More generic solution for limiting per-call timeout.

[libserialport.git] / serialport.c

diff --git a/serialport.c b/serialport.c
index 1a9b4415438422afebc989a6b20cc6f6767a32a7..1f18392ccbe6b8c6a4b1608a6e7a4e16fd07abb3 100644 (file)
--- a/serialport.c
+++ b/serialport.c
@@ -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) {