RazorProjectEngineFeatureBase: Clean up and add Initialize method

This is similar to the last commit. All IRazorProjectEngineFeature implementations now inherit from RazorProjectEngineFeatureBase.

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorProjectEngineFeatureBaseTest.cs

@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -16,7 +14,7 @@ public void ProjectEngineSetter_CallsOnInitialized()
         var testFeature = new TestFeature();
 
         // Act
-        testFeature.ProjectEngine = RazorProjectEngine.CreateEmpty();
+        testFeature.Initialize(RazorProjectEngine.CreateEmpty());
 
         // Assert
         Assert.Equal(1, testFeature.InitializationCount);

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Components/ComponentImportProjectFeature.cs

@@ -11,7 +11,7 @@
 
 namespace Microsoft.AspNetCore.Razor.Language.Components;
 
-internal class ComponentImportProjectFeature : IImportProjectFeature
+internal class ComponentImportProjectFeature : RazorProjectEngineFeatureBase, IImportProjectFeature
 {
     // Using explicit newlines here to avoid fooling our baseline tests
     private const string DefaultUsingImportContent =
@@ -22,8 +22,6 @@ internal class ComponentImportProjectFeature : IImportProjectFeature
         "@using global::System.Threading.Tasks\r\n" +
         "@using global::" + ComponentsApi.RenderFragment.Namespace + "\r\n"; // Microsoft.AspNetCore.Components
 
-    public RazorProjectEngine ProjectEngine { get; set; }
-
     public IReadOnlyList<RazorProjectItem> GetImports(RazorProjectItem projectItem)
     {
         if (projectItem == null)

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/IRazorProjectEngineFeature.cs

@@ -1,11 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 namespace Microsoft.AspNetCore.Razor.Language;
 
 public interface IRazorProjectEngineFeature : IRazorFeature
 {
-    RazorProjectEngine ProjectEngine { get; set; }
+    RazorProjectEngine ProjectEngine { get; init; }
+
+    void Initialize(RazorProjectEngine projectEngine);
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngine.cs

@@ -37,7 +37,7 @@ internal RazorProjectEngine(
 
         foreach (var projectFeature in features)
         {
-            projectFeature.ProjectEngine = this;
+            projectFeature.Initialize(this);
         }
     }
 

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngineFeatureBase.cs

@@ -1,29 +1,31 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System;
+using System.Threading;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
 public abstract class RazorProjectEngineFeatureBase : IRazorProjectEngineFeature
 {
-    private RazorProjectEngine _projectEngine;
+    private RazorProjectEngine? _projectEngine;
 
-    public virtual RazorProjectEngine ProjectEngine
+    public RazorProjectEngine ProjectEngine
     {
-        get => _projectEngine;
-        set
-        {
-            if (value == null)
-            {
-                throw new ArgumentNullException(nameof(value));
-            }
+        get => _projectEngine.AssumeNotNull(Resources.FeatureMustBeInitialized);
+        init => Initialize(value);
+    }
 
-            _projectEngine = value;
-            OnInitialized();
+    public void Initialize(RazorProjectEngine projectEngine)
+    {
+        ArgHelper.ThrowIfNull(projectEngine);
+
+        if (Interlocked.CompareExchange(ref _projectEngine, projectEngine, null) is not null)
+        {
+            throw new InvalidOperationException(Resources.FeatureAlreadyInitialized);
         }
+
+        OnInitialized();
     }
 
     protected virtual void OnInitialized()

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Language/IntegrationTests/RazorToolingIntegrationTestBase.cs

@@ -410,7 +410,7 @@ public void Configure(RazorCodeGenerationOptionsBuilder options)
         }
     }
 
-    private class TestImportProjectFeature : IImportProjectFeature
+    private class TestImportProjectFeature : RazorProjectEngineFeatureBase, IImportProjectFeature
     {
         private readonly List<RazorProjectItem> _imports;
 
@@ -419,8 +419,6 @@ public TestImportProjectFeature(List<RazorProjectItem> imports)
             _imports = imports;
         }
 
-        public RazorProjectEngine ProjectEngine { get; set; }
-
         public IReadOnlyList<RazorProjectItem> GetImports(RazorProjectItem projectItem)
         {
             return _imports;

src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/IntegrationTestBase.cs

@@ -810,7 +810,7 @@ protected override void OnInitialized()
         {
             if (_inner != null)
             {
-                _inner.ProjectEngine = ProjectEngine;
+                _inner.Initialize(ProjectEngine);
             }
         }
 

src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorIntegrationTestBase.cs

@@ -519,7 +519,7 @@ public void Configure(RazorCodeGenerationOptionsBuilder options)
         }
     }
 
-    private class TestImportProjectFeature : IImportProjectFeature
+    private class TestImportProjectFeature : RazorProjectEngineFeatureBase, IImportProjectFeature
     {
         private readonly List<RazorProjectItem> _imports;
 
@@ -528,8 +528,6 @@ public TestImportProjectFeature(List<RazorProjectItem> imports)
             _imports = imports;
         }
 
-        public RazorProjectEngine? ProjectEngine { get; set; }
-
         public IReadOnlyList<RazorProjectItem> GetImports(RazorProjectItem projectItem)
         {
             return _imports;