Add foreground dispatcher

src/Microsoft.VisualStudio.LanguageServices.Razor/Editor/ForegroundThreadAffinitizedObject.cs

@@ -1,34 +0,0 @@
-// 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.Threading;
-
-namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
-{
-    internal class ForegroundThreadAffinitizedObject
-    {
-        private readonly Thread _foregroundThread;
-
-        public ForegroundThreadAffinitizedObject()
-        {
-            _foregroundThread = Thread.CurrentThread;
-        }
-
-        public void AssertIsForeground()
-        {
-            if (Thread.CurrentThread != _foregroundThread)
-            {
-                throw new InvalidOperationException("Expected to be on the foreground thread and was not.");
-            }
-        }
-
-        public void AssertIsBackground()
-        {
-            if (Thread.CurrentThread == _foregroundThread)
-            {
-                throw new InvalidOperationException("Expected to be on a background thread and was not.");
-            }
-        }
-    }
-}

src/Microsoft.VisualStudio.LanguageServices.Razor/Editor/VisualStudioRazorParser.cs

@@ -22,11 +22,16 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
         private const int IdleDelay = 3000;
         private readonly ICompletionBroker _completionBroker;
         private readonly BackgroundParser _parser;
-        private readonly ForegroundThreadAffinitizedObject _foregroundThreadAffinitizedObject;
+        private readonly ForegroundDispatcher _dispatcher;
         private RazorSyntaxTreePartialParser _partialParser;
 
-        public VisualStudioRazorParser(ITextBuffer buffer, RazorTemplateEngine templateEngine, string filePath, ICompletionBroker completionBroker)
+        public VisualStudioRazorParser(ForegroundDispatcher dispatcher, ITextBuffer buffer, RazorTemplateEngine templateEngine, string filePath, ICompletionBroker completionBroker)
         {
+            if (dispatcher == null)
+            {
+                throw new ArgumentNullException(nameof(dispatcher));
+            }
+
             if (buffer == null)
             {
                 throw new ArgumentNullException(nameof(buffer));
@@ -47,6 +52,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
                 throw new ArgumentNullException(nameof(completionBroker));
             }
 
+            _dispatcher = dispatcher;
             TemplateEngine = templateEngine;
             FilePath = filePath;
             _textBuffer = buffer;
@@ -56,7 +62,6 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             _idleTimer = new Timer(IdleDelay);
             _idleTimer.Elapsed += Onidle;
             _parser.ResultsReady += OnResultsReady;
-            _foregroundThreadAffinitizedObject = new ForegroundThreadAffinitizedObject();
 
             _parser.Start();
         }
@@ -80,7 +85,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 
         public void Dispose()
         {
-            _foregroundThreadAffinitizedObject.AssertIsForeground();
+            _dispatcher.AssertForegroundThread();
 
             _textBuffer.Changed -= TextBuffer_OnChanged;
             _parser.Dispose();
@@ -89,7 +94,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 
         private void TextBuffer_OnChanged(object sender, TextContentChangedEventArgs contentChange)
         {
-            _foregroundThreadAffinitizedObject.AssertIsForeground();
+            _dispatcher.AssertForegroundThread();
 
             if (contentChange.Changes.Count > 0)
             {
@@ -144,7 +149,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 
         private void Onidle(object sender, ElapsedEventArgs e)
         {
-            _foregroundThreadAffinitizedObject.AssertIsBackground();
+            _dispatcher.AssertBackgroundThread();
 
             var textViews = Array.Empty<ITextView>();
 
@@ -162,7 +167,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 
         private void OnResultsReady(object sender, DocumentStructureChangedEventArgs args)
         {
-            _foregroundThreadAffinitizedObject.AssertIsBackground();
+            _dispatcher.AssertBackgroundThread();
 
             if (DocumentStructureChanged != null)
             {

src/Microsoft.VisualStudio.LanguageServices.Razor/ForegroundDispatcher.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;
+using System.Runtime.CompilerServices;
+
+namespace Microsoft.VisualStudio.LanguageServices.Razor
+{
+    internal abstract class ForegroundDispatcher
+    {
+        public abstract bool IsForegroundThread { get; }
+
+        public virtual void AssertForegroundThread([CallerMemberName] string caller = null)
+        {
+            if (!IsForegroundThread)
+            {
+                caller = caller == null ? Resources.ForegroundDispatcher_NoMethodNamePlaceholder : $"'{caller}'";
+                throw new InvalidOperationException(Resources.FormatForegroundDispatcher_AssertForegroundThread(caller));
+            }
+        }
+
+        public virtual void AssertBackgroundThread([CallerMemberName] string caller = null)
+        {
+            if (IsForegroundThread)
+            {
+                caller = caller == null ? Resources.ForegroundDispatcher_NoMethodNamePlaceholder : $"'{caller}'";
+                throw new InvalidOperationException(Resources.FormatForegroundDispatcher_AssertBackgroundThread(caller));
+            }
+        }
+    }
+}

src/Microsoft.VisualStudio.LanguageServices.Razor/Properties/Resources.Designer.cs

@@ -24,6 +24,48 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor
         internal static string FormatArgumentCannotBeNullOrEmpty()
             => GetString("ArgumentCannotBeNullOrEmpty");
 
+        /// <summary>
+        /// {0} must be called on a background thread.
+        /// </summary>
+        internal static string ForegroundDispatcher_AssertBackgroundThread
+        {
+            get => GetString("ForegroundDispatcher_AssertBackgroundThread");
+        }
+
+        /// <summary>
+        /// {0} must be called on a background thread.
+        /// </summary>
+        internal static string FormatForegroundDispatcher_AssertBackgroundThread(object p0)
+            => string.Format(CultureInfo.CurrentCulture, GetString("ForegroundDispatcher_AssertBackgroundThread"), p0);
+
+        /// <summary>
+        /// {0} must be called on the foreground thread.
+        /// </summary>
+        internal static string ForegroundDispatcher_AssertForegroundThread
+        {
+            get => GetString("ForegroundDispatcher_AssertForegroundThread");
+        }
+
+        /// <summary>
+        /// {0} must be called on the foreground thread.
+        /// </summary>
+        internal static string FormatForegroundDispatcher_AssertForegroundThread(object p0)
+            => string.Format(CultureInfo.CurrentCulture, GetString("ForegroundDispatcher_AssertForegroundThread"), p0);
+
+        /// <summary>
+        /// The method
+        /// </summary>
+        internal static string ForegroundDispatcher_NoMethodNamePlaceholder
+        {
+            get => GetString("ForegroundDispatcher_NoMethodNamePlaceholder");
+        }
+
+        /// <summary>
+        /// The method
+        /// </summary>
+        internal static string FormatForegroundDispatcher_NoMethodNamePlaceholder()
+            => GetString("ForegroundDispatcher_NoMethodNamePlaceholder");
+
         /// <summary>
         /// An unexpected exception occurred when invoking '{0}.{1}' on the Razor language service.
         /// </summary>

src/Microsoft.VisualStudio.LanguageServices.Razor/Resources.resx

@@ -120,6 +120,15 @@
   <data name="ArgumentCannotBeNullOrEmpty" xml:space="preserve">
     <value>Value cannot be null or an empty string.</value>
   </data>
+  <data name="ForegroundDispatcher_AssertBackgroundThread" xml:space="preserve">
+    <value>{0} must be called on a background thread.</value>
+  </data>
+  <data name="ForegroundDispatcher_AssertForegroundThread" xml:space="preserve">
+    <value>{0} must be called on the foreground thread.</value>
+  </data>
+  <data name="ForegroundDispatcher_NoMethodNamePlaceholder" xml:space="preserve">
+    <value>The method</value>
+  </data>
   <data name="UnexpectedException" xml:space="preserve">
     <value>An unexpected exception occurred when invoking '{0}.{1}' on the Razor language service.</value>
   </data>

test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Editor/VisualStudioRazorParserTest.cs

@@ -18,20 +18,20 @@ using Xunit;
 
 namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
 {
-    public class VisualStudioRazorParserTest
+    public class VisualStudioRazorParserTest : ForegroundDispatcherTestBase
     {
         private const string TestLinePragmaFileName = "C:\\This\\Path\\Is\\Just\\For\\Line\\Pragmas.cshtml";
 
         [Fact]
         public void ConstructorRequiresNonNullPhysicalPath()
         {
-            Assert.Throws<ArgumentException>("filePath", () => new VisualStudioRazorParser(new TestTextBuffer(null), CreateTemplateEngine(), null, new TestCompletionBroker()));
+            Assert.Throws<ArgumentException>("filePath", () => new VisualStudioRazorParser(Dispatcher, new TestTextBuffer(null), CreateTemplateEngine(), null, new TestCompletionBroker()));
         }
 
         [Fact]
         public void ConstructorRequiresNonEmptyPhysicalPath()
         {
-            Assert.Throws<ArgumentException>("filePath", () => new VisualStudioRazorParser(new TestTextBuffer(null), CreateTemplateEngine(), string.Empty, new TestCompletionBroker()));
+            Assert.Throws<ArgumentException>("filePath", () => new VisualStudioRazorParser(Dispatcher, new TestTextBuffer(null), CreateTemplateEngine(), string.Empty, new TestCompletionBroker()));
         }
 
         [Fact]
@@ -40,7 +40,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             // Arrange
             var original = new StringTextSnapshot("Foo @bar Baz");
             var testBuffer = new TestTextBuffer(original);
-            using (var parser = new VisualStudioRazorParser(testBuffer, CreateTemplateEngine(), TestLinePragmaFileName, new TestCompletionBroker()))
+            using (var parser = new VisualStudioRazorParser(Dispatcher, testBuffer, CreateTemplateEngine(), TestLinePragmaFileName, new TestCompletionBroker()))
             {
                 parser._idleTimer.Interval = 100;
                 var changed = new StringTextSnapshot("Foo @bap Daz");
@@ -519,9 +519,9 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             RunTypeKeywordTest("class");
         }
 
-        private static TestParserManager CreateParserManager(ITextSnapshot originalSnapshot)
+        private TestParserManager CreateParserManager(ITextSnapshot originalSnapshot, int idleDelay = 50)
         {
-            var parser = new VisualStudioRazorParser(new TestTextBuffer(originalSnapshot), CreateTemplateEngine(), TestLinePragmaFileName, new TestCompletionBroker());
+            var parser = new VisualStudioRazorParser(Dispatcher, new TestTextBuffer(originalSnapshot), CreateTemplateEngine(), TestLinePragmaFileName, new TestCompletionBroker());
 
             return new TestParserManager(parser);
         }
@@ -552,7 +552,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Razor.Editor
             return templateEngine;
         }
 
-        private static void RunTypeKeywordTest(string keyword)
+        private void RunTypeKeywordTest(string keyword)
         {
             // Arrange
             var before = "@" + keyword.Substring(0, keyword.Length - 1);

test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ForegroundDispatcherTestBase.cs

@@ -0,0 +1,19 @@
+// 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.Threading;
+
+namespace Microsoft.VisualStudio.LanguageServices.Razor
+{
+    public abstract class ForegroundDispatcherTestBase
+    {
+        internal ForegroundDispatcher Dispatcher { get; } = new SingleThreadedForegroundDispatcher();
+
+        private class SingleThreadedForegroundDispatcher : ForegroundDispatcher
+        {
+            private Thread Thread { get; } = Thread.CurrentThread;
+
+            public override bool IsForegroundThread => Thread.CurrentThread == Thread;
+        }
+    }
+}