From 129f6403d832d3293a02d39e3e3ac0e0a68d5e63 Mon Sep 17 00:00:00 2001
From: InvictusMB <invictusmb@gmail.com>
Date: Sun, 21 Jun 2020 18:16:36 +0200
Subject: [PATCH] Fix high CPU load #708

---
 .../CursesDriver/UnixMainLoop.cs              | 35 ++++++++-----------
 Terminal.Gui/ConsoleDrivers/WindowsDriver.cs  | 30 ++++++++--------
 Terminal.Gui/Core/MainLoop.cs                 |  4 ++-
 3 files changed, 31 insertions(+), 38 deletions(-)

diff --git a/Terminal.Gui/ConsoleDrivers/CursesDriver/UnixMainLoop.cs b/Terminal.Gui/ConsoleDrivers/CursesDriver/UnixMainLoop.cs
index 83ccf9837..d6fc9d987 100644
--- a/Terminal.Gui/ConsoleDrivers/CursesDriver/UnixMainLoop.cs
+++ b/Terminal.Gui/ConsoleDrivers/CursesDriver/UnixMainLoop.cs
@@ -168,45 +168,38 @@ namespace Terminal.Gui {
 
 		bool IMainLoopDriver.EventsPending (bool wait)
 		{
-			int pollTimeout = 0;
-			int n;
-
-			if (CkeckTimeout (wait, ref pollTimeout))
+			if (CheckTimers (wait, out var pollTimeout)) {
 				return true;
+			}
 
 			UpdatePollMap ();
 
-			while (true) {
-				n = poll (pollmap, (uint)pollmap.Length, 0);
-				if (pollmap != null) {
-					break;
-				}
-				if (mainLoop.idleHandlers.Count > 0 || CkeckTimeout (wait, ref pollTimeout)) {
-					return true;
-				}
-			}
-			int ic;
-			lock (mainLoop.idleHandlers)
-				ic = mainLoop.idleHandlers.Count;
-			return n > 0 || mainLoop.timeouts.Count > 0 && ((mainLoop.timeouts.Keys [0] - DateTime.UtcNow.Ticks) < 0) || ic > 0;
+			var n = poll (pollmap, (uint)pollmap.Length, pollTimeout);
+			
+			return n > 0 || CheckTimers (wait, out pollTimeout);
 		}
 
-		bool CkeckTimeout (bool wait, ref int pollTimeout)
+		bool CheckTimers (bool wait, out int pollTimeout)
 		{
 			long now = DateTime.UtcNow.Ticks;
 
 			if (mainLoop.timeouts.Count > 0) {
 				pollTimeout = (int)((mainLoop.timeouts.Keys [0] - now) / TimeSpan.TicksPerMillisecond);
-				if (pollTimeout < 0)
+				if (pollTimeout < 0) {
 					return true;
-
+				}
 			} else
 				pollTimeout = -1;
 
 			if (!wait)
 				pollTimeout = 0;
 
-			return false;
+			int ic;
+			lock (mainLoop.idleHandlers) {
+				ic = mainLoop.idleHandlers.Count;
+			}
+
+			return ic > 0;
 		}
 
 		void IMainLoopDriver.MainIteration ()
diff --git a/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs b/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
index 9c85fec76..c507f9122 100644
--- a/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
+++ b/Terminal.Gui/ConsoleDrivers/WindowsDriver.cs
@@ -615,24 +615,16 @@ namespace Terminal.Gui {
 
 		bool IMainLoopDriver.EventsPending (bool wait)
 		{
-			int waitTimeout = 0;
-
-			if (CkeckTimeout (wait, ref waitTimeout))
+			if (CheckTimers (wait, out var waitTimeout)) {
 				return true;
+			}
 
 			result = null;
 			waitForProbe.Set ();
 
 			try {
-				while (result == null) {
-					if (!tokenSource.IsCancellationRequested)
-						eventReady.Wait (0, tokenSource.Token);
-					if (result != null) {
-						break;
-					}
-					if (mainLoop.idleHandlers.Count > 0 || CkeckTimeout (wait, ref waitTimeout)) {
-						return true;
-					}
+				if (!tokenSource.IsCancellationRequested) {
+					eventReady.Wait (waitTimeout, tokenSource.Token);
 				}
 			} catch (OperationCanceledException) {
 				return true;
@@ -640,15 +632,16 @@ namespace Terminal.Gui {
 				eventReady.Reset ();
 			}
 
-			if (!tokenSource.IsCancellationRequested)
-				return result != null;
+			if (!tokenSource.IsCancellationRequested) {
+				return result != null || CheckTimers (wait, out waitTimeout);
+			}
 
 			tokenSource.Dispose ();
 			tokenSource = new CancellationTokenSource ();
 			return true;
 		}
 
-		bool CkeckTimeout (bool wait, ref int waitTimeout)
+		bool CheckTimers (bool wait, out int waitTimeout)
 		{
 			long now = DateTime.UtcNow.Ticks;
 
@@ -663,7 +656,12 @@ namespace Terminal.Gui {
 			if (!wait)
 				waitTimeout = 0;
 
-			return false;
+			int ic;
+			lock (mainLoop.idleHandlers) {
+				ic = mainLoop.idleHandlers.Count;
+			}
+
+			return ic > 0;
 		}
 
 		Action<KeyEvent> keyHandler;
diff --git a/Terminal.Gui/Core/MainLoop.cs b/Terminal.Gui/Core/MainLoop.cs
index 8e1217ad6..22bfa372a 100644
--- a/Terminal.Gui/Core/MainLoop.cs
+++ b/Terminal.Gui/Core/MainLoop.cs
@@ -95,9 +95,11 @@ namespace Terminal.Gui {
 		/// <param name="idleHandler">Token that can be used to remove the idle handler with <see cref="RemoveIdle(Func{bool})"/> .</param>
 		public Func<bool> AddIdle (Func<bool> idleHandler)
 		{
-			lock (idleHandlers)
+			lock (idleHandlers) {
 				idleHandlers.Add (idleHandler);
+			}
 
+			Driver.Wakeup ();
 			return idleHandler;
 		}