Make C# completion list rewriting synchronous

C# completion list is currently split across three "rewriter" objects that are async. However, none of them need to be async if they're passed a RazorCodeDocument. So, this change acquires a RazorCodeDocument up front before calling the rewriters. With this in place, the rewriters can be synchronous.

Author: DustinCampbell

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/DelegatedCompletionHelper.cs

@@ -113,17 +113,18 @@ public static async ValueTask<VSInternalCompletionList> RewriteCSharpResponseAsy
             return new VSInternalCompletionList() { IsIncomplete = true, Items = [] };
         }
 
+        var codeDocument = await documentContext.GetCodeDocumentAsync(cancellationToken).ConfigureAwait(false);
+
         var rewrittenResponse = delegatedResponse;
 
         foreach (var rewriter in s_delegatedCSharpCompletionResponseRewriters)
         {
-            rewrittenResponse = await rewriter.RewriteAsync(
+            rewrittenResponse = rewriter.Rewrite(
                 rewrittenResponse,
+                codeDocument,
                 absoluteIndex,
-                documentContext,
                 projectedPosition,
-                completionOptions,
-                cancellationToken).ConfigureAwait(false);
+                completionOptions);
         }
 
         return rewrittenResponse;

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/DesignTimeHelperResponseRewriter.cs

@@ -3,12 +3,10 @@
 
 using System.Collections.Frozen;
 using System.Diagnostics;
-using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.PooledObjects;
-using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using RazorSyntaxNode = Microsoft.AspNetCore.Razor.Language.Syntax.SyntaxNode;
@@ -32,23 +30,24 @@ internal class DesignTimeHelperResponseRewriter : IDelegatedCSharpCompletionResp
         "BuildRenderTree"
     }.ToFrozenSet();
 
-    public async Task<VSInternalCompletionList> RewriteAsync(
+    public VSInternalCompletionList Rewrite(
         VSInternalCompletionList completionList,
+        RazorCodeDocument codeDocument,
         int hostDocumentIndex,
-        DocumentContext hostDocumentContext,
         Position projectedPosition,
-        RazorCompletionOptions completionOptions,
-        CancellationToken cancellationToken)
+        RazorCompletionOptions completionOptions)
     {
-        var syntaxTree = await hostDocumentContext.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
-        var owner = syntaxTree.Root.FindInnermostNode(hostDocumentIndex);
+        var owner = codeDocument
+            .GetRequiredSyntaxRoot()
+            .FindInnermostNode(hostDocumentIndex);
+
         if (owner is null)
         {
             Debug.Fail("Owner should never be null.");
             return completionList;
         }
 
-        var sourceText = await hostDocumentContext.GetSourceTextAsync(cancellationToken).ConfigureAwait(false);
+        var sourceText = codeDocument.Source.Text;
 
         // We should remove Razor design-time helpers from C#'s completion list. If the current identifier
         // being targeted does not start with a double underscore, we trim out all items starting with "__"

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/IDelegatedCSharpCompletionResponseRewriter.cs

@@ -1,20 +1,17 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.Razor.Completion.Delegation;
 
 internal interface IDelegatedCSharpCompletionResponseRewriter
 {
-    Task<VSInternalCompletionList> RewriteAsync(
+    VSInternalCompletionList Rewrite(
         VSInternalCompletionList completionList,
+        RazorCodeDocument codeDocument,
         int hostDocumentIndex,
-        DocumentContext hostDocumentContext,
         Position projectedPosition,
-        RazorCompletionOptions completionOptions,
-        CancellationToken cancellationToken);
+        RazorCompletionOptions completionOptions);
 }

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/SnippetResponseRewriter.cs

@@ -1,10 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System.Threading;
-using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
-using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.Razor.Completion.Delegation;
@@ -17,13 +15,12 @@ namespace Microsoft.CodeAnalysis.Razor.Completion.Delegation;
 /// </remarks>
 internal class SnippetResponseRewriter : IDelegatedCSharpCompletionResponseRewriter
 {
-    public Task<VSInternalCompletionList> RewriteAsync(
+    public VSInternalCompletionList Rewrite(
         VSInternalCompletionList completionList,
+        RazorCodeDocument codeDocument,
         int hostDocumentIndex,
-        DocumentContext hostDocumentContext,
         Position projectedPosition,
-        RazorCompletionOptions completionOptions,
-        CancellationToken cancellationToken)
+        RazorCompletionOptions completionOptionsn)
     {
         using var items = new PooledArrayBuilder<CompletionItem>(completionList.Items.Length);
 
@@ -43,6 +40,6 @@ public Task<VSInternalCompletionList> RewriteAsync(
             completionList.Items = items.ToArray();
         }
 
-        return Task.FromResult(completionList);
+        return completionList;
     }
 }

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/Delegation/TextEditResponseRewriter.cs

@@ -1,24 +1,21 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.Razor.Completion.Delegation;
 
 internal class TextEditResponseRewriter : IDelegatedCSharpCompletionResponseRewriter
 {
-    public async Task<VSInternalCompletionList> RewriteAsync(
+    public VSInternalCompletionList Rewrite(
         VSInternalCompletionList completionList,
+        RazorCodeDocument codeDocument,
         int hostDocumentIndex,
-        DocumentContext hostDocumentContext,
         Position projectedPosition,
-        RazorCompletionOptions completionOptions,
-        CancellationToken cancellationToken)
+        RazorCompletionOptions completionOptions)
     {
-        var sourceText = await hostDocumentContext.GetSourceTextAsync(cancellationToken).ConfigureAwait(false);
+        var sourceText = codeDocument.Source.Text;
 
         var hostDocumentPosition = sourceText.GetPosition(hostDocumentIndex);
         completionList = TranslateTextEdits(hostDocumentPosition, projectedPosition, completionList);

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/RazorCodeDocumentExtensions.cs

@@ -22,6 +22,12 @@ internal static class RazorCodeDocumentExtensions
 {
     private static readonly object s_csharpSyntaxTreeKey = new();
 
+    public static RazorSyntaxTree GetRequiredSyntaxTree(this RazorCodeDocument codeDocument)
+        => codeDocument.GetSyntaxTree().AssumeNotNull();
+
+    public static Syntax.SyntaxNode GetRequiredSyntaxRoot(this RazorCodeDocument codeDocument)
+        => codeDocument.GetRequiredSyntaxTree().Root;
+
     public static SourceText GetCSharpSourceText(this RazorCodeDocument document)
         => document.GetCSharpDocument().Text;