C++设计模式之代理模式

    {
        SAFE_DELETE(m_pRealSubject);
    }
 
    void Request()
    {
        if (NULL == m_pRealSubject)
        {
            m_pRealSubject = new CRealSubject();
        }
        cout<<"CProxy Request"<<endl;
        m_pRealSubject->Request();
    }
 
private:
    CRealSubject *m_pRealSubject;
};
 
int main()
{
    CSubject *pSubject = new CProxy();
    pSubject->Request();
    SAFE_DELETE(pSubject);
}

 

上面的实现，就是对代理模式的最原始体现，现在提供一个有血有肉的实际应用级的体现：

 

复制代码
#include <iostream>
#include <windows.h>
using namespace std;
 
#define SAFE_DELETE(p) if (p) { delete p; p = NULL; }
 
class KRefCount
{
public:
    KRefCount():m_nCount(0){}
 
public:
    unsigned AddRef(){ return InterlockedIncrement(&m_nCount); }
    unsigned Release(){ return InterlockedDecrement(&m_nCount); }
    void Reset(){ m_nCount = 0; }
 
private:
    unsigned long m_nCount;
};
 
template <typename T>
class SmartPtr
{
public:
    SmartPtr(void)
        : m_pData(NULL)
    {
        m_pReference = new KRefCount();
        m_pReference->AddRef();
    }
 
    SmartPtr(T* pValue)
        : m_pData(pValue)
    {
        m_pReference = new KRefCount();
        m_pReference->AddRef();
    }
 
    SmartPtr(const SmartPtr<T>& sp)
        : m_pData(sp.m_pData)
        , m_pReference(sp.m_pReference)
    {