4 * This module tracks any timers set up by schedule_timer(). It
5 * keeps all the currently active timers in a list; it informs the
6 * front end of when the next timer is due to go off if that
7 * changes; and, very importantly, it tracks the context pointers
8 * passed to schedule_timer(), so that if a context is freed all
9 * the timers associated with it can be immediately annulled.
24 static tree234 *timers = NULL;
25 static tree234 *timer_contexts = NULL;
28 static int compare_timers(void *av, void *bv)
30 struct timer *a = (struct timer *)av;
31 struct timer *b = (struct timer *)bv;
32 long at = a->now - now;
33 long bt = b->now - now;
41 * Failing that, compare on the other two fields, just so that
42 * we don't get unwanted equality.
45 /* lcc won't let us compare function pointers. Legal, but annoying. */
47 int c = memcmp(&a->fn, &b->fn, sizeof(a->fn));
56 else if (a->fn > b->fn)
62 else if (a->ctx > b->ctx)
66 * Failing _that_, the two entries genuinely are equal, and we
67 * never have a need to store them separately in the tree.
72 static int compare_timer_contexts(void *av, void *bv)
83 static void init_timers(void)
86 timers = newtree234(compare_timers);
87 timer_contexts = newtree234(compare_timer_contexts);
92 long schedule_timer(int ticks, timer_fn_t fn, void *ctx)
95 struct timer *t, *first;
99 when = ticks + GETTICKCOUNT();
100 assert(when - now > 0);
102 t = snew(struct timer);
107 if (t != add234(timers, t)) {
108 sfree(t); /* identical timer already exists */
110 add234(timer_contexts, t->ctx);/* don't care if this fails */
113 first = (struct timer *)index234(timers, 0);
116 * This timer is the very first on the list, so we must
117 * notify the front end.
119 timer_change_notify(first->now);
126 * Call to run any timers whose time has reached the present.
127 * Returns the time (in ticks) expected until the next timer after
130 int run_timers(long anow, long *next)
139 first = (struct timer *)index234(timers, 0);
142 return FALSE; /* no timers remaining */
144 if (find234(timer_contexts, first->ctx, NULL) == NULL) {
146 * This timer belongs to a context that has been
147 * expired. Delete it without running.
149 delpos234(timers, 0);
151 } else if (first->now - now <= 0) {
153 * This timer is active and has reached its running
156 delpos234(timers, 0);
157 first->fn(first->ctx, first->now);
161 * This is the first still-active timer that is in the
162 * future. Return how long it has yet to go.
171 * Call to expire all timers associated with a given context.
173 void expire_timer_context(void *ctx)
178 * We don't bother to check the return value; if the context
179 * already wasn't in the tree (presumably because no timers
180 * ever actually got scheduled for it) then that's fine and we
181 * simply don't need to do anything.
183 del234(timer_contexts, ctx);