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#pragma once
#include "hazard_ptr.h"
#include "intrusive_ptr.h"
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
// Overload for TIntrusivePtr<T> MakeStrong(T* p).
template <class T>
TIntrusivePtr<T> MakeStrong(const THazardPtr<T>& ptr);
////////////////////////////////////////////////////////////////////////////////
//! Holds an atomic pointer to an instance of ref-counted type |T| enabling concurrent
//! read and write access.
template <class T, bool EnableAcquireHazard = false>
class TAtomicPtr
{
public:
TAtomicPtr() = default;
TAtomicPtr(std::nullptr_t);
explicit TAtomicPtr(TIntrusivePtr<T> other);
TAtomicPtr(TAtomicPtr&& other);
~TAtomicPtr();
TAtomicPtr& operator=(TIntrusivePtr<T> other);
TAtomicPtr& operator=(std::nullptr_t);
void Reset();
//! Acquires a hazard pointer.
/*!
*
* Returning a hazard pointer avoids contention on ref-counter in read-heavy scenarios.
* The user, however, must not keep this hazard pointer alive for longer
* than needed. Currently there are limits on the number of HPs that a thread
* may concurrently maintain.
*/
THazardPtr<T> AcquireHazard() const;
//! Attempts to acquire an intrusive pointer.
//! May return null in case of a race.
TIntrusivePtr<T> AcquireWeak() const;
//! Acquires an intrusive pointer.
TIntrusivePtr<T> Acquire() const;
TAtomicPtr<T, EnableAcquireHazard> Exchange(TIntrusivePtr<T> other);
void Store(TIntrusivePtr<T> other);
TAtomicPtr<T, EnableAcquireHazard> SwapIfCompare(THazardPtr<T>& compare, TIntrusivePtr<T> target);
bool SwapIfCompare(T* comparePtr, TIntrusivePtr<T> target);
bool SwapIfCompare(const TIntrusivePtr<T>& compare, TIntrusivePtr<T> target);
bool SwapIfCompare(const TIntrusivePtr<T>& compare, TIntrusivePtr<T>* target);
explicit operator bool() const;
private:
explicit TAtomicPtr(T* ptr);
template <class T_, bool EnableAcquireHazard_>
friend bool operator==(const TAtomicPtr<T_, EnableAcquireHazard_>& lhs, const TIntrusivePtr<T_>& rhs);
template <class T_, bool EnableAcquireHazard_>
friend bool operator==(const TIntrusivePtr<T_>& lhs, const TAtomicPtr<T_, EnableAcquireHazard_>& rhs);
std::atomic<T*> Ptr_ = nullptr;
THazardPtr<T> DoAcquireHazard() const;
void Drop(T* ptr);
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
#define ATOMIC_PTR_INL_H_
#include "atomic_ptr-inl.h"
#undef ATOMIC_PTR_INL_H_
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