Support line folding only in folding ranges

Author: davidwengier

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/FoldingRanges/RemoteFoldingRangeService.cs

@@ -7,6 +7,7 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.CodeAnalysis.Razor.FoldingRanges;
+using Microsoft.CodeAnalysis.Razor.Protocol;
 using Microsoft.CodeAnalysis.Razor.Protocol.Folding;
 using Microsoft.CodeAnalysis.Razor.Remote;
 using Microsoft.CodeAnalysis.Remote.Razor.ProjectSystem;
@@ -23,6 +24,7 @@ protected override IRemoteFoldingRangeService CreateService(in ServiceArgs args)
     }
 
     private readonly IFoldingRangeService _foldingRangeService = args.ExportProvider.GetExportedValue<IFoldingRangeService>();
+    private readonly IClientCapabilitiesService _clientCapabilitiesService = args.ExportProvider.GetExportedValue<IClientCapabilitiesService>();
 
     public ValueTask<ImmutableArray<RemoteFoldingRange>> GetFoldingRangesAsync(
         RazorPinnedSolutionInfoWrapper solutionInfo,
@@ -44,7 +46,8 @@ private async ValueTask<ImmutableArray<RemoteFoldingRange>> GetFoldingRangesAsyn
             .GetGeneratedDocumentAsync(cancellationToken)
             .ConfigureAwait(false);
 
-        var csharpRanges = await ExternalHandlers.FoldingRanges.GetFoldingRangesAsync(generatedDocument, cancellationToken).ConfigureAwait(false);
+        var lineFoldingOnly = _clientCapabilitiesService.ClientCapabilities.TextDocument?.FoldingRange?.LineFoldingOnly ?? false;
+        var csharpRanges = await ExternalHandlers.FoldingRanges.GetFoldingRangesAsync(generatedDocument, lineFoldingOnly, cancellationToken).ConfigureAwait(false);
 
         var convertedCSharp = csharpRanges.SelectAsArray(ToFoldingRange);
         var convertedHtml = htmlRanges.SelectAsArray(RemoteFoldingRange.ToVsFoldingRange);

src/Razor/test/Microsoft.VisualStudioCode.RazorExtension.Test/Endpoints/Shared/CohostFoldingRangeEndpointTest.cs

@@ -239,8 +239,79 @@ public void M() {[|
             }|]
             """);
 
-    private async Task VerifyFoldingRangesAsync(string input, RazorFileKind? fileKind = null, bool miscellaneousFile = false, string? razorFilePath = null)
+    [Fact]
+    public Task CSharp_LineFoldingOnly()
+        => VerifyFoldingRangesAsync("""
+            <div>{|html:
+              Hello @_name
+            </div>|}
+
+            @code {[|
+                class C { public void M1() {[|
+                        var x = 1;
+            |]        }
+                }
+            }|]
+            """,
+            lineFoldingOnly: true);
+
+    [Fact]
+    public Task CSharp_NotLineFoldingOnly()
+    => VerifyFoldingRangesAsync("""
+            <div>{|html:
+              Hello @_name
+            </div>|}
+
+            @code {[|
+                class C { public void M1() {[|
+                        var x = 1;
+                    }
+                }|]
+            }|]
+            """,
+        lineFoldingOnly: false);
+
+    [Fact]
+    public Task IfElseStatements_LineFoldingOnly()
+      => VerifyFoldingRangesAsync("""
+            <div>
+              @if (true) {[|
+                <div>
+                  Hello World
+                </div>
+                } else {[|
+                <div>
+                    Goodbye World
+                </div>
+            |]    }
+            |]  }
+            </div>
+
+            @code[|
+            {
+                void M()[|
+                {
+                    if (true) {[|
+            |]            var x = 1;
+                    } else {[|
+                        var y = 2;
+            |]        }
+            |]    }
+            }|]
+            """,
+            lineFoldingOnly: true);
+
+    private async Task VerifyFoldingRangesAsync(string input, RazorFileKind? fileKind = null, bool miscellaneousFile = false, string? razorFilePath = null, bool lineFoldingOnly = false)
     {
+        UpdateClientLSPInitializationOptions(c =>
+        {
+            c.ClientCapabilities.TextDocument!.FoldingRange = new FoldingRangeSetting()
+            {
+                LineFoldingOnly = lineFoldingOnly,
+            };
+            return c;
+        });
+
         TestFileMarkupParser.GetSpans(input, out var source, out ImmutableDictionary<string, ImmutableArray<TextSpan>> spans);
         var document = CreateProjectAndRazorDocument(source, fileKind, miscellaneousFile: miscellaneousFile, documentFilePath: razorFilePath);
         var inputText = await document.GetTextAsync(DisposalToken);