From edea37dba6beaae7c10f48a1cae29da18d585727 Mon Sep 17 00:00:00 2001
From: Brent Simmons <brent@ranchero.com>
Date: Sat, 21 Oct 2017 12:14:15 -0700
Subject: [PATCH] Add TreeController.normalizeSelectedNodes and supporting
 functions in Node.

---
 Frameworks/RSTree/RSTree/Node.swift           | 28 +++++++++++++++++++
 Frameworks/RSTree/RSTree/TreeController.swift | 16 ++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/Frameworks/RSTree/RSTree/Node.swift b/Frameworks/RSTree/RSTree/Node.swift
index 8fe38a466..c97649080 100644
--- a/Frameworks/RSTree/RSTree/Node.swift
+++ b/Frameworks/RSTree/RSTree/Node.swift
@@ -103,6 +103,34 @@ public final class Node: Equatable {
 		}
 		return nil
 	}
+
+	public func hasAncestor(in nodes: [Node]) -> Bool {
+
+		for node in nodes {
+			if node.isAncestor(of: self) {
+				return true
+			}
+		}
+		return false
+	}
+
+	public func isAncestor(of node: Node) -> Bool {
+
+		if node == self {
+			return false
+		}
+
+		var nomad = node
+		while true {
+			guard let parent = nomad.parent else {
+				return false
+			}
+			if parent == self {
+				return true
+			}
+			nomad = parent
+		}
+	}
 }
 
 
diff --git a/Frameworks/RSTree/RSTree/TreeController.swift b/Frameworks/RSTree/RSTree/TreeController.swift
index 8ff3785d8..435b9087e 100644
--- a/Frameworks/RSTree/RSTree/TreeController.swift
+++ b/Frameworks/RSTree/RSTree/TreeController.swift
@@ -67,6 +67,21 @@ public final class TreeController {
 
 		return nodeInArrayRepresentingObject(nodes: [rootNode], representedObject: representedObject, recurse: true)
 	}
+
+	public func normalizedSelectedNodes(_ nodes: [Node]) -> [Node] {
+
+		// An array of nodes might include a leaf node and its parent. Remove the leaf node.
+
+		var normalizedNodes = [Node]()
+
+		for node in nodes {
+			if !node.hasAncestor(in: nodes) {
+				normalizedNodes += [node]
+			}
+		}
+
+		return normalizedNodes
+	}
 }
 
 private extension TreeController {
@@ -117,5 +132,4 @@ private extension TreeController {
 
 		return childNodesDidChange
 	}
-	
 }