Cache the IUIProvider, no sense looking it up every time

Author: shana

src/GitHub.Exports/Extensions/VSExtensions.cs

@@ -1,29 +1,38 @@
-using GitHub.Services;
-using Microsoft.TeamFoundation.Controls;
+using Microsoft.TeamFoundation.Controls;
 using System;
 using System.Diagnostics;
 
 namespace GitHub.Extensions
 {
+    using Services;
     using VisualStudio;
 
     public static class VSExtensions
     {
+        static IUIProvider uiProvider = null;
+
         public static T TryGetService<T>(this IServiceProvider serviceProvider) where T : class
         {
             return serviceProvider.TryGetService(typeof(T)) as T;
         }
 
         public static object TryGetService(this IServiceProvider serviceProvider, Type type)
         {
+            var isRequestingMainProvider = type == typeof(IUIProvider);
+            if (uiProvider != null && isRequestingMainProvider)
+                return uiProvider;
+
             var ui = serviceProvider as IUIProvider;
             if (ui != null)
                 return ui.TryGetService(type);
             else
             {
                 try
                 {
-                    return serviceProvider.GetService(type);
+                    var ret = serviceProvider.GetService(type);
+                    if (isRequestingMainProvider)
+                        uiProvider = ret as IUIProvider;
+                    return ret;
                 }
                 catch (Exception ex)
                 {
@@ -35,15 +44,34 @@ public static object TryGetService(this IServiceProvider serviceProvider, Type t
 
         public static T GetService<T>(this IServiceProvider serviceProvider)
         {
-            return (T)serviceProvider.GetService(typeof(T));
+            var isRequestingMainProvider = typeof(T) == typeof(IUIProvider);
+            if (uiProvider != null && isRequestingMainProvider)
+                return (T)uiProvider;
+
+            var ret = serviceProvider.GetService(typeof(T));
+
+            if (isRequestingMainProvider)
+                uiProvider = ret as IUIProvider;
+
+            return (T)ret;
         }
 
         public static T GetExportedValue<T>(this IServiceProvider serviceProvider)
         {
+            var isRequestingMainProvider = typeof(T) == typeof(IUIProvider);
+            if (uiProvider != null && isRequestingMainProvider)
+                return (T)uiProvider;
+
             var ui = serviceProvider as IUIProvider;
             if (ui != null)
                 return ui.GetService<T>();
-            return Services.ComponentModel.DefaultExportProvider.GetExportedValue<T>();
+            else
+            {
+                var ret = Services.ComponentModel.DefaultExportProvider.GetExportedValue<T>();
+                if (isRequestingMainProvider)
+                    uiProvider = ret as IUIProvider;
+                return (T)ret;
+            }
         }
 
         public static ITeamExplorerSection GetSection(this IServiceProvider serviceProvider, Guid section)