Initial commit of SqlTools Service API

ServiceHost/Server/LanguageServerBase.cs

@@ -0,0 +1,84 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.PowerShell.EditorServices.Protocol.LanguageServer;
+using Microsoft.PowerShell.EditorServices.Protocol.MessageProtocol;
+using Microsoft.PowerShell.EditorServices.Protocol.MessageProtocol.Channel;
+using System.Threading.Tasks;
+
+namespace Microsoft.PowerShell.EditorServices.Protocol.Server
+{
+    public abstract class LanguageServerBase : ProtocolEndpoint
+    {
+        private bool isStarted;
+        private ChannelBase serverChannel;
+        private TaskCompletionSource<bool> serverExitedTask;
+
+        public LanguageServerBase(ChannelBase serverChannel) : 
+            base(serverChannel, MessageProtocolType.LanguageServer)
+        {
+            this.serverChannel = serverChannel;
+        }
+
+        protected override Task OnStart()
+        {
+            // Register handlers for server lifetime messages
+            this.SetRequestHandler(ShutdownRequest.Type, this.HandleShutdownRequest);
+            this.SetEventHandler(ExitNotification.Type, this.HandleExitNotification);
+
+            // Initialize the implementation class
+            this.Initialize();
+
+            return Task.FromResult(true);
+        }
+
+        protected override async Task OnStop()
+        {
+            await this.Shutdown();
+        }
+
+        /// <summary>
+        /// Overridden by the subclass to provide initialization
+        /// logic after the server channel is started.
+        /// </summary>
+        protected abstract void Initialize();
+
+        /// <summary>
+        /// Can be overridden by the subclass to provide shutdown
+        /// logic before the server exits.  Subclasses do not need
+        /// to invoke or return the value of the base implementation.
+        /// </summary>
+        protected virtual Task Shutdown()
+        {
+            // No default implementation yet.
+            return Task.FromResult(true);
+        }
+
+        private async Task HandleShutdownRequest(
+            object shutdownParams,
+            RequestContext<object> requestContext)
+        {
+            // Allow the implementor to shut down gracefully
+            await this.Shutdown();
+
+            await requestContext.SendResult(new object());
+        }
+
+        private async Task HandleExitNotification(
+            object exitParams,
+            EventContext eventContext)
+        {
+            // Stop the server channel
+            await this.Stop();
+
+            // Notify any waiter that the server has exited
+            if (this.serverExitedTask != null)
+            {
+                this.serverExitedTask.SetResult(true);
+            }
+        }
+    }
+}
+