Делегаты на C++, Шаргин Александр

Делегаты на C++

на обложку

Шаргин Александр

Шрифт:

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

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