Javascript: When there is javascript running then it will spin the CPU at 100%

Zero timers on Windows would continue to fire even after being stopped
as long as a new timer was started that reused the pointer address of
the zero timer. Fix this by only re-firing zero timers if the zero
timer hadn't been stopped (we can check this by looking at the
inTimerEvent flag, which is set to false by registerTimer()).

Task-number: 247401
Reviewed-by: Denis Dzyubenko
Reviewed-by: Prasanth Ullattil

1 files changed, 12 insertions, 3 deletions

diff --git a/src/corelib/kernel/qeventdispatcher_win.cpp b/src/corelib/kernel/qeventdispatcher_win.cpp
index 880e95c..c4061f4 100644
--- a/src/corelib/kernel/qeventdispatcher_win.cpp
+++ b/src/corelib/kernel/qeventdispatcher_win.cpp
@@ -1059,11 +1059,20 @@ bool QEventDispatcherWin32::event(QEvent *e)
         QZeroTimerEvent *zte = static_cast<QZeroTimerEvent*>(e);
         WinTimerInfo *t = d->timerDict.value(zte->timerId());
         if (t) {
+            t->inTimerEvent = true;
+
             QTimerEvent te(zte->timerId());
             QCoreApplication::sendEvent(t->obj, &te);
-            WinTimerInfo *tn = d->timerDict.value(zte->timerId());
-            if (tn && t == tn)
-                QCoreApplication::postEvent(this, new QZeroTimerEvent(zte->timerId()));
+
+            t = d->timerDict.value(zte->timerId());
+            if (t) {
+                if (t->interval == 0 && t->inTimerEvent) {
+                    // post the next zero timer event as long as the timer was not restarted
+                    QCoreApplication::postEvent(this, new QZeroTimerEvent(zte->timerId()));
+                }
+
+                t->inTimerEvent = false;
+            }
         }
         return true;
     } else if (e->type() == QEvent::Timer) {