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More generic solution for limiting per-call timeout.

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This commit is contained in:
Martin Ling 2020-01-03 23:33:48 +00:00
parent 32dbe2d298
commit 08eb25f53a
1 changed files with 17 additions and 13 deletions
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30
serialport.c
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@ -64,17 +64,12 @@ struct time {
};
struct timeout {
unsigned int ms;
struct time start, delta, now, end;
unsigned int ms, limit_ms;
struct time start, now, end, delta, delta_max;
struct timeval delta_tv;
bool overflow;
};
#define TIME_ZERO {.tv = {0, 0}}
#define TIME_MS(ms) {.tv = {ms / 1000, (ms % 1000) * 1000}}
const struct time max_delta = TIME_MS(INT_MAX);
static void time_get(struct time *time)
{
#ifdef HAVE_CLOCK_GETTIME
@ -132,14 +127,21 @@ static void timeout_start(struct timeout *timeout, unsigned int timeout_ms)
{
timeout->ms = timeout_ms;
timeout->overflow = (timeout->ms > INT_MAX);
/* Get time at start of operation. */
time_get(&timeout->start);
/* Define duration of timeout. */
time_set_ms(&timeout->delta, timeout_ms);
/* Calculate time at which we should give up. */
time_add(&timeout->start, &timeout->delta, &timeout->end);
/* Disable limit unless timeout_limit() called. */
timeout->limit_ms = 0;
}
static void timeout_limit(struct timeout *timeout, unsigned int limit_ms)
{
timeout->limit_ms = limit_ms;
timeout->overflow = (timeout->ms > timeout->limit_ms);
time_set_ms(&timeout->delta_max, timeout->limit_ms);
}
static bool timeout_check(struct timeout *timeout)
@ -149,8 +151,9 @@ static bool timeout_check(struct timeout *timeout)
time_get(&timeout->now);
time_sub(&timeout->end, &timeout->now, &timeout->delta);
if ((timeout->overflow = time_greater(&timeout->delta, &max_delta)))
timeout->delta = max_delta;
if (timeout->limit_ms)
if ((timeout->overflow = time_greater(&timeout->delta, &timeout->delta_max)))
timeout->delta = timeout->delta_max;
return time_greater(&timeout->now, &timeout->end);
}
@ -169,8 +172,8 @@ static unsigned int timeout_remaining_ms(struct timeout *timeout)
{
if (timeout->ms == 0)
return -1;
else if (timeout->overflow)
return INT_MAX;
else if (timeout->limit_ms && timeout->overflow)
return timeout->limit_ms;
else
return time_as_ms(&timeout->delta);
}
@ -1570,6 +1573,7 @@ SP_API enum sp_return sp_wait(struct sp_event_set *event_set,
}
timeout_start(&timeout, timeout_ms);
timeout_limit(&timeout, INT_MAX);
/* Loop until an event occurs. */
while (1) {