Avoid double registration of text change handlers (they also can be double registered by dynamic registration!)

Author: david-driscoll

src/Protocol/Client/Capabilities/SynchronizationCapability.cs

@@ -1,10 +1,11 @@
 using Newtonsoft.Json;
 using OmniSharp.Extensions.LanguageServer.Protocol;
 using OmniSharp.Extensions.LanguageServer.Protocol.Serialization;
+using OmniSharp.Extensions.LanguageServer.Protocol.Server;
 
 namespace OmniSharp.Extensions.LanguageServer.Protocol.Client.Capabilities
 {
-    public class SynchronizationCapability : DynamicCapability
+    public class SynchronizationCapability : DynamicCapability, ConnectedCapability<IDidChangeTextDocumentHandler>, ConnectedCapability<IDidCloseTextDocumentHandler>, ConnectedCapability<IDidOpenTextDocumentHandler>, ConnectedCapability<IDidSaveTextDocumentHandler>, ConnectedCapability<IWillSaveTextDocumentHandler>, ConnectedCapability<IWillSaveWaitUntilTextDocumentHandler>
     {
         /// <summary>
         /// The client supports sending will save notifications.

src/Protocol/Models/IExecuteCommandOptions.cs

@@ -4,4 +4,4 @@ public interface IExecuteCommandOptions
     {
         Container<string> Commands { get; set; }
     }
-}
+}

src/Protocol/Models/ITextDocumentSyncOptions.cs

@@ -0,0 +1,13 @@
+using OmniSharp.Extensions.LanguageServer.Protocol.Server.Capabilities;
+
+namespace OmniSharp.Extensions.LanguageServer.Protocol.Models
+{
+    public interface ITextDocumentSyncOptions
+    {
+        bool OpenClose { get; set; }
+        TextDocumentSyncKind Change { get; set; }
+        bool WillSave { get; set; }
+        bool WillSaveWaitUntil { get; set; }
+        SaveOptions Save { get; set; }
+    }
+}

src/Protocol/Server/Capabilities/TextDocumentSyncOptions.cs

@@ -1,10 +1,13 @@
+using System.Collections.Generic;
+using System.Linq;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
+using OmniSharp.Extensions.LanguageServer.Protocol.Models;
 using OmniSharp.Extensions.LanguageServer.Protocol.Serialization;
 
 namespace OmniSharp.Extensions.LanguageServer.Protocol.Server.Capabilities
 {
-    public class TextDocumentSyncOptions
+    public class TextDocumentSyncOptions : ITextDocumentSyncOptions
     {
         /// <summary>
         ///  Open and close notifications are sent to the server.
@@ -32,5 +35,20 @@ public class TextDocumentSyncOptions
         /// </summary>
         [Optional]
         public SaveOptions Save { get; set; }
+
+        public static TextDocumentSyncOptions Of(IEnumerable<ITextDocumentSyncOptions> options)
+        {
+            return new TextDocumentSyncOptions() {
+                OpenClose = options.Any(z => z.OpenClose),
+                Change = options
+                        .Where(x => x.Change != TextDocumentSyncKind.None)
+                        .Min(z => z.Change),
+                WillSave = options.Any(z => z.WillSave),
+                WillSaveWaitUntil = options.Any(z => z.WillSaveWaitUntil),
+                Save = new SaveOptions() {
+                    IncludeText = options.Any(z => z.Save?.IncludeText == true)
+                }
+             };
+        }
     }
 }

src/Server/LanguageServer.cs

@@ -307,6 +307,7 @@ async Task<InitializeResult> IRequestHandler<InitializeParams, InitializeResult>
                 DocumentRangeFormattingProvider = ccp.HasStaticHandler(textDocumentCapabilities.RangeFormatting),
                 DocumentSymbolProvider = ccp.HasStaticHandler(textDocumentCapabilities.DocumentSymbol),
                 ExecuteCommandProvider = ccp.GetStaticOptions(workspaceCapabilities.ExecuteCommand).Reduce<IExecuteCommandOptions, ExecuteCommandOptions>(ExecuteCommandOptions.Of),
+                TextDocumentSync = ccp.GetStaticOptions(textDocumentCapabilities.Synchronization).Reduce<ITextDocumentSyncOptions, TextDocumentSyncOptions>(TextDocumentSyncOptions.Of),
                 HoverProvider = ccp.HasStaticHandler(textDocumentCapabilities.Hover),
                 ReferencesProvider = ccp.HasStaticHandler(textDocumentCapabilities.References),
                 RenameProvider = ccp.GetStaticOptions(textDocumentCapabilities.Rename).Get<IRenameOptions, RenameOptions>(RenameOptions.Of),
@@ -330,30 +331,33 @@ async Task<InitializeResult> IRequestHandler<InitializeParams, InitializeResult>
                 };
             }
 
-            var textDocumentSyncKind = _collection.ContainsHandler(typeof(IDidChangeTextDocumentHandler))
-                ? _collection
-                    .Select(x => x.Handler)
-                    .OfType<IDidChangeTextDocumentHandler>()
-                    .Where(x => x.Change != TextDocumentSyncKind.None)
-                    .Min(z => z.Change)
-                : TextDocumentSyncKind.None;
-
-            if (_clientVersion == ClientVersion.Lsp2)
+            if (ccp.HasStaticHandler(textDocumentCapabilities.Synchronization))
             {
-                serverCapabilities.TextDocumentSync = textDocumentSyncKind;
-            }
-            else
-            {
-                serverCapabilities.TextDocumentSync = new TextDocumentSyncOptions()
+                var textDocumentSyncKind = _collection.ContainsHandler(typeof(IDidChangeTextDocumentHandler))
+                    ? _collection
+                        .Select(x => x.Handler)
+                        .OfType<IDidChangeTextDocumentHandler>()
+                        .Where(x => x.Change != TextDocumentSyncKind.None)
+                        .Min(z => z.Change)
+                    : TextDocumentSyncKind.None;
+
+                if (_clientVersion == ClientVersion.Lsp2)
                 {
-                    Change = textDocumentSyncKind,
-                    OpenClose = _collection.ContainsHandler(typeof(IDidOpenTextDocumentHandler)) || _collection.ContainsHandler(typeof(IDidCloseTextDocumentHandler)),
-                    Save = _collection.ContainsHandler(typeof(IDidSaveTextDocumentHandler)) ?
-                        new SaveOptions() { IncludeText = true /* TODO: Make configurable */ } :
-                        null,
-                    WillSave = _collection.ContainsHandler(typeof(IWillSaveTextDocumentHandler)),
-                    WillSaveWaitUntil = _collection.ContainsHandler(typeof(IWillSaveWaitUntilTextDocumentHandler))
-                };
+                    serverCapabilities.TextDocumentSync = textDocumentSyncKind;
+                }
+                else
+                {
+                    serverCapabilities.TextDocumentSync = new TextDocumentSyncOptions()
+                    {
+                        Change = textDocumentSyncKind,
+                        OpenClose = _collection.ContainsHandler(typeof(IDidOpenTextDocumentHandler)) || _collection.ContainsHandler(typeof(IDidCloseTextDocumentHandler)),
+                        Save = _collection.ContainsHandler(typeof(IDidSaveTextDocumentHandler)) ?
+                            new SaveOptions() { IncludeText = true /* TODO: Make configurable */ } :
+                            null,
+                        WillSave = _collection.ContainsHandler(typeof(IWillSaveTextDocumentHandler)),
+                        WillSaveWaitUntil = _collection.ContainsHandler(typeof(IWillSaveWaitUntilTextDocumentHandler))
+                    };
+                }
             }
 
             // TODO: Need a call back here