Делегаты на C++

Шаргин Александр

class C_STATIC_DELEGATE: public I_DELEGATE‹TRet TEMPLATE_ARGS› {

public:

 typedef TRet (*PFunc)(PARAMS);

 C_STATIC_DELEGATE(PFunc pFunc) { m_pFunc = pFunc; }

 virtual TRet Invoke(PARAMS) { return m_pFunc(ARGS); }

 virtual bool Compare(I_DELEGATE‹TRet TEMPLATE_ARGS›* pDelegate) {

C_STATIC_DELEGATE‹TRet TEMPLATE_ARGS›* pStaticDel = dynamic_cast‹C_STATIC_DELEGATE‹TRet TEMPLATE_ARGS›*›(pDelegate);

if (pStaticDel == NULL || pStaticDel-›m_pFunc != m_pFunc) return false;

return true;

 }

private:

 PFunc m_pFunc;

};

template‹class TObj, class TRet TEMPLATE_PARAMS›

class C_METHOD_DELEGATE: public I_DELEGATE‹TRet TEMPLATE_ARGS› {

public:

 typedef TRet (TObj::*PMethod)(PARAMS);

 C_METHOD_DELEGATE(TObj* pObj, PMethod pMethod) {

m_pObj = pObj;

m_pMethod = pMethod;

 }

 virtual TRet Invoke(PARAMS) { return (m_pObj-›*m_pMethod)(ARGS); }

 virtual bool Compare(I_DELEGATE‹TRet TEMPLATE_ARGS›* pDelegate) {

C_METHOD_DELEGATE‹TObj, TRet TEMPLATE_ARGS›* pMethodDel = dynamic_cast‹C_METHOD_DELEGATE‹TObj, TRet TEMPLATE_ARGS›*›(pDelegate);

if (pMethodDel == NULL || pMethodDel-›m_pObj != m_pObj || pMethodDel-›m_pMethod != m_pMethod) { return false; }

return true;

 }

private:

 TObj *m_pObj;

 PMethod m_pMethod;

};

template‹class TRet TEMPLATE_PARAMS›

I_DELEGATE‹TRet TEMPLATE_ARGS›* NewDelegate(TRet (*pFunc)(PARAMS)) {

 return new C_STATIC_DELEGATE‹TRet TEMPLATE_ARGS›(pFunc);

}

template ‹class TObj, class TRet TEMPLATE_PARAMS›

I_DELEGATE‹TRet TEMPLATE_ARGS›* NewDelegate(TObj* pObj, TRet (TObj::*pMethod)(PARAMS)) {

 return new C_METHOD_DELEGATE‹TObj, TRet TEMPLATE_ARGS› (pObj, pMethod);

}

template‹class TRet TEMPLATE_PARAMS›

class C_DELEGATE {

public:

 typedef I_DELEGATE‹TRet TEMPLATE_ARGS› IDelegate;

 typedef std::list‹IDelegate*› DelegateList;

 C_DELEGATE(IDelegate* pDelegate = NULL) {

Add(pDelegate); }

 ~C_DELEGATE { RemoveAll; }

 bool IsNull { return (m_DelegateList.empty); }

 C_DELEGATE‹TRet TEMPLATE_ARGS›& operator=(IDelegate* pDelegate) {

RemoveAll;

Add(pDelegate);

return *this;

 }

 C_DELEGATE‹TRet TEMPLATE_ARGS›& operator+=(IDelegate* pDelegate) {

Add(pDelegate);

return *this;

 }

 C_DELEGATE‹TRet TEMPLATE_ARGS›& operator-=(IDelegate* pDelegate) {

Remove(pDelegate);

return *this;

 }

 TRet operator(PARAMS) {

return Invoke(ARGS);

 }

private:

 void Add(IDelegate* pDelegate) {

if(pDelegate != NULL) m_DelegateList.push_back(pDelegate);

 }

 void Remove(IDelegate* pDelegate) {

DelegateList::iterator it;

for(it = m_DelegateList.begin; it!= m_DelegateList.end; ++it) {

if((*it)-›Compare(pDelegate)) {

delete (*it);

m_DelegateList.erase(it);

break;

}

}

 }

 void RemoveAll {

DelegateList::iterator it;

for(it = m_DelegateList.begin; it!= m_DelegateList.end; ++it) delete (*it);

m_DelegateList.clear;

 }

 TRet Invoke(PARAMS) {

DelegateList::const_iterator it;

for (it = m_DelegateList.begin; it != --m_DelegateList.end; ++it) (*it)-›Invoke(ARGS);

return m_DelegateList.back-›Invoke(ARGS);

 }

private:

 DelegateList m_DelegateList;

};

Вынеся

обобщённый таким образом делегат в отдельный файл delegate_impl.h, мы можем сгенерировать его специализацию для любого количества параметров. Например, специализация делегата для пяти параметров получается так:

// 5 parameters…

#define SUFFIX 5

#define TEMPLATE_PARAMS \

, class TP1, class TP2, class TP3, class TP4, class TP5

#define TEMPLATE_ARGS , TP1, TP2, TP3, TP4, TP5