Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/Hosting/PreloadHost.cs

@@ -0,0 +1,55 @@
+//------------------------------------------------------------------------------
+// <copyright file="PreloadHost.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.Hosting {
+    
+    using System;
+    using System.Web;
+    using System.Web.Util;
+    using System.Configuration;
+
+    internal sealed class PreloadHost : MarshalByRefObject, IRegisteredObject {
+
+        public PreloadHost() {
+            HostingEnvironment.RegisterObject(this);
+        }
+
+        public void CreateIProcessHostPreloadClientInstanceAndCallPreload(string preloadObjTypeName, string[] paramsForStartupObj) {
+
+            using (new ApplicationImpersonationContext()) {
+                // Check the type
+                Type preloadObjType = null;
+                try {
+                    preloadObjType = Type.GetType(preloadObjTypeName, true);
+                }
+                catch (Exception e) {
+                    throw new InvalidOperationException (
+                        Misc.FormatExceptionMessage(e, new string[]{
+                            SR.GetString(SR.Failure_Create_Application_Preload_Provider_Type, preloadObjTypeName)} ));
+                }
+
+                if (!typeof(IProcessHostPreloadClient).IsAssignableFrom(preloadObjType)) {
+                    throw new ConfigurationErrorsException(SR.GetString(SR.Invalid_Application_Preload_Provider_Type, preloadObjTypeName));
+                }
+
+                // Let all other exceptons fall through to the default AppDomain
+                IProcessHostPreloadClient preloadClient = (IProcessHostPreloadClient)Activator.CreateInstance(preloadObjType);
+                preloadClient.Preload(paramsForStartupObj);
+            }
+        }
+
+        internal Exception InitializationException { get { return HttpRuntime.InitializationException; } }
+
+        void IRegisteredObject.Stop(bool immediate) {
+            HostingEnvironment.UnregisterObject(this);
+        }
+
+        public override Object InitializeLifetimeService() {
+            return null; // never expire lease
+        }
+    }
+}
+