COMPtr #2

template<typename Interface>
class COMPtr {
private:
    Interface * mInterface;
public:
    COMPtr() {
        mInterface = nullptr;
    }

    // for Direct3DCreate9
    void Set( Interface * iface ) {
        mInterface = iface;
    }

    ~COMPtr() {
        if( mInterface ) {
            mInterface->Release();
        }
    }

    inline Interface ** operator & () {
        return &mInterface;
    }

    inline Interface * operator -> () {
        return mInterface;
    }

    operator Interface* () {
        return mInterface;
    }

    Interface * operator = ( Interface * iface ) {
        iface->AddRef();
        mInterface = iface;
        return mInterface;
    }
};