Dogcows Code - chaz/openbox/blob - openbox/timer.c

   1 #include "timer.h"
   2
   3 #ifdef    HAVE_SYS_TIME_H
   4 #  include <sys/time.h>
   5 #endif
   6
   7 static GTimeVal now;
   8 static GTimeVal ret_wait;
   9 static GSList *timers; /* nearest timer is at the top */
  10
  11 #define NEAREST_TIMEOUT (((Timer*)timers->data)->timeout)
  12
  13 static void insert_timer(Timer *self)
  14 {
  15     GSList *it;
  16     for (it = timers; it != NULL; it = it->next) {
  17         Timer *t = it->data;
  18         if (!timercmp(&self->timeout, &t->timeout, >)) {
  19             timers = g_slist_insert_before(timers, it, self);
  20             break;
  21         }
  22     }
  23     if (it == NULL) /* didnt fit anywhere in the list */
  24         timers = g_slist_append(timers, self);
  25 }
  26
  27 void timer_startup()
  28 {
  29     g_get_current_time(&now);
  30     timers = NULL;
  31 }
  32
  33 void timer_shutdown()
  34 {
  35     GSList *it;
  36     for (it = timers; it != NULL; it = it->next) {
  37         g_free(it->data);
  38     }
  39     g_slist_free(timers);
  40     timers = NULL;
  41 }
  42
  43 Timer *timer_start(long delay, TimeoutHandler cb, void *data)
  44 {
  45     Timer *self = g_new(Timer, 1);
  46     self->delay = delay;
  47     self->action = cb;
  48     self->data = data;
  49     self->del_me = FALSE;
  50     self->last = self->timeout = now;
  51     g_time_val_add(&self->timeout, delay);
  52
  53     insert_timer(self);
  54
  55     return self;
  56 }
  57
  58 void timer_stop(Timer *self)
  59 {
  60     self->del_me = TRUE;
  61 }
  62
  63 /* find the time to wait for the nearest timeout */
  64 static gboolean nearest_timeout_wait(GTimeVal *tm)
  65 {
  66   if (timers == NULL)
  67     return FALSE;
  68
  69   tm->tv_sec = NEAREST_TIMEOUT.tv_sec - now.tv_sec;
  70   tm->tv_usec = NEAREST_TIMEOUT.tv_usec - now.tv_usec;
  71
  72   while (tm->tv_usec < 0) {
  73     tm->tv_usec += G_USEC_PER_SEC;
  74     tm->tv_sec--;
  75   }
  76   tm->tv_sec += tm->tv_usec / G_USEC_PER_SEC;
  77   tm->tv_usec %= G_USEC_PER_SEC;
  78   if (tm->tv_sec < 0)
  79     tm->tv_sec = 0;
  80
  81   return TRUE;
  82 }
  83
  84
  85 void timer_dispatch(GTimeVal **wait)
  86 {
  87     g_get_current_time(&now);
  88
  89     while (timers != NULL) {
  90         Timer *curr = timers->data; /* get the top element */
  91         /* since timer_stop doesn't actually free the timer, we have to do our
  92            real freeing in here.
  93         */
  94         if (curr->del_me) {
  95             timers = g_slist_delete_link(timers, timers); /* delete the top */
  96             g_free(curr);
  97             continue;
  98         }
  99
 100         /* the queue is sorted, so if this timer shouldn't fire, none are
 101            ready */
 102         if (!timercmp(&now, &NEAREST_TIMEOUT, >))
 103             break;
 104
 105         /* we set the last fired time to delay msec after the previous firing,
 106            then re-insert.  timers maintain their order and may trigger more
 107            than once if they've waited more than one delay's worth of time.
 108         */
 109         timers = g_slist_delete_link(timers, timers);
 110         g_time_val_add(&curr->last, curr->delay);
 111         curr->action(curr->data);
 112         g_time_val_add(&curr->timeout, curr->delay);
 113         insert_timer(curr);
 114
 115         /* if at least one timer fires, then don't wait on X events, as there
 116            may already be some in the queue from the timer callbacks.
 117         */
 118         ret_wait.tv_sec = ret_wait.tv_usec = 0;
 119         *wait = &ret_wait;
 120         return;
 121     }
 122
 123     if (nearest_timeout_wait(&ret_wait))
 124         *wait = &ret_wait;
 125     else
 126         *wait = NULL;
 127 }