Make code more clearer with decorator? - c++

Question

For example, I have such function which performs some useful work (for event-driven simulation):
int function()
{
do_useful_work();
return 0;
}
If I need do measurements of performance of this useful_work I should do:
int function()
{
count_time(time_before);
count_X_metrics(X_before);
do_useful_work();
count_time(time_after);
count_X_metrics(X_after);
return 0;
}
This approach makes code more clumsy. Is there a way, patters to do these countings outside of int function() to make code clearer?

Answer 1

You could create your own decorator like the following:
#include<functional>
#include <iostream>
void count_time() {};
void count_X_metrics() {};
void decorator(std::function<void()> work)
{
count_time();
count_X_metrics();
work();
count_time();
count_X_metrics();
}
void do_work_1() {
std::cout << "Hello, World 1!" << std::endl;
}
void do_work_2() {
std::cout << "Hello, World 2!" << std::endl;
}
int main() {
decorator(do_work_1);
decorator(do_work_2);
}
Edit: I'm not sure how your count_time and count_X_metrics functions work, but if you need something more complicated, or a way to keep track of state, you can create an object that will do that work for you. This is certainly different than you need, but hopefully it conveys the point I am trying to make:
#include<functional>
#include <iostream>
int current_time() { return 0; }
int x_metric() { return 0; }
class Timer {
public:
void time(std::function<void()> work) {
// Capture state before
int starttime = current_time();
int startmetric = x_metric();
work();
// Capture state after
int endtime = current_time();
int endmetric = x_metric();
// Update results
ellapsed = endtime - starttime;
metric = endmetric - startmetric;
// Possibly do something with the metrics here.
// ...
}
int get_ellapsed() { return ellapsed; }
int get_metric() { return metric; }
private:
int ellapsed;
int metric;
};
void do_work_1() {
std::cout << "Hello, World 1!" << std::endl;
}
void do_work_2() {
std::cout << "Hello, World 2!" << std::endl;
}
int main() {
Timer t;
t.time(do_work_1);
// Possibly do something with the metrics here.
// cout << t.get_ellapsed();
t.time(do_work_2);
}