From b6cb1927f39786de37d829a8677fe9cac2693a94 Mon Sep 17 00:00:00 2001
From: Guille Polito <guillermopolito@gmail.com>
Date: Wed, 31 Oct 2018 10:46:37 +0100
Subject: [PATCH] Consume all events in the event queue to avoid application
 lockups

---
 .../vm/OSX/sqSqueakOSXApplication+events.m    | 50 +++++++++++--------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m b/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
index d61fff7c5a..b7ccfff7c5 100644
--- a/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
+++ b/platforms/iOS/vm/OSX/sqSqueakOSXApplication+events.m
@@ -67,27 +67,37 @@ - (sqButton) resolveModifier:(sqModifier)modifier forMouseButton:(sqButton)mouse
 
 @implementation sqSqueakOSXApplication (events)
 
+// Consume all pending events in the NSApp
+// Events may come from the window open by the VM or windows open by other windowing systems
+// We need to consume all events in the queue, otherwise this may produce lockups when e.g., switching resolutions
+// If the event does not correspond to this window, we take it from the event queue anyways and re-post it afterwards
+// This gives other windows the opportunity to consume their events
 - (void) pumpRunLoopEventSendAndSignal:(BOOL)signal {
-    NSEvent *event;
-    while (event = [NSApp nextEventMatchingMask:NSEventMaskAny
-                                       untilDate:nil
-                                          inMode:NSEventTrackingRunLoopMode
-                                         dequeue:NO]) {
-        // If the event is not a system event or an event of *this* window, stop consuming events
-        // In case of multi window applications, it is the responsibility of the other windowing systems to consume their own events
-        // This is a cooperative event handling mechanism for simplicity
-        // Single window systems will be not affected by it
-        if (!(event.window == 0 || event.window == gDelegateApp.window)){
-          break;
-        }
-        [NSApp sendEvent: [NSApp nextEventMatchingMask:NSEventMaskAny
-                                 untilDate:nil
-                                 inMode:NSEventTrackingRunLoopMode
-                                 dequeue:YES]];
-        if (signal) {
-            interpreterProxy->signalSemaphoreWithIndex(gDelegateApp.squeakApplication.inputSemaphoreIndex);
-        }
-    }
+       NSEvent *event;
+       NSMutableArray *alienEventQueue = [[NSMutableArray alloc] init];
+       while (event = [NSApp nextEventMatchingMask:NSEventMaskAny
+                             untilDate:nil
+                             inMode:NSEventTrackingRunLoopMode
+                             dequeue:YES]) {
+         // If the event is not a system event or an event of *this* window, queue the event
+         // Otherwise treat the event normally and send it to the app
+         if (event.window && event.window != gDelegateApp.window){
+           [alienEventQueue addObject: event];
+         }else{
+           [NSApp sendEvent: event];
+           if (signal) {
+               interpreterProxy->signalSemaphoreWithIndex(gDelegateApp.squeakApplication.inputSemaphoreIndex);
+           }
+         }
+     }
+
+     // Put back in the queue all events that did not belong to this window
+     // They will be managed by other windowing systems
+     // (or by a subsequent invocation to this function)
+     while (event = [alienEventQueue firstObject]){
+       [NSApp postEvent: event atStart: NO];
+       [alienEventQueue removeObject: event];
+     }
 }
 
 - (void) pumpRunLoop {