/// <summary>
/// Determines if figure directly or indirectly depends
/// on <paramref name="possibleDependency"/>
/// </summary>
/// <param name="figure">figure to check</param>
/// <param name="possibleDependency"></param>
/// <returns></returns>
public static bool DependsOn(this IFigure figure, IFigure possibleDependency)
{
// we consider that a figure depends on itself
if (figure == possibleDependency)
{
return(true);
}
// quick rejection - if it doesn't depend on anything,
// it certainly doesn't depend on possibleDependency
if (figure.Dependencies.IsEmpty())
{
return(false);
}
// first do the cheap pre-test without going deep
if (figure.DirectlyDependsOn(possibleDependency))
{
return(true);
}
// if that failed, go deeper using recursion
foreach (var directDependency in figure.Dependencies)
{
if (directDependency.DependsOn(possibleDependency))
{
return(true);
}
}
// depth-first search didn't find anything
return(false);
}