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eloop: add ev_timer_drain() helper

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This helper reads the current expiration-count from a timer. This can be
used when waking up from an idle-period or similar to reset the timer.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
This commit is contained in:
David Herrmann 2012-09-18 16:24:06 +02:00
parent 0cf2f8efbd
commit d3a0358797
2 changed files with 65 additions and 24 deletions
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88
src/eloop.c
View File

@ -1443,44 +1443,63 @@ void ev_eloop_rm_fd(struct ev_fd *fd)
* real precision depends on the operating-system and hardware.
*/
static int timer_drain(struct ev_timer *timer, uint64_t *out)
{
int len;
uint64_t expirations;
if (out)
*out = 0;
len = read(timer->fd, &expirations, sizeof(expirations));
if (len < 0) {
if (errno == EAGAIN) {
return 0;
} else {
llog_warning(timer, "cannot read timerfd (%d): %m",
errno);
return errno;
}
} else if (len == 0) {
llog_warning(timer, "EOF on timer source");
return -EFAULT;
} else if (len != sizeof(expirations)) {
llog_warn(timer, "invalid size %d read on timerfd", len);
return -EFAULT;
} else {
if (out)
*out = expirations;
return 0;
}
}
static void timer_cb(struct ev_fd *fd, int mask, void *data)
{
struct ev_timer *timer = data;
uint64_t expirations;
int len;
int ret;
if (mask & (EV_HUP | EV_ERR)) {
llog_warn(fd, "HUP/ERR on timer source");
if (timer->cb)
timer->cb(timer, 0, timer->data);
return;
goto err_cb;
}
if (mask & EV_READABLE) {
len = read(timer->fd, &expirations, sizeof(expirations));
if (len < 0) {
if (errno != EAGAIN) {
llog_warning(fd, "cannot read timerfd (%d): %m",
errno);
ev_timer_disable(timer);
if (timer->cb)
timer->cb(timer, 0, timer->data);
}
} else if (len == 0) {
llog_warning(fd, "EOF on timer source");
ev_timer_disable(timer);
if (timer->cb)
timer->cb(timer, 0, timer->data);
} else if (len != sizeof(expirations)) {
llog_warn(fd, "invalid size %d read on timerfd", len);
ev_timer_disable(timer);
if (timer->cb)
timer->cb(timer, 0, timer->data);
} else if (expirations > 0) {
ret = timer_drain(timer, &expirations);
if (ret)
goto err_cb;
if (expirations > 0) {
if (timer->cb)
timer->cb(timer, expirations, timer->data);
}
}
return;
err_cb:
ev_timer_disable(timer);
if (timer->cb)
timer->cb(timer, 0, timer->data);
}
/**
@ -1687,6 +1706,27 @@ int ev_timer_update(struct ev_timer *timer, const struct itimerspec *spec)
return 0;
}
/**
* ev_timer_drain:
* @timer: valid timer object
* @expirations: destination to save result or NULL
*
* This reads the current expiration-count from the timer object @timer and
* saves it in @expirations (if it is non-NULL). This can be used to clear the
* timer after an idle-period or similar.
* Note that the timer_cb() callback function automatically calls this before
* calling the user-supplied callback.
*
* Returns: 0 on success, negative error code on failure.
*/
int ev_timer_drain(struct ev_timer *timer, uint64_t *expirations)
{
if (!timer)
return -EINVAL;
return timer_drain(timer, expirations);
}
/**
* ev_eloop_new_timer:
* @loop: event loop

1
src/eloop.h
View File

@ -190,6 +190,7 @@ bool ev_timer_is_enabled(struct ev_timer *timer);
bool ev_timer_is_bound(struct ev_timer *timer);
void ev_timer_set_cb_data(struct ev_timer *timer, ev_timer_cb cb, void *data);
int ev_timer_update(struct ev_timer *timer, const struct itimerspec *spec);
int ev_timer_drain(struct ev_timer *timer, uint64_t *expirations);
int ev_eloop_new_timer(struct ev_eloop *loop, struct ev_timer **out,
const struct itimerspec *spec, ev_timer_cb cb,