Adding support for Razor precompilation

Fixes #3917

Author: pranavkm

src/Microsoft.AspNetCore.Mvc.Core/ApplicationParts/AssemblyPart.cs

@@ -12,8 +12,27 @@ namespace Microsoft.AspNetCore.Mvc.ApplicationParts
     /// <summary>
     /// An <see cref="ApplicationPart"/> backed by an <see cref="Assembly"/>.
     /// </summary>
-    public class AssemblyPart : ApplicationPart, IApplicationPartTypeProvider, ICompilationReferencesProvider
+    public class AssemblyPart :
+        ApplicationPart,
+        IApplicationPartTypeProvider,
+        ICompilationReferencesProvider,
+        IViewsProvider
     {
+        /// <summary>
+        /// Gets the suffix for the view assembly.
+        /// </summary>
+        public static readonly string PrecompiledViewsAssemblySuffix = ".PrecompiledViews";
+
+        /// <summary>
+        /// Gets the namespace for the <see cref="ViewInfoContainer"/> type in the view assembly.
+        /// </summary>
+        public static readonly string ViewInfoContainerNamespace = "AspNetCore";
+
+        /// <summary>
+        /// Gets the type name for the view collection type in the view assembly.
+        /// </summary>
+        public static readonly string ViewInfoContainerTypeName = "__PrecompiledViewCollection";
+
         /// <summary>
         /// Initalizes a new <see cref="AssemblyPart"/> instance.
         /// </summary>
@@ -41,6 +60,27 @@ public AssemblyPart(Assembly assembly)
         /// <inheritdoc />
         public IEnumerable<TypeInfo> Types => Assembly.DefinedTypes;
 
+        /// <inheritdoc />
+        public IEnumerable<ViewInfo> Views
+        {
+            get
+            {
+                var precompiledAssemblyName = new AssemblyName(Assembly.FullName);
+                precompiledAssemblyName.Name = precompiledAssemblyName.Name + PrecompiledViewsAssemblySuffix;
+
+                var typeName = $"{ViewInfoContainerNamespace}.{ViewInfoContainerTypeName},{precompiledAssemblyName}";
+                var viewInfoContainerTypeName = Type.GetType(typeName);
+
+                if (viewInfoContainerTypeName == null)
+                {
+                    return null;
+                }
+
+                var precompiledViews = (ViewInfoContainer)Activator.CreateInstance(viewInfoContainerTypeName);
+                return precompiledViews.ViewInfos;
+            }
+        }
+
         /// <inheritdoc />
         public IEnumerable<string> GetReferencePaths()
         {

src/Microsoft.AspNetCore.Mvc.Core/ApplicationParts/IViewsProvider.cs

@@ -0,0 +1,18 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Mvc.ApplicationParts
+{
+    /// <summary>
+    /// Exposes a sequence of views associated with an <see cref="ApplicationPart"/> .
+    /// </summary>
+    public interface IViewsProvider
+    {
+        /// <summary>
+        /// Gets the sequence of <see cref="ViewInfo"/>.
+        /// </summary>
+        IEnumerable<ViewInfo> Views { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/ApplicationParts/ViewInfo.cs

@@ -0,0 +1,34 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Mvc.ApplicationParts
+{
+    /// <summary>
+    /// Provides information for precompiled views.
+    /// </summary>
+    public class ViewInfo
+    {
+        /// <summary>
+        /// Creates a new instance of <see cref="ViewInfo" />.
+        /// </summary>
+        /// <param name="path">The path of the view.</param>
+        /// <param name="type">The view <see cref="System.Type"/>.</param>
+        public ViewInfo(string path, Type type)
+        {
+            Path = path;
+            Type = type;
+        }
+
+        /// <summary>
+        /// The path of the view.
+        /// </summary>
+        public string Path { get; }
+
+        /// <summary>
+        /// The view <see cref="System.Type"/>.
+        /// </summary>
+        public Type Type { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/ApplicationParts/ViewInfoContainer.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Mvc.ApplicationParts
+{
+    /// <summary>
+    /// A container for <see cref="ViewInfo"/> instances.
+    /// </summary>
+    public class ViewInfoContainer
+    {
+        /// <summary>
+        /// Initializes a new instance of <see cref="ViewInfos"/>.
+        /// </summary>
+        /// <param name="views">The sequence of <see cref="ViewInfo"/>.</param>
+        public ViewInfoContainer(IReadOnlyList<ViewInfo> views)
+        {
+            ViewInfos = views;
+        }
+
+        /// <summary>
+        /// The <see cref="IReadOnlyList{T}"/> of <see cref="ViewInfo"/>.
+        /// </summary>
+        public IReadOnlyList<ViewInfo> ViewInfos { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/IDesignTimeMvcBuilderConfiguration.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// Configures the <see cref="IMvcBuilder"/>. Implement this interface to enable design-time configuration
+    /// (for instance during pre-compilation of views) of <see cref="IMvcBuilder"/>.
+    /// </summary>
+    public interface IDesignTimeMvcBuilderConfiguration
+    {
+        /// <summary>
+        /// Configures the <see cref="IMvcBuilder"/>.
+        /// </summary>
+        /// <param name="builder">The <see cref="IMvcBuilder"/>.</param>
+        void ConfigureMvc(IMvcBuilder builder);
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/Compilation/ViewsFeature.cs

@@ -0,0 +1,14 @@
+// Copyright (c) .NET Foundation. 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.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Compilation
+{
+    public class ViewsFeature
+    {
+        public IDictionary<string, Type> Views { get; } =
+            new Dictionary<string, Type>(StringComparer.OrdinalIgnoreCase);
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/Compilation/ViewsFeatureProvider.cs

@@ -0,0 +1,31 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.AspNetCore.Mvc.ApplicationParts;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Compilation
+{
+    /// <summary>
+    /// An <see cref="IApplicationFeatureProvider{TFeature}"/> for <see cref="ViewsFeature"/>.
+    /// </summary>
+    public class ViewsFeatureProvider : IApplicationFeatureProvider<ViewsFeature>
+    {
+        /// <inheritdoc />
+        public void PopulateFeature(IEnumerable<ApplicationPart> parts, ViewsFeature feature)
+        {
+            foreach (var provider in parts.OfType<IViewsProvider>())
+            {
+                var precompiledViews = provider.Views;
+                if (precompiledViews != null)
+                {
+                    foreach (var viewInfo in precompiledViews)
+                    {
+                        feature.Views[viewInfo.Path] = viewInfo.Type;
+                    }
+                }
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/DependencyInjection/MvcRazorMvcCoreBuilderExtensions.cs

@@ -72,6 +72,11 @@ private static void AddRazorViewEngineFeatureProviders(IMvcCoreBuilder builder)
             {
                 builder.PartManager.FeatureProviders.Add(new MetadataReferenceFeatureProvider());
             }
+
+            if (!builder.PartManager.FeatureProviders.OfType<ViewsFeatureProvider>().Any())
+            {
+                builder.PartManager.FeatureProviders.Add(new ViewsFeatureProvider());
+            }
         }
 
         /// <summary>
@@ -127,6 +132,8 @@ public static IMvcCoreBuilder InitializeTagHelper<TTagHelper>(
         // Internal for testing.
         internal static void AddRazorViewEngineServices(IServiceCollection services)
         {
+            services.TryAddSingleton<CSharpCompiler>();
+            services.TryAddSingleton<RazorReferenceManager>();
             // This caches compilation related details that are valid across the lifetime of the application.
             services.TryAddSingleton<ICompilationService, DefaultRoslynCompilationService>();
 
@@ -165,7 +172,7 @@ internal static void AddRazorViewEngineServices(IServiceCollection services)
             // creating the singleton RazorViewEngine instance.
             services.TryAddTransient<IRazorPageFactoryProvider, DefaultRazorPageFactoryProvider>();
             services.TryAddTransient<IRazorCompilationService, RazorCompilationService>();
-            services.TryAddTransient<IMvcRazorHost,MvcRazorHost>();
+            services.TryAddTransient<IMvcRazorHost, MvcRazorHost>();
 
             // This caches Razor page activation details that are valid for the lifetime of the application.
             services.TryAddSingleton<IRazorPageActivator, RazorPageActivator>();

src/Microsoft.AspNetCore.Mvc.Razor/Internal/CSharpCompiler.cs

@@ -0,0 +1,51 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.Emit;
+using Microsoft.CodeAnalysis.Text;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Mvc.Razor.Internal
+{
+    public class CSharpCompiler
+    {
+        private readonly CSharpCompilationOptions _compilationOptions;
+        private readonly CSharpParseOptions _parseOptions;
+        private readonly RazorReferenceManager _referenceManager;
+        private readonly DebugInformationFormat _pdbFormat =
+#if NET451
+            SymbolsUtility.SupportsFullPdbGeneration() ?
+                DebugInformationFormat.Pdb :
+                DebugInformationFormat.PortablePdb;
+#else
+            DebugInformationFormat.PortablePdb;
+#endif
+
+        public CSharpCompiler(RazorReferenceManager manager, IOptions<RazorViewEngineOptions> optionsAccessor)
+        {
+            _referenceManager = manager;
+            _compilationOptions = optionsAccessor.Value.CompilationOptions;
+            _parseOptions = optionsAccessor.Value.ParseOptions;
+            EmitOptions = new EmitOptions(debugInformationFormat: _pdbFormat);
+        }
+
+        public EmitOptions EmitOptions { get; }
+
+        public SyntaxTree CreateSyntaxTree(SourceText sourceText)
+        {
+            return CSharpSyntaxTree.ParseText(
+                sourceText,
+                options: _parseOptions);
+        }
+
+        public CSharpCompilation CreateCompilation(string assemblyName)
+        {
+            return CSharpCompilation.Create(
+                assemblyName,
+                options: _compilationOptions,
+                references: _referenceManager.CompilationReferences);
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Razor/Internal/CompilerCache.cs

@@ -42,22 +42,22 @@ public CompilerCache(IFileProvider fileProvider)
 
         /// <summary>
         /// Initializes a new instance of <see cref="CompilerCache"/> populated with precompiled views
-        /// specified by <paramref name="precompiledViews"/>.
+        /// specified by <paramref name="views"/>.
         /// </summary>
         /// <param name="fileProvider"><see cref="IFileProvider"/> used to locate Razor views.</param>
-        /// <param name="precompiledViews">A mapping of application relative paths of view to the precompiled view
-        /// <see cref="Type"/>s.</param>
+        /// <param name="views">A mapping of application relative paths of view to <see cref="Type"/>s that
+        /// have already been compiled.</param>
         public CompilerCache(
             IFileProvider fileProvider,
-            IDictionary<string, Type> precompiledViews)
+            IDictionary<string, Type> views)
             : this(fileProvider)
         {
-            if (precompiledViews == null)
+            if (views == null)
             {
-                throw new ArgumentNullException(nameof(precompiledViews));
+                throw new ArgumentNullException(nameof(views));
             }
 
-            foreach (var item in precompiledViews)
+            foreach (var item in views)
             {
                 var cacheEntry = new CompilerCacheResult(item.Key, new CompilationResult(item.Value));
                 _cache.Set(GetNormalizedPath(item.Key), Task.FromResult(cacheEntry));

src/Microsoft.AspNetCore.Mvc.Razor/Internal/DefaultCompilerCacheProvider.cs

@@ -1,7 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using Microsoft.Extensions.Options;
+using Microsoft.AspNetCore.Mvc.ApplicationParts;
+using Microsoft.AspNetCore.Mvc.Razor.Compilation;
 
 namespace Microsoft.AspNetCore.Mvc.Razor.Internal
 {
@@ -13,10 +14,15 @@ public class DefaultCompilerCacheProvider : ICompilerCacheProvider
         /// <summary>
         /// Initializes a new instance of <see cref="DefaultCompilerCacheProvider"/>.
         /// </summary>
+        /// <param name="applicationPartManager">The <see cref="ApplicationPartManager" /></param>
         /// <param name="fileProviderAccessor">The <see cref="IRazorViewEngineFileProviderAccessor"/>.</param>
-        public DefaultCompilerCacheProvider(IRazorViewEngineFileProviderAccessor fileProviderAccessor)
+        public DefaultCompilerCacheProvider(
+            ApplicationPartManager applicationPartManager,
+            IRazorViewEngineFileProviderAccessor fileProviderAccessor)
         {
-            Cache = new CompilerCache(fileProviderAccessor.FileProvider);
+            var feature = new ViewsFeature();
+            applicationPartManager.PopulateFeature(feature);
+            Cache = new CompilerCache(fileProviderAccessor.FileProvider, feature.Views);
         }
 
         /// <inheritdoc />