C++实现委托机制之完整代码实现

头文件 MyDelegate.h 代码如下：

#pragma once#include <typeinfo.h>#include <list>#include <vector>namespace Delegate{// IDelegate   提供接口的基类template<typename ReturnType, typename ...ParamType>class IDelegate{public:IDelegate(){}virtual ~IDelegate(){}virtual bool isType(const std::type_info& _type) = 0;virtual ReturnType invoke(ParamType ... params) = 0;virtual bool compare(IDelegate<ReturnType, ParamType...> *_delegate) const = 0;};//StaticDelegate 普通函数的委托template<typename ReturnType, typename ...ParamType>class CStaticDelegate :public IDelegate<ReturnType, ParamType...>{public:typedef  ReturnType(*Func)(ParamType...);CStaticDelegate(Func _func) : mFunc(_func) { }virtual bool isType(const std::type_info& _type) { return typeid(CStaticDelegate<ReturnType, ParamType...>) == _type; }virtual ReturnType invoke(ParamType ... params) { return mFunc(params...); }virtual bool compare(IDelegate<ReturnType, ParamType ...> *_delegate)const{if (0 == _delegate || !_delegate->isType(typeid(CStaticDelegate<ReturnType, ParamType ...>))) return false;CStaticDelegate<ReturnType, ParamType ...> * cast = static_cast<CStaticDelegate<ReturnType, ParamType ...>*>(_delegate);return cast->mFunc == mFunc;}virtual ~CStaticDelegate(){}private:Func mFunc;};//普通函数的委托特化版本template<typename ReturnType, typename ...ParamType>class CStaticDelegate<ReturnType(*)(ParamType ...)> :public IDelegate<ReturnType, ParamType ...>{public://定义 Func 为 void (void) 函数类型指针。typedef  ReturnType(*Func)(ParamType...);CStaticDelegate(Func _func) : mFunc(_func) { }virtual bool isType(const std::type_info& _type) { return typeid(CStaticDelegate<ReturnType(*)(ParamType ...)>) == _type; }virtual ReturnType invoke(ParamType ... params) { return mFunc(params...); }virtual bool compare(IDelegate<ReturnType, ParamType ...> *_delegate)const{if (0 == _delegate || !_delegate->isType(typeid(CStaticDelegate<ReturnType(*)(ParamType ...)>))) return false;CStaticDelegate<ReturnType(*)(ParamType ...)> * cast = static_cast<CStaticDelegate<ReturnType(*)(ParamType ...)>*>(_delegate);return cast->mFunc == mFunc;}virtual ~CStaticDelegate(){}private:Func mFunc;};//成员函数委托template<typename T, typename ReturnType, typename ...ParamType>class CMethodDelegate :public IDelegate<ReturnType, ParamType...>{public:typedef ReturnType(T::*Method)(ParamType...);CMethodDelegate(T * _object, Method _method) : mObject(_object), mMethod(_method) { }virtual bool isType(const std::type_info& _type) { return typeid(CMethodDelegate<T, ReturnType, ParamType...>) == _type; }virtual ReturnType invoke(ParamType...params){(mObject->*mMethod)(params...);}virtual bool compare(IDelegate<ReturnType, ParamType...> *_delegate) const{if (0 == _delegate || !_delegate->isType(typeid(CMethodDelegate<ReturnType, ParamType...>))) return false;CMethodDelegate<ReturnType, ParamType...>* cast = static_cast<CMethodDelegate<ReturnType, ParamType...>*>(_delegate);return cast->mObject == mObject && cast->mMethod == mMethod;}CMethodDelegate(){}virtual ~CMethodDelegate(){}private:T * mObject;Method mMethod;};//成员函数委托特化template<typename T, typename ReturnType, typename ...ParamType>class CMethodDelegate<T,ReturnType (T:: *)(ParamType...)> :public IDelegate<ReturnType, ParamType...>{public:typedef ReturnType(T::*Method)(ParamType...);CMethodDelegate(T * _object, Method _method) : mObject(_object), mMethod(_method) { }virtual bool isType(const std::type_info& _type) { return typeid(CMethodDelegate<T,ReturnType(T:: *)(ParamType...)>) == _type; }virtual ReturnType invoke(ParamType...params){return (mObject->*mMethod)(params...);}virtual bool compare(IDelegate<ReturnType, ParamType...> *_delegate) const{if (0 == _delegate || !_delegate->isType(typeid(CMethodDelegate<T, ReturnType(T:: *)(ParamType...)>))) return false;CMethodDelegate<T, ReturnType(T:: *)(ParamType...)>* cast = static_cast<CMethodDelegate<T, ReturnType(T:: *)(ParamType...)>*>(_delegate);return cast->mObject == mObject && cast->mMethod == mMethod;}CMethodDelegate(){}virtual ~CMethodDelegate(){}private:T * mObject;Method mMethod;};//多播委托template<typename ReturnType, typename ...ParamType>class CMultiDelegate{public:typedef std::list<IDelegate<ReturnType, ParamType...>*> ListDelegate;typedef typename ListDelegate::iterator ListDelegateIterator;typedef typename ListDelegate::const_iterator ConstListDelegateIterator;CMultiDelegate() { }~CMultiDelegate() { clear(); }bool empty() const{for (ConstListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if (*iter) return false;}return true;}void clear(){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if (*iter){delete (*iter);(*iter) = nullptr;}}}CMultiDelegate<ReturnType, ParamType...>& operator+=(IDelegate<ReturnType, ParamType...>* _delegate){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if ((*iter) && (*iter)->compare(_delegate)){delete _delegate;return *this;}}mListDelegates.push_back(_delegate);return *this;}CMultiDelegate<ReturnType, ParamType...>& operator-=(IDelegate<ReturnType, ParamType...>* _delegate){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if ((*iter) && (*iter)->compare(_delegate)){if ((*iter) != _delegate) delete (*iter);       //避免同一个地址被delete两次(*iter) = 0;break;}}delete _delegate;return *this;}std::vector<ReturnType> operator()(ParamType... params){ListDelegateIterator iter = mListDelegates.begin();std::vector<ReturnType> _Results;while (iter != mListDelegates.end()){if (0 == (*iter)){iter = mListDelegates.erase(iter);}else{_Results.push_back((*iter)->invoke(params...));++iter;}}return _Results;}private:CMultiDelegate<ReturnType, ParamType...>(const CMultiDelegate& _event);CMultiDelegate<ReturnType, ParamType...>& operator=(const CMultiDelegate& _event);private:ListDelegate mListDelegates;};template< typename ...ParamType>class CMultiDelegate<void, ParamType...>{public:typedef std::list<IDelegate<void, ParamType...>*> ListDelegate;typedef typename ListDelegate::iterator ListDelegateIterator;typedef typename ListDelegate::const_iterator ConstListDelegateIterator;CMultiDelegate() { }~CMultiDelegate() { clear(); }bool empty() const{for (ConstListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if (*iter) return false;}return true;}void clear(){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if (*iter){delete (*iter);(*iter) = nullptr;}}}CMultiDelegate<void, ParamType...>& operator+=(IDelegate<void, ParamType...>* _delegate){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if ((*iter) && (*iter)->compare(_delegate)){delete _delegate;return *this;}}mListDelegates.push_back(_delegate);return *this;}CMultiDelegate<void, ParamType...>& operator-=(IDelegate<void, ParamType...>* _delegate){for (ListDelegateIterator iter = mListDelegates.begin(); iter != mListDelegates.end(); ++iter){if ((*iter) && (*iter)->compare(_delegate)){if ((*iter) != _delegate) delete (*iter);       //避免同一个地址被delete两次(*iter) = 0;break;}}delete _delegate;return *this;}void operator()(ParamType... params){ListDelegateIterator iter = mListDelegates.begin();while (iter != mListDelegates.end()){if (0 == (*iter)){iter = mListDelegates.erase(iter);}else{(*iter)->invoke(params...);++iter;}}}private:CMultiDelegate<void, ParamType...>(const CMultiDelegate& _event);CMultiDelegate<void, ParamType...>& operator=(const CMultiDelegate& _event);private:ListDelegate mListDelegates;};template< typename T>CStaticDelegate<T>* newDelegate(T func){return new CStaticDelegate<T>(func);}template< typename T,typename F>CMethodDelegate<T,F>* newDelegate(T * _object, F func){return new CMethodDelegate<T, F>(_object, func);}}

源文件 main.cpp 代码如下：

int _tmain(int argc, _TCHAR* argv[]){CMultiDelegate<void,int> e;              //void(int)e += newDelegate([](int a){ printf("这是lambda表达式\n"); });  //请尽量不要使用这种方式。e -= newDelegate([](int a){ printf("这是lambda表达式\n"); });  //这样是无法注销的。因为上面那个lambda表达式和下面这个类型不一样！！//请使用下面这种方式：auto func = newDelegate([](int a){ printf("这是lambda表达式\n"); });;e += func;e -= func;return 0;}