www.pudn.com > COM技术内幕配书源码.rar > REFCOUNT.CPP

// 
// RefCount.cpp 
// To compile, use: cl RefCount.cpp UUID.lib 
// 
#include  
#include  
 
void trace(const char* msg) { cout << msg << endl ;} 
 
// Forward references for GUIDs 
extern const IID IID_IX ; 
extern const IID IID_IY ; 
extern const IID IID_IZ ; 
 
// Interfaces 
interface IX : IUnknown 
{ 
	virtual void __stdcall Fx() = 0 ; 
} ; 
 
interface IY : IUnknown 
{ 
	virtual void __stdcall Fy() = 0 ; 
} ; 
 
interface IZ : IUnknown 
{ 
	virtual void __stdcall Fz() = 0 ; 
} ; 
 
 
// 
// Component 
// 
class CA : public IX, 
           public IY 
{ 
	// IUnknown implementation 
	virtual HRESULT __stdcall QueryInterface(const IID& iid, void** ppv) ;			 
	virtual ULONG __stdcall AddRef() ; 
	virtual ULONG __stdcall Release() ; 
 
	// Interface IX implementation 
	virtual void __stdcall Fx() { cout << "Fx" << endl ;} 
 
	// Interface IY implementation 
	virtual void __stdcall Fy() { cout << "Fy" << endl ;} 
 
public: 
	// Constructor 
	CA() : m_cRef(0) {} 
 
	// Destructor 
	~CA() { trace("CA:     Destroy self.") ;} 
 
private: 
	long m_cRef; 
} ; 
 
HRESULT __stdcall CA::QueryInterface(const IID& iid, void** ppv) 
{ 	 
	if (iid == IID_IUnknown) 
	{ 
		trace("CA QI:  Return pointer to IUnknown.") ; 
		*ppv = static_cast(this) ; 
	}  
	else if (iid == IID_IX) 
	{ 
		trace("CA QI:  Return pointer to IX.") ; 
		*ppv = static_cast(this) ; 
	} 
	else if (iid == IID_IY) 
	{ 
		trace("CA QI:  Return pointer to IY.") ; 
		*ppv = static_cast(this) ; 
	} 
	else 
	{  	    
		trace("CA QI:  Interface not supported.") ; 
		*ppv = NULL ; 
		return E_NOINTERFACE; 
	} 
	reinterpret_cast(*ppv)->AddRef() ;  
	return S_OK ; 
} 
 
ULONG __stdcall CA::AddRef() 
{ 
	cout << "CA:     AddRef = " << m_cRef+1 << '.' << endl ; 
	return InterlockedIncrement(&m_cRef) ; 
} 
 
ULONG __stdcall CA::Release()  
{ 
	cout << "CA:     Release = " << m_cRef-1 << '.' << endl ; 
 
	if (InterlockedDecrement(&m_cRef) == 0) 
	{ 
		delete this ; 
		return 0 ; 
	} 
	return m_cRef ; 
} 
 
// 
// Creation function 
// 
IUnknown* CreateInstance() 
{ 
	IUnknown* pI = static_cast(new CA) ; 
	pI->AddRef() ; 
	return pI ; 
} 
 
// 
// IIDs 
// 
// {32bb8320-b41b-11cf-a6bb-0080c7b2d682} 
static const IID IID_IX =  
	{0x32bb8320, 0xb41b, 0x11cf, 
	{0xa6, 0xbb, 0x0, 0x80, 0xc7, 0xb2, 0xd6, 0x82}} ; 
 
// {32bb8321-b41b-11cf-a6bb-0080c7b2d682} 
static const IID IID_IY =  
	{0x32bb8321, 0xb41b, 0x11cf, 
	{0xa6, 0xbb, 0x0, 0x80, 0xc7, 0xb2, 0xd6, 0x82}} ; 
 
// {32bb8322-b41b-11cf-a6bb-0080c7b2d682} 
static const IID IID_IZ =  
	{0x32bb8322, 0xb41b, 0x11cf, 
	{0xa6, 0xbb, 0x0, 0x80, 0xc7, 0xb2, 0xd6, 0x82}} ; 
 
// 
// Client 
// 
int main() 
{ 
	HRESULT hr ; 
 
	trace("Client: Get an IUnknown pointer.") ; 
	IUnknown* pIUnknown = CreateInstance() ; 
 
 
	trace("Client: Get interface IX.") ; 
 
	IX* pIX = NULL ;  
	hr = pIUnknown->QueryInterface(IID_IX, (void**)&pIX) ; 
 
	if (SUCCEEDED(hr)) 
	{ 
		trace("Client: Succeeded getting IX.") ; 
		pIX->Fx() ;          // Use interface IX. 
		pIX->Release() ; 
	} 
 
 
	trace("Client: Get interface IY.") ; 
 
	IY* pIY = NULL ; 
	hr = pIUnknown->QueryInterface(IID_IY, (void**)&pIY) ; 
	if (SUCCEEDED(hr)) 
	{ 
		trace("Client: Succeeded getting IY.") ; 
		pIY->Fy() ;          // Use interface IY. 
		pIY->Release() ; 
	} 
 
 
	trace("Client: Ask for an unsupported interface.") ; 
 
	IZ* pIZ = NULL ; 
	hr = pIUnknown->QueryInterface(IID_IZ, (void**)&pIZ) ; 
	if (SUCCEEDED(hr)) 
	{ 
		trace("Client: Succeeded in getting interface IZ.") ; 
		pIZ->Fz() ; 
		pIZ->Release() ; 
	} 
	else 
	{ 
		trace("Client: Could not get interface IZ.") ; 
	} 
 
 
	trace("Client: Release IUnknown interface.") ; 
	pIUnknown->Release() ; 
 
	return 0; 
}