Add mapped edits helper (dotnet#11146)

Razor side of implementing IRazorMappingService.

Adds a RazorEditorHelper that specifically is designed to handle complex edits in csharp files that are generated by razor. Handles adding, removing, renaming, and a mix of both for usings. The rest of edits are put exactly where they map to.

Author: Andrew Hall

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/TextChangeExtensions.cs

@@ -1,9 +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 System;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis.Text;
 

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Extensions/IServiceCollectionExtensions.cs

@@ -180,6 +180,7 @@ public static void AddTextDocumentServices(this IServiceCollection services, Lan
         services.AddHandler<DocumentDidSaveEndpoint>();
 
         services.AddHandler<RazorMapToDocumentRangesEndpoint>();
+        services.AddHandler<RazorMapToDocumentEditsEndpoint>();
         services.AddHandler<RazorLanguageQueryEndpoint>();
     }
 

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/LspDocumentMappingService.cs

@@ -17,25 +17,26 @@ internal sealed class LspDocumentMappingService(
     IFilePathService filePathService,
     IDocumentContextFactory documentContextFactory,
     ILoggerFactory loggerFactory)
-    : AbstractDocumentMappingService(filePathService, loggerFactory.GetOrCreateLogger<LspDocumentMappingService>())
+    : AbstractDocumentMappingService(loggerFactory.GetOrCreateLogger<LspDocumentMappingService>())
 {
+    private readonly IFilePathService _filePathService = filePathService;
     private readonly IDocumentContextFactory _documentContextFactory = documentContextFactory;
 
     public async Task<(Uri MappedDocumentUri, LinePositionSpan MappedRange)> MapToHostDocumentUriAndRangeAsync(
         Uri generatedDocumentUri,
         LinePositionSpan generatedDocumentRange,
         CancellationToken cancellationToken)
     {
-        var razorDocumentUri = FilePathService.GetRazorDocumentUri(generatedDocumentUri);
+        var razorDocumentUri = _filePathService.GetRazorDocumentUri(generatedDocumentUri);
 
         // For Html we just map the Uri, the range will be the same
-        if (FilePathService.IsVirtualHtmlFile(generatedDocumentUri))
+        if (_filePathService.IsVirtualHtmlFile(generatedDocumentUri))
         {
             return (razorDocumentUri, generatedDocumentRange);
         }
 
         // We only map from C# files
-        if (!FilePathService.IsVirtualCSharpFile(generatedDocumentUri))
+        if (!_filePathService.IsVirtualCSharpFile(generatedDocumentUri))
         {
             return (generatedDocumentUri, generatedDocumentRange);
         }
@@ -47,7 +48,7 @@ internal sealed class LspDocumentMappingService(
 
         var codeDocument = await documentContext.GetCodeDocumentAsync(cancellationToken).ConfigureAwait(false);
 
-        if (!codeDocument.TryGetGeneratedDocument(generatedDocumentUri, FilePathService, out var generatedDocument))
+        if (!codeDocument.TryGetGeneratedDocument(generatedDocumentUri, _filePathService, out var generatedDocument))
         {
             return Assumed.Unreachable<(Uri, LinePositionSpan)>();
         }

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Mapping/RazorMapToDocumentEditsEndpoint.cs

@@ -0,0 +1,88 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.LanguageServer.EndpointContracts;
+using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.CodeAnalysis.Razor.DocumentMapping;
+using Microsoft.CodeAnalysis.Razor.Logging;
+using Microsoft.CodeAnalysis.Razor.Protocol;
+using Microsoft.CodeAnalysis.Razor.Protocol.DocumentMapping;
+using Microsoft.CodeAnalysis.Text;
+using Microsoft.CommonLanguageServerProtocol.Framework;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Mapping;
+
+[RazorLanguageServerEndpoint(LanguageServerConstants.RazorMapToDocumentEditsEndpoint)]
+internal partial class RazorMapToDocumentEditsEndpoint(IDocumentMappingService documentMappingService, ITelemetryReporter telemetryReporter, ILoggerFactory loggerFactory) :
+    IRazorDocumentlessRequestHandler<RazorMapToDocumentEditsParams, RazorMapToDocumentEditsResponse?>,
+    ITextDocumentIdentifierHandler<RazorMapToDocumentEditsParams, Uri>
+{
+    private readonly IDocumentMappingService _documentMappingService = documentMappingService;
+    private readonly ITelemetryReporter _telemetryReporter = telemetryReporter;
+    private readonly ILogger _logger = loggerFactory.GetOrCreateLogger<RazorMapToDocumentEditsEndpoint>();
+
+    public bool MutatesSolutionState => false;
+
+    public Uri GetTextDocumentIdentifier(RazorMapToDocumentEditsParams request)
+    {
+        return request.RazorDocumentUri;
+    }
+
+    public async Task<RazorMapToDocumentEditsResponse?> HandleRequestAsync(RazorMapToDocumentEditsParams request, RazorRequestContext requestContext, CancellationToken cancellationToken)
+    {
+        var documentContext = requestContext.DocumentContext;
+        if (documentContext is null)
+        {
+            return null;
+        }
+
+        if (request.TextChanges.Length == 0)
+        {
+            return null;
+        }
+
+        if (request.Kind != RazorLanguageKind.CSharp)
+        {
+            // All other non-C# requests map directly to where they are in the document,
+            // so the edits do as well
+            return new RazorMapToDocumentEditsResponse()
+            {
+                TextChanges = request.TextChanges,
+                HostDocumentVersion = documentContext.Snapshot.Version,
+            };
+        }
+
+        var mappedEdits = await RazorEditHelper.MapCSharpEditsAsync(
+            request.TextChanges.ToImmutableArray(),
+            documentContext.Snapshot,
+            _documentMappingService,
+            _telemetryReporter,
+            cancellationToken).ConfigureAwait(false);
+
+        _logger.LogTrace($"""
+            Before:
+            {DisplayEdits(request.TextChanges)}
+
+            After:
+            {DisplayEdits(mappedEdits)}
+            """);
+
+        return new RazorMapToDocumentEditsResponse()
+        {
+            TextChanges = mappedEdits.ToArray(),
+        };
+    }
+
+    private static string DisplayEdits(IEnumerable<RazorTextChange> changes)
+        => string.Join(
+            Environment.NewLine,
+            changes.Select(e => $"{e.Span} => '{e.NewText}'"));
+}

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/DocumentMapping/AbstractDocumentMappingService.cs

@@ -11,15 +11,13 @@
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor.Logging;
-using Microsoft.CodeAnalysis.Razor.Workspaces;
 using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.Razor.DocumentMapping;
 
-internal abstract class AbstractDocumentMappingService(IFilePathService filePathService, ILogger logger) : IDocumentMappingService
+internal abstract class AbstractDocumentMappingService(ILogger logger) : IDocumentMappingService
 {
-    protected readonly IFilePathService FilePathService = filePathService;
     protected readonly ILogger Logger = logger;
 
     public IEnumerable<TextChange> GetHostDocumentEdits(IRazorGeneratedDocument generatedDocument, ImmutableArray<TextChange> generatedDocumentChanges)

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/DocumentMapping/RangeComparer.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+
+namespace Microsoft.CodeAnalysis.Razor.Workspaces.DocumentMapping;
+
+internal sealed class RangeComparer : IComparer<Range>
+{
+    public static readonly RangeComparer Instance = new();
+
+    public int Compare(Range? x, Range? y)
+    {
+        if (x is null)
+        {
+            return y is null ? 0 : 1;
+        }
+
+        if (y is null)
+        {
+            return -1;
+        }
+
+        return x.CompareTo(y);
+    }
+}