// XDWHolder.tlh
//

#pragma once


template <typename T> class XDWHolder
{
	typedef T __BASE;

private:
	struct MetaData
	{
		long	nRefs;				// reference count
	};

protected:
	T			* m_pObject;
	MetaData    * m_pMetaData;

public:
	XDWHolder ();
	explicit XDWHolder (T * object);
	XDWHolder (const XDWHolder & h);
	XDWHolder (XDWHolder && h);

	virtual ~XDWHolder ();

public:
	void Attach (T * object);
	T * Detach ();

	// real copy from another XDWHolder
	void CopyFrom (const XDWHolder & h);
	// ref-counted copy from another XDWHolder
	void ShadowCopyFrom (const XDWHolder & h);

	XDWHolder & operator = (const XDWHolder & h);

	XDWHolder & operator = (T * object);

	operator bool () const;
	operator T * ();
	operator const T * () const;

	// Allow usage as a pointer	
	T * operator -> () 
	{
		return m_pObject;
	}

	const T * operator -> ()  const
	{
		return m_pObject;
	}

	inline bool operator == (const XDWHolder & holder) const
	{
		return m_pObject == holder.m_pObject;
	}

	inline bool operator != (const XDWHolder & holder) const
	{
		return m_pObject != holder.m_pObject;
	}

	T * As ()
	{
		return m_pObject;
	}

	const T * As () const
	{
		return m_pObject;
	}

	template <typename C> C * AS ()
	{
		return (C *) m_pObject;
	}

	template <typename C> const C * AS () const
	{
		return (const C *) m_pObject;
	}

	bool IsEmpty () const;

	void Release ();

protected:
	inline MetaData * GetData() const
	{
		return m_pMetaData;
	}

protected:
	void Init ();

	virtual T * NewObject (const T * fromObject) const;
};