scope_exit.hpp

#ifndef SCOPE_EXIT_HPP_
#define SCOPE_EXIT_HPP_

#include <functional>

namespace base {

    template <typename handler_t>
    class scope_exit {
    private:
        handler_t handler_;
        bool dismissed_;

    private: // noncopyable
        scope_exit(scope_exit const&);
        scope_exit& operator=(scope_exit const&);

    public:
        explicit scope_exit(handler_t&& handler) 
            : handler_(std::forward<handler_t>(handler)), dismissed_(false) {
        }

        ~scope_exit() { 
            if(!dismissed_) {
                handler_();
            }
        }

        scope_exit(scope_exit&& rhs) 
            : handler_(std::move(rhs.handler_)), dismissed_(rhs.dismissed_) {
        }

        scope_exit& operator=(scope_exit&& rhs) {
            if (&rhs != this) {
                handler_ = std::move(rhs.handler_);
            }
            return *this;
        }

        void dismiss() {
            dismissed_ = true;
        }
    };

    template <typename handler_t>
    inline scope_exit<handler_t> make_scope_exit(handler_t&& handler)
    {
        return scope_exit<handler_t>(std::forward<handler_t>(handler));
    }

}  // namespace base

#define SCOPEGUARD_LINENAME_CAT(name, line) name##line
#define SCOPEGUARD_LINENAME(name, line) SCOPEGUARD_LINENAME_CAT(name, line)
#define ON_SCOPE_EXIT(callback) auto SCOPEGUARD_LINENAME(EXIT, __LINE__) =  base::make_scope_exit(callback)

#endif // SCOPE_EXIT_HPP_