Add request concurrency information for processing by the RequestExec…

src/Features/LanguageServer/Microsoft.CommonLanguageServerProtocol.Framework.UnitTests/HandlerProviderTests.cs

@@ -6,7 +6,6 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CommonLanguageServerProtocol.Framework;
 using Xunit;
 
 namespace Microsoft.CommonLanguageServerProtocol.Framework.UnitTests;

src/Features/LanguageServer/Microsoft.CommonLanguageServerProtocol.Framework.UnitTests/RequestExecutionQueueTests.cs

@@ -6,8 +6,6 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Elfie.Diagnostics;
-using Microsoft.CommonLanguageServerProtocol.Framework;
 using Moq;
 using Nerdbank.Streams;
 using StreamJsonRpc;

src/Features/LanguageServer/Microsoft.CommonLanguageServerProtocol.Framework/QueueItem.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.Threading;

src/Features/LanguageServer/Microsoft.CommonLanguageServerProtocol.Framework/RequestExecutionQueue.cs

@@ -3,16 +3,17 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Concurrent;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.Threading;
-using System.Collections.Immutable;
 
 namespace Microsoft.CommonLanguageServerProtocol.Framework;
 
 /// <summary>
-/// Coordinates the exectution of LSP messages to ensure correct results are sent back.
+/// Coordinates the execution of LSP messages to ensure correct results are sent back.
 /// </summary>
 /// <remarks>
 /// <para>
@@ -21,7 +22,7 @@ namespace Microsoft.CommonLanguageServerProtocol.Framework;
 /// (via textDocument/didChange for example).
 /// </para>
 /// <para>
-/// This class acheives this by distinguishing between mutating and non-mutating requests, and ensuring that
+/// This class achieves this by distinguishing between mutating and non-mutating requests, and ensuring that
 /// when a mutating request comes in, its processing blocks all subsequent requests. As each request comes in
 /// it is added to a queue, and a queue item will not be retrieved while a mutating request is running. Before
 /// any request is handled the solution state is created by merging workspace solution state, which could have
@@ -89,6 +90,8 @@ protected IMethodHandler GetMethodHandler<TRequest, TResponse>(string methodName
         return handler;
     }
 
+    protected virtual bool EmptyQueueUponSerialRequest => false;
+
     /// <summary>
     /// Queues a request to be handled by the specified handler, with mutating requests blocking subsequent requests
     /// from starting until the mutation is complete.
@@ -156,6 +159,8 @@ private async Task ProcessQueueAsync()
         ILspServices? lspServices = null;
         try
         {
+            var pendingTasks = new ConcurrentDictionary<Task, CancellationTokenSource>();
+
             while (!_cancelSource.IsCancellationRequested)
             {
                 // First attempt to de-queue the work item in its own try-catch.
@@ -179,13 +184,39 @@ private async Task ProcessQueueAsync()
 
                     var cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(CancellationToken, cancellationToken);
 
+                    // Use the linked cancellation token so it can be cancelled if a RequestConcurrency.RequiresPreviousQueueItemsCancelled
+                    // request is encountered before this request completes.
+                    cancellationToken = cancellationTokenSource.Token;
+
                     // Restore our activity id so that logging/tracking works across asynchronous calls.
                     Trace.CorrelationManager.ActivityId = activityId;
                     // The request context must be created serially inside the queue to so that requests always run
                     // on the correct snapshot as of the last request.
                     var context = await work.CreateRequestContextAsync(cancellationToken).ConfigureAwait(false);
                     if (work.MutatesServerState)
                     {
+                        if (EmptyQueueUponSerialRequest)
+                        {
+                            if (pendingTasks.Count > 0)
+                            {
+                                // Cancel all pending tasks
+                                var pendingTasksArray = pendingTasks.ToArray();
+                                for (var i = 0; i < pendingTasksArray.Length; i++)
+                                {
+                                    pendingTasksArray[i].Value.Cancel();
+                                }
+
+                                try
+                                {
+                                    // wait for all pending tasks to complete their cancellation
+                                    await Task.WhenAll(pendingTasksArray.Select(kvp => kvp.Key)).ConfigureAwait(false);
+                                }
+                                catch (TaskCanceledException)
+                                {
+                                }
+                            }
+                        }
+
                         // Mutating requests block other requests from starting to ensure an up to date snapshot is used.
                         // Since we're explicitly awaiting exceptions to mutating requests will bubble up here.
                         await WrapStartRequestTaskAsync(work.StartRequestAsync(context, cancellationToken), rethrowExceptions: true).ConfigureAwait(false);
@@ -196,13 +227,23 @@ private async Task ProcessQueueAsync()
                         // will be sent back to the client but they can also be captured via HandleNonMutatingRequestError,
                         // though these errors don't put us into a bad state as far as the rest of the queue goes.
                         // Furthermore we use Task.Run here to protect ourselves against synchronous execution of work
-                        // blocking the request queue for longer periods of time (it enforces parallelizabilty).
-                        _ = WrapStartRequestTaskAsync(Task.Run(() => work.StartRequestAsync(context, cancellationToken), cancellationToken), rethrowExceptions: false);
+                        // blocking the request queue for longer periods of time (it enforces parallelizability).
+                        var pendingTask = WrapStartRequestTaskAsync(Task.Run(() => work.StartRequestAsync(context, cancellationToken), cancellationToken), rethrowExceptions: false);
+
+                        pendingTasks.TryAdd(pendingTask, cancellationTokenSource);
+
+                        _ = pendingTask.ContinueWith(t =>
+                        {
+                            if (pendingTasks.TryRemove(t, out var pendingCancellationTokenSource))
+                            {
+                                pendingCancellationTokenSource.Dispose();
+                            }
+                        }, TaskScheduler.Default);
                     }
                 }
                 catch (OperationCanceledException ex) when (ex.CancellationToken == queueItem.cancellationToken)
                 {
-                    // Explicitly ignore this exception as cancellation occured as a result of our linked cancellation token.
+                    // Explicitly ignore this exception as cancellation occurred as a result of our linked cancellation token.
                     // This means either the queue is shutting down or the request itself was cancelled.
                     //   1.  If the queue is shutting down, then while loop will exit before the next iteration since it checks for cancellation.
                     //   2.  Request cancellations are normal so no need to report anything there.
@@ -227,7 +268,7 @@ private async Task ProcessQueueAsync()
     }
 
     /// <summary>
-    /// Provides an extensiblity point to log or otherwise inspect errors thrown from non-mutating requests,
+    /// Provides an extensibility point to log or otherwise inspect errors thrown from non-mutating requests,
     /// which would otherwise be lost to the fire-and-forget task in the queue.
     /// </summary>
     /// <param name="nonMutatingRequestTask">The task to be inspected.</param>

src/Features/LanguageServer/Protocol/Handler/CodeLens/CodeLensResolveHandler.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeLens;

src/Features/LanguageServer/Protocol/Handler/Completion/CompletionHandler.cs

@@ -8,7 +8,6 @@
 using System.Composition;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Completion;
@@ -19,7 +18,6 @@
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
-using Microsoft.VisualStudio.Text.Adornments;
 using Roslyn.Utilities;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
 

src/Features/LanguageServer/Protocol/Handler/Diagnostics/AbstractPullDiagnosticHandler.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;

src/Features/LanguageServer/Protocol/Handler/DocumentChanges/DidOpenHandler.cs

@@ -9,7 +9,6 @@
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Text;
 using Microsoft.CommonLanguageServerProtocol.Framework;
-using Roslyn.Utilities;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.Handler.DocumentChanges

src/Features/LanguageServer/Protocol/Handler/Formatting/FormatDocumentOnTypeHandler.cs

@@ -3,8 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Composition;
 using System.Linq;
 using System.Threading;
@@ -15,9 +13,7 @@
 using Microsoft.CodeAnalysis.Indentation;
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.PooledObjects;
-using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
-using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.Handler
 {

src/Features/LanguageServer/Protocol/Handler/OnAutoInsert/OnAutoInsertHandler.cs

@@ -18,7 +18,6 @@
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
-using Roslyn.Utilities;
 using static Microsoft.CodeAnalysis.Completion.Utilities;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
 

src/Features/LanguageServer/Protocol/Handler/References/FindAllReferencesHandler.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Composition;
-using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.FindUsages;

src/Features/LanguageServer/Protocol/Handler/References/FindImplementationsHandler.cs

@@ -10,7 +10,6 @@
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Extensions;
-using Roslyn.Utilities;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.Handler

src/Features/LanguageServer/Protocol/Handler/ServerLifetime/InitializeHandler.cs

@@ -3,10 +3,8 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Newtonsoft.Json;

src/Features/LanguageServer/Protocol/Handler/ServerLifetime/InitializedHandler.cs

@@ -2,11 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
-using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.Handler;

src/Features/LanguageServer/Protocol/Handler/SignatureHelp/SignatureHelpHandler.cs

@@ -10,9 +10,9 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.SignatureHelp;
-using Microsoft.CodeAnalysis.Options;
 using Microsoft.VisualStudio.Text.Adornments;
 using LSP = Microsoft.VisualStudio.LanguageServer.Protocol;
 

src/Features/LanguageServer/Protocol/Handler/SpellCheck/AbstractSpellCheckingHandler.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;

src/Features/LanguageServer/ProtocolUnitTests/Ordering/FailingMutatingRequestHandler.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering
 {

src/Features/LanguageServer/ProtocolUnitTests/Ordering/FailingRequestHandler.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering
 {

src/Features/LanguageServer/ProtocolUnitTests/Ordering/LongRunningNonMutatingRequestHandler.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Xunit.Sdk;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering

src/Features/LanguageServer/ProtocolUnitTests/Ordering/MutatingRequestHandler.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering
 {

src/Features/LanguageServer/ProtocolUnitTests/Ordering/NonLSPSolutionRequestHandlerProvider.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Xunit;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering

src/Features/LanguageServer/ProtocolUnitTests/Ordering/NonMutatingRequestHandler.cs

@@ -8,7 +8,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
-using Microsoft.VisualStudio.LanguageServer.Protocol;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests.RequestOrdering
 {

src/Features/LanguageServer/ProtocolUnitTests/VSTypeScriptHandlerTests.cs

@@ -7,7 +7,6 @@
 using System.Composition;
 using System.IO;
 using System.Linq;
-using System.ServiceModel.Syndication;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Xml.Linq;
@@ -16,7 +15,6 @@
 using Microsoft.CodeAnalysis.ExternalAccess.VSTypeScript;
 using Microsoft.CodeAnalysis.ExternalAccess.VSTypeScript.Api;
 using Microsoft.CodeAnalysis.Host.Mef;
-using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Nerdbank.Streams;

src/VisualStudio/Xaml/Impl/Implementation/LanguageServer/Handler/Commands/CreateEventCommandHandler.cs

@@ -14,7 +14,6 @@
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Microsoft.VisualStudio.LanguageServices.Xaml.Features.Commands;
 using Microsoft.VisualStudio.LanguageServices.Xaml.Features.Completion;
-using Microsoft.VisualStudio.LanguageServices.Xaml.LanguageServer;
 using Newtonsoft.Json.Linq;
 using Roslyn.Utilities;
 

src/VisualStudio/Xaml/Impl/Implementation/LanguageServer/Handler/Completion/CompletionResolveHandler.cs

@@ -8,12 +8,11 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Editor.Xaml;
 using Microsoft.CodeAnalysis.Host.Mef;
-using Microsoft.CodeAnalysis.Options;
-using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.LanguageServer;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
+using Microsoft.CodeAnalysis.LanguageService;
+using Microsoft.CodeAnalysis.Options;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Microsoft.VisualStudio.LanguageServices.Xaml.Features.Completion;
 using Microsoft.VisualStudio.LanguageServices.Xaml.Implementation.LanguageServer.Extensions;

src/VisualStudio/Xaml/Impl/Implementation/LanguageServer/Handler/FoldingRanges/FoldingRangesHandler.cs

@@ -6,9 +6,7 @@
 using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Editor.Xaml;
 using Microsoft.CodeAnalysis.Host.Mef;
-using Microsoft.CodeAnalysis.LanguageServer;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.VisualStudio.LanguageServer.Protocol;

src/VisualStudio/Xaml/Impl/Implementation/LanguageServer/Handler/Formatting/AbstractFormatDocumentHandlerBase.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;

src/VisualStudio/Xaml/Impl/Implementation/LanguageServer/Handler/Formatting/FormatDocumentOnTypeHandler.cs

@@ -3,17 +3,14 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Composition;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Editor.Xaml;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.LanguageServer;
 using Microsoft.CodeAnalysis.LanguageServer.Handler;
 using Microsoft.CodeAnalysis.PooledObjects;
-using Microsoft.CodeAnalysis.Text;
 using Microsoft.VisualStudio.LanguageServer.Protocol;
 using Microsoft.VisualStudio.LanguageServices.Xaml.Features.Formatting;