Reset console mode for calls to external code

For an unknown reason - SetConsoleMode calls fail when setting certain
modes.  One such case is when PowerShell calls SetConsoleMode in it's
implementation of PSHostRawUserInterface.ReadKey.

PowerTab calls this method - and it's possible that other custom
key handlers might want to use that api, so I will reset the console
mode to what it was before calling PSReadline for the duration of
the external code (tab completion or custom handlers) and reset it
when the external code completes.

Fixes #125.

Author: lzybkr

PSReadLine/Completion.cs

@@ -22,7 +22,8 @@ public partial class PSConsoleReadLine
         [ExcludeFromCodeCoverage]
         CommandCompletion IPSConsoleReadLineMockableMethods.CompleteInput(string input, int cursorIndex, Hashtable options, PowerShell powershell)
         {
-            return CommandCompletion.CompleteInput(input, cursorIndex, options, powershell);
+            return CalloutUsingDefaultConsoleMode(
+                () => CommandCompletion.CompleteInput(input, cursorIndex, options, powershell));
         }
 
         /// <summary>

PSReadLine/Options.cs

@@ -163,7 +163,7 @@ private void SetKeyHandlerInternal(string[] keys, Action<ConsoleKeyInfo?, object
                 var chord = ConsoleKeyChordConverter.Convert(key);
                 if (chord.Length == 1)
                 {
-                    _dispatchTable[chord[0]] = MakeKeyHandler(handler, briefDescription, longDescription);
+                    _dispatchTable[chord[0]] = MakeKeyHandler(handler, briefDescription, longDescription, scriptBlock);
                 }
                 else
                 {
@@ -174,7 +174,7 @@ private void SetKeyHandlerInternal(string[] keys, Action<ConsoleKeyInfo?, object
                         secondDispatchTable = new Dictionary<ConsoleKeyInfo, KeyHandler>();
                         _chordDispatchTable[chord[0]] = secondDispatchTable;
                     }
-                    secondDispatchTable[chord[1]] = MakeKeyHandler(handler, briefDescription, longDescription);
+                    secondDispatchTable[chord[1]] = MakeKeyHandler(handler, briefDescription, longDescription, scriptBlock);
                 }
             }
         }

PSReadLine/ReadLine.cs

@@ -28,6 +28,7 @@ public partial class PSConsoleReadLine : IPSConsoleReadLineMockableMethods
         private WaitHandle[] _waitHandles;
         private bool _captureKeys;
         private readonly Queue<ConsoleKeyInfo> _savedKeys;
+        private uint _prePSReadlineConsoleMode;
 
         private readonly StringBuilder _buffer;
         private readonly StringBuilder _statusBuffer;
@@ -211,16 +212,15 @@ private bool BreakHandler(ConsoleBreakSignal signal)
         /// <returns>The complete command line.</returns>
         public static string ReadLine(Runspace remoteRunspace = null)
         {
-            uint dwConsoleMode;
             var handle = NativeMethods.GetStdHandle((uint) StandardHandleId.Input);
-            NativeMethods.GetConsoleMode(handle, out dwConsoleMode);
+            NativeMethods.GetConsoleMode(handle, out _singleton._prePSReadlineConsoleMode);
             try
             {
                 // Clear a couple flags so we can actually receive certain keys:
                 //     ENABLE_PROCESSED_INPUT - enables Ctrl+C
                 //     ENABLE_LINE_INPUT - enables Ctrl+S
                 NativeMethods.SetConsoleMode(handle,
-                    dwConsoleMode & ~(NativeMethods.ENABLE_PROCESSED_INPUT | NativeMethods.ENABLE_LINE_INPUT));
+                    _singleton._prePSReadlineConsoleMode & ~(NativeMethods.ENABLE_PROCESSED_INPUT | NativeMethods.ENABLE_LINE_INPUT));
 
                 _singleton.Initialize(remoteRunspace);
                 return _singleton.InputLoop();
@@ -265,7 +265,7 @@ public static string ReadLine(Runspace remoteRunspace = null)
             }
             finally
             {
-                NativeMethods.SetConsoleMode(handle, dwConsoleMode);
+                NativeMethods.SetConsoleMode(handle, _singleton._prePSReadlineConsoleMode);
             }
         }
 
@@ -343,6 +343,27 @@ private string InputLoop()
             }
         }
 
+        T CalloutUsingDefaultConsoleMode<T>(Func<T> func)
+        {
+            var handle = NativeMethods.GetStdHandle((uint) StandardHandleId.Input);
+            uint psReadlineConsoleMode;
+            NativeMethods.GetConsoleMode(handle, out psReadlineConsoleMode);
+            try
+            {
+                NativeMethods.SetConsoleMode(handle, _prePSReadlineConsoleMode);
+                return func();
+            }
+            finally
+            {
+                NativeMethods.SetConsoleMode(handle, psReadlineConsoleMode);
+            }
+        }
+
+        void CalloutUsingDefaultConsoleMode(Action action)
+        {
+            CalloutUsingDefaultConsoleMode<object>(() => { action(); return null; });
+        }
+
         void ProcessOneKey(ConsoleKeyInfo key, Dictionary<ConsoleKeyInfo, KeyHandler> dispatchTable, bool ignoreIfNoAction, object arg)
         {
             KeyHandler handler;
@@ -360,7 +381,14 @@ void ProcessOneKey(ConsoleKeyInfo key, Dictionary<ConsoleKeyInfo, KeyHandler> di
             {
                 _renderForDemoNeeded = _demoMode;
 
-                handler.Action(key, arg);
+                if (handler.ScriptBlock != null)
+                {
+                    CalloutUsingDefaultConsoleMode(() => handler.Action(key, arg));
+                }
+                else
+                {
+                    handler.Action(key, arg);
+                }
 
                 if (_renderForDemoNeeded)
                 {