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#pragma once
#include <concepts>
#include <memory>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
constexpr size_t ErasedStorageMaxByteSize = 32;
////////////////////////////////////////////////////////////////////////////////
class TErasedStorage;
////////////////////////////////////////////////////////////////////////////////
template <class T>
concept CTriviallyErasable =
std::default_initializable<T> &&
std::is_trivially_destructible_v<T> &&
std::is_trivially_copyable_v<T> &&
(sizeof(T) <= ErasedStorageMaxByteSize) &&
(alignof(T) <= ErasedStorageMaxByteSize) &&
!std::is_reference_v<T> &&
!std::same_as<T, TErasedStorage>;
////////////////////////////////////////////////////////////////////////////////
// This class does not call dtor of erased object
// thus we require trivial destructability.
class TErasedStorage
{
public:
template <CTriviallyErasable TDecayedConcrete>
explicit TErasedStorage(TDecayedConcrete concrete) noexcept;
TErasedStorage(const TErasedStorage& other) = default;
TErasedStorage& operator=(const TErasedStorage& other) = default;
template <CTriviallyErasable TDecayedConcrete>
TDecayedConcrete& AsConcrete() & noexcept;
template <CTriviallyErasable TDecayedConcrete>
const TDecayedConcrete& AsConcrete() const & noexcept;
template <CTriviallyErasable TDecayedConcrete>
TDecayedConcrete&& AsConcrete() && noexcept;
private:
// NB(arkady-e1ppa): aligned_storage is deprecated.
alignas(ErasedStorageMaxByteSize) std::byte Bytes_[ErasedStorageMaxByteSize];
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
#define ERASED_STORAGE_INL_H_
#include "erased_storage-inl.h"
#undef ERASED_STORAGE_INL_H_
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