Add LanguageServerExtensions.IsUntitled.

Add Diagnostic.EmptyDiagnostics.
Update demo.

Author: CXuesong

DemoLanguageServer/Services/TextDocumentService.cs

@@ -5,6 +5,7 @@
 using System.Threading.Tasks;
 using JsonRpc.Standard.Contracts;
 using JsonRpc.Standard.Server;
+using LanguageServer.VsCode;
 using LanguageServer.VsCode.Contracts;
 using LanguageServer.VsCode.Server;
 
@@ -52,7 +53,10 @@ public void WillSave(TextDocumentIdentifier textDocument, TextDocumentSaveReason
         [JsonRpcMethod(IsNotification = true)]
         public async Task DidClose(TextDocumentIdentifier textDocument)
         {
-            await Client.Document.PublishDiagnostics(textDocument.Uri, new Diagnostic[0]);
+            if (textDocument.Uri.IsUntitled())
+            {
+                await Client.Document.PublishDiagnostics(textDocument.Uri, new Diagnostic[0]);
+            }
             Documents.Remove(textDocument);
         }
 

LanguageServer.VsCode/Contracts/Client/IDocument.cs

@@ -14,7 +14,8 @@ public interface IDocument
         /// Diagnostics notification are sent from the server to the client to signal results of validation runs.
         /// </summary>
         /// <param name="uri">The URI for which diagnostic information is reported.</param>
-        /// <param name="diagnostics"> An array of diagnostic information items.</param>
+        /// <param name="diagnostics">An array of diagnostic information items.
+        /// To clear the existing diagnostics, pass <see cref="Diagnostic.EmptyDiagnostics"/> instead of <c>null</c>.</param>
         [JsonRpcMethod(IsNotification = true)]
         Task PublishDiagnostics(Uri uri, IEnumerable<Diagnostic> diagnostics);
     }

LanguageServer.VsCode/Contracts/Diagnostic.cs

@@ -36,6 +36,12 @@ public enum DiagnosticSeverity
     [JsonObject(MemberSerialization.OptIn)]
     public class Diagnostic
     {
+
+        /// <summary>
+        /// Represents an empty array of <see cref="Diagnostic"/>
+        /// </summary>
+        public static readonly Diagnostic[] EmptyDiagnostics = { };
+
         [JsonConstructor]
         public Diagnostic()
         {

LanguageServer.VsCode/LanguageServer.VsCode.csproj

@@ -5,7 +5,7 @@
     <PackageId>CXuesong.LanguageServer.VsCode</PackageId>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <Authors>CXuesong</Authors>
-    <Version>0.1.0-int0</Version>
+    <Version>0.1.0-int1</Version>
     <Company />
     <Description>A .NET Language Server library for VSCode.</Description>
     <Copyright>Copyright 2017 CXuesong</Copyright>

LanguageServer.VsCode/JsonRpcHostExtensions.cs renamed to LanguageServer.VsCode/LanguageServerExtensions.cs

@@ -36,5 +36,13 @@ public static void UseCancellationHandling(this ServiceHostBuilder builder)
                 }
             });
         }
+
+        /// <summary>
+        /// Determines whether the specified document URI indeicates an unsaved document.
+        /// </summary>
+        public static bool IsUntitled(this Uri documentUri)
+        {
+            return documentUri.Scheme == "untitled";
+        }
     }
 }