IUnknown

与CUnKnow相类似的是IUnknown，其定义如下：

#undef INTERFACE
#define INTERFACE IUnknown
DECLARE_INTERFACE(IUnknown)
{
    STDMETHOD_(NTSTATUS,QueryInterface)
    (   THIS_
        _In_            REFIID,
        _COM_Outptr_    PVOID *
    )   PURE;

    STDMETHOD_(ULONG,AddRef)
    (   THIS
    )   PURE;

    STDMETHOD_(ULONG,Release)
    (   THIS
    )   PURE;
};
#undef INTERFACE

typedef IUnknown *PUNKNOWN;

和CUnKnow一样，其只是一个结构体，其包括三个函数：

#define DECLARE_INTERFACE(iface)    interface DECLSPEC_NOVTABLE iface

而这与CUnknown::m_pUnknownOuter成员DECLARE_STD_UNKNOWN与之相对应。

CUnknown::m_pUnknownOuter成员

默认CUnknown构造为NULL时，使用的是NonDelegating_XX系列函数。但如果不为NULL时，则使用

#define DECLARE_STD_UNKNOWN()                                   \
    STDMETHODIMP_(NTSTATUS) NonDelegatingQueryInterface         \
        (                                                       \
                _In_            REFIID          iid,            \
                _COM_Outptr_    PVOID *     ppvObject           \
        );                                                      \
    STDMETHODIMP_(NTSTATUS) QueryInterface(_In_ REFIID riid, _COM_Outptr_ void **ppv)        \
    {                                                           \
        return GetOuterUnknown()->QueryInterface(riid,ppv);     \
    };                                                          \
    STDMETHODIMP_(ULONG) AddRef()                               \
    {                                                           \
        return GetOuterUnknown()->AddRef();                     \
    };                                                          \
    STDMETHODIMP_(ULONG) Release()                              \
    {                                                           \
        return GetOuterUnknown()->Release();                    \
    };

如对于电源类：

class AdapterPowerMgr: 
     public IAdapterPowerManagement,
     public CUnknown
{

public:
    // Default CUnknown
    DECLARE_STD_UNKNOWN();                          //定义Delegating
    AdapterPowerMgr( PUNKNOWN pUnknownOuter);
    ~AdapterPowerMgr();
};

其实PortClass提供的几个MINI端口驱动我们在创建我们的适配器端口驱动时，都是以这种方式实现：

• WaveCyclic

  class WaveCyclic:
     public IMiniportWaveCyclic,
     public CUnknown
  {
  public:
    ////
    DECLARE_STD_UNKNOWN();                          //定义Delegating
    WaveCyclic( PUNKNOWN pUnknownOuter); 
    ~WaveCyclic();
  }
  

• WaveStream

class WaveStream:
     public IMiniportWaveCyclicStream,
     public IDmaChannel,
     public CUnknown
{
public:
    ///
    DECLARE_STD_UNKNOWN();                         //定义Delegating
    WaveStream( PUNKNOWN pUnknownOuter);
    ~WaveStream();

• Topology

class Topology:
    public IMiniportTopology,
    public CUnknown
{

public:
    /////
    DECLARE_STD_UNKNOWN();                     //定义Delegating
    Topology( PUNKNOWN pUnknownOuter); 
    ~Topology();