diff options
Diffstat (limited to 'tevent/tevent_timed.c')
| -rw-r--r-- | tevent/tevent_timed.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/tevent/tevent_timed.c b/tevent/tevent_timed.c new file mode 100644 index 00000000..ba821371 --- /dev/null +++ b/tevent/tevent_timed.c @@ -0,0 +1,230 @@ +/* + Unix SMB/CIFS implementation. + + common events code for timed events + + Copyright (C) Andrew Tridgell 2003-2006 + Copyright (C) Stefan Metzmacher 2005 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include <sys/time.h> +#include <time.h> +#include "replace.h" +#include "system/filesys.h" +#include "system/select.h" +#include "tevent.h" +#include "tevent_internal.h" +#include "tevent_util.h" + +/** + compare two timeval structures. + Return -1 if tv1 < tv2 + Return 0 if tv1 == tv2 + Return 1 if tv1 > tv2 +*/ +static int ev_timeval_compare(const struct timeval *tv1, const struct timeval *tv2) +{ + if (tv1->tv_sec > tv2->tv_sec) return 1; + if (tv1->tv_sec < tv2->tv_sec) return -1; + if (tv1->tv_usec > tv2->tv_usec) return 1; + if (tv1->tv_usec < tv2->tv_usec) return -1; + return 0; +} + +/** + return a zero timeval +*/ +static struct timeval ev_timeval_zero(void) +{ + struct timeval tv; + tv.tv_sec = 0; + tv.tv_usec = 0; + return tv; +} + +/** + return a timeval for the current time +*/ +static struct timeval ev_timeval_current(void) +{ + struct timeval tv; + gettimeofday(&tv, NULL); + return tv; +} + +/** + return a timeval struct with the given elements +*/ +static struct timeval ev_timeval_set(uint32_t secs, uint32_t usecs) +{ + struct timeval tv; + tv.tv_sec = secs; + tv.tv_usec = usecs; + return tv; +} + +/** + return the difference between two timevals as a timeval + if tv1 comes after tv2, then return a zero timeval + (this is *tv2 - *tv1) +*/ +static struct timeval ev_timeval_until(const struct timeval *tv1, + const struct timeval *tv2) +{ + struct timeval t; + if (ev_timeval_compare(tv1, tv2) >= 0) { + return ev_timeval_zero(); + } + t.tv_sec = tv2->tv_sec - tv1->tv_sec; + if (tv1->tv_usec > tv2->tv_usec) { + t.tv_sec--; + t.tv_usec = 1000000 - (tv1->tv_usec - tv2->tv_usec); + } else { + t.tv_usec = tv2->tv_usec - tv1->tv_usec; + } + return t; +} + +/** + return true if a timeval is zero +*/ +bool ev_timeval_is_zero(const struct timeval *tv) +{ + return tv->tv_sec == 0 && tv->tv_usec == 0; +} + +/* + destroy a timed event +*/ +static int common_event_timed_destructor(struct timed_event *te) +{ + struct event_context *ev = talloc_get_type(te->event_ctx, + struct event_context); + DLIST_REMOVE(ev->timed_events, te); + return 0; +} + +static int common_event_timed_deny_destructor(struct timed_event *te) +{ + return -1; +} + +/* + add a timed event + return NULL on failure (memory allocation error) +*/ +struct timed_event *common_event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx, + struct timeval next_event, + event_timed_handler_t handler, + void *private_data) +{ + struct timed_event *te, *last_te, *cur_te; + + te = talloc(mem_ctx?mem_ctx:ev, struct timed_event); + if (te == NULL) return NULL; + + te->event_ctx = ev; + te->next_event = next_event; + te->handler = handler; + te->private_data = private_data; + te->additional_data = NULL; + + /* keep the list ordered */ + last_te = NULL; + for (cur_te = ev->timed_events; cur_te; cur_te = cur_te->next) { + /* if the new event comes before the current one break */ + if (ev_timeval_compare(&te->next_event, &cur_te->next_event) < 0) { + break; + } + + last_te = cur_te; + } + + DLIST_ADD_AFTER(ev->timed_events, te, last_te); + + talloc_set_destructor(te, common_event_timed_destructor); + + return te; +} + +/* + do a single event loop using the events defined in ev + + return the delay untill the next timed event, + or zero if a timed event was triggered +*/ +struct timeval common_event_loop_timer_delay(struct event_context *ev) +{ + struct timeval current_time = ev_timeval_zero(); + struct timed_event *te = ev->timed_events; + + if (!te) { + /* have a default tick time of 30 seconds. This guarantees + that code that uses its own timeout checking will be + able to proceeed eventually */ + return ev_timeval_set(30, 0); + } + + /* + * work out the right timeout for the next timed event + * + * avoid the syscall to gettimeofday() if the timed event should + * be triggered directly + * + * if there's a delay till the next timed event, we're done + * with just returning the delay + */ + if (!ev_timeval_is_zero(&te->next_event)) { + struct timeval delay; + + current_time = ev_timeval_current(); + + delay = ev_timeval_until(¤t_time, &te->next_event); + if (!ev_timeval_is_zero(&delay)) { + return delay; + } + } + + /* + * ok, we have a timed event that we'll process ... + */ + + /* deny the handler to free the event */ + talloc_set_destructor(te, common_event_timed_deny_destructor); + + /* We need to remove the timer from the list before calling the + * handler because in a semi-async inner event loop called from the + * handler we don't want to come across this event again -- vl */ + DLIST_REMOVE(ev->timed_events, te); + + /* + * If the timed event was registered for a zero current_time, + * then we pass a zero timeval here too! To avoid the + * overhead of gettimeofday() calls. + * + * otherwise we pass the current time + */ + te->handler(ev, te, current_time, te->private_data); + + /* The destructor isn't necessary anymore, we've already removed the + * event from the list. */ + talloc_set_destructor(te, NULL); + + talloc_free(te); + + return ev_timeval_zero(); +} + |