Added DocumentHighlight support to TextDocumentClient.

Author: ezolotko

src/Client/Clients/TextDocumentClient.Definition.cs

@@ -28,7 +28,7 @@ public partial class TextDocumentClient
         ///     An optional <see cref="CancellationToken"/> that can be used to cancel the request.
         /// </param>
         /// <returns>
-        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no completions are available at the specified position.
+        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no definitions are available at the specified position.
         /// </returns>
         public Task<LocationOrLocationLinks> Definition(string filePath, int line, int column, CancellationToken cancellationToken = default(CancellationToken))
         {
@@ -56,7 +56,7 @@ public partial class TextDocumentClient
         ///     An optional <see cref="CancellationToken"/> that can be used to cancel the request.
         /// </param>
         /// <returns>
-        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no completions are available at the specified position.
+        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no definitions are available at the specified position.
         /// </returns>
         public Task<LocationOrLocationLinks> Definition(Uri documentUri, int line, int column, CancellationToken cancellationToken = default(CancellationToken))
         {

src/Client/Clients/TextDocumentClient.DocumentHighlight.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using OmniSharp.Extensions.LanguageServer.Client.Utilities;
+using OmniSharp.Extensions.LanguageServer.Protocol;
+using OmniSharp.Extensions.LanguageServer.Protocol.Models;
+
+namespace OmniSharp.Extensions.LanguageServer.Client.Clients
+{
+    /// <summary>
+    ///     Client for the LSP Text Document API.
+    /// </summary>
+    public partial class TextDocumentClient
+    {
+        /// <summary>
+        ///     Request document highlights at the specified document position.
+        /// </summary>
+        /// <param name="filePath">
+        ///     The full file-system path of the text document.
+        /// </param>
+        /// <param name="line">
+        ///     The target line (0-based).
+        /// </param>
+        /// <param name="column">
+        ///     The target column (0-based).
+        /// </param>
+        /// <param name="cancellationToken">
+        ///     An optional <see cref="CancellationToken"/> that can be used to cancel the request.
+        /// </param>
+        /// <returns>
+        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no document highlights are available at the specified position.
+        /// </returns>
+        public Task<DocumentHighlightContainer> DocumentHighlight(string filePath, int line, int column, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            if (string.IsNullOrWhiteSpace(filePath))
+                throw new ArgumentException($"Argument cannot be null, empty, or entirely composed of whitespace: {nameof(filePath)}.", nameof(filePath));
+
+            var documentUri = DocumentUri.FromFileSystemPath(filePath);
+
+            return DocumentHighlight(documentUri, line, column, cancellationToken);
+        }
+
+        /// <summary>
+        ///     Request document highlights at the specified document position.
+        /// </summary>
+        /// <param name="documentUri">
+        ///     The document URI.
+        /// </param>
+        /// <param name="line">
+        ///     The target line (0-based).
+        /// </param>
+        /// <param name="column">
+        ///     The target column (0-based).
+        /// </param>
+        /// <param name="cancellationToken">
+        ///     An optional <see cref="CancellationToken"/> that can be used to cancel the request.
+        /// </param>
+        /// <returns>
+        ///     A <see cref="Task{TResult}"/> that resolves to the completions or <c>null</c> if no document highlights are available at the specified position.
+        /// </returns>
+        public Task<DocumentHighlightContainer> DocumentHighlight(Uri documentUri, int line, int column, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            return PositionalRequest<DocumentHighlightContainer>(DocumentNames.DocumentHighlight, documentUri, line, column, cancellationToken);
+        }
+    }
+}

test/Client.Tests/ClientTests.cs

@@ -301,7 +301,7 @@ public async Task Definition_Success()
 
             var actualDefinitions = definitions.ToArray();
             Assert.Collection(actualDefinitions, actualDefinition => {
-                var expectedDefinition = expectedDefinitions.First();
+                var expectedDefinition = expectedDefinitions.Single();
 
                 Assert.NotNull(actualDefinition.Location);
                 Assert.Equal(expectedDefinition.Location.Uri, actualDefinition.Location.Uri);
@@ -316,6 +316,63 @@ public async Task Definition_Success()
             });
         }
 
+        /// <summary>
+        ///     Ensure that the language client can successfully request DocumentHighlight.
+        /// </summary>
+        [Fact(DisplayName = "Language client can successfully request document highlights", Skip = "Periodic failures")]
+        public async Task DocumentHighlight_Success()
+        {
+            await Connect();
+
+            const int line = 5;
+            const int column = 5;
+            var expectedDocumentPath = AbsoluteDocumentPath;
+            var expectedDocumentUri = DocumentUri.FromFileSystemPath(expectedDocumentPath);
+
+            var expectedHighlights = new DocumentHighlightContainer(
+                new DocumentHighlight {
+                    Kind = DocumentHighlightKind.Write,
+                    Range = new Range {
+                        Start = new Position {
+                            Line = line,
+                            Character = column
+                        },
+                        End = new Position {
+                            Line = line,
+                            Character = column
+                        }
+                    },
+                });
+
+            ServerDispatcher.HandleRequest<DocumentHighlightParams, DocumentHighlightContainer>(DocumentNames.DocumentHighlight, (request, cancellationToken) => {
+                Assert.NotNull(request.TextDocument);
+
+                Assert.Equal(expectedDocumentUri, request.TextDocument.Uri);
+
+                Assert.Equal(line, request.Position.Line);
+                Assert.Equal(column, request.Position.Character);
+
+                return Task.FromResult(expectedHighlights);
+            });
+
+            var definitions = await LanguageClient.TextDocument.DocumentHighlight(AbsoluteDocumentPath, line, column);
+
+            var actualDefinitions = definitions.ToArray();
+            Assert.Collection(actualDefinitions, actualHighlight => {
+                var expectedHighlight = expectedHighlights.Single();
+
+                Assert.Equal(DocumentHighlightKind.Write, expectedHighlight.Kind);
+
+                Assert.NotNull(actualHighlight.Range);
+                Assert.NotNull(actualHighlight.Range.Start);
+                Assert.NotNull(actualHighlight.Range.End);
+                Assert.Equal(expectedHighlight.Range.Start.Line, actualHighlight.Range.Start.Line);
+                Assert.Equal(expectedHighlight.Range.Start.Character, actualHighlight.Range.Start.Character);
+                Assert.Equal(expectedHighlight.Range.End.Line, actualHighlight.Range.End.Line);
+                Assert.Equal(expectedHighlight.Range.End.Character, actualHighlight.Range.End.Character);
+            });
+        }
+
         /// <summary>
         ///     Ensure that the language client can successfully receive Diagnostics from the server.
         /// </summary>