diff options
Diffstat (limited to 'lib/qtimers.c')
| -rw-r--r-- | lib/qtimers.c | 180 |
1 files changed, 110 insertions, 70 deletions
diff --git a/lib/qtimers.c b/lib/qtimers.c index 508fc7d7..8c08a6bc 100644 --- a/lib/qtimers.c +++ b/lib/qtimers.c @@ -81,8 +81,11 @@ enum { qdebug = * 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 EXCEPT that the qtimer structure may NOT be - * freed. + * on... there are no restrictions EXCEPT that may NOT recurse into the + * dispatch function. + * + * If nothing is done with the time during the action function, the timer is + * implicitly unset when the action function returns. */ static int @@ -99,7 +102,8 @@ qtimer_cmp(qtimer* a, qtimer* b) /* the heap discipline */ * qtimer_pile handling */ -/* Initialise a timer pile -- allocating it if required. +/*------------------------------------------------------------------------------ + * Initialise a timer pile -- allocating it if required. * * Returns the qtimer_pile. */ @@ -114,6 +118,7 @@ qtimer_pile_init_new(qtimer_pile qtp) /* Zeroising has initialised: * * timers -- invalid heap -- need to properly initialise + * current = NULL -- no current timer */ /* (The typedef is required to stop Eclipse (3.4.2 with CDT 5.0) whining @@ -126,13 +131,14 @@ 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. +/*------------------------------------------------------------------------------ + * 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 +extern qtime_t qtimer_pile_top_wait(qtimer_pile qtp, qtime_t max_wait) { qtime_t top_wait ; @@ -146,7 +152,8 @@ qtimer_pile_top_wait(qtimer_pile qtp, qtime_t max_wait) return (top_wait < max_wait) ? top_wait : max_wait ; } ; -/* Dispatch the next timer whose time is <= the given "upto" time. +/*------------------------------------------------------------------------------ + * Dispatch the next timer whose time is <= the given "upto" time. * * The upto time must be a qtimer time (!) -- see qtimer_time_now(). * @@ -155,8 +162,10 @@ qtimer_pile_top_wait(qtimer_pile qtp, qtime_t max_wait) * * Returns true <=> dispatched a timer, and there may be more to do. * false <=> nothing to do (and nothing done). + * + * NB: it is a sad, very sad, mistake to recurse into this ! */ -int +extern bool qtimer_pile_dispatch_next(qtimer_pile qtp, qtime_mono_t upto) { qtimer qtr ; @@ -165,23 +174,26 @@ qtimer_pile_dispatch_next(qtimer_pile qtp, qtime_mono_t upto) qtimer_pile_verify(qtp) ; qtr = heap_top_item(&qtp->timers) ; - if ((qtr != NULL) && (qtr->time <= upto)) - { - passert(qtp == qtr->pile); - qtr->state = qtr_state_unset_pending ; - qtr->action(qtr, qtr->timer_info, upto) ; + if ((qtr == NULL) || (qtr->time > upto)) + return 0 ; - if (qtr->state == qtr_state_unset_pending) - qtimer_unset(qtr) ; + passert((qtp == qtr->pile) && (qtr->active)) ; - return 1 ; - } + qtp->implicit_unset = qtr ; /* Timer must be unset if is still here + when the action function returns */ + qtr->action(qtr, qtr->timer_info, upto) ; + + if (qtp->implicit_unset == qtr) + qtimer_unset(qtr) ; else - return 0 ; + assert(qtp->implicit_unset == NULL) ; /* check for tidy-ness */ + + return 1 ; } ; -/* Ream out (another) item from qtimer_pile. +/*------------------------------------------------------------------------------ + * Ream out (another) item from qtimer_pile. * * If pile is empty, release the qtimer_pile structure, if required. * @@ -207,7 +219,7 @@ qtimer_pile_ream(qtimer_pile qtp, int free_structure) qtr = heap_ream_keep(&qtp->timers) ; /* ream, keeping the heap structure */ if (qtr != NULL) - qtr->state = qtr_state_inactive ; /* has been removed from pile */ + qtr->active = false ; /* has been removed from pile */ else if (free_structure) /* pile is empty, may now free it */ XFREE(MTYPE_QTIMER_PILE, qtp) ; @@ -219,7 +231,8 @@ qtimer_pile_ream(qtimer_pile qtp, int free_structure) * qtimer handling */ -/* Initialise qtimer structure -- allocating one if required. +/*------------------------------------------------------------------------------ + * Initialise qtimer structure -- allocating one if required. * * Associates qtimer with the given pile of timers, and sets up the action and * the timer_info. @@ -242,7 +255,7 @@ qtimer_init_new(qtimer qtr, qtimer_pile qtp, * pile -- NULL -- not in any pile (yet) * backlink -- unset * - * state -- not active + * active -- false * * time -- unset * action -- NULL -- no action set (yet) @@ -251,8 +264,6 @@ qtimer_init_new(qtimer qtr, qtimer_pile qtp, * interval -- unset */ - confirm(qtr_state_inactive == 0) ; - qtr->pile = qtp ; qtr->action = action ; qtr->timer_info = timer_info ; @@ -260,53 +271,54 @@ qtimer_init_new(qtimer qtr, qtimer_pile qtp, return qtr ; } ; -/* Free given timer. +/*------------------------------------------------------------------------------ + * Free given timer -- if any. * - * Unsets it first if it is active. + * Unsets it first if it is active or pending unset. * - * The timer MAY NOT be currently the subject of qtimer_pile_dispatch_next(). + * Returns: NULL */ -void +extern qtimer qtimer_free(qtimer qtr) { - assert(qtr->state != qtr_state_unset_pending) ; + /* Note that if is the current dispatched timer and an unset is still + * pending, then it must still be active. + */ + if (qtr != NULL) + { + if (qtr->active) + qtimer_unset(qtr) ; - if (qtr->state != qtr_state_inactive) - qtimer_unset(qtr) ; + XFREE(MTYPE_QTIMER, qtr) ; + } ; - XFREE(MTYPE_QTIMER, qtr) ; + return NULL ; } ; -/* Set pile in which given timer belongs. +/*------------------------------------------------------------------------------ + * Set pile in which given timer belongs. + * + * Does nothing if timer already belongs to the given pile. * - * Unsets the timer if active in another pile. - * (Does nothing if active in the "new" pile.) + * Unsets the timer if active in another pile, before reassigning it. */ -void +extern void qtimer_set_pile(qtimer qtr, qtimer_pile qtp) { - if (qtr_is_active(qtr) && (qtr->pile != qtp)) + if (qtr->pile == qtp) + return ; + + /* Note that if is the current dispatched timer and an unset is still + * pending, then it must still be active. + */ + if (qtr->active) qtimer_unset(qtr) ; + qtr->pile = qtp ; } -/* Set action for given timer. - */ -void -qtimer_set_action(qtimer qtr, qtimer_action* action) -{ - qtr->action = action ; -} ; - -/* Set timer_info for given timer. - */ -void -qtimer_set_info(qtimer qtr, void* timer_info) -{ - qtr->timer_info = timer_info ; -} ; - -/* Set given timer. +/*------------------------------------------------------------------------------ + * Set given timer. * * Setting a -ve time => qtimer_unset. * @@ -319,7 +331,7 @@ qtimer_set_info(qtimer qtr, void* timer_info) * * It is an error to set a timer which has a NULL action. */ -void +extern void qtimer_set(qtimer qtr, qtime_mono_t when, qtimer_action* action) { qtimer_pile qtp ; @@ -328,20 +340,30 @@ qtimer_set(qtimer qtr, qtime_mono_t when, qtimer_action* action) return qtimer_unset(qtr) ; qtp = qtr->pile ; - dassert(qtp != NULL) ; + assert(qtp != NULL) ; + if (qdebug) qtimer_pile_verify(qtp) ; qtr->time = when ; - if (qtr_is_active(qtr)) - heap_update_item(&qtp->timers, qtr) ; /* update in heap */ + if (qtr->active) + { + /* Is active, so update the timer in the pile. */ + heap_update_item(&qtp->timers, qtr) ; + + if (qtr == qtp->implicit_unset) + qtp->implicit_unset = NULL ; /* no unset required, now */ + } else - heap_push_item(&qtp->timers, qtr) ; /* add to heap */ + { + /* Is not active, so insert the timer into the pile. */ + heap_push_item(&qtp->timers, qtr) ; - assert(qtp == qtr->pile); + assert(qtr != qtp->implicit_unset) ; /* because it's not active */ - qtr->state = qtr_state_active ; /* overrides any unset pending */ + qtr->active = true ; + } ; if (action != NULL) qtr->action = action ; @@ -352,28 +374,35 @@ qtimer_set(qtimer qtr, qtime_mono_t when, qtimer_action* action) qtimer_pile_verify(qtp) ; } ; -/* Unset given timer +/*------------------------------------------------------------------------------ + * Unset given timer * * If the timer is active, removes from pile and sets inactive. */ -void +extern void qtimer_unset(qtimer qtr) { - if (qtr_is_active(qtr)) - { - qtimer_pile qtp = qtr->pile ; - dassert(qtp != NULL) ; + qtimer_pile qtp = qtr->pile ; - if (qdebug) - qtimer_pile_verify(qtp) ; + assert(qtp != NULL) ; + + if (qdebug) + qtimer_pile_verify(qtp) ; + + if (qtr->active) + { + if (qtr == qtp->implicit_unset) + qtp->implicit_unset = NULL ; /* no unset required, now */ heap_delete_item(&qtp->timers, qtr) ; if (qdebug) qtimer_pile_verify(qtp) ; - qtr->state = qtr_state_inactive ; /* overrides any unset pending */ - } ; + qtr->active = false ; + } + else + assert(qtr != qtp->implicit_unset) ; } ; /*============================================================================== @@ -387,6 +416,9 @@ qtimer_pile_verify(qtimer_pile qtp) vector_index i ; vector_index e ; qtimer qtr ; + bool seen ; + + assert(qtp != NULL) ; /* (The typedef is required to stop Eclipse (3.4.2 with CDT 5.0) whining * about first argument of offsetof().) @@ -402,9 +434,17 @@ qtimer_pile_verify(qtimer_pile qtp) for (i = 0 ; i < e ; ++i) { qtr = vector_get_item(v, i) ; + assert(qtr != NULL) ; + + if (qtr == qtp->implicit_unset) + seen = 1 ; + + assert(qtr->active) ; assert(qtr->pile == qtp) ; assert(qtr->backlink == i) ; assert(qtr->action != NULL) ; } ; + + assert(seen || (qtp->implicit_unset == NULL)) ; } ; |