Use Roslyn project info in cohost endpoints

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Cohost/CohostDocumentContextFactory.cs

@@ -0,0 +1,31 @@
+// 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 Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Cohost;
+
+// NOTE: This is not a "normal" MEF export (ie, exporting an interface) purely because of a strange desire to keep API in
+//       RazorCohostRequestContextExtensions looking like the previous code in the non-cohost world.
+[ExportRazorStatelessLspService(typeof(CohostDocumentContextFactory))]
+[method: ImportingConstructor]
+internal class CohostDocumentContextFactory(DocumentSnapshotFactory documentSnapshotFactory, IDocumentVersionCache documentVersionCache) : AbstractRazorLspService
+{
+    private readonly DocumentSnapshotFactory _documentSnapshotFactory = documentSnapshotFactory;
+    private readonly IDocumentVersionCache _documentVersionCache = documentVersionCache;
+
+    public VersionedDocumentContext Create(Uri documentUri, TextDocument textDocument)
+    {
+        var documentSnapshot = _documentSnapshotFactory.GetOrCreate(textDocument);
+
+        // HACK: For cohosting, we just grab the "current" version, because we know it will have been updated
+        //       since the change handling is synchronous. In future we can just remove the whole concept of
+        //       document versions because TextDocument is inherently versioned.
+        var version = _documentVersionCache.GetLatestDocumentVersion(documentSnapshot.FilePath.AssumeNotNull());
+
+        return new VersionedDocumentContext(documentUri, documentSnapshot, null, version);
+    }
+}

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Cohost/CohostDocumentSnapshot.cs

@@ -0,0 +1,73 @@
+// 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.Immutable;
+using System.Diagnostics.CodeAnalysis;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Cohost;
+
+internal class CohostDocumentSnapshot(TextDocument textDocument, IProjectSnapshot projectSnapshot) : IDocumentSnapshot
+{
+    private readonly TextDocument _textDocument = textDocument;
+    private readonly IProjectSnapshot _projectSnapshot = projectSnapshot;
+
+    private RazorCodeDocument? _codeDocument;
+
+    public string? FileKind => FileKinds.GetFileKindFromFilePath(FilePath);
+
+    public string? FilePath => _textDocument.FilePath;
+
+    public string? TargetPath => _textDocument.FilePath;
+
+    public IProjectSnapshot Project => _projectSnapshot;
+
+    public bool SupportsOutput => true;
+
+    public Task<SourceText> GetTextAsync() => _textDocument.GetTextAsync();
+
+    public Task<VersionStamp> GetTextVersionAsync() => _textDocument.GetTextVersionAsync();
+
+    public bool TryGetText([NotNullWhen(true)] out SourceText? result) => _textDocument.TryGetText(out result);
+
+    public bool TryGetTextVersion(out VersionStamp result) => _textDocument.TryGetTextVersion(out result);
+
+    public ImmutableArray<IDocumentSnapshot> GetImports()
+    {
+        return DocumentState.GetImportsCore(Project, FilePath.AssumeNotNull(), FileKind.AssumeNotNull());
+    }
+
+    public async Task<RazorCodeDocument> GetGeneratedOutputAsync()
+    {
+        // TODO: We don't need to worry about locking if we get called from the didOpen/didChange LSP requests, as CLaSP
+        //       takes care of that for us, and blocks requests until those are complete. If that doesn't end up happening,
+        //       then a locking mechanism here would prevent concurrent compilations.
+        if (_codeDocument is not null)
+        {
+            return _codeDocument;
+        }
+
+        // The non-cohosted DocumentSnapshot implementation uses DocumentState to get the generated output, and we could do that too
+        // but most of that code is optimized around caching pre-computed results when things change that don't affect the compilation.
+        // We can't do that here because we are using Roslyn's project snapshots, which don't contain the info that Razor needs. We could
+        // in future provide a side-car mechanism so we can cache things, but still take advantage of snapshots etc. but the working
+        // assumption for this code is that the source generator will be used, and it will do all of that, so this implementation is naive
+        // and simply compiles when asked, and if a new document snapshot comes in, we compile again. This is presumably worse for perf
+        // but since we don't expect users to ever use cohosting without source generators, it's fine for now.
+
+        var imports = await DocumentState.ComputedStateTracker.GetImportsAsync(this).ConfigureAwait(false);
+        _codeDocument = await DocumentState.ComputedStateTracker.GenerateCodeDocumentAsync(Project, this, imports).ConfigureAwait(false);
+
+        return _codeDocument;
+    }
+
+    public bool TryGetGeneratedOutput([NotNullWhen(true)] out RazorCodeDocument? result)
+    {
+        result = _codeDocument;
+        return result is not null;
+    }
+}

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Cohost/CohostProjectSnapshot.cs

@@ -0,0 +1,160 @@
+// 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.IO;
+using System.Linq;
+using System.Threading;
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.PooledObjects;
+using Microsoft.AspNetCore.Razor.ProjectEngineHost;
+using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.AspNetCore.Razor.Utilities;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.Razor;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+using Microsoft.VisualStudio.Threading;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Cohost;
+
+internal class CohostProjectSnapshot : IProjectSnapshot
+{
+    private static readonly EmptyProjectEngineFactory s_fallbackProjectEngineFactory = new();
+    private static readonly (IProjectEngineFactory Value, ICustomProjectEngineFactoryMetadata)[] s_projectEngineFactories = ProjectEngineFactories.Factories.Select(f => (f.Item1.Value, f.Item2)).ToArray();
+
+    private readonly Project _project;
+    private readonly DocumentSnapshotFactory _documentSnapshotFactory;
+    private readonly ITelemetryReporter _telemetryReporter;
+    private readonly ProjectKey _projectKey;
+    private readonly Lazy<RazorConfiguration> _lazyConfiguration;
+    private readonly Lazy<RazorProjectEngine> _lazyProjectEngine;
+    private readonly AsyncLazy<ImmutableArray<TagHelperDescriptor>> _tagHelpersLazy;
+    private readonly Lazy<ImmutableDictionary<string, ImmutableArray<string>>> _importsToRelatedDocumentsLazy;
+
+    public CohostProjectSnapshot(Project project, DocumentSnapshotFactory documentSnapshotFactory, ITelemetryReporter telemetryReporter, JoinableTaskContext joinableTaskContext)
+    {
+        _project = project;
+        _documentSnapshotFactory = documentSnapshotFactory;
+        _telemetryReporter = telemetryReporter;
+        _projectKey = ProjectKey.From(_project)!.Value;
+
+        _lazyConfiguration = new Lazy<RazorConfiguration>(CreateRazorConfiguration);
+        _lazyProjectEngine = new Lazy<RazorProjectEngine>(() => DefaultProjectEngineFactory.Create(
+            Configuration,
+            fileSystem: RazorProjectFileSystem.Create(Path.GetDirectoryName(FilePath)),
+            configure: builder =>
+            {
+                builder.SetRootNamespace(RootNamespace);
+                builder.SetCSharpLanguageVersion(CSharpLanguageVersion);
+                builder.SetSupportLocalizedComponentNames();
+            },
+            fallback: s_fallbackProjectEngineFactory,
+            factories: s_projectEngineFactories));
+
+        _tagHelpersLazy = new AsyncLazy<ImmutableArray<TagHelperDescriptor>>(() =>
+        {
+            var resolver = new CompilationTagHelperResolver(_telemetryReporter);
+            return resolver.GetTagHelpersAsync(_project, GetProjectEngine(), CancellationToken.None).AsTask();
+        }, joinableTaskContext.Factory);
+
+        _importsToRelatedDocumentsLazy = new Lazy<ImmutableDictionary<string, ImmutableArray<string>>>(() =>
+        {
+            var importsToRelatedDocuments = ImmutableDictionary.Create<string, ImmutableArray<string>>(FilePathNormalizer.Comparer);
+            foreach (var document in DocumentFilePaths)
+            {
+                var importTargetPaths = ProjectState.GetImportDocumentTargetPaths(document, FileKinds.GetFileKindFromFilePath(document), GetProjectEngine());
+                importsToRelatedDocuments = ProjectState.AddToImportsToRelatedDocuments(importsToRelatedDocuments, document, importTargetPaths);
+            }
+
+            return importsToRelatedDocuments;
+        });
+    }
+
+    public ProjectKey Key => _projectKey;
+
+    public RazorConfiguration Configuration => _lazyConfiguration.Value;
+
+    public IEnumerable<string> DocumentFilePaths
+        => _project.AdditionalDocuments
+            .Where(d => d.FilePath!.EndsWith(".razor", StringComparison.OrdinalIgnoreCase) || d.FilePath.EndsWith(".cshtml", StringComparison.OrdinalIgnoreCase))
+            .Select(d => d.FilePath.AssumeNotNull());
+
+    public string FilePath => _project.FilePath!;
+
+    public string IntermediateOutputPath => FilePathNormalizer.GetNormalizedDirectoryName(_project.CompilationOutputInfo.AssemblyPath);
+
+    public string? RootNamespace => _project.DefaultNamespace ?? "ASP";
+
+    public string DisplayName => _project.Name;
+
+    public VersionStamp Version => _project.Version;
+
+    public LanguageVersion CSharpLanguageVersion => ((CSharpParseOptions)_project.ParseOptions!).LanguageVersion;
+
+    public ImmutableArray<TagHelperDescriptor> TagHelpers => _tagHelpersLazy.GetValue();
+
+    public ProjectWorkspaceState ProjectWorkspaceState => ProjectWorkspaceState.Create(TagHelpers, CSharpLanguageVersion);
+
+    public IDocumentSnapshot? GetDocument(string filePath)
+    {
+        var textDocument = _project.AdditionalDocuments.FirstOrDefault(d => d.FilePath == filePath);
+        if (textDocument is null)
+        {
+            return null;
+        }
+
+        return _documentSnapshotFactory.GetOrCreate(textDocument);
+    }
+
+    public RazorProjectEngine GetProjectEngine() => _lazyProjectEngine.Value;
+
+    public ImmutableArray<IDocumentSnapshot> GetRelatedDocuments(IDocumentSnapshot document)
+    {
+        var targetPath = document.TargetPath.AssumeNotNull();
+
+        if (!_importsToRelatedDocumentsLazy.Value.TryGetValue(targetPath, out var relatedDocuments))
+        {
+            return ImmutableArray<IDocumentSnapshot>.Empty;
+        }
+
+        using var _ = ArrayBuilderPool<IDocumentSnapshot>.GetPooledObject(out var builder);
+
+        foreach (var relatedDocumentFilePath in relatedDocuments)
+        {
+            if (GetDocument(relatedDocumentFilePath) is { } relatedDocument)
+            {
+                builder.Add(relatedDocument);
+            }
+        }
+
+        return builder.ToImmutableArray();
+    }
+
+    public bool IsImportDocument(IDocumentSnapshot document)
+    {
+        return document.TargetPath is { } targetPath && _importsToRelatedDocumentsLazy.Value.ContainsKey(targetPath);
+    }
+
+    private RazorConfiguration CreateRazorConfiguration()
+    {
+        // See RazorSourceGenerator.RazorProviders.cs
+
+        var globalOptions = _project.AnalyzerOptions.AnalyzerConfigOptionsProvider.GlobalOptions;
+
+        globalOptions.TryGetValue("build_property.RazorConfiguration", out var configurationName);
+
+        configurationName ??= "MVC-3.0"; // TODO: Source generator uses "default" here??
+
+        if (!globalOptions.TryGetValue("build_property.RazorLangVersion", out var razorLanguageVersionString) ||
+            !RazorLanguageVersion.TryParse(razorLanguageVersionString, out var razorLanguageVersion))
+        {
+            razorLanguageVersion = RazorLanguageVersion.Latest;
+        }
+
+        return RazorConfiguration.Create(razorLanguageVersion, configurationName, Enumerable.Empty<RazorExtension>(), useConsolidatedMvcViews: true);
+    }
+}

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Cohost/DocumentSnapshotFactory.cs

@@ -0,0 +1,31 @@
+// 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.Runtime.CompilerServices;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Cohost;
+
+[Export(typeof(DocumentSnapshotFactory)), Shared]
+[method: ImportingConstructor]
+internal class DocumentSnapshotFactory(Lazy<ProjectSnapshotFactory> projectSnapshotFactory)
+{
+    private readonly Lazy<ProjectSnapshotFactory> _projectSnapshotFactory = projectSnapshotFactory;
+
+    private readonly ConditionalWeakTable<TextDocument, IDocumentSnapshot> _documentSnapshots = new();
+
+    public IDocumentSnapshot GetOrCreate(TextDocument textDocument)
+    {
+        if (!_documentSnapshots.TryGetValue(textDocument, out var documentSnapshot))
+        {
+            var projectSnapshot = _projectSnapshotFactory.Value.GetOrCreate(textDocument.Project);
+            documentSnapshot = new CohostDocumentSnapshot(textDocument, projectSnapshot);
+            _documentSnapshots.Add(textDocument, documentSnapshot);
+        }
+
+        return documentSnapshot;
+    }
+}

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Cohost/ProjectSnapshotFactory.cs

@@ -0,0 +1,33 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System.Composition;
+using System.Runtime.CompilerServices;
+using Microsoft.AspNetCore.Razor.Telemetry;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
+using Microsoft.VisualStudio.Threading;
+
+namespace Microsoft.AspNetCore.Razor.LanguageServer.Cohost;
+
+[Export(typeof(ProjectSnapshotFactory)), Shared]
+[method: ImportingConstructor]
+internal class ProjectSnapshotFactory(DocumentSnapshotFactory documentSnapshotFactory, ITelemetryReporter telemetryReporter, JoinableTaskContext joinableTaskContext)
+{
+    private readonly DocumentSnapshotFactory _documentSnapshotFactory = documentSnapshotFactory;
+    private readonly ITelemetryReporter _telemetryReporter = telemetryReporter;
+    private readonly JoinableTaskContext _joinableTaskContext = joinableTaskContext;
+
+    private readonly ConditionalWeakTable<Project, IProjectSnapshot> _projectSnapshots = new();
+
+    public IProjectSnapshot GetOrCreate(Project project)
+    {
+        if (!_projectSnapshots.TryGetValue(project, out var projectSnapshot))
+        {
+            projectSnapshot = new CohostProjectSnapshot(project, _documentSnapshotFactory, _telemetryReporter, _joinableTaskContext);
+            _projectSnapshots.Add(project, projectSnapshot);
+        }
+
+        return projectSnapshot;
+    }
+}

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

@@ -64,6 +64,18 @@ private void TrackDocumentVersion(IDocumentSnapshot documentSnapshot, int versio
         }
     }
 
+    public int GetLatestDocumentVersion(string filePath)
+    {
+        using var _ = _lock.EnterReadLock();
+
+        if (!DocumentLookup_NeedsLock.TryGetValue(filePath, out var documentEntries))
+        {
+            return -1;
+        }
+
+        return documentEntries[^1].Version;
+    }
+
     public bool TryGetDocumentVersion(IDocumentSnapshot documentSnapshot, [NotNullWhen(true)] out int? version)
     {
         if (documentSnapshot is null)

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

@@ -10,4 +10,7 @@ internal interface IDocumentVersionCache
 {
     bool TryGetDocumentVersion(IDocumentSnapshot documentSnapshot, [NotNullWhen(true)] out int? version);
     void TrackDocumentVersion(IDocumentSnapshot documentSnapshot, int version);
+
+    // HACK: This is temporary to allow the cohosting and normal language server to co-exist and share code
+    int GetLatestDocumentVersion(string filePath);
 }