ExactRefCountedCast<TDerived>(base), std::bad_cast);
EXPECT_EQ(&ExactRefCountedCast<TMoreDerived>(base), object.Get());
}
TEST(TExactRefCountedCastTest, RefConstnessPreserved)
{
auto object = New<TDerived>();
const TBase& base = *object;
static_assert(std::is_same_v<decltype(ExactRefCountedCast<TDerived>(base)), const TDerived&>);
EXPECT_EQ(&ExactRefCountedCast<TDerived>(base), object.Get());
}
////////////////////////////////////////////////////////////////////////////////
} // namespace
} // namespace NYT
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