implement periodic reschedule callbacks

2 files changed, 35 insertions, 20 deletions

diff --git a/ev.c b/ev.c
index 5405357..b852e45 100644
--- a/ev.c
+++ b/ev.c
@@ -962,7 +962,14 @@ periodics_reify (EV_P)
       assert (("inactive timer on periodic heap detected", ev_is_active (w)));
 
       /* first reschedule or stop timer */
-      if (w->interval)
+      if (w->reschedule_cb)
+        {
+          ev_tstamp at = ((WT)w)->at = w->reschedule_cb (w, rt_now + 0.0001);
+
+          assert (("ev_periodic reschedule callback returned time in the past", ((WT)w)->at > rt_now));
+          downheap ((WT *)periodics, periodiccnt, 0);
+        }
+      else if (w->interval)
         {
           ((WT)w)->at += floor ((rt_now - ((WT)w)->at) / w->interval + 1.) * w->interval;
           assert (("ev_periodic timeout in the past detected while processing timers, negative interval?", ((WT)w)->at > rt_now));
@@ -985,19 +992,15 @@ periodics_reschedule (EV_P)
     {
       struct ev_periodic *w = periodics [i];
 
-      if (w->interval)
-        {
-          ev_tstamp diff = ceil ((rt_now - ((WT)w)->at) / w->interval) * w->interval;
-
-          if (fabs (diff) >= 1e-4)
-            {
-              ev_periodic_stop (EV_A_ w);
-              ev_periodic_start (EV_A_ w);
-
-              i = 0; /* restart loop, inefficient, but time jumps should be rare */
-            }
-        }
+      if (w->reschedule_cb)
+        ((WT)w)->at = w->reschedule_cb (w, rt_now);
+      else if (w->interval)
+        ((WT)w)->at += ceil ((rt_now - ((WT)w)->at) / w->interval) * w->interval;
     }
+
+  /* now rebuild the heap */
+  for (i = periodiccnt >> 1; i--; )
+    downheap ((WT *)periodics, periodiccnt, i);
 }
 
 inline int
@@ -1311,11 +1314,14 @@ ev_periodic_start (EV_P_ struct ev_periodic *w)
   if (ev_is_active (w))
     return;
 
-  assert (("ev_periodic_start called with negative interval value", w->interval >= 0.));
-
-  /* this formula differs from the one in periodic_reify because we do not always round up */
-  if (w->interval)
-    ((WT)w)->at += ceil ((rt_now - ((WT)w)->at) / w->interval) * w->interval;
+  if (w->reschedule_cb)
+    ((WT)w)->at = w->reschedule_cb (w, rt_now);
+  else if (w->interval)
+    {
+      assert (("ev_periodic_start called with negative interval value", w->interval >= 0.));
+      /* this formula differs from the one in periodic_reify because we do not always round up */
+      ((WT)w)->at += ceil ((rt_now - ((WT)w)->at) / w->interval) * w->interval;
+    }
 
   ev_start (EV_A_ (W)w, ++periodiccnt);
   array_needsize (struct ev_periodic *, periodics, periodicmax, periodiccnt, (void));
@@ -1344,6 +1350,13 @@ ev_periodic_stop (EV_P_ struct ev_periodic *w)
 }
 
 void
+ev_periodic_again (EV_P_ struct ev_periodic *w)
+{
+  ev_periodic_stop (EV_A_ w);
+  ev_periodic_start (EV_A_ w);
+}
+
+void
 ev_idle_start (EV_P_ struct ev_idle *w)
 {
   if (ev_is_active (w))
diff --git a/ev.h b/ev.h
index aa746a5..61c88a5 100644
--- a/ev.h
+++ b/ev.h
@@ -141,6 +141,7 @@ struct ev_periodic
   EV_WATCHER_TIME (ev_periodic);
 
   ev_tstamp interval; /* rw */
+  ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now); /* rw */
 };
 
 /* invoked when fd is either EV_READable or EV_WRITEable */
@@ -298,7 +299,7 @@ void ev_once (EV_P_ int fd, int events, ev_tstamp timeout, void (*cb)(int revent
 
 #define ev_io_set(ev,fd_,events_)           do { (ev)->fd = (fd_); (ev)->events = (events_); } while (0)
 #define ev_timer_set(ev,after_,repeat_)     do { (ev)->at = (after_); (ev)->repeat = (repeat_); } while (0)
-#define ev_periodic_set(ev,at_,interval_)   do { (ev)->at = (at_); (ev)->interval = (interval_); } while (0)
+#define ev_periodic_set(ev,at_,ival_,res_)  do { (ev)->at = (at_); (ev)->interval = (ival_); (ev)->reschedule_cb= (res_); } while (0)
 #define ev_signal_set(ev,signum_)           do { (ev)->signum = (signum_); } while (0)
 #define ev_idle_set(ev)                     /* nop, yes, this is a serious in-joke */
 #define ev_prepare_set(ev)                  /* nop, yes, this is a serious in-joke */
@@ -307,7 +308,7 @@ void ev_once (EV_P_ int fd, int events, ev_tstamp timeout, void (*cb)(int revent
 
 #define ev_io_init(ev,cb,fd,events)         do { ev_watcher_init ((ev), (cb)); ev_io_set ((ev),(fd),(events)); } while (0)
 #define ev_timer_init(ev,cb,after,repeat)   do { ev_watcher_init ((ev), (cb)); ev_timer_set ((ev),(after),(repeat)); } while (0)
-#define ev_periodic_init(ev,cb,at,interval) do { ev_watcher_init ((ev), (cb)); ev_periodic_set ((ev),(at),(interval)); } while (0)
+#define ev_periodic_init(ev,cb,at,ival,res) do { ev_watcher_init ((ev), (cb)); ev_periodic_set ((ev),(at),(ival),(res)); } while (0)
 #define ev_signal_init(ev,cb,signum)        do { ev_watcher_init ((ev), (cb)); ev_signal_set ((ev), (signum)); } while (0)
 #define ev_idle_init(ev,cb)                 do { ev_watcher_init ((ev), (cb)); ev_idle_set ((ev)); } while (0)
 #define ev_prepare_init(ev,cb)              do { ev_watcher_init ((ev), (cb)); ev_prepare_set ((ev)); } while (0)
@@ -335,6 +336,7 @@ void ev_timer_again    (EV_P_ struct ev_timer *w);
 
 void ev_periodic_start (EV_P_ struct ev_periodic *w);
 void ev_periodic_stop  (EV_P_ struct ev_periodic *w);
+void ev_periodic_again (EV_P_ struct ev_periodic *w);
 
 void ev_idle_start     (EV_P_ struct ev_idle *w);
 void ev_idle_stop      (EV_P_ struct ev_idle *w);