Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System.Web/Util/QueryableUtility.cs

@@ -0,0 +1,29 @@
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+
+namespace System.Web.Util {
+    internal static class QueryableUtility {
+        private static readonly string[] _orderMethods = new[] { "OrderBy", "ThenBy", "OrderByDescending", "ThenByDescending" };
+        private static readonly MethodInfo[] _methods = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static);
+
+        private static MethodInfo GetQueryableMethod(Expression expression) {
+            if (expression.NodeType == ExpressionType.Call) {
+                var call = (MethodCallExpression)expression;
+                if (call.Method.IsStatic && call.Method.DeclaringType == typeof(Queryable)) {
+                    return call.Method.GetGenericMethodDefinition();
+                }
+            }
+            return null;
+        }
+
+        public static bool IsQueryableMethod(Expression expression, string method) {
+            return _methods.Where(m => m.Name == method).Contains(GetQueryableMethod(expression));
+        }
+
+        public static bool IsOrderingMethod(Expression expression) {
+            return _orderMethods.Any(method => IsQueryableMethod(expression, method));
+        }
+
+    }
+}