Commit e9134b045a6eea1d9bea2046ddcefb669ab6e016
2022-01-06T19:38:10
events: Only add sentinels for pumping done inside SDL_WaitEventTimeout() We don't want to catch explicit SDL_PumpEvents() calls by the application with our polling check to avoid stale data. If the call to SDL_PumpEvents() produced no events, there will be a sentinel sitting in the queue that will cause SDL_PollEvent() to immediately return 0 next time it is called. Our SDL_WaitEventTimeout() implementation avoids this issue by always popping an event after calling SDL_PumpEvents(). This will remove the new sentinel if we didn't get any new events.
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diff --git a/src/events/SDL_events.c b/src/events/SDL_events.c
index 4459896..ff079c5 100644
--- a/src/events/SDL_events.c
+++ b/src/events/SDL_events.c
@@ -809,7 +809,7 @@ SDL_FlushEvents(Uint32 minType, Uint32 maxType)
/* Run the system dependent event loops */
void
-SDL_PumpEvents(void)
+SDL_PumpEventsInternal(SDL_bool push_sentinel)
{
SDL_VideoDevice *_this = SDL_GetVideoDevice();
@@ -837,7 +837,7 @@ SDL_PumpEvents(void)
SDL_SendPendingSignalEvents(); /* in case we had a signal handler fire, etc. */
- if (SDL_GetEventState(SDL_POLLSENTINEL) == SDL_ENABLE) {
+ if (push_sentinel && SDL_GetEventState(SDL_POLLSENTINEL) == SDL_ENABLE) {
SDL_Event sentinel;
SDL_zero(sentinel);
@@ -846,6 +846,12 @@ SDL_PumpEvents(void)
}
}
+void
+SDL_PumpEvents()
+{
+ SDL_PumpEventsInternal(SDL_FALSE);
+}
+
/* Public functions */
int
@@ -885,7 +891,7 @@ SDL_WaitEventTimeout_Device(_THIS, SDL_Window *wakeup_window, SDL_Event * event,
c) Periodic processing that takes place in some platform PumpEvents() functions happens
d) Signals received in WaitEventTimeout() are turned into SDL events
*/
- SDL_PumpEvents();
+ SDL_PumpEventsInternal(SDL_TRUE);
if (!_this->wakeup_lock || SDL_LockMutex(_this->wakeup_lock) == 0) {
int status = SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_FIRSTEVENT, SDL_LASTEVENT);
@@ -984,7 +990,7 @@ SDL_WaitEventTimeout(SDL_Event * event, int timeout)
/* If there isn't a poll sentinel event pending, pump events and add one */
if (SDL_AtomicGet(&SDL_sentinel_pending) == 0) {
- SDL_PumpEvents();
+ SDL_PumpEventsInternal(SDL_TRUE);
}
/* First check for existing events */
@@ -1031,7 +1037,7 @@ SDL_WaitEventTimeout(SDL_Event * event, int timeout)
}
for (;;) {
- SDL_PumpEvents();
+ SDL_PumpEventsInternal(SDL_TRUE);
switch (SDL_PeepEvents(event, 1, SDL_GETEVENT, SDL_FIRSTEVENT, SDL_LASTEVENT)) {
case -1:
return 0;