MFC로 Aggregation 구현하기

DECLARE_INTERFACE_(ISimpleCal, IUnknown)
{   
    STDMETHOD_(int, Sum)() PURE;   
    STDMETHOD_(int, Sub)() PURE;
};

DECLARE_INTERFACE_(IRadius, IUnknown)
{   
    STDMETHOD(Radius)(int x, int y, double* z) PURE;
};


#include "Interface.h"

class CSimpleCal2 : public CCmdTarget
{
...
// Attributes
public:
    IUnknown* m_pAgrUnknown;
...
// Implementation
protected:
    virtual BOOL OnCreateAggregates();
    virtual ~CSimpleCal2();

    BEGIN_INTERFACE_PART(CInnerSimpleCal2, IRadius)
        STDMETHOD(Radius)(int x, int y, double* z);
    END_INTERFACE_PART(CInnerSimpleCal2)

    DECLARE_INTERFACE_MAP()
...
};


#include "SpcAgr1.h"
...
BEGIN_INTERFACE_MAP(CSimpleCal2, CCmdTarget)
   INTERFACE_PART(CSimpleCal2, IID_IRadius, CInnerSimpleCal2)
   INTERFACE_AGGREGATE(CSimpleCal2, m_pAgrUnknown)
END_INTERFACE_MAP()

CSimpleCal2::CSimpleCal2() : m_pAgrUnknown(NULL)
{
// {
    EnableAggregation();
// }
    AfxOleLockApp();
}

CSimpleCal2::~CSimpleCal2()
{
// {
    if (m_pAgrUnknown)
    {
        m_pAgrUnknown->Release();
        m_pAgrUnknown = NULL;
    }
// }
    AfxOleUnlockApp();
}

BOOL CSimpleCal2::OnCreateAggregates()
{
    HRESULT hr;

    hr = CoCreateInstance(SPC_COMPONENT,
                            GetControllingUnknown(),
                            CLSCTX_INPROC_SERVER,
                            IID_IUnknown,
                            (LPVOID*) &m_pAgrUnknown);
    if(FAILED(hr))
    {
//        AfxMessageBox("내부 컴포넌트 생성에 실패");
        return FALSE;
    }

    return TRUE;
}
...

STDMETHODIMP
CSimpleCal2::XCInnerSimpleCal2::Radius(int x, int y, double* z)   
{   
    int x2, y2, z2;
    HRESULT hr;

    METHOD_PROLOGUE(CSimpleCal2, CInnerSimpleCal2)
   
    ISimpleCal* pISc = NULL;

    hr = pThis->m_pAgrUnknown->QueryInterface(IID_ISimpleCal, (void**)&pISc);

    pISc->Sum();
    *z = sqrt(z2);

//    pThis->m_pAgrUnknown->Release(); ??

    return S_OK;    
}


DECLARE_INTERFACE_(ISimpleCal, IUnknown)
{   
    STDMETHOD_(int, Sum)() PURE;   
    STDMETHOD_(int, Sub)() PURE;
};

CSimpleCalc::CSimpleCalc()
{
// {
    EnableAggregation();
// }
...
   AfxOleLockApp();
}