My job is to refactor an old library for GIS vector data processing. The main class encapsulates a collection of building outlines, and offers different methods for checking data consistency. Those checking functions have an optional parameter that allows to perform some process. For instance:
std::vector<Point> checkIntersections(int process_mode = 0);
This method tests if some building outlines are intersecting, and return the intersection points. But if you pass a non null argument, the method will modify the outlines to remove the intersection.
I think it's pretty bad (at call
site, a reader not familiar with the code base will assume that a method called checkSomething only performs a check and doesn't modifiy data) and I want to change this.
I also want to avoid code duplication as check and process methods are mostly similar.
So I was thinking to something like this:
// a private worker
std::vector<Point> workerIntersections(int process_mode = 0)
{
// it's the equivalent of the current checkIntersections, it may perform
// a process depending on process_mode
}
// public interfaces for check and process
std::vector<Point> checkIntersections() /* const */
{
workerIntersections(0);
}
std::vector<Point> processIntersections(int process_mode /*I have different process modes*/)
{
workerIntersections(process_mode);
}
But that forces me to break const correctness as workerIntersections is a non-const method.
How can I separate check and process, avoiding code duplication and keeping const-correctness?
