From d259b12ae7ccb28c701a0c5ba4e81d8d60ff6532 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 8 Jul 2019 11:01:17 +0530
Subject: [PATCH] Micro-optimization: Avoid repeated calls to XQLength

---
 glfw/x11_window.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/glfw/x11_window.c b/glfw/x11_window.c
index 935f6f55a..8baa95cb1 100644
--- a/glfw/x11_window.c
+++ b/glfw/x11_window.c
@@ -2473,14 +2473,12 @@ void _glfwPlatformSetWindowOpacity(_GLFWwindow* window, float opacity)
 }
 
 static inline unsigned
-dispatch_x11_queued_events(void) {
-    unsigned dispatched = 0;
-    while (XQLength(_glfw.x11.display) > 0)
-    {
+dispatch_x11_queued_events(int num_events) {
+    unsigned dispatched = num_events > 0 ? num_events : 0;
+    while (num_events-- > 0) {
         XEvent event;
         XNextEvent(_glfw.x11.display, &event);
         processEvent(&event);
-        dispatched += 1;
     }
     return dispatched;
 }
@@ -2493,8 +2491,7 @@ _glfwDispatchX11Events(void) {
 #if defined(__linux__)
     _glfwDetectJoystickConnectionLinux();
 #endif
-    XPending(_glfw.x11.display);
-    dispatched += dispatch_x11_queued_events();
+    dispatched += dispatch_x11_queued_events(XEventsQueued(_glfw.x11.display, QueuedAfterFlush));
 
     window = _glfw.x11.disabledCursorWindow;
     if (window)
@@ -2512,8 +2509,10 @@ _glfwDispatchX11Events(void) {
     }
 
     XFlush(_glfw.x11.display);
-    // XFlush can cause events to be queued
-    dispatched += dispatch_x11_queued_events();
+    // XFlush can cause events to be queued, we dont use QueuedAfterFlush here
+    // as something might have inserted events into the queue, but we want to guarantee
+    // a flush.
+    dispatched += dispatch_x11_queued_events(XEventsQueued(_glfw.x11.display, QueuedAlready));
     return dispatched;
 }