/// <summary>
/// Performs a depth-first walk down the expand tree, copying and adding to the current path as it goes. When the bottom of a path is reached, the path is added to the overall set of paths.
/// </summary>
/// <param name="currentPath">The current path so far for this depth-first traversal of the tree. Starts out null.</param>
/// <param name="currentNode">The current node of the expand tree.</param>
/// <param name="rootNode">The root node of the expand tree.</param>
private void ExtractExpandPathSegmentCollections(ExpandSegmentCollection currentPath, ExpandedProjectionNode currentNode, RootProjectionNode rootNode)
{
ExpandSegmentCollection nextPath = null;
foreach (ExpandedNavigationSelectItem expandItem in currentNode.SelectExpandClause.SelectedItems.OfType<ExpandedNavigationSelectItem>())
{
rootNode.ExpansionsSpecified = true;
if (currentPath == null)
{
nextPath = new ExpandSegmentCollection();
}
else
{
// create a copy of the current path.
nextPath = new ExpandSegmentCollection(currentPath.Count);
nextPath.AddRange(currentPath);
}
var segment = this.CreateExpandSegment(expandItem, currentNode.ResourceType);
nextPath.Add(segment);
ExpandedProjectionNode childNode = currentNode.AddExpandedNode(segment, expandItem.SelectAndExpand);
// if there are any derived expansions in the tree, set the rootNode.DerivedExpansionsSpecified to true.
if (currentNode.HasExpandedPropertyOnDerivedType)
{
rootNode.ExpansionOnDerivedTypesSpecified = true;
}
this.ExtractExpandPathSegmentCollections(nextPath, childNode, rootNode);
}
if (nextPath == null && currentPath != null)
{
this.expandPaths.Add(currentPath);
}
}
