386159/386164: Review all double-check locks

5 files changed, 19 insertions, 38 deletions

diff --git a/src/System.Web.Mvc/Async/TaskAsyncActionDescriptor.cs b/src/System.Web.Mvc/Async/TaskAsyncActionDescriptor.cs
index 22e8e8b1..8f957861 100644
--- a/src/System.Web.Mvc/Async/TaskAsyncActionDescriptor.cs
+++ b/src/System.Web.Mvc/Async/TaskAsyncActionDescriptor.cs
@@ -131,8 +131,7 @@ namespace System.Web.Mvc.Async
                             tokenSource.Cancel();
                         }
                     }
-                },
-                                               state: null, dueTime: timeout, period: Timeout.Infinite);
+                }, state: null, dueTime: timeout, period: Timeout.Infinite);
             }
 
             Task taskUser = dispatcher.Execute(controllerContext.Controller, parametersArray) as Task;
diff --git a/src/System.Web.Mvc/ControllerTypeCache.cs b/src/System.Web.Mvc/ControllerTypeCache.cs
index 7b560f4a..a4a8ca7a 100644
--- a/src/System.Web.Mvc/ControllerTypeCache.cs
+++ b/src/System.Web.Mvc/ControllerTypeCache.cs
@@ -7,7 +7,7 @@ namespace System.Web.Mvc
     {
         private const string TypeCacheName = "MVC-ControllerTypeCache.xml";
 
-        private Dictionary<string, ILookup<string, Type>> _cache;
+        private volatile Dictionary<string, ILookup<string, Type>> _cache;
         private object _lockObj = new object();
 
         internal int Count
diff --git a/src/System.Web.Mvc/MultiServiceResolver.cs b/src/System.Web.Mvc/MultiServiceResolver.cs
index d3506fa2..0eedd385 100644
--- a/src/System.Web.Mvc/MultiServiceResolver.cs
+++ b/src/System.Web.Mvc/MultiServiceResolver.cs
@@ -6,7 +6,7 @@ namespace System.Web.Mvc
     internal class MultiServiceResolver<TService> : IResolver<IEnumerable<TService>>
         where TService : class
     {
-        private IEnumerable<TService> _itemsFromService;
+        private Lazy<IEnumerable<TService>> _itemsFromService;
         private Func<IEnumerable<TService>> _itemsThunk;
         private Func<IDependencyResolver> _resolverThunk;
 
@@ -19,6 +19,7 @@ namespace System.Web.Mvc
 
             _itemsThunk = itemsThunk;
             _resolverThunk = () => DependencyResolver.Current;
+            _itemsFromService = new Lazy<IEnumerable<TService>>(() => _resolverThunk().GetServices<TService>());
         }
 
         internal MultiServiceResolver(Func<IEnumerable<TService>> itemsThunk, IDependencyResolver resolver)
@@ -32,20 +33,7 @@ namespace System.Web.Mvc
 
         public IEnumerable<TService> Current
         {
-            get
-            {
-                if (_itemsFromService == null)
-                {
-                    lock (_itemsThunk)
-                    {
-                        if (_itemsFromService == null)
-                        {
-                            _itemsFromService = _resolverThunk().GetServices<TService>();
-                        }
-                    }
-                }
-                return _itemsFromService.Concat(_itemsThunk());
-            }
+            get { return _itemsFromService.Value.Concat(_itemsThunk()); }
         }
     }
 }
diff --git a/src/System.Web.Mvc/SingleServiceResolver.cs b/src/System.Web.Mvc/SingleServiceResolver.cs
index b1f5c344..ae2400c0 100644
--- a/src/System.Web.Mvc/SingleServiceResolver.cs
+++ b/src/System.Web.Mvc/SingleServiceResolver.cs
@@ -6,7 +6,7 @@ namespace System.Web.Mvc
     internal class SingleServiceResolver<TService> : IResolver<TService>
         where TService : class
     {
-        private TService _currentValueFromResolver;
+        private Lazy<TService> _currentValueFromResolver;
         private Func<TService> _currentValueThunk;
         private TService _defaultValue;
         private Func<IDependencyResolver> _resolverThunk;
@@ -24,6 +24,7 @@ namespace System.Web.Mvc
             }
 
             _resolverThunk = () => DependencyResolver.Current;
+            _currentValueFromResolver = new Lazy<TService>(GetValueFromResolver);
             _currentValueThunk = currentValueThunk;
             _defaultValue = defaultValue;
             _callerMethodName = callerMethodName;
@@ -40,26 +41,19 @@ namespace System.Web.Mvc
 
         public TService Current
         {
-            get
-            {
-                if (_resolverThunk != null)
-                {
-                    lock (_currentValueThunk)
-                    {
-                        if (_resolverThunk != null)
-                        {
-                            _currentValueFromResolver = _resolverThunk().GetService<TService>();
-                            _resolverThunk = null;
+            get { return _currentValueFromResolver.Value ?? _currentValueThunk() ?? _defaultValue; }
+        }
+
+        private TService GetValueFromResolver()
+        {
+            TService result = _resolverThunk().GetService<TService>();
 
-                            if (_currentValueFromResolver != null && _currentValueThunk() != null)
-                            {
-                                throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, MvcResources.SingleServiceResolver_CannotRegisterTwoInstances, typeof(TService).Name.ToString(), _callerMethodName));
-                            }
-                        }
-                    }
-                }
-                return _currentValueFromResolver ?? _currentValueThunk() ?? _defaultValue;
+            if (result != null && _currentValueThunk() != null)
+            {
+                throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, MvcResources.SingleServiceResolver_CannotRegisterTwoInstances, typeof(TService).Name.ToString(), _callerMethodName));
             }
+
+            return result;
         }
     }
 }
diff --git a/src/System.Web.Mvc/UrlRewriterHelper.cs b/src/System.Web.Mvc/UrlRewriterHelper.cs
index 265f7202..5a08542b 100644
--- a/src/System.Web.Mvc/UrlRewriterHelper.cs
+++ b/src/System.Web.Mvc/UrlRewriterHelper.cs
@@ -9,7 +9,7 @@ namespace System.Web.Mvc
 
         private object _lockObject = new object();
         private bool _urlRewriterIsTurnedOnValue;
-        private bool _urlRewriterIsTurnedOnCalculated = false;
+        private volatile bool _urlRewriterIsTurnedOnCalculated = false;
 
         private static bool WasThisRequestRewritten(HttpContextBase httpContext)
         {