Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/Configuration/ImpersonateTokenRef.cs

@@ -0,0 +1,45 @@
+//------------------------------------------------------------------------------
+// <copyright file="ImpersonateTokenRef.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.Configuration {
+    using System;
+    using System.Xml;
+    using System.Configuration;
+    using System.Collections.Specialized;
+    using System.Collections;
+    using System.IO;
+    using System.Text;
+    using System.Web.Util;
+    using System.Web.Configuration;
+
+    // class IdentitySection
+    internal sealed class ImpersonateTokenRef : IDisposable {
+        private IntPtr _handle;
+
+        internal ImpersonateTokenRef(IntPtr token) {
+            _handle = token;
+        }
+
+        internal IntPtr Handle {
+            get { return _handle; }
+        }
+
+        // The handle can be kept alive by HttpContext.s_appIdentityConfig (see ASURT#121815)
+        ~ImpersonateTokenRef() {
+            if (_handle != IntPtr.Zero) {
+                UnsafeNativeMethods.CloseHandle(_handle);
+                _handle = IntPtr.Zero;
+            }
+        }
+        void IDisposable.Dispose() {
+            if (_handle != IntPtr.Zero) {
+                UnsafeNativeMethods.CloseHandle(_handle);
+                _handle = IntPtr.Zero;
+            }
+            GC.SuppressFinalize(this);
+        }
+    }
+}