Use Libevent 2.0's periodic timers where available.

These timers behave better with non-monotonic clocks than our old
ones, and also try harder to make once-per-second events get called
one second apart, rather than one-plus-epsilon seconds apart.

This fixes bug 943 for everybody using Libevent 2.0 or later.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/common/compat_libevent.h b/src/common/compat_libevent.h
index eedd9da43d..fdf5e0a18f 100644
--- a/src/common/compat_libevent.h
+++ b/src/common/compat_libevent.h
@@ -38,8 +38,14 @@ void tor_event_free(struct event *ev);
 #define tor_evdns_add_server_port evdns_add_server_port
 #endif
 
-/* XXXX022 If we can drop support for Libevent before 1.1, we can
- * do without this wrapper. */
+typedef struct periodic_timer_t periodic_timer_t;
+
+periodic_timer_t *periodic_timer_new(struct event_base *base,
+             const struct timeval *tv,
+             void (*cb)(periodic_timer_t *timer, void *data),
+             void *data);
+void periodic_timer_free(periodic_timer_t *);
+
 #ifdef HAVE_EVENT_BASE_LOOPEXIT
 #define tor_event_base_loopexit event_base_loopexit
 #else