Merge pull request #777 from heejaechang/solutionCancel

make solution crawler to cancel all running tasks on global operation

src/Features/Core/SolutionCrawler/WorkCoordinator.AsyncDocumentWorkItemQueue.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using Microsoft.CodeAnalysis.Internal.Log;
 using Roslyn.Utilities;

src/Features/Core/SolutionCrawler/WorkCoordinator.AsyncWorkItemQueue.cs

@@ -99,6 +99,15 @@ public bool AddOrReplace(WorkItem item)
                     }
                 }
 
+                public void RequestCancellationOnRunningTasks()
+                {
+                    lock (_gate)
+                    {
+                        // request to cancel all running works
+                        _cancellationMap.Do(p => p.Value.Cancel());
+                    }
+                }
+
                 public void Dispose()
                 {
                     lock (_gate)

src/Features/Core/SolutionCrawler/WorkCoordinator.GlobalOperationAwareIdleProcessor.cs

@@ -45,6 +45,8 @@ private abstract class GlobalOperationAwareIdleProcessor : IdleProcessor
                         _globalOperationNotificationService.Stopped += OnGlobalOperationStopped;
                     }
 
+                    protected abstract void PauseOnGlobalOperation();
+
                     private void OnGlobalOperationStarted(object sender, EventArgs e)
                     {
                         Contract.ThrowIfFalse(_globalOperation == null);
@@ -54,6 +56,8 @@ private void OnGlobalOperationStarted(object sender, EventArgs e)
                         _globalOperationTask = _globalOperation.Task;
 
                         SolutionCrawlerLogger.LogGlobalOperation(this.Processor._logAggregator);
+
+                        PauseOnGlobalOperation();
                     }
 
                     private void OnGlobalOperationStopped(object sender, GlobalOperationEventArgs e)

src/Features/Core/SolutionCrawler/WorkCoordinator.LowPriorityProcessor.cs

@@ -75,6 +75,11 @@ protected override async Task ExecuteAsync()
                         }
                     }
 
+                    protected override void PauseOnGlobalOperation()
+                    {
+                        _workItemQueue.RequestCancellationOnRunningTasks();
+                    }
+
                     public void Enqueue(WorkItem item)
                     {
                         this.UpdateLastAccessTime();

src/Features/Core/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs

@@ -183,6 +183,11 @@ protected override async Task ExecuteAsync()
                         }
                     }
 
+                    protected override void PauseOnGlobalOperation()
+                    {
+                        _workItemQueue.RequestCancellationOnRunningTasks();
+                    }
+
                     private void SetProjectProcessing(ProjectId currentProject)
                     {
                         if (currentProject != _currentProjectProcessing)