diff options
Diffstat (limited to 'lib/qtimers.c')
| -rw-r--r-- | lib/qtimers.c | 100 |
1 files changed, 61 insertions, 39 deletions
diff --git a/lib/qtimers.c b/lib/qtimers.c index 6d3932fc..f4959983 100644 --- a/lib/qtimers.c +++ b/lib/qtimers.c @@ -44,8 +44,8 @@ * Timers are triggered by calling qtimer_dispatch_next(). This is given the * current qtimer time (see below), and it dispatches the first timer whose * time has come (or been passed). Dispatching a timer means calling its - * action function (see below). Each call of qtimer_dispatch_next triggers at - * most one timer. + * action function (see below). Each call of qtimer_dispatch_next() triggers + * at most one timer. * * Time Base * --------- @@ -65,7 +65,8 @@ * timer (which may, or may not, be the current qtimer time). * * During an action function timers may be set/unset, actions changed, and so - * on... there are no restrictions. + * on... there are no restrictions EXCEPT that the qtimer structure may NOT be + * freed. */ static int @@ -92,7 +93,7 @@ qtimer_pile_init_new(qtimer_pile qtp) if (qtp == NULL) qtp = XCALLOC(MTYPE_QTIMER_PILE, sizeof(struct qtimer_pile)) ; else - memset(qtp, 0, sizeof(struct qtimer_pile)) ; + memset(qtp, 0, sizeof(struct qtimer_pile)) ; /* Zeroising has initialised: * @@ -109,6 +110,23 @@ qtimer_pile_init_new(qtimer_pile qtp) return qtp ; } ; +/* Get the timer time for the first timer due to go off in the given pile. + * + * The caller must provide a maximum acceptable time. If the qtimer pile is + * empty, or the top entry times out after the maximum time, then the maximum + * is returned. + */ +qtime_t +qtimer_pile_top_time(qtimer_pile qtp, qtime_t max_time) +{ + qtimer qtr = heap_top_item(&qtp->timers) ; + + if ((qtr == NULL) || (qtr->time >= max_time)) + return max_time ; + else + return qtr->time ; +} ; + /* Dispatch the next timer whose time is <= the given "upto" time. * * The upto time must be a qtimer time (!) -- see qtimer_time_now(). @@ -124,18 +142,15 @@ qtimer_pile_dispatch_next(qtimer_pile qtp, qtime_t upto) { qtimer qtr ; - if (qtp->unset_pending != NULL) - qtimer_unset(qtp->unset_pending) ; /* just in case recurse through here */ - qtr = heap_top_item(&qtp->timers) ; if ((qtr != NULL) && (qtr->time <= upto)) { - qtp->unset_pending = qtr ; /* delay unset of top item, pro tem...*/ + qtr->state = qtr_state_unset_pending ; qtr->action(qtr, qtr->timer_info, upto) ; - if (qtp->unset_pending != NULL) /* ...now must unset if not yet done */ - qtimer_unset(qtp->unset_pending) ; + if (qtr->state == qtr_state_unset_pending) + qtimer_unset(qtr) ; return 1 ; } @@ -147,9 +162,12 @@ qtimer_pile_dispatch_next(qtimer_pile qtp, qtime_t upto) * * If pile is empty, release the qtimer_pile structure, if required. * + * See: #define qtimer_pile_ream_free(qtp) + * #define qtimer_pile_ream_keep(qtp) + * * Useful for emptying out and discarding a pile of timers: * - * while ((p_qtr = qtimer_pile_ream(qtp, 1))) + * while ((p_qtr = qtimer_pile_ream_free(qtp))) * ... do what's required to release the item p_qtr * * Returns NULL when timer pile is empty (and has been released, if required). @@ -166,15 +184,10 @@ qtimer_pile_ream(qtimer_pile qtp, int free_structure) qtr = heap_ream_keep(&qtp->timers) ; /* ream, keeping the heap structure */ if (qtr != NULL) - qtr->active = 0 ; /* already removed from pile */ + qtr->state = qtr_state_inactive ; /* has been removed from pile */ else - { - if (free_structure) - XFREE(MTYPE_QTIMER_PILE, qtp) ; - else - qtp->unset_pending = NULL ; /* heap is empty, so this is last thing */ - /* to be tidied up. */ - } ; + if (free_structure) /* pile is empty, may now free it */ + XFREE(MTYPE_QTIMER_PILE, qtp) ; return qtr ; } ; @@ -186,7 +199,7 @@ qtimer_pile_ream(qtimer_pile qtp, int free_structure) /* Initialise qtimer structure -- allocating one if required. * * Associates qtimer with the given pile of timers, and sets up the action and - * the timer_info ready for use. + * the timer_info. * * Once initialised, the timer may be set. * @@ -199,20 +212,22 @@ qtimer_init_new(qtimer qtr, qtimer_pile qtp, if (qtr == NULL) qtr = XCALLOC(MTYPE_QTIMER, sizeof(struct qtimer)) ; else - memset(qtr, 0, sizeof(struct qtimer)) ; + memset(qtr, 0, sizeof(struct qtimer)) ; /* Zeroising has initialised: * * pile -- NULL -- not in any pile (yet) * backlink -- unset * - * active -- not active + * state -- not active * * time -- unset * action -- NULL -- no action set (yet) * timer_info -- NULL -- no timer info set (yet) */ + confirm(qtr_state_inactive == 0) ; + qtr->pile = qtp ; qtr->action = action ; qtr->timer_info = timer_info ; @@ -223,11 +238,15 @@ qtimer_init_new(qtimer qtr, qtimer_pile qtp, /* Free given timer. * * Unsets it first if it is active. + * + * The timer MAY NOT be currently the subject of qtimer_pile_dispatch_next(). */ void qtimer_free(qtimer qtr) { - if (qtr->active) + assert(qtr->state != qtr_state_unset_pending) ; + + if (qtr->state != qtr_state_inactive) qtimer_unset(qtr) ; XFREE(MTYPE_QTIMER, qtr) ; @@ -241,7 +260,7 @@ qtimer_free(qtimer qtr) void qtimer_set_pile(qtimer qtr, qtimer_pile qtp) { - if ((qtr->active) && (qtr->pile != qtp)) + if (qtr_is_active(qtr) && (qtr->pile != qtp)) qtimer_unset(qtr) ; qtr->pile = qtp ; } @@ -266,12 +285,17 @@ qtimer_set_info(qtimer qtr, void* timer_info) * * Setting a -ve time => qtimer_unset. * + * Sets any given action -- if the action given is NULL, retains previously set + * action. + * * If the timer is already active, sets the new time & updates pile. * * Otherwise, sets the time and adds to pile -- making timer active. + * + * It is an error to set a timer which has a NULL action. */ void -qtimer_set(qtimer qtr, qtime_t when) +qtimer_set(qtimer qtr, qtime_t when, qtimer_action* action) { qtimer_pile qtp ; @@ -283,17 +307,17 @@ qtimer_set(qtimer qtr, qtime_t when) qtr->time = when ; - if (qtr->active) - { - heap_update_item(&qtp->timers, qtr) ; /* update in heap */ - if (qtr == qtp->unset_pending) - qtp->unset_pending = NULL ; /* dealt with. */ - } + if (qtr_is_active(qtr)) + heap_update_item(&qtp->timers, qtr) ; /* update in heap */ else - { - heap_push_item(&qtp->timers, qtr) ; /* add to heap */ - qtr->active = 1 ; - } ; + heap_push_item(&qtp->timers, qtr) ; /* add to heap */ + + qtr->state = qtr_state_active ; /* overrides any unset pending */ + + if (action != NULL) + qtr->action = action ; + else + dassert(qtr->action != NULL) ; } ; /* Unset given timer @@ -303,15 +327,13 @@ qtimer_set(qtimer qtr, qtime_t when) void qtimer_unset(qtimer qtr) { - if (qtr->active) + if (qtr_is_active(qtr)) { qtimer_pile qtp = qtr->pile ; dassert(qtp != NULL) ; heap_delete_item(&qtp->timers, qtr) ; - if (qtr == qtp->unset_pending) - qtp->unset_pending = NULL ; - qtr->active = 0 ; + qtr->state = qtr_state_inactive ; /* overrides any unset pending */ } ; } ; |