CWE-ou-minkata/Sources/Plasma/CoreLib/hsRefCnt.h

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*==LICENSE==*/
#ifndef hsRefCnt_Defiend
#define hsRefCnt_Defiend

#include <atomic>

class hsRefCnt {
private:
    std::atomic<int> fRefCnt;

public:
                hsRefCnt(int initRefs = 1);
    virtual     ~hsRefCnt();

    inline int  RefCnt() const { return fRefCnt; }
    void        UnRef(const char* tag = nullptr);
    void        Ref(const char* tag = nullptr);

    // Useless, but left here for debugging compatibility with AtomicRef
    void        TransferRef(const char* oldTag, const char* newTag);


    // The stored reference count of an hsRefCnt-derived object should never
    // be copied! Therefore, if you want a copyable hsRefCnt-based class, you
    // should implement your own copy constructor / assignment operator.
    hsRefCnt(const hsRefCnt &) = delete;
    hsRefCnt &operator=(const hsRefCnt &) = delete;
};

#define hsRefCnt_SafeRef(obj)   do { if (obj) (obj)->Ref(); } while (0)
#define hsRefCnt_SafeUnRef(obj) do { if (obj) (obj)->UnRef(); } while (0)

#define hsRefCnt_SafeAssign(dst, src)   \
        do {                            \
            hsRefCnt_SafeRef(src);      \
            hsRefCnt_SafeUnRef(dst);    \
            dst = src;                  \
        } while (0)


template <class _Ref>
class hsRef
{
public:
    hsRef() : fObj(nullptr) { }
    hsRef(nullptr_t) : fObj(nullptr) { }
    hsRef(_Ref *obj) : fObj(obj) { if (fObj) fObj->Ref(); }
    hsRef(const hsRef<_Ref> &copy) : fObj(copy.fObj) { if (fObj) fObj->Ref(); }
    hsRef(hsRef<_Ref> &&move) : fObj(move.fObj) { move.fObj = nullptr; }

    ~hsRef() { if (fObj) fObj->UnRef(); }

    hsRef<_Ref> &operator=(_Ref *obj)
    {
        if (obj)
            obj->Ref();
        if (fObj)
            fObj->UnRef();
        fObj = obj;
        return *this;
    }
    hsRef<_Ref> &operator=(const hsRef<_Ref> &copy) { return operator=(copy.fObj); }

    hsRef<_Ref> &operator=(hsRef<_Ref> &&move)
    {
        if (fObj)
            fObj->UnRef();
        fObj = move.fObj;
        move.fObj = nullptr;
        return *this;
    }

    hsRef<_Ref> &operator=(nullptr_t)
    {
        if (fObj)
            fObj->UnRef();
        fObj = nullptr;
        return *this;
    }

    bool operator==(const hsRef<_Ref> &other) const { return fObj == other.fObj; }
    bool operator!=(const hsRef<_Ref> &other) const { return fObj != other.fObj; }
    bool operator> (const hsRef<_Ref> &other) const { return fObj >  other.fObj; }
    bool operator< (const hsRef<_Ref> &other) const { return fObj <  other.fObj; }
    bool operator>=(const hsRef<_Ref> &other) const { return fObj >= other.fObj; }
    bool operator<=(const hsRef<_Ref> &other) const { return fObj <= other.fObj; }
    bool operator==(_Ref *other) const { return fObj == other; }
    bool operator!=(_Ref *other) const { return fObj != other; }

    _Ref &operator*() const { return *fObj; }
    _Ref *const operator->() const { return fObj; }
    operator _Ref *const() const { return fObj; }

private:
    _Ref *fObj;
};

#endif