Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Data.Entity/System/Data/Query/InternalTrees/NodeCounter.cs

@@ -0,0 +1,53 @@
+//---------------------------------------------------------------------
+// <copyright file="NodeCounter.cs" company="Microsoft">
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//
+// @owner  [....]
+// @backupOwner [....]
+//---------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Diagnostics;
+using System.Data.Common;
+using md=System.Data.Metadata.Edm;
+
+namespace System.Data.Query.InternalTrees
+{
+    /// <summary>
+    /// Counts the number of nodes in a tree
+    /// </summary>
+    internal class NodeCounter : BasicOpVisitorOfT<int>
+    {
+        /// <summary>
+        /// Public entry point - Calculates the nubmer of nodes in the given subTree
+        /// </summary>
+        /// <param name="subTree"></param>
+        /// <returns></returns>
+        internal static int Count(Node subTree)
+        {
+            NodeCounter counter = new NodeCounter();
+            return counter.VisitNode(subTree);
+        }
+
+        /// <summary>
+        /// Common processing for all node types
+        /// Count = 1 (self) + count of children
+        /// </summary>
+        /// <param name="n"></param>
+        /// <returns></returns>
+        protected override int VisitDefault(Node n)
+        {
+            int count = 1;
+            foreach (Node child in n.Children)
+            {
+                count += VisitNode(child);
+            }
+            return count;
+        }
+    }
+}
+
+