Fix ReadKeyAsync on Linux

Author: daviwil

src/PowerShellEditorServices/Console/ConsoleReadLine.cs

@@ -11,6 +11,7 @@
 
 namespace Microsoft.PowerShell.EditorServices.Console
 {
+    using Microsoft.PowerShell.EditorServices.Utility;
     using System;
     using System.Management.Automation;
     using System.Management.Automation.Language;
@@ -21,6 +22,8 @@ internal class ConsoleReadLine
         #region Private Fields
 
         private PowerShellContext powerShellContext;
+        private AsyncQueue<ConsoleKeyInfo> readKeyQueue = new AsyncQueue<ConsoleKeyInfo>();
+        private CancellationTokenSource readLoopCancellationToken;
 
         #endregion
 
@@ -54,6 +57,8 @@ public async Task<string> ReadCommandLine(CancellationToken cancellationToken)
 
             int currentCursorIndex = 0;
 
+            this.StartReadLoop();
+
             while (!cancellationToken.IsCancellationRequested)
             {
                 ConsoleKeyInfo? possibleKeyInfo = await this.ReadKeyAsync(cancellationToken);
@@ -382,19 +387,41 @@ public Task<SecureString> ReadSecureLine()
 
         #region Private Methods
 
-        private async Task<ConsoleKeyInfo?> ReadKeyAsync(CancellationToken cancellationToken)
+        private void StartReadLoop()
         {
-            while (!cancellationToken.IsCancellationRequested)
+            if (this.readLoopCancellationToken == null)
             {
-                if (Console.KeyAvailable)
-                {
-                    return Console.ReadKey(true);
-               }
+                this.readLoopCancellationToken = new CancellationTokenSource();
 
-                await Task.Delay(50);
+                var terminalThreadTask =
+                    Task.Factory.StartNew(
+                        async () =>
+                        {
+                                    // Set the thread's name to help with debugging
+                                    Thread.CurrentThread.Name = "ConsoleReadLine Thread";
+
+                            while (!this.readLoopCancellationToken.IsCancellationRequested)
+                            {
+                                await this.readKeyQueue.EnqueueAsync(
+                                    Console.ReadKey(true));
+                            }
+                        },
+                        CancellationToken.None,
+                        TaskCreationOptions.LongRunning,
+                        TaskScheduler.Default);
             }
+        }
 
-            return null;
+        private async Task<ConsoleKeyInfo?> ReadKeyAsync(CancellationToken cancellationToken)
+        {
+            try
+            {
+                return await this.readKeyQueue.DequeueAsync(cancellationToken);
+            }
+            catch (TaskCanceledException)
+            {
+                return null;
+            }
         }
 
         private int CalculateIndexFromCursor(