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 (((ObTimer*)timers->data)->timeout)
  12
  13 static long timecompare(GTimeVal *a, GTimeVal *b)
  14 {
  15     long r;
  16
  17     if ((r = b->tv_sec - a->tv_sec)) return r;
  18     return b->tv_usec - a->tv_usec;
  19
  20 }
  21
  22 static void insert_timer(ObTimer *self)
  23 {
  24     GSList *it;
  25     for (it = timers; it != NULL; it = it->next) {
  26         ObTimer *t = it->data;
  27         if (timecompare(&self->timeout, &t->timeout) <= 0) {
  28             timers = g_slist_insert_before(timers, it, self);
  29             break;
  30         }
  31     }
  32     if (it == NULL) /* didnt fit anywhere in the list */
  33         timers = g_slist_append(timers, self);
  34 }
  35
  36 void timer_startup()
  37 {
  38     g_get_current_time(&now);
  39     timers = NULL;
  40 }
  41
  42 void timer_shutdown()
  43 {
  44     GSList *it;
  45     for (it = timers; it != NULL; it = it->next) {
  46         g_free(it->data);
  47     }
  48     g_slist_free(timers);
  49     timers = NULL;
  50 }
  51
  52 ObTimer *timer_start(long delay, ObTimeoutHandler cb, void *data)
  53 {
  54     ObTimer *self = g_new(ObTimer, 1);
  55     self->delay = delay;
  56     self->action = cb;
  57     self->data = data;
  58     self->del_me = FALSE;
  59     g_get_current_time(&now);
  60     self->last = self->timeout = now;
  61     g_time_val_add(&self->timeout, delay);
  62
  63     insert_timer(self);
  64
  65     return self;
  66 }
  67
  68 void timer_stop(ObTimer *self)
  69 {
  70     self->del_me = TRUE;
  71 }
  72
  73 /* find the time to wait for the nearest timeout */
  74 static gboolean nearest_timeout_wait(GTimeVal *tm)
  75 {
  76   if (timers == NULL)
  77     return FALSE;
  78
  79   tm->tv_sec = NEAREST_TIMEOUT.tv_sec - now.tv_sec;
  80   tm->tv_usec = NEAREST_TIMEOUT.tv_usec - now.tv_usec;
  81
  82   while (tm->tv_usec < 0) {
  83     tm->tv_usec += G_USEC_PER_SEC;
  84     tm->tv_sec--;
  85   }
  86   tm->tv_sec += tm->tv_usec / G_USEC_PER_SEC;
  87   tm->tv_usec %= G_USEC_PER_SEC;
  88   if (tm->tv_sec < 0)
  89     tm->tv_sec = 0;
  90
  91   return TRUE;
  92 }
  93
  94
  95 void timer_dispatch(GTimeVal **wait)
  96 {
  97     g_get_current_time(&now);
  98
  99     while (timers != NULL) {
 100         ObTimer *curr = timers->data; /* get the top element */
 101         /* since timer_stop doesn't actually free the timer, we have to do our
 102            real freeing in here.
 103         */
 104         if (curr->del_me) {
 105             timers = g_slist_delete_link(timers, timers); /* delete the top */
 106             g_free(curr);
 107             continue;
 108         }
 109
 110         /* the queue is sorted, so if this timer shouldn't fire, none are
 111            ready */
 112         if (timecompare(&NEAREST_TIMEOUT, &now) <= 0)
 113             break;
 114
 115         /* we set the last fired time to delay msec after the previous firing,
 116            then re-insert.  timers maintain their order and may trigger more
 117            than once if they've waited more than one delay's worth of time.
 118         */
 119         timers = g_slist_delete_link(timers, timers);
 120         g_time_val_add(&curr->last, curr->delay);
 121         curr->action(curr, curr->data);
 122         g_time_val_add(&curr->timeout, curr->delay);
 123         insert_timer(curr);
 124
 125         /* if at least one timer fires, then don't wait on X events, as there
 126            may already be some in the queue from the timer callbacks.
 127         */
 128         ret_wait.tv_sec = ret_wait.tv_usec = 0;
 129         *wait = &ret_wait;
 130         return;
 131     }
 132
 133     if (nearest_timeout_wait(&ret_wait))
 134         *wait = &ret_wait;
 135     else
 136         *wait = NULL;
 137 }