Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Runtime.Caching/System/Caching/SRef.cs

@@ -0,0 +1,51 @@
+// <copyright file="SRef.cs" company="Microsoft">
+//   Copyright (c) 2009 Microsoft Corporation.  All rights reserved.
+// </copyright>
+using System;
+using System.Globalization;
+using System.Reflection;
+using System.Security;
+using System.Security.Permissions;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.Runtime.Caching {
+    internal class SRef {
+        private static Type s_type = Type.GetType("System.SizedReference", true, false);
+        private Object _sizedRef;
+
+        internal SRef(Object target) {
+            _sizedRef = Activator.CreateInstance(s_type,
+                    BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.CreateInstance,
+                    null,
+                    new object[] { target },
+                    null);
+        }
+
+        internal long ApproximateSize {
+            [SecuritySafeCritical]
+            [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
+            get {
+                object o = s_type.InvokeMember("ApproximateSize",
+                                               BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty,
+                                               null, // binder
+                                               _sizedRef, // target
+                                               null, // args
+                                               CultureInfo.InvariantCulture);
+                return (long)o;
+            }
+        }
+
+        // 
+        [SuppressMessage("Microsoft.Security", "CA2106:SecureAsserts", Justification = "Grandfathered suppression from original caching code checkin")]
+        [SecuritySafeCritical]
+        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
+        internal void Dispose() {
+            s_type.InvokeMember("Dispose",
+                                BindingFlags.Public | BindingFlags.Instance | BindingFlags.InvokeMethod,
+                                null, // binder
+                                _sizedRef, // target
+                                null, // args
+                                CultureInfo.InvariantCulture);
+        }
+    }
+}