Overhaul time support API

This patch changes the duration_* API in several ways.  First, it
updates the API to use better names.  Second, string formatting has
been removed from the API (with its associated malloc).  Finally, a
new function added to convert the time into seconds, which can be
used (or formatted) by the caller.  This eliminates hidden calls to
malloc that require associated calls to free().

This patch also removes the useless extern keyword from prototypes,
and it eliminates the duration_t typedef (use 'struct duration').
These API also allows proper error checking, as it is possible for
gettimeofday to fail in certain circumstances.

The consumers have all been chased to use this new API as well, as
there were relatively few cases doing this type of measurement.
In most cases, the code performs additional checks for errors, but
the calling code looks much cleaner in every case.

1 files changed, 18 insertions, 10 deletions

diff --git a/src/helper/time_support.h b/src/helper/time_support.h
index a8036766..9e8e61f1 100644
--- a/src/helper/time_support.h
+++ b/src/helper/time_support.h
@@ -37,19 +37,27 @@
 # endif
 #endif
 
-extern int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y);
-extern int timeval_add(struct timeval *result, struct timeval *x, struct timeval *y);
-extern int timeval_add_time(struct timeval *result, int sec, int usec);
-/* gettimeofday() timeval in 64 bit ms */
-extern long long timeval_ms(void);
+int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y);
+int timeval_add(struct timeval *result, struct timeval *x, struct timeval *y);
+int timeval_add_time(struct timeval *result, int sec, int usec);
 
-typedef struct duration_s
+/// @returns gettimeofday() timeval as 64-bit in ms
+long long timeval_ms(void);
+
+struct duration
 {
 	struct timeval start;
-	struct timeval duration;
-} duration_t;
+	struct timeval elapsed;
+};
+
+/// Update the duration->start field to start the @a duration measurement.
+int duration_start(struct duration *duration);
+/// Update the duration->elapsed field to finish the @a duration measurment.
+int duration_measure(struct duration *duration);
 
-extern void duration_start_measure(duration_t *duration);
-extern int duration_stop_measure(duration_t *duration, char **text);
+/// @returns Elapsed time in seconds.
+float duration_elapsed(struct duration *duration);
+/// @returns KB/sec for the elapsed @a duration and @a count bytes.
+float duration_kbps(struct duration *duration, size_t count);
 
 #endif /* TIME_SUPPORT_H */