Convert endpoint to dynamic registration

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Common/VSInternalServerCapabilitiesExtensions.cs

@@ -24,16 +24,20 @@ public static void EnableDocumentColorProvider(this VSInternalServerCapabilities
 
     public static void EnableSemanticTokens(this VSInternalServerCapabilities serverCapabilities, ISemanticTokensLegendService legend)
     {
-        serverCapabilities.SemanticTokensOptions = new SemanticTokensOptions
+        serverCapabilities.SemanticTokensOptions = new SemanticTokensOptions().EnableSemanticTokens(legend);
+    }
+
+    public static SemanticTokensOptions EnableSemanticTokens(this SemanticTokensOptions options, ISemanticTokensLegendService legend)
+    {
+        options.Full = false;
+        options.Legend = new SemanticTokensLegend
         {
-            Full = false,
-            Legend = new SemanticTokensLegend
-            {
-                TokenModifiers = legend.TokenModifiers.All,
-                TokenTypes = legend.TokenTypes.All
-            },
-            Range = true,
+            TokenModifiers = legend.TokenModifiers.All,
+            TokenTypes = legend.TokenTypes.All
         };
+        options.Range = true;
+
+        return options;
     }
 
     public static void EnableHoverProvider(this VSInternalServerCapabilities serverCapabilities)

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/SemanticTokens/RemoteCSharpSemanticTokensProvider.cs

@@ -32,6 +32,11 @@ internal class RemoteCSharpSemanticTokensProvider(IFilePathService filePathServi
         // We have a razor document, lets find the generated C# document
         var generatedDocument = GetGeneratedDocument(documentContext);
 
+        var csharpSourceText = await documentContext.GetCSharpSourceTextAsync(cancellationToken).ConfigureAwait(false);
+
+        // HACK: We're not in the same solution fork as the LSP server that provides content for this document
+        generatedDocument = generatedDocument.WithText(csharpSourceText);
+
         var data = await SemanticTokensRange.GetSemanticTokensAsync(
             generatedDocument,
             csharpRanges,

src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/CohostEndpointAttribute.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CommonLanguageServerProtocol.Framework;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+internal class CohostEndpointAttribute : LanguageServerEndpointAttribute
+{
+    public CohostEndpointAttribute(string method)
+        : base(method, Constants.RazorLanguageName)
+    {
+    }
+}

src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/CohostSemanticTokensRangeEndpoint.cs

@@ -6,8 +6,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
-using Microsoft.AspNetCore.Razor.LanguageServer;
-using Microsoft.AspNetCore.Razor.LanguageServer.Common;
 using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
 using Microsoft.CodeAnalysis.Razor.Logging;
@@ -20,16 +18,15 @@
 namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
 
 [Shared]
-[RazorLanguageServerEndpoint(Methods.TextDocumentSemanticTokensRangeName)]
-[ExportRazorStatelessLspService(typeof(CohostSemanticTokensRangeEndpoint))]
-[Export(typeof(ICapabilitiesProvider))]
+[CohostEndpoint(Methods.TextDocumentSemanticTokensRangeName)]
+[ExportCohostStatelessLspService(typeof(CohostSemanticTokensRangeEndpoint))]
 [method: ImportingConstructor]
 internal sealed class CohostSemanticTokensRangeEndpoint(
     IOutOfProcSemanticTokensService semanticTokensInfoService,
     ISemanticTokensLegendService semanticTokensLegendService,
     ITelemetryReporter telemetryReporter,
     IRazorLoggerFactory loggerFactory)
-    : AbstractRazorCohostDocumentRequestHandler<SemanticTokensRangeParams, SemanticTokens?>, ICapabilitiesProvider
+    : AbstractRazorCohostDocumentRequestHandler<SemanticTokensRangeParams, SemanticTokens?>
 {
     private readonly IOutOfProcSemanticTokensService _semanticTokensInfoService = semanticTokensInfoService;
     private readonly ISemanticTokensLegendService _semanticTokensLegendService = semanticTokensLegendService;
@@ -42,11 +39,6 @@ internal sealed class CohostSemanticTokensRangeEndpoint(
     protected override RazorTextDocumentIdentifier? GetRazorTextDocumentIdentifier(SemanticTokensRangeParams request)
         => request.TextDocument.ToRazorTextDocumentIdentifier();
 
-    public void ApplyCapabilities(VSInternalServerCapabilities serverCapabilities, VSInternalClientCapabilities clientCapabilities)
-    {
-        serverCapabilities.EnableSemanticTokens(_semanticTokensLegendService);
-    }
-
     protected override async Task<SemanticTokens?> HandleRequestAsync(SemanticTokensRangeParams request, RazorCohostRequestContext context, CancellationToken cancellationToken)
     {
         var correlationId = Guid.NewGuid();

src/Razor/src/Microsoft.VisualStudio.LanguageServerClient.Razor/Cohost/RazorCohostDynamicRegistrationService.cs

@@ -0,0 +1,75 @@
+// 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.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor;
+using Microsoft.AspNetCore.Razor.LanguageServer.Common;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+using Microsoft.CodeAnalysis.Razor.Logging;
+using Microsoft.CodeAnalysis.Razor.SemanticTokens;
+using Microsoft.CodeAnalysis.Razor.Workspaces;
+using Microsoft.CodeAnalysis.Razor.Workspaces.Protocol;
+using Microsoft.Extensions.Logging;
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+using Newtonsoft.Json;
+
+namespace Microsoft.VisualStudio.LanguageServerClient.Razor.Cohost;
+
+[Shared]
+[Export(typeof(IRazorCohostDynamicRegistrationService))]
+[Export(typeof(IClientCapabilitiesService))]
+[method: ImportingConstructor]
+internal class RazorCohostDynamicRegistrationService(LanguageServerFeatureOptions languageServerFeatureOptions, Lazy<ISemanticTokensLegendService> semanticTokensLegendService, IRazorLoggerFactory loggerFactory) : IRazorCohostDynamicRegistrationService, IClientCapabilitiesService
+{
+    private readonly string _id = Guid.NewGuid().ToString();
+    private readonly DocumentFilter[] _filter = [new DocumentFilter()
+    {
+        Language = Constants.RazorLanguageName,
+        Pattern = "**/*.{razor,cshtml}"
+    }];
+
+    private readonly LanguageServerFeatureOptions _languageServerFeatureOptions = languageServerFeatureOptions;
+    private readonly Lazy<ISemanticTokensLegendService> _semanticTokensLegendService = semanticTokensLegendService;
+    private readonly ILogger _logger = loggerFactory.CreateLogger<RazorCohostDynamicRegistrationService>();
+
+    private VSInternalClientCapabilities? _clientCapabilities;
+
+    public bool CanGetClientCapabilities => _clientCapabilities is not null;
+
+    public VSInternalClientCapabilities ClientCapabilities => _clientCapabilities.AssumeNotNull();
+
+    public async Task RegisterAsync(string clientCapabilities, IRazorCohostClientLanguageServerManager razorCohostClientLanguageServerManager, CancellationToken cancellationToken)
+    {
+        if (!_languageServerFeatureOptions.UseRazorCohostServer)
+        {
+            return;
+        }
+
+        _clientCapabilities = JsonConvert.DeserializeObject<VSInternalClientCapabilities>(clientCapabilities) ?? new();
+
+        // TODO: Get the options from the from the endpoints somehow
+        if (_clientCapabilities.TextDocument?.SemanticTokens?.DynamicRegistration == true)
+        {
+            await razorCohostClientLanguageServerManager.SendRequestAsync(
+                Methods.ClientRegisterCapabilityName,
+                new RegistrationParams()
+                {
+                    Registrations = [
+                        new Registration()
+                        {
+                            Id = _id,
+                            Method = Methods.TextDocumentSemanticTokensRangeName,
+                            RegisterOptions = new SemanticTokensRegistrationOptions()
+                            {
+                                DocumentSelector = _filter,
+                            }.EnableSemanticTokens(_semanticTokensLegendService.Value)
+                        }
+                    ]
+                },
+                cancellationToken).ConfigureAwait(false);
+        }
+    }
+}