Updating CompilerCache to use IMemoryCache and file system watcher to

expire files in razor file cache.

Add a functional test to ensure the compiler cache does not get
initialized until the first request to a View.

Fixes #1708

Mvc.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 14
-VisualStudioVersion = 14.0.22512.0
+VisualStudioVersion = 14.0.22604.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "samples", "samples", "{DAAE4C74-D06F-4874-A166-33305D2643CE}"
 EndProject
@@ -132,6 +132,8 @@ Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Microsoft.AspNet.Mvc.Xml.Te
 EndProject
 Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "FormatFilterWebSite", "test\WebSites\FormatFilterWebSite\FormatFilterWebSite.kproj", "{AC9BE567-540E-4C70-90C2-AAF021307A80}"
 EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "RazorCompilerCacheWebSite", "test\WebSites\RazorCompilerCacheWebSite\RazorCompilerCacheWebSite.kproj", "{42C5D417-4060-48F4-BB28-E9E179007779}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -694,18 +696,6 @@ Global
 		{BDEEBE09-C0C4-433C-B0B8-8478C9776996}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{BDEEBE09-C0C4-433C-B0B8-8478C9776996}.Release|x86.ActiveCfg = Release|Any CPU
 		{BDEEBE09-C0C4-433C-B0B8-8478C9776996}.Release|x86.Build.0 = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|x86.Build.0 = Debug|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Any CPU.Build.0 = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Mixed Platforms.Build.0 = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|x86.ActiveCfg = Release|Any CPU
-		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|x86.Build.0 = Release|Any CPU
 		{0449D6D2-BE1B-4E29-8E1B-444420802C03}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{0449D6D2-BE1B-4E29-8E1B-444420802C03}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{0449D6D2-BE1B-4E29-8E1B-444420802C03}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
@@ -730,6 +720,18 @@ Global
 		{C3123A70-41C4-4122-AD1C-D35DF8958DD7}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{C3123A70-41C4-4122-AD1C-D35DF8958DD7}.Release|x86.ActiveCfg = Release|Any CPU
 		{C3123A70-41C4-4122-AD1C-D35DF8958DD7}.Release|x86.Build.0 = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Debug|x86.Build.0 = Debug|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Any CPU.Build.0 = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|x86.ActiveCfg = Release|Any CPU
+		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0}.Release|x86.Build.0 = Release|Any CPU
 		{22019146-BDFA-442E-8C8E-345FB9644578}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{22019146-BDFA-442E-8C8E-345FB9644578}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{22019146-BDFA-442E-8C8E-345FB9644578}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
@@ -754,6 +756,18 @@ Global
 		{AC9BE567-540E-4C70-90C2-AAF021307A80}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{AC9BE567-540E-4C70-90C2-AAF021307A80}.Release|x86.ActiveCfg = Release|Any CPU
 		{AC9BE567-540E-4C70-90C2-AAF021307A80}.Release|x86.Build.0 = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Debug|x86.Build.0 = Debug|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|Any CPU.Build.0 = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|x86.ActiveCfg = Release|Any CPU
+		{42C5D417-4060-48F4-BB28-E9E179007779}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -818,5 +832,6 @@ Global
 		{87AB84B2-22C1-43C6-BB8A-1D327B446FB0} = {16703B76-C9F7-4C75-AE6C-53D92E308E3C}
 		{22019146-BDFA-442E-8C8E-345FB9644578} = {3BA657BF-28B1-42DA-B5B0-1C4601FCF7B1}
 		{AC9BE567-540E-4C70-90C2-AAF021307A80} = {16703B76-C9F7-4C75-AE6C-53D92E308E3C}
+		{42C5D417-4060-48F4-BB28-E9E179007779} = {16703B76-C9F7-4C75-AE6C-53D92E308E3C}
 	EndGlobalSection
 EndGlobal

src/Microsoft.AspNet.Mvc.Razor/Compilation/CompilerCache.cs

@@ -2,19 +2,21 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using Microsoft.AspNet.FileProviders;
+using Microsoft.Framework.Cache.Memory;
 
 namespace Microsoft.AspNet.Mvc.Razor
 {
-    /// <inheritdoc />
+    /// <summary>
+    /// Caches the result of runtime compilation of Razor files for the duration of the app lifetime.
+    /// </summary>
     public class CompilerCache : ICompilerCache
     {
-        private readonly ConcurrentDictionary<string, CompilerCacheEntry> _cache;
         private readonly IFileProvider _fileProvider;
+        private readonly IMemoryCache _cache;
 
         /// <summary>
         /// Initializes a new instance of <see cref="CompilerCache"/> populated with precompiled views
@@ -33,36 +35,39 @@ namespace Microsoft.AspNet.Mvc.Razor
         }
 
         // Internal for unit testing
-        internal CompilerCache(IEnumerable<RazorFileInfoCollection> viewCollections, IFileProvider fileProvider)
+        internal CompilerCache(IEnumerable<RazorFileInfoCollection> razorFileInfoCollection,
+                               IFileProvider fileProvider)
         {
             _fileProvider = fileProvider;
-            _cache = new ConcurrentDictionary<string, CompilerCacheEntry>(StringComparer.OrdinalIgnoreCase);
+            _cache = new MemoryCache(new MemoryCacheOptions { ListenForMemoryPressure = false });
-
+            var cacheEntries = new List<CompilerCacheEntry>();
-            foreach (var viewCollection in viewCollections)
+            foreach (var viewCollection in razorFileInfoCollection)
             {
+                var containingAssembly = viewCollection.GetType().GetTypeInfo().Assembly;
                 foreach (var fileInfo in viewCollection.FileInfos)
                 {
-                    var containingAssembly = viewCollection.GetType().GetTypeInfo().Assembly;
                     var viewType = containingAssembly.GetType(fileInfo.FullTypeName);
                     var cacheEntry = new CompilerCacheEntry(fileInfo, viewType);
 
                     // There shouldn't be any duplicates and if there are any the first will win.
                     // If the result doesn't match the one on disk its going to recompile anyways.
-                    _cache.TryAdd(NormalizePath(fileInfo.RelativePath), cacheEntry);
+                    _cache.Set(NormalizePath(fileInfo.RelativePath), cacheEntry, PopulateCacheSetContext);
+
+                    cacheEntries.Add(cacheEntry);
                 }
             }
 
             // Set up ViewStarts
-            foreach (var entry in _cache)
+            foreach (var entry in cacheEntries)
             {
-                var viewStartLocations = ViewStartUtility.GetViewStartLocations(entry.Key);
+                var viewStartLocations = ViewStartUtility.GetViewStartLocations(entry.RelativePath);
                 foreach (var location in viewStartLocations)
                 {
-                    CompilerCacheEntry viewStartEntry;
+                    var viewStartEntry = _cache.Get<CompilerCacheEntry>(location);
-                    if (_cache.TryGetValue(location, out viewStartEntry))
+                    if (viewStartEntry != null)
                     {
                         // Add the the composite _ViewStart entry as a dependency.
-                        entry.Value.AssociatedViewStartEntry = viewStartEntry;
+                        entry.AssociatedViewStartEntry = viewStartEntry;
                         break;
                     }
                 }
@@ -105,14 +110,19 @@ namespace Microsoft.AspNet.Mvc.Razor
                                             Func<RelativeFileInfo, CompilationResult> compile,
                                             out CompilationResult result)
         {
-            CompilerCacheEntry cacheEntry;
             var normalizedPath = NormalizePath(relativeFileInfo.RelativePath);
-            if (!_cache.TryGetValue(normalizedPath, out cacheEntry))
+            var cacheEntry = _cache.Get<CompilerCacheEntry>(normalizedPath);
+            if (cacheEntry == null)
             {
                 return OnCacheMiss(relativeFileInfo, normalizedPath, compile, out result);
             }
-            else
+            else if (cacheEntry.IsPreCompiled && !cacheEntry.IsValidatedPreCompiled)
             {
+                // For precompiled views, the first time the entry is read, we need to ensure that no changes were made
+                // either to the file associated with this entry, or any _ViewStart associated with it between the time
+                // the View was precompiled and the time EnsureInitialized was called. For later iterations, we can
+                // rely on expiration triggers ensuring the validity of the entry.
+
                 var fileInfo = relativeFileInfo.FileInfo;
                 if (cacheEntry.Length != fileInfo.Length)
                 {
@@ -129,6 +139,9 @@ namespace Microsoft.AspNet.Mvc.Razor
                 if (cacheEntry.LastModified == fileInfo.LastModified)
                 {
                     result = CompilationResult.Successful(cacheEntry.CompiledType);
+                    // Assigning to IsValidatedPreCompiled is an atomic operation and will result in a safe race
+                    // if it is being concurrently updated and read.
+                    cacheEntry.IsValidatedPreCompiled = true;
                     return cacheEntry;
                 }
 
@@ -139,9 +152,10 @@ namespace Microsoft.AspNet.Mvc.Razor
                                   StringComparison.Ordinal))
                 {
                     // Cache hit, but we need to update the entry.
-                    // Assigning to LastModified is an atomic operation and will result in a safe race if it is
+                    // Assigning to LastModified and IsValidatedPreCompiled are atomic operations and will result in safe races
-                    // being concurrently read and written or updated concurrently.
+                    // if the entry is being concurrently read or updated.
                     cacheEntry.LastModified = fileInfo.LastModified;
+                    cacheEntry.IsValidatedPreCompiled = true;
                     result = CompilationResult.Successful(cacheEntry.CompiledType);
 
                     return cacheEntry;
@@ -150,6 +164,9 @@ namespace Microsoft.AspNet.Mvc.Razor
                 // it's not a match, recompile
                 return OnCacheMiss(relativeFileInfo, normalizedPath, compile, out result);
             }
+
+            result = CompilationResult.Successful(cacheEntry.CompiledType);
+            return cacheEntry;
         }
 
         private CompilerCacheEntry OnCacheMiss(RelativeFileInfo file,
@@ -159,15 +176,24 @@ namespace Microsoft.AspNet.Mvc.Razor
         {
             result = compile(file);
 
-            var cacheEntry = new CompilerCacheEntry(file, result.CompiledType)
+            var cacheEntry = new CompilerCacheEntry(file, result.CompiledType);
-            {
-                AssociatedViewStartEntry = GetCompositeViewStartEntry(normalizedPath, compile)
-            };
 
-            // The cache is a concurrent dictionary, so concurrent addition to it with the same key would result in a
+            // Concurrent addition to MemoryCache with the same key result in safe race.
-            // safe race.
+            return _cache.Set(normalizedPath, cacheEntry, PopulateCacheSetContext);
-            _cache[normalizedPath] = cacheEntry;
+        }
-            return cacheEntry;
+
+        private CompilerCacheEntry PopulateCacheSetContext(ICacheSetContext cacheSetContext)
+        {
+            var entry = (CompilerCacheEntry)cacheSetContext.State;
+            cacheSetContext.AddExpirationTrigger(_fileProvider.Watch(entry.RelativePath));
+
+            var viewStartLocations = ViewStartUtility.GetViewStartLocations(cacheSetContext.Key);
+            foreach (var location in viewStartLocations)
+            {
+                cacheSetContext.AddExpirationTrigger(_fileProvider.Watch(location));
+            }
+
+            return entry;
         }
 
         private bool AssociatedViewStartsChanged(CompilerCacheEntry entry,

src/Microsoft.AspNet.Mvc.Razor/Compilation/CompilerCacheEntry.cs

@@ -82,5 +82,10 @@ namespace Microsoft.AspNet.Mvc.Razor
         /// depends on.
         /// </summary>
         public CompilerCacheEntry AssociatedViewStartEntry { get; set; }
+
+        /// <summary>
+        /// Gets or sets a flag that determines if the validity of this cache entry was performed at runtime.
+        /// </summary>
+        public bool IsValidatedPreCompiled { get; set; }
     }
 }

src/Microsoft.AspNet.Mvc.Razor/Razor/PreCompileViews/RazorPreCompiler.cs

@@ -167,13 +167,16 @@ namespace Microsoft.AspNet.Mvc.Razor
 
                     if (fullTypeName != null)
                     {
-                        var hash = RazorFileHash.GetHash(fileInfo.FileInfo, RazorFileHash.HashAlgorithmVersion1);
+                        var hashAlgorithmVersion = RazorFileHash.HashAlgorithmVersion1;
+                        var hash = RazorFileHash.GetHash(fileInfo.FileInfo, hashAlgorithmVersion);
                         var razorFileInfo = new RazorFileInfo
                         {
                             RelativePath = fileInfo.RelativePath,
                             LastModified = fileInfo.FileInfo.LastModified,
                             Length = fileInfo.FileInfo.Length,
-                            FullTypeName = fullTypeName
+                            FullTypeName = fullTypeName,
+                            Hash = hash,
+                            HashAlgorithmVersion = hashAlgorithmVersion
                         };
 
                         return new PrecompilationCacheEntry(razorFileInfo, syntaxTree);

test/Microsoft.AspNet.Mvc.FunctionalTests/PrecompilationTest.cs

@@ -167,6 +167,41 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             Assert.Equal(expected, responseContent.Trim());
         }
 
+        [Fact]
+        public async Task DeletingPrecompiledViewStart_PriorToFirstRequestToAView_CausesViewToBeRecompiled()
+        {
+            // Arrange
+            var expected = typeof(Startup).GetTypeInfo().Assembly.GetName().ToString();
+            var server = TestServer.Create(_services, _app);
+            var client = server.CreateClient();
+
+            var applicationEnvironment = _services.GetRequiredService<IApplicationEnvironment>();
+
+            var viewsDirectory = Path.Combine(applicationEnvironment.ApplicationBasePath, "Views", "ViewStartDelete");
+            var viewStartPath = Path.Combine(viewsDirectory, "_ViewStart.cshtml");
+            var viewStartContent = File.ReadAllText(viewStartPath);
+
+            // Act - 1
+            // Query the Test view so we know the compiler cache gets populated.
+            var response = await client.GetStringAsync("/Test");
+
+            // Assert - 1
+            Assert.Equal("Test", response.Trim());
+
+            try
+            {
+                // Act - 2
+                var response2 = await client.GetStringAsync("http://localhost/Home/ViewStartDeletedPriorToFirstRequest");
+
+                // Assert - 2
+                Assert.NotEqual(expected, response2.Trim());
+            }
+            finally
+            {
+                File.WriteAllText(viewStartPath, viewStartContent);
+            }
+        }
+
         private static Task TouchFile(string viewsDir, string file)
         {
             File.AppendAllText(Path.Combine(viewsDir, file), " ");

test/Microsoft.AspNet.Mvc.FunctionalTests/RazorCompilerCacheTest.cs

@@ -0,0 +1,48 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Net;
+using System.Threading.Tasks;
+using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.TestHost;
+using RazorCompilerCacheWebSite;
+using Xunit;
+
+namespace Microsoft.AspNet.Mvc.FunctionalTests
+{
+    public class RazorCompilerCacheTest
+    {
+        private readonly IServiceProvider _provider = TestHelper.CreateServices(nameof(RazorCompilerCacheWebSite));
+        private readonly Action<IApplicationBuilder> _app = new Startup().Configure;
+
+        [Fact]
+        public async Task CompilerCache_IsNotInitializedUntilFirstViewRequest()
+        {
+            // Arrange
+            var server = TestServer.Create(_provider, _app);
+            var client = server.CreateClient();
+            client.BaseAddress = new Uri("http://localhost");
+
+            // Act - 1
+            // Visit a sampling of controller actions that do not produce ViewResult
+            var result1 = await client.GetAsync("/file");
+            var result2 = await client.GetAsync("/statuscode");
+            var result3 = await client.GetStringAsync("/cache-status");
+
+            // Assert - 1
+            Assert.Equal(HttpStatusCode.OK, result1.StatusCode);
+            Assert.Equal(HttpStatusCode.OK, result2.StatusCode);
+            // Ensure the cache was not initialized.
+            Assert.Equal(bool.FalseString, result3);
+
+            // Act - 2
+            var result4 = await client.GetStringAsync("/view");
+            var result5 = await client.GetStringAsync("/cache-status");
+
+            // Assert - 2
+            Assert.Equal("Hello from view!", result4);
+            Assert.Equal(bool.TrueString, result5);
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.FunctionalTests/project.json

@@ -26,6 +26,7 @@
         "PrecompilationWebSite": "1.0.0",
         "RoutingWebSite": "1.0.0",
         "RazorWebSite": "1.0.0",
+        "RazorCompilerCacheWebSite": "1.0.0",
         "RazorInstrumentationWebsite": "1.0.0",
         "RazorViewEngineOptionsWebsite": "1.0.0",
         "RequestServicesWebSite": "1.0.0",

test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileProvider.cs

@@ -13,6 +13,8 @@ namespace Microsoft.AspNet.Mvc.Razor
     {
         private readonly Dictionary<string, IFileInfo> _lookup =
             new Dictionary<string, IFileInfo>(StringComparer.Ordinal);
+        private readonly Dictionary<string, TestFileTrigger> _fileTriggers =
+            new Dictionary<string, TestFileTrigger>(StringComparer.Ordinal);
 
         public IDirectoryContents GetDirectoryContents(string subpath)
         {
@@ -56,7 +58,19 @@ namespace Microsoft.AspNet.Mvc.Razor
 
         public IExpirationTrigger Watch(string filter)
         {
-            throw new NotImplementedException();
+            TestFileTrigger trigger;
+            if (!_fileTriggers.TryGetValue(filter, out trigger) || trigger.IsExpired)
+            {
+                trigger = new TestFileTrigger();
+                _fileTriggers[filter] = trigger;
+            }
+
+            return trigger;
+        }
+
+        public TestFileTrigger GetTrigger(string filter)
+        {
+            return _fileTriggers[filter];
         }
     }
 }

test/Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileTrigger.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.Framework.Expiration.Interfaces;
+
+namespace Microsoft.AspNet.Mvc.Razor
+{
+    public class TestFileTrigger : IExpirationTrigger
+    {
+        public bool ActiveExpirationCallbacks { get; } = false;
+
+        public bool IsExpired { get; set; }
+
+        public IDisposable RegisterExpirationCallback(Action<object> callback, object state)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

test/Microsoft.AspNet.Mvc.Razor.Test/Compilation/CompilerCacheTest.cs

@@ -262,7 +262,8 @@ namespace Microsoft.AspNet.Mvc.Razor
             Assert.Equal(typeof(PreCompile), actual1.CompiledType);
 
             // Act 2
-            fileProvider.AddFile("Views\\_ViewStart.cshtml", "");
+            var viewStartTrigger = fileProvider.GetTrigger("Views\\_ViewStart.cshtml");
+            viewStartTrigger.IsExpired = true;
             var actual2 = cache.GetOrAdd(relativeFile,
                                          compile: _ => CompilationResult.Successful(expectedType));
 
@@ -318,7 +319,8 @@ namespace Microsoft.AspNet.Mvc.Razor
             Assert.Equal(typeof(PreCompile), actual1.CompiledType);
 
             // Act 2
-            fileProvider.DeleteFile(viewStartFileInfo.PhysicalPath);
+            var trigger = fileProvider.GetTrigger(viewStartFileInfo.PhysicalPath);
+            trigger.IsExpired = true;
             var actual2 = cache.GetOrAdd(fileInfo,
                                          compile: _ => CompilationResult.Successful(expectedType));
 

test/Microsoft.AspNet.Mvc.Razor.Test/project.json

@@ -2,7 +2,8 @@
     "code": [
         "**/*.cs",
         "../Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileProvider.cs",
-        "../Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileInfo.cs" 
+        "../Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileInfo.cs",
+        "../Microsoft.AspNet.Mvc.Razor.Host.Test/TestFileTrigger.cs"
     ],
     "dependencies": {
         "Microsoft.AspNet.Mvc.Razor": "6.0.0-*",

test/WebSites/PrecompilationWebSite/Controllers/HomeController.cs

@@ -16,5 +16,16 @@ namespace PrecompilationWebSite.Controllers
         {
             return View("~/Views/ViewsConsumingCompilationOptions/Index");
         }
+
+        public IActionResult ViewStartDeletedPriorToFirstRequest()
+        {
+            return View("~/Views/ViewStartDelete/Index");
+        }
+
+        [HttpGet("/Test")]
+        public IActionResult TestView()
+        {
+            return View("~/Views/Test/Index");
+        }
     }
 }

test/WebSites/PrecompilationWebSite/Views/Home/Index.cshtml

@@ -1 +1 @@
-index:@GetType().GetTypeInfo().Assembly.GetName() 
+index:@GetType().GetTypeInfo().Assembly.GetName()

test/WebSites/PrecompilationWebSite/Views/Home/Layout.cshtml

@@ -1,2 +1,2 @@
 Layout:@GetType().GetTypeInfo().Assembly.FullName
-@RenderBody()    
+@RenderBody()

test/WebSites/PrecompilationWebSite/Views/Home/_ViewStart.cshtml

@@ -1,4 +1,3 @@
 @using System.Reflection
-@{ Layout = "/views/Home/Layout.cshtml";}
+@{ Layout = "/Views/Home/Layout.cshtml";}
 _viewstart:@GetType().GetTypeInfo().Assembly.FullName
-     

test/WebSites/PrecompilationWebSite/Views/Test/Index.cshtml

@@ -0,0 +1 @@
+Test

test/WebSites/PrecompilationWebSite/Views/ViewStartDelete/Index.cshtml

@@ -0,0 +1,2 @@
+@using System.Reflection;
+@GetType().GetTypeInfo().Assembly.FullName

test/WebSites/PrecompilationWebSite/Views/ViewStartDelete/_ViewStart.cshtml

@@ -0,0 +1 @@
+_ViewStart content

test/WebSites/RazorCompilerCacheWebSite/CompilerCacheController.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+
+namespace RazorCompilerCacheWebSite
+{
+    public class CompilerCacheController : Controller
+    {
+        [HttpGet("/cache-status")]
+        [Produces("text/plain")]
+        public ContentResult GetCompilerCacheInitializationStatus(
+            [FromServices] CompilerCacheInitialiedService service)
+        {
+            return Content(service.Initialized.ToString());
+        }
+
+        [HttpGet("/statuscode")]
+        public IActionResult StatusCodeAction()
+        {
+            return new EmptyResult();
+        }
+
+        [HttpGet("/file")]
+        public IActionResult FileAction()
+        {
+            return File("readme.md", "application/text");
+        }
+
+        [HttpGet("/view")]
+        public ViewResult Index()
+        {
+            return View("~/Index");
+        }
+    }
+}

test/WebSites/RazorCompilerCacheWebSite/Index.cshtml

@@ -0,0 +1 @@
+Hello from view!

test/WebSites/RazorCompilerCacheWebSite/RazorCompilerCacheWebSite.kproj

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="__ToolsVersion__" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\AspNet\Microsoft.Web.AspNet.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>42c5d417-4060-48f4-bb28-e9e179007779</ProjectGuid>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x86'" Label="Configuration">
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x86'" Label="Configuration">
+  </PropertyGroup>
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+    <DevelopmentServerPort>42473</DevelopmentServerPort>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\AspNet\Microsoft.Web.AspNet.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

test/WebSites/RazorCompilerCacheWebSite/Services/CompilerCacheInitialiedService.cs

@@ -0,0 +1,10 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+namespace RazorCompilerCacheWebSite
+{
+    public class CompilerCacheInitialiedService
+    {
+        public bool Initialized { get; set; }
+    }
+}

test/WebSites/RazorCompilerCacheWebSite/Services/CustomCompilerCache.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Mvc;
+using Microsoft.AspNet.Mvc.Razor;
+
+namespace RazorCompilerCacheWebSite
+{
+    public class CustomCompilerCache : CompilerCache
+    {
+        public CustomCompilerCache(IAssemblyProvider assemblyProvider,
+                                   IRazorFileProviderCache fileProvider,
+                                   CompilerCacheInitialiedService cacheInitializedService)
+            : base(assemblyProvider, fileProvider)
+        {
+            cacheInitializedService.Initialized = true;
+        }
+    }
+}

test/WebSites/RazorCompilerCacheWebSite/Startup.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Mvc.Razor;
+using Microsoft.Framework.DependencyInjection;
+
+namespace RazorCompilerCacheWebSite
+{
+    public class Startup
+    {
+        public void Configure(IApplicationBuilder app)
+        {
+            var configuration = app.GetTestConfiguration();
+
+            app.UseServices(services =>
+            {
+                services.AddMvc(configuration);
+                services.AddSingleton<ICompilerCache, CustomCompilerCache>();
+                services.AddSingleton<CompilerCacheInitialiedService>();
+            });
+
+            app.UseMvc();
+        }
+    }
+}

test/WebSites/RazorCompilerCacheWebSite/project.json

@@ -0,0 +1,19 @@
+{
+    "commands": {
+        "web": "Microsoft.AspNet.Hosting server=Microsoft.AspNet.Server.WebListener server.urls=http://localhost:5001",
+        "kestrel": "Microsoft.AspNet.Hosting --server Kestrel --server.urls http://localhost:5000"
+    },
+    "dependencies": {
+        "Kestrel": "1.0.0-*",
+        "Microsoft.AspNet.Mvc": "6.0.0-*",
+        "Microsoft.AspNet.Mvc.TestConfiguration": "1.0.0",
+        "Microsoft.AspNet.Server.IIS": "1.0.0-*",
+        "Microsoft.AspNet.Server.WebListener": "1.0.0-*",
+        "Microsoft.AspNet.StaticFiles": "1.0.0-*"
+    },
+    "frameworks": {
+        "aspnet50": { },
+        "aspnetcore50": { }
+    },
+    "webroot": "wwwroot"
+}

test/WebSites/RazorCompilerCacheWebSite/wwwroot/readme.md

@@ -0,0 +1 @@
+A functional test website to verify that the Razor compiler cache gets lazily initialized.