Add handling of configuration events from client

This change introduces the 'workspace/didChangeConfiguration' notification
which the client will send to the language server when the user changes
their settings.  It also introduces a new configuration section for script
analysis settings so that the user can turn on/off script analysis.  More
settings will be added later.

Author: daviwil

src/PowerShellEditorServices.Host/LanguageServer.cs

@@ -25,6 +25,7 @@ internal class LanguageServer : IMessageProcessor
         private static CancellationTokenSource existingRequestCancellation;
 
         private MessageDispatcher<EditorSession> messageDispatcher;
+        private LanguageServerSettings currentSettings = new LanguageServerSettings();
 
         public LanguageServer()
         {
@@ -42,6 +43,7 @@ public void Initialize()
             this.AddEventHandler(DidOpenTextDocumentNotification.Type, this.HandleDidOpenTextDocumentNotification);
             this.AddEventHandler(DidCloseTextDocumentNotification.Type, this.HandleDidCloseTextDocumentNotification);
             this.AddEventHandler(DidChangeTextDocumentNotification.Type, this.HandleDidChangeTextDocumentNotification);
+            this.AddEventHandler(DidChangeConfigurationNotification<SettingsWrapper>.Type, this.HandleDidChangeConfigurationNotification);
 
             this.AddRequestHandler(DefinitionRequest.Type, this.HandleDefinitionRequest);
             this.AddRequestHandler(ReferencesRequest.Type, this.HandleReferencesRequest);
@@ -226,6 +228,36 @@ protected Task HandleDidChangeTextDocumentNotification(
             return Task.FromResult(true);
         }
 
+        protected async Task HandleDidChangeConfigurationNotification(
+            DidChangeConfigurationParams<SettingsWrapper> configChangeParams,
+            EditorSession editorSession,
+            EventContext eventContext)
+        {
+            bool oldScriptAnalysisEnabled = 
+                this.currentSettings.ScriptAnalysis.Enable.HasValue;
+
+            this.currentSettings.Update(
+                configChangeParams.Settings.Powershell);
+
+            if (oldScriptAnalysisEnabled != this.currentSettings.ScriptAnalysis.Enable)
+            {
+                // If the user just turned off script analysis, send a diagnostics
+                // event to clear the analysis markers that they already have
+                if (!this.currentSettings.ScriptAnalysis.Enable.Value)
+                {
+                    ScriptFileMarker[] emptyAnalysisDiagnostics = new ScriptFileMarker[0];
+
+                    foreach (var scriptFile in editorSession.Workspace.GetOpenedFiles())
+                    {
+                        await PublishScriptDiagnostics(
+                            scriptFile,
+                            emptyAnalysisDiagnostics,
+                            eventContext);
+                    }
+                }
+            }
+        }
+
         protected async Task HandleDefinitionRequest(
             TextDocumentPosition textDocumentPosition,
             EditorSession editorSession,
@@ -744,6 +776,12 @@ private Task RunScriptDiagnostics(
             EditorSession editorSession,
             EventContext eventContext)
         {
+            if (!this.currentSettings.ScriptAnalysis.Enable.Value)
+            {
+                // If the user has disabled script analysis, skip it entirely
+                return TaskConstants.Completed;
+            }
+
             // If there's an existing task, attempt to cancel it
             try
             {
@@ -827,24 +865,36 @@ private static async Task DelayThenInvokeDiagnostics(
 
                 var allMarkers = scriptFile.SyntaxMarkers.Concat(semanticMarkers);
 
-                // Always send syntax and semantic errors.  We want to 
-                // make sure no out-of-date markers are being displayed.
-                await eventContext.SendEvent(
-                    PublishDiagnosticsNotification.Type,
-                    new PublishDiagnosticsNotification
-                    {
-                        Uri = scriptFile.ClientFilePath,
-                        Diagnostics =
-                           allMarkers
-                                .Select(GetDiagnosticFromMarker)
-                                .ToArray()
-                    });
-
+                await PublishScriptDiagnostics(
+                    scriptFile,
+                    semanticMarkers,
+                    eventContext);
             }
 
             Logger.Write(LogLevel.Verbose, "Analysis complete.");
         }
 
+        private async static Task PublishScriptDiagnostics(
+            ScriptFile scriptFile,
+            ScriptFileMarker[] semanticMarkers,
+            EventContext eventContext)
+        {
+            var allMarkers = scriptFile.SyntaxMarkers.Concat(semanticMarkers);
+
+            // Always send syntax and semantic errors.  We want to 
+            // make sure no out-of-date markers are being displayed.
+            await eventContext.SendEvent(
+                PublishDiagnosticsNotification.Type,
+                new PublishDiagnosticsNotification
+                {
+                    Uri = scriptFile.ClientFilePath,
+                    Diagnostics = 
+                       allMarkers 
+                            .Select(GetDiagnosticFromMarker)
+                            .ToArray()
+                });
+        }
+
         private static Diagnostic GetDiagnosticFromMarker(ScriptFileMarker scriptFileMarker)
         {
             return new Diagnostic

src/PowerShellEditorServices.Host/LanguageServerSettings.cs

@@ -0,0 +1,52 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.PowerShell.EditorServices.Host
+{
+    internal class LanguageServerSettings
+    {
+        public ScriptAnalysisSettings ScriptAnalysis { get; set; }
+
+        public LanguageServerSettings()
+        {
+            this.ScriptAnalysis = new ScriptAnalysisSettings();
+        }
+
+        public void Update(LanguageServerSettings settings)
+        {
+            if (settings != null)
+            {
+                this.ScriptAnalysis.Update(settings.ScriptAnalysis);
+            }
+        }
+    }
+
+    internal class ScriptAnalysisSettings
+    {
+        public bool? Enable { get; set; }
+
+        public ScriptAnalysisSettings()
+        {
+            this.Enable = true;
+        }
+
+        public void Update(ScriptAnalysisSettings settings)
+        {
+            if (settings != null)
+            {
+                this.Enable = settings.Enable;
+            }
+        }
+    }
+
+    internal class SettingsWrapper
+    {
+        // NOTE: This property is capitalized as 'Powershell' because the
+        // mode name sent from the client is written as 'powershell' and
+        // JSON.net is using camelCasing.
+
+        public LanguageServerSettings Powershell { get; set; }
+    }
+}

src/PowerShellEditorServices.Host/PowerShellEditorServices.Host.csproj

@@ -62,6 +62,7 @@
     <Compile Include="DebugAdapter.cs" />
     <Compile Include="IMessageProcessor.cs" />
     <Compile Include="LanguageServer.cs" />
+    <Compile Include="LanguageServerSettings.cs" />
     <Compile Include="MessageLoop.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

src/PowerShellEditorServices.Protocol/LanguageServer/Configuration.cs

@@ -0,0 +1,21 @@
+//
+// 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.MessageProtocol;
+
+namespace Microsoft.PowerShell.EditorServices.Protocol.LanguageServer
+{
+    public class DidChangeConfigurationNotification<TConfig> 
+    {
+        public static readonly
+            EventType<DidChangeConfigurationParams<TConfig>> Type =
+            EventType<DidChangeConfigurationParams<TConfig>>.Create("workspace/didChangeConfiguration");
+    }
+
+    public class DidChangeConfigurationParams<TConfig>
+    {
+        public TConfig Settings { get; set; }
+    }
+}

src/PowerShellEditorServices.Protocol/PowerShellEditorServices.Protocol.csproj

@@ -89,6 +89,7 @@
     <Compile Include="DebugAdapter\V8MessageSerializer.cs" />
     <Compile Include="DebugAdapter\Variable.cs" />
     <Compile Include="DebugAdapter\VariablesRequest.cs" />
+    <Compile Include="LanguageServer\Configuration.cs" />
     <Compile Include="LanguageServer\Definition.cs" />
     <Compile Include="LanguageServer\DocumentHighlight.cs" />
     <Compile Include="LanguageServer\Hover.cs" />