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#pragma once
#include <util/generic/ptr.h>
#include <functional>
#include <utility>
namespace NYql {
template <class T>
class TLazyInitHolder
: public TPointerBase<TLazyInitHolder<T>, T>
{
public:
using TFactory = std::function<THolder<T>()>;
TLazyInitHolder(TFactory&& factory)
: Factory_(std::move(factory))
{
}
T* Get() const noexcept {
if (!Value_) {
Value_ = Factory_();
}
return Value_.Get();
}
inline explicit operator bool() const noexcept {
return !!Value_.Get();
}
private:
TFactory Factory_;
mutable THolder<T> Value_;
};
} // NYql
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