[Levent-commits] [Libevent/master 2/3] Fix a bug in resetting timeouts on persistent events when IO triggers.

[Nick M. <ni...@us...>]

Author: Nick Mathewson <ni...@to...>
Date: Tue, 23 Feb 2010 14:24:10 -0500
Subject: Fix a bug in resetting timeouts on persistent events when IO triggers.
Commit: 38ec0a773b73375410cbb5a4eaeece3d0ab1caa0

When we fixed persistent timeouts to make them reset themselves
based on the previous scheduled time rather than the current
time... we made them do so regardless of whether the event was
triggering because of a timeout or not!

This was of course bogus.  When a _timeout_ triggers, we should
schedule the event for N seconds based on the last
_schedule_ time... but when IO triggers, we should reset the
timeout for N seconds after now.
---
 event.c |   27 +++++++++++++++++++--------
 1 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/event.c b/event.c
index 07a4336..e66fb30 100644
--- a/event.c
+++ b/event.c
@@ -1083,24 +1083,35 @@ event_persist_closure(struct event_base *base, struct event *ev)
 {
 	/* reschedule the persistent event if we have a timeout. */
 	if (ev->ev_io_timeout.tv_sec || ev->ev_io_timeout.tv_usec) {
-		/* We want it to run at an interval of ev_io_timeout after the
-		 * last time it was _scheduled_ for, not ev_io_timeout after
-		 * _now_. */
+		/* If there was a timeout, we want it to run at an interval of
+		 * ev_io_timeout after the last time it was _scheduled_ for,
+		 * not ev_io_timeout after _now_.  If it fired for another
+		 * reason, though, the timeout ought to start ticking _now_. */
 		struct timeval run_at;
 		EVUTIL_ASSERT(is_same_common_timeout(&ev->ev_timeout,
 			&ev->ev_io_timeout));
 		if (is_common_timeout(&ev->ev_timeout, base)) {
 			ev_uint32_t usec_mask;
-			struct timeval delay, last_at;
-			last_at = ev->ev_timeout;
+			struct timeval delay, relative_to;
 			delay = ev->ev_io_timeout;
 			usec_mask = delay.tv_usec & ~MICROSECONDS_MASK;
-			last_at.tv_usec &= MICROSECONDS_MASK;
 			delay.tv_usec &= MICROSECONDS_MASK;
-			evutil_timeradd(&last_at, &delay, &run_at);
+			if (ev->ev_res & EV_TIMEOUT) {
+				relative_to = ev->ev_timeout;
+				relative_to.tv_usec &= MICROSECONDS_MASK;
+			} else {
+				gettime(base, &relative_to);
+			}
+			evutil_timeradd(&relative_to, &delay, &run_at);
 			run_at.tv_usec |= usec_mask;
 		} else {
-			evutil_timeradd(&ev->ev_io_timeout, &ev->ev_timeout,
+			struct timeval relative_to;
+			if (ev->ev_res & EV_TIMEOUT) {
+				relative_to = ev->ev_timeout;
+			} else {
+				gettime(base, &relative_to);
+			}
+			evutil_timeradd(&ev->ev_io_timeout, &relative_to,
 			    &run_at);
 		}
 		event_add_internal(ev, &run_at, 1);
-- 
1.6.3