Consolidate code

Author: Andrew Hall

src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/Services/DynamicFileInfoProvider.cs

@@ -1,24 +1,13 @@
 // 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 Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor.Features;
 
 namespace Microsoft.VisualStudioCode.RazorExtension.Services;
 
-[ExportRazorLspServiceFactory(typeof(RazorLspDynamicFileInfoProvider)), Shared]
-internal sealed class DynamicFileProviderFactory : AbstractRazorLspServiceFactory
-{
-    protected override AbstractRazorLspService CreateService(IRazorLspServices lspServices)
-    {
-        var clientLanguageServerManager = lspServices.GetRequiredService<IRazorClientLanguageServerManager>();
-        return new LspDynamicFileProvider(clientLanguageServerManager);
-    }
-}
-
-file sealed class LspDynamicFileProvider(IRazorClientLanguageServerManager clientLanguageServerManager) : RazorLspDynamicFileInfoProvider
+internal sealed partial class LspDynamicFileProvider(IRazorClientLanguageServerManager clientLanguageServerManager) : RazorLspDynamicFileInfoProvider
 {
     private const string ProvideRazorDynamicFileInfoMethodName = "razor/provideDynamicFileInfo";
     private const string RemoveRazorDynamicFileInfoMethodName = "razor/removeDynamicFileInfo";

src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/Services/DynamicFileProviderFactory.cs

@@ -0,0 +1,19 @@
+// 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 Microsoft.CodeAnalysis.ExternalAccess.Razor;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor.Features;
+
+namespace Microsoft.VisualStudioCode.RazorExtension.Services;
+
+[ExportRazorLspServiceFactory(typeof(RazorLspDynamicFileInfoProvider)), Shared]
+internal sealed class DynamicFileProviderFactory : AbstractRazorLspServiceFactory
+{
+    protected override AbstractRazorLspService CreateService(IRazorLspServices lspServices)
+    {
+        var clientLanguageServerManager = lspServices.GetRequiredService<IRazorClientLanguageServerManager>();
+        return new LspDynamicFileProvider(clientLanguageServerManager);
+    }
+}
+

src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/Services/LspDynamicFileProvider.LspTextChangesTextLoader.cs

@@ -0,0 +1,107 @@
+// 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.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.ExternalAccess.Razor;
+using Microsoft.CodeAnalysis.Razor.Protocol;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.VisualStudioCode.RazorExtension.Services;
+
+internal sealed partial class LspDynamicFileProvider
+{
+    private sealed class LspTextChangesTextLoader(
+        TextDocument? document,
+        RazorTextChange[] changes,
+        byte[] checksum,
+        SourceHashAlgorithm checksumAlgorithm,
+        int? codePage,
+        Uri razorUri,
+        IRazorClientLanguageServerManager razorClientLanguageServerManager) : TextLoader
+    {
+        private readonly TextDocument? _document = document;
+        private readonly ImmutableArray<TextChange> _changes = changes.SelectAsArray(c => c.ToTextChange());
+        private readonly byte[] _checksum = checksum;
+        private readonly SourceHashAlgorithm _checksumAlgorithm = checksumAlgorithm;
+        private readonly int? _codePage = codePage;
+        private readonly Uri _razorUri = razorUri;
+        private readonly IRazorClientLanguageServerManager _razorClientLanguageServerManager = razorClientLanguageServerManager;
+        private readonly Lazy<SourceText> _emptySourceText = new(() =>
+        {
+            var encoding = codePage is null ? null : Encoding.GetEncoding(codePage.Value);
+            return SourceText.From("", checksumAlgorithm: checksumAlgorithm, encoding: encoding);
+        });
+
+        public override async Task<TextAndVersion> LoadTextAndVersionAsync(LoadTextOptions options, CancellationToken cancellationToken)
+        {
+            if (_document is null)
+            {
+                var text = ApplyChanges(_emptySourceText.Value, _changes);
+                return TextAndVersion.Create(text, VersionStamp.Default.GetNewerVersion());
+            }
+
+            var sourceText = await _document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+
+            // Validate the checksum information so the edits are known to be correct
+            if (IsSourceTextMatching(sourceText))
+            {
+                var version = await _document.GetTextVersionAsync(cancellationToken).ConfigureAwait(false);
+                var newText = ApplyChanges(sourceText, _changes);
+                return TextAndVersion.Create(newText, version.GetNewerVersion());
+            }
+
+            return await GetFullDocumentFromServerAsync(cancellationToken).ConfigureAwait(false);
+        }
+
+        private bool IsSourceTextMatching(SourceText sourceText)
+        {
+            if (sourceText.ChecksumAlgorithm != _checksumAlgorithm)
+            {
+                return false;
+            }
+
+            if (sourceText.Encoding?.CodePage != _codePage)
+            {
+                return false;
+            }
+
+            if (!sourceText.GetChecksum().SequenceEqual(_checksum))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        private async Task<TextAndVersion> GetFullDocumentFromServerAsync(CancellationToken cancellationToken)
+        {
+            var response = await _razorClientLanguageServerManager.SendRequestAsync<RazorProvideDynamicFileParams, RazorProvideDynamicFileResponse>(
+                ProvideRazorDynamicFileInfoMethodName,
+                new RazorProvideDynamicFileParams
+                {
+                    RazorDocument = new()
+                    {
+                        Uri = _razorUri,
+                    },
+                    FullText = true
+                },
+                cancellationToken).ConfigureAwait(false);
+
+            var text = ApplyChanges(_emptySourceText.Value, response.Edits.SelectAsArray(e => e.ToTextChange()));
+            return TextAndVersion.Create(text, VersionStamp.Default.GetNewerVersion());
+        }
+
+        private static SourceText ApplyChanges(SourceText sourceText, ImmutableArray<TextChange> changes)
+        {
+            foreach (var change in changes)
+            {
+                sourceText = sourceText.WithChanges(change);
+            }
+
+            return sourceText;
+        }
+    }
+}
+