timer: make timer_del() idempotent, add timer_init().

[ccan] / ccan / timer / timer.c

diff --git a/ccan/timer/timer.c b/ccan/timer/timer.c
index cf3bfd9d1edada106c9c5d0e24126e83a7a47e5c..0abf05cd419ee8111312450872e80b53fee1ebb2 100644 (file)
--- a/ccan/timer/timer.c
+++ b/ccan/timer/timer.c
@@ -12,23 +12,23 @@ struct timer_level {
        struct list_head list[PER_LEVEL];
 };
 
-static uint64_t time_to_grains(struct timespec ts)
+static uint64_t time_to_grains(struct timeabs t)
 {
-       return ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
-               + (ts.tv_nsec / TIMER_GRANULARITY);
+       return t.ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
+               + (t.ts.tv_nsec / TIMER_GRANULARITY);
 }
 
-static struct timespec grains_to_time(uint64_t grains)
+static struct timeabs grains_to_time(uint64_t grains)
 {
-       struct timespec ts;
+       struct timeabs t;
 
-       ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
-       ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
+       t.ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
+       t.ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
                * TIMER_GRANULARITY;
-       return ts;
+       return t;
 }
 
-void timers_init(struct timers *timers, struct timespec start)
+void timers_init(struct timers *timers, struct timeabs start)
 {
        unsigned int i;
 
@@ -63,8 +63,20 @@ static void timer_add_raw(struct timers *timers, struct timer *t)
        list_add_tail(l, &t->list);
 }
 
-void timer_add(struct timers *timers, struct timer *t, struct timespec when)
+void timer_init(struct timer *t)
 {
+       list_node_init(&t->list);
+}
+
+static bool list_node_initted(const struct list_node *n)
+{
+       return n->prev == n;
+}
+
+void timer_add(struct timers *timers, struct timer *t, struct timeabs when)
+{
+       assert(list_node_initted(&t->list));
+
        t->time = time_to_grains(when);
 
        /* Added in the past?  Treat it as imminent. */
@@ -79,7 +91,7 @@ void timer_add(struct timers *timers, struct timer *t, struct timespec when)
 /* FIXME: inline */
 void timer_del(struct timers *timers, struct timer *t)
 {
-       list_del(&t->list);
+       list_del_init(&t->list);
 }
 
 static void timers_far_get(struct timers *timers,
@@ -203,7 +215,7 @@ static bool update_first(struct timers *timers)
        return true;
 }
 
-bool timer_earliest(struct timers *timers, struct timespec *first)
+bool timer_earliest(struct timers *timers, struct timeabs *first)
 {
        if (!update_first(timers))
                return false;
@@ -259,37 +271,37 @@ static void timer_fast_forward(struct timers *timers, uint64_t time)
                timer_add_raw(timers, i);
 }
 
-/* Fills list of expired timers. */
-void timers_expire(struct timers *timers,
-                  struct timespec expire,
-                  struct list_head *list)
+/* Returns an expired timer. */
+struct timer *timers_expire(struct timers *timers, struct timeabs expire)
 {
        uint64_t now = time_to_grains(expire);
        unsigned int off;
+       struct timer *t;
 
        assert(now >= timers->base);
 
-       list_head_init(list);
-
        if (!timers->level[0]) {
                if (list_empty(&timers->far))
-                       return;
+                       return NULL;
                add_level(timers, 0);
        }
 
        do {
                if (timers->first > now) {
                        timer_fast_forward(timers, now);
-                       break;
+                       return NULL;
                }
 
                timer_fast_forward(timers, timers->first);
                off = timers->base % PER_LEVEL;
 
-               list_append_list(list, &timers->level[0]->list[off]);
-               if (timers->base == now)
-                       break;
-       } while (update_first(timers));
+               /* This *may* be NULL, if we deleted the first timer */
+               t = list_pop(&timers->level[0]->list[off], struct timer, list);
+               if (t)
+                       list_node_init(&t->list);
+       } while (!t && update_first(timers));
+
+       return t;
 }
 
 static bool timer_list_check(const struct list_head *l,