/// <summary>
/// Expands a node into child nodes.
/// </summary>
/// <param name="node">The node to expand</param>
/// <param name="model">The ODCM model</param>
/// <returns>The child nodes if the node can be expanded, otherwise an empty list.</returns>
private static IEnumerable <OdcmNode> CreateChildNodes(this OdcmNode node, OdcmModel model)
{
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (model == null)
{
throw new ArgumentNullException(nameof(model));
}
// Identify the kind of ODCM element this node represents and expand it if we need to
OdcmProperty obj = node.OdcmProperty;
IEnumerable <OdcmProperty> childObjects = obj.Type.GetChildObjects(model);
// Don't allow loops in the list of ODCM nodes
ICollection <string> parents = new HashSet <string>();
OdcmNode currentNode = node;
while (currentNode != null)
{
parents.Add(currentNode.OdcmProperty.CanonicalName());
currentNode = currentNode.Parent;
}
return(childObjects
// Filter out the children we've already seen so we can avoid loops
.Where(child => !parents.Contains(child.CanonicalName()))
// Add the child nodes to the current node
.Select(child => node.CreateChildNode(child)));
}
