Added Definition support to TextDocumentClient.

Author: ezolotko

src/Client/Clients/TextDocumentClient.Definition.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 definition 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 completions are available at the specified position.
+        /// </returns>
+        public Task<LocationOrLocationLinks> Definition(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 Definition(documentUri, line, column, cancellationToken);
+        }
+
+        /// <summary>
+        ///     Request definition 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 completions are available at the specified position.
+        /// </returns>
+        public Task<LocationOrLocationLinks> Definition(Uri documentUri, int line, int column, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            return PositionalRequest<LocationOrLocationLinks>(DocumentNames.Definition, documentUri, line, column, cancellationToken);
+        }
+    }
+}

test/Client.Tests/ClientTests.cs

@@ -258,6 +258,64 @@ public async Task SignatureHelp_Success()
             });
         }
 
+        /// <summary>
+        ///     Ensure that the language client can successfully request Definition.
+        /// </summary>
+        [Fact(DisplayName = "Language client can successfully request definition", Skip = "Periodic failures")]
+        public async Task Definition_Success()
+        {
+            await Connect();
+
+            const int line = 5;
+            const int column = 5;
+            var expectedDocumentPath = AbsoluteDocumentPath;
+            var expectedDocumentUri = DocumentUri.FromFileSystemPath(expectedDocumentPath);
+
+            var expectedDefinitions = new LocationOrLocationLinks(
+                new LocationOrLocationLink(new Location {
+                    Uri = expectedDocumentUri,
+                    Range = new Range {
+                        Start = new Position {
+                            Line = line,
+                            Character = column
+                        },
+                        End = new Position {
+                            Line = line,
+                            Character = column
+                        }
+                    },
+                }));
+
+            ServerDispatcher.HandleRequest<TextDocumentPositionParams, LocationOrLocationLinks>(DocumentNames.Definition, (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(expectedDefinitions);
+            });
+
+            var definitions = await LanguageClient.TextDocument.Definition(AbsoluteDocumentPath, line, column);
+
+            var actualDefinitions = definitions.ToArray();
+            Assert.Collection(actualDefinitions, actualDefinition => {
+                var expectedDefinition = expectedDefinitions.First();
+
+                Assert.NotNull(actualDefinition.Location);
+                Assert.Equal(expectedDefinition.Location.Uri, actualDefinition.Location.Uri);
+
+                Assert.NotNull(actualDefinition.Location.Range);
+                Assert.NotNull(actualDefinition.Location.Range.Start);
+                Assert.NotNull(actualDefinition.Location.Range.End);
+                Assert.Equal(expectedDefinition.Location.Range.Start.Line, actualDefinition.Location.Range.Start.Line);
+                Assert.Equal(expectedDefinition.Location.Range.Start.Character, actualDefinition.Location.Range.Start.Character);
+                Assert.Equal(expectedDefinition.Location.Range.End.Line, actualDefinition.Location.Range.End.Line);
+                Assert.Equal(expectedDefinition.Location.Range.End.Character, actualDefinition.Location.Range.End.Character);
+            });
+        }
+
         /// <summary>
         ///     Ensure that the language client can successfully receive Diagnostics from the server.
         /// </summary>