简易信号-槽机制的C++实现

 

信号-槽机制的实现

#include<vector>
#include<functional>

template<class... Args>
class Signal{
    std::vector<std::function<void(Args...)>> slots;
    template <class T, size_t... Index>
    void connectMemberFunc(T *obj, void (T::*func)(Args...), std::index_sequence<Index...>)
    {
#ifdef __GNUC__
        std::function<void(Args...)> f { 
            std::bind(func, obj, std::_Placeholder<Index + 1>{}...)
        };
#elif defined _MSC_VER
        std::function<void(Args...)> f { 
            std::bind(func, obj, std::_Ph<Index + 1>{}...)
        };
#endif
        this->slots.push_back(f);
    }
public:
    void send(Args&& ...args){
        for(auto& slot:this->slots)
            slot(std::forward<Args>(args)...);
    }
    template<class Callable>
    void connect(Callable slot){
        this->slots.push_back(slot);
    }
    void connect(void(*slot)(Args...)) {
        this->slots.push_back(slot);
    }
    template <class T>
    void connect(T* obj, void (T::* slot)(Args...)) {
        this->connectMemberFunc(obj, slot, std::index_sequence_for<Args...>());
    }
};

// 无参特化
template<>
class Signal<void> {
    std::vector<std::function<void(void)>> slots;
public:
    void send() {
        for (auto& slot : this->slots)
            slot();
    }
    template<class Callable>
    void connect(Callable slot) {
        this->slots.push_back(slot);
    }
    void connect(void(*slot)(void)) {
        this->slots.push_back(slot);
    }
    template <class T>
    void connect(T* obj, void (T::* slot)(void)) {
        this->slots.push_back(std::bind(slot, obj));
    }
};

 

 

测试实现

#include<iostream>

struct A {
    void operator()() {
        std::cout << "No Args Callable Object" << std::endl;
    }
    void operator()(int a) {
        std::cout << "Args Callable Object:" << a << std::endl;
    }
    void func() {
        std::cout << "No Args Member Function" << std::endl;
    }
    void func(int a) {
        std::cout << "Args Member Function:" << a << std::endl;
    }
};

void func() {
    std::cout << "No Args Function" << std::endl;
}
void func(int a) {
    std::cout << "Args Function:" << a << std::endl;
}

int main() {
    // 定义信号
    Signal<void> s1;
    Signal<int> s2;
    A a;
    // 连接槽
    s1.connect(func);
    s1.connect(&a, &A::func);
    s1.connect(a);

    s2.connect(func);
    s2.connect(&a, &A::func);
    s2.connect(a);
    // 发出信号
    s1.send();
    s2.send(5);

    return 0;
}