/// <summary>
/// Initializes a new instance of the <see cref="Path"/> class.
/// </summary>
/// <param name="next">The next node in the path; or <see langword="null"/>.</param>
/// <param name="link">The associated link; or <see langword="null"/>.</param>
/// <param name="frame">The associated stack frame.</param>
/// <param name="length"></param>
public Path(Path next, Link link, Frame frame, int length)
{
#region Contract
Contract.Requires<ArgumentNullException>(frame != null);
Contract.Requires<ArgumentOutOfRangeException>(length >= 0);
#endregion
this.Next = next;
this.Link = link;
this.Frame = frame;
this.Length = length;
this.AncestorCount = next != null ? next.AncestorCount + 1 : 0;
this.label = this.Link?.Label;
}
/// <summary>
/// Determines all paths from this frame to the root frame.
/// </summary>
/// <param name="parent"></param>
/// <param name="targetLink">The link to look for, or <see langword="null"/> to find all paths.</param>
/// <param name="seen">Whether <paramref name="targetLink"/> has been seen.</param>
/// <param name="arity"></param>
/// <param name="length"></param>
/// <returns></returns>
private IEnumerable<Path> DoGetAllPathsToRoot(Path parent, Link targetLink, bool seen, int arity, int length)
{
// TODO: Understand!
if (arity == 0 && seen)
{
return new[] { new Path(parent, null, this, length) };
}
else if (arity > 0)
{
List<Path> paths = new List<Path>();
foreach (var link in this.Links.Reverse())
{
bool seenIt = seen || (link == targetLink);
Path n = new Path(parent, link, this, link.Length);
paths.AddRange(link.Parent.DoGetAllPathsToRoot(n, targetLink, seenIt, arity - 1, length + link.Length));
}
return paths;
}
else
return Enumerable.Empty<Path>();
}