用于处理自定义异常的类

Question

我想创建一个类,它接受std :: function并允许处理指定的异常,但我不确定它是否可行.

这是一些伪草案:

//exception types
template<class... Args>
class CustomExceptionHandler
{
public:
    CustomExceptionHandler(std::function<void()> clb): clb_(std::move(clb)){}

    void ExecuteCallback()
    {
        try
        {
            clb_();
        }
        /*catch specified exception types*/
    }

private:
    std::function<void()> clb_;
};

//usage
CustomExceptionHandler<std::out_of_range, std::overflow_error> handler(clb);
handler.ExecuteCallback();

我不知道如何使用可变参数模板来获取异常类型并在以后使用它.可能吗 ？

我猜那个元组可能会有所帮助.

Answer 1

这是可能的!我已经提出了一个解决方案(你可以在这里运行),它将异常类型的参数包扩展为一系列递归函数调用,其中每个函数都试图捕获一种类型的异常.然后,最里面的递归调用调用回调.

namespace detail {    
    template<typename First>
    void catcher(std::function<void()>& clb){
        try {
            clb(); // invoke the callback directly
        } catch (const First& e){
            // TODO: handle error as needed
            std::cout << "Caught an exception with type \"" << typeid(e).name();
            std::cout << "\" and message \"" << e.what() << "\"\n";
        }
    }

    template<typename First, typename Second, typename... Rest>
    void catcher(std::function<void()>& clb){
        try {
            catcher<Second, Rest...>(clb); // invoke the callback inside of other handlers
        } catch (const First& e){
            // TODO: handle error as needed
            std::cout << "Caught an exception with type \"" << typeid(e).name();
            std::cout << "\" and message \"" << e.what() << "\"\n";
        }
    }
}

template<class... Args>
class CustomExceptionHandler
{
public:
    CustomExceptionHandler(std::function<void()> clb): clb_(std::move(clb)){}

    void ExecuteCallback()
    {
        detail::catcher<Args...>(clb_);
    }

private:
    std::function<void()> clb_;
};

int main(){

    std::function<void()> clb = [](){
        std::cout << "I'm gonna barf!\n";
        throw std::out_of_range("Yuck");
        //throw std::overflow_error("Ewww");
    };

    CustomExceptionHandler<std::out_of_range, std::overflow_error> handler(clb);
    handler.ExecuteCallback();

    return 0;
}

输出:

I'm gonna barf!

Caught an exception with type "St12out_of_range" and message "Yuck"

我希望有所帮助!快乐的编码