Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/System/sys/system/configuration/ConfigurationManagerInternalFactory.cs

@@ -0,0 +1,30 @@
+//------------------------------------------------------------------------------
+// <copyright file="ConfigurationManagerInternalFactory.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Configuration {
+
+    using System.Configuration.Internal;
+
+    //
+    // class ConfigurationManagerInternalFactory manages access to a 
+    // single instance of ConfigurationManagerInternal.
+    //
+    internal static class ConfigurationManagerInternalFactory {
+        private const string ConfigurationManagerInternalTypeString = "System.Configuration.Internal.ConfigurationManagerInternal, " + AssemblyRef.SystemConfiguration;
+
+        static private volatile IConfigurationManagerInternal    s_instance;
+
+        static internal IConfigurationManagerInternal Instance {
+            get {
+                if (s_instance == null) {
+                    s_instance = (IConfigurationManagerInternal) TypeUtil.CreateInstanceWithReflectionPermission(ConfigurationManagerInternalTypeString);
+                }
+
+                return s_instance;
+            }
+        }
+    }
+}