C++中如何设计事件总线_发布订阅模式

#include <iostream>
#include <vector>
#include <map>
#include <functional>
#include <memory>

// 定义事件基类
class Event {
public:
    virtual ~Event() = default;
};

// 定义事件处理函数的类型别名
using EventHandler = std::function<void(Event*)>;

// 事件总线类
class EventBus {
public:
    // 订阅事件
    void subscribe(const std::string& eventType, EventHandler handler) {
        subscribers_[eventType].push_back(handler);
    }

    // 取消订阅事件
    void unsubscribe(const std::string& eventType, EventHandler handler) {
        auto& subs = subscribers_[eventType];
        subs.erase(std::remove_if(subs.begin(), subs.end(),
                                  [&](const EventHandler& h) { return h.target<void(Event*)>() == handler.target<void(Event*)>(); }),
                   subs.end());
    }

    // 发布事件
    void publish(Event* event) {
        const std::string eventType = typeid(*event).name(); // 获取事件类型名称
        auto it = subscribers_.find(eventType);
        if (it != subscribers_.end()) {
            for (const auto& handler : it->second) {
                handler(event);
            }
        }
        delete event; // 重要：事件由发布者创建，总线负责传递，最后由总线释放内存
    }

private:
    std::map<std::string, std::vector<EventHandler>> subscribers_;
};

// 示例事件类
class ButtonClickEvent : public Event {
public:
    ButtonClickEvent(int buttonId) : buttonId_(buttonId) {}
    int buttonId() const { return buttonId_; }
private:
    int buttonId_;
};

// 示例订阅者类
class Logger {
public:
    void onButtonClick(Event* event) {
        ButtonClickEvent* clickEvent = dynamic_cast<ButtonClickEvent*>(event);
        if (clickEvent) {
            std::cout << "Button " << clickEvent->buttonId() << " clicked!" << std::endl;
        }
    }
};

int main() {
    EventBus bus;
    Logger logger;

    // 订阅事件
    bus.subscribe(typeid(ButtonClickEvent).name(), std::bind(&Logger::onButtonClick, &logger, std::placeholders::_1));

    // 发布事件
    bus.publish(new ButtonClickEvent(1));
    bus.publish(new ButtonClickEvent(2));

    return 0;
}