[PATCH 1/2] Add date formatting and parsing functions relative to a given time

[PATCH 1/2] Add date formatting and parsing functions relative to a given time

[Alex Riesen]

The main purpose is to allow predictable testing of the code.
---

Rebased on current master.

 cache.h |    2 +
 date.c  |  150 ++++++++++++++++++++++++++++++++++++--------------------------
 2 files changed, 89 insertions(+), 63 deletions(-)

diff --git a/cache.h b/cache.h
index dd7f71e..3fb0166 100644
--- a/cache.h
+++ b/cache.h
@@ -731,9 +731,11 @@ enum date_mode {
 };
 
 const char *show_date(unsigned long time, int timezone, enum date_mode mode);
+const char *show_date_relative(unsigned long time, int tz, const struct timeval *now);
 int parse_date(const char *date, char *buf, int bufsize);
 void datestamp(char *buf, int bufsize);
 unsigned long approxidate(const char *);
+unsigned long approxidate_relative(const char *date, const struct timeval *now);
 enum date_mode parse_date_format(const char *format);
 
 #define IDENT_WARN_ON_NO_NAME  1
diff --git a/date.c b/date.c
index f011692..0840e77 100644
--- a/date.c
+++ b/date.c
@@ -84,6 +84,67 @@ static int local_tzoffset(unsigned long time)
 	return offset * eastwest;
 }
 
+const char *show_date_relative(unsigned long time, int tz, const struct timeval *now)
+{
+	static char timebuf[100 /* TODO: can be optimized */];
+	unsigned long diff;
+	if (now->tv_sec < time)
+		return "in the future";
+	diff = now->tv_sec - time;
+	if (diff < 90) {
+		snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
+		return timebuf;
+	}
+	/* Turn it into minutes */
+	diff = (diff + 30) / 60;
+	if (diff < 90) {
+		snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
+		return timebuf;
+	}
+	/* Turn it into hours */
+	diff = (diff + 30) / 60;
+	if (diff < 36) {
+		snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
+		return timebuf;
+	}
+	/* We deal with number of days from here on */
+	diff = (diff + 12) / 24;
+	if (diff < 14) {
+		snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
+		return timebuf;
+	}
+	/* Say weeks for the past 10 weeks or so */
+	if (diff < 70) {
+		snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
+		return timebuf;
+	}
+	/* Say months for the past 12 months or so */
+	if (diff < 360) {
+		snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
+		return timebuf;
+	}
+	/* Give years and months for 5 years or so */
+	if (diff < 1825) {
+		unsigned long years = diff / 365;
+		unsigned long months = (diff % 365 + 15) / 30;
+		int n;
+		n = snprintf(timebuf, sizeof(timebuf), "%lu year%s",
+			     years, (years > 1 ? "s" : ""));
+		if (months)
+			snprintf(timebuf + n, sizeof(timebuf) - n,
+				 ", %lu month%s ago",
+				 months, (months > 1 ? "s" : ""));
+		else
+			snprintf(timebuf + n, sizeof(timebuf) - n,
+				 " ago");
+		return timebuf;
+	}
+	/* Otherwise, just years. Centuries is probably overkill. */
+	snprintf(timebuf, sizeof(timebuf), "%lu years ago", (diff + 183) / 365);
+	return timebuf;
+
+}
+
 const char *show_date(unsigned long time, int tz, enum date_mode mode)
 {
 	struct tm *tm;
@@ -95,63 +156,9 @@ const char *show_date(unsigned long time, int tz, enum date_mode mode)
 	}
 
 	if (mode == DATE_RELATIVE) {
-		unsigned long diff;
 		struct timeval now;
 		gettimeofday(&now, NULL);
-		if (now.tv_sec < time)
-			return "in the future";
-		diff = now.tv_sec - time;
-		if (diff < 90) {
-			snprintf(timebuf, sizeof(timebuf), "%lu seconds ago", diff);
-			return timebuf;
-		}
-		/* Turn it into minutes */
-		diff = (diff + 30) / 60;
-		if (diff < 90) {
-			snprintf(timebuf, sizeof(timebuf), "%lu minutes ago", diff);
-			return timebuf;
-		}
-		/* Turn it into hours */
-		diff = (diff + 30) / 60;
-		if (diff < 36) {
-			snprintf(timebuf, sizeof(timebuf), "%lu hours ago", diff);
-			return timebuf;
-		}
-		/* We deal with number of days from here on */
-		diff = (diff + 12) / 24;
-		if (diff < 14) {
-			snprintf(timebuf, sizeof(timebuf), "%lu days ago", diff);
-			return timebuf;
-		}
-		/* Say weeks for the past 10 weeks or so */
-		if (diff < 70) {
-			snprintf(timebuf, sizeof(timebuf), "%lu weeks ago", (diff + 3) / 7);
-			return timebuf;
-		}
-		/* Say months for the past 12 months or so */
-		if (diff < 360) {
-			snprintf(timebuf, sizeof(timebuf), "%lu months ago", (diff + 15) / 30);
-			return timebuf;
-		}
-		/* Give years and months for 5 years or so */
-		if (diff < 1825) {
-			unsigned long years = diff / 365;
-			unsigned long months = (diff % 365 + 15) / 30;
-			int n;
-			n = snprintf(timebuf, sizeof(timebuf), "%lu year%s",
-					years, (years > 1 ? "s" : ""));
-			if (months)
-				snprintf(timebuf + n, sizeof(timebuf) - n,
-					", %lu month%s ago",
-					months, (months > 1 ? "s" : ""));
-			else
-				snprintf(timebuf + n, sizeof(timebuf) - n,
-					" ago");
-			return timebuf;
-		}
-		/* Otherwise, just years. Centuries is probably overkill. */
-		snprintf(timebuf, sizeof(timebuf), "%lu years ago", (diff + 183) / 365);
-		return timebuf;
+		return show_date_relative(time, tz, &now);
 	}
 
 	if (mode == DATE_LOCAL)
@@ -866,19 +873,13 @@ static const char *approxidate_digit(const char *date, struct tm *tm, int *num)
 	return end;
 }
 
-unsigned long approxidate(const char *date)
+static unsigned long approximation(const char *date, const struct timeval *tv)
 {
 	int number = 0;
 	struct tm tm, now;
-	struct timeval tv;
 	time_t time_sec;
-	char buffer[50];
 
-	if (parse_date(date, buffer, sizeof(buffer)) > 0)
-		return strtoul(buffer, NULL, 10);
-
-	gettimeofday(&tv, NULL);
-	time_sec = tv.tv_sec;
+	time_sec = tv->tv_sec;
 	localtime_r(&time_sec, &tm);
 	now = tm;
 	for (;;) {
@@ -899,3 +900,26 @@ unsigned long approxidate(const char *date)
 		tm.tm_year--;
 	return mktime(&tm);
 }
+
+unsigned long approxidate_relative(const char *date, const struct timeval *tv)
+{
+	char buffer[50];
+
+	if (parse_date(date, buffer, sizeof(buffer)) > 0)
+		return strtoul(buffer, NULL, 10);
+
+	return approximation(date, tv);
+}
+
+unsigned long approxidate(const char *date)
+{
+	struct timeval tv;
+	char buffer[50];
+
+	if (parse_date(date, buffer, sizeof(buffer)) > 0)
+		return strtoul(buffer, NULL, 10);
+
+	gettimeofday(&tv, NULL);
+	return approximation(date, &tv);
+}
+
-- 
1.6.4.1.263.g468a

[PATCH 2/2] Allow testing of _relative family of time formatting and parsing functions

[Alex Riesen]

To complement the testability of approxidate.
---
 test-date.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/test-date.c b/test-date.c
index 62e8f23..dcc7973 100644
--- a/test-date.c
+++ b/test-date.c
@@ -4,6 +4,17 @@ int main(int argc, char **argv)
 {
 	int i;
 
+	struct tm tm;
+	struct timeval when = {0, 0};
+	tm.tm_sec  = 0;
+	tm.tm_min  = 0;
+	tm.tm_hour = 12;
+	tm.tm_mday = 1;
+	tm.tm_mon  = 0  /* January */;
+	tm.tm_year = 90 /* 1990 */ ;
+	tm.tm_isdst = -1;
+	when.tv_sec = mktime(&tm);
+
 	for (i = 1; i < argc; i++) {
 		char result[100];
 		time_t t;
@@ -15,6 +26,12 @@ int main(int argc, char **argv)
 
 		t = approxidate(argv[i]);
 		printf("%s -> %s\n", argv[i], ctime(&t));
+
+		t = approxidate_relative(argv[i], &when);
+		printf("relative: %s -> %s\n", argv[i], ctime(&t));
+
+		printf("relative: %s, out of %s\n",
+		       show_date_relative(t, 0, &when), ctime(&t));
 	}
 	return 0;
 }
-- 
1.6.4.1.263.g468a

Re: [PATCH 1/2] Add date formatting and parsing functions relative to a given time

[Jeff King]

On Fri, Aug 28, 2009 at 11:04:04PM +0200, Alex Riesen wrote:

> +const char *show_date_relative(unsigned long time, int tz, const struct timeval *now)
> +{
> +	static char timebuf[100 /* TODO: can be optimized */];

This was 200 in the original version. I doubt that it makes a
difference, but I think in a refactoring patch I think it is best to
simply reorganize and make no other changes.

> +static unsigned long approximation(const char *date, const struct timeval *tv)

I know it's static, but this is a terribly undescriptive function name.
Approximation of what?  Can we call it approxidate_internal or
something?

-Peff

Re: [PATCH 1/2] Add date formatting and parsing functions relative to a given time

[Alex Riesen]

On Sun, Aug 30, 2009 at 09:36, Jeff King<peff@peff.net> wrote:
> On Fri, Aug 28, 2009 at 11:04:04PM +0200, Alex Riesen wrote:
>
>> +const char *show_date_relative(unsigned long time, int tz, const struct timeval *now)
>> +{
>> +     static char timebuf[100 /* TODO: can be optimized */];
>
> This was 200 in the original version. I doubt that it makes a
> difference, but I think in a refactoring patch I think it is best to
> simply reorganize and make no other changes.

Yes, I just noticed that 200 was much too much, made the note
to fix it sometime and forgot the note in the final submission.

>> +static unsigned long approximation(const char *date, const struct timeval *tv)
>
> I know it's static, but this is a terribly undescriptive function name.
> Approximation of what?  Can we call it approxidate_internal or
> something?

Been there, tried that. Didn't like it, because it didn't feel enough
approxidate (the original) anymore. Not even internally, because
of missing parse_date. My other attempts were guessdate and
approxidate_bottom_half (but only very shortly).

The "approximation", if you consider the functions arguments,
seems to me the closest to what the function _is_. OTOH,
maybe I should have used a verb...

[PATCH 2/2] Allow testing of _relative family of time formatting and parsing functions

[Alex Riesen]

To complement the testability of approxidate.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
---

Alex Riesen, Sun, Aug 30, 2009 11:13:46 +0200:
> test-date.c is updated and shall follow in a moment.

here it goes.

 test-date.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/test-date.c b/test-date.c
index 62e8f23..4cb146d 100644
--- a/test-date.c
+++ b/test-date.c
@@ -4,6 +4,19 @@ int main(int argc, char **argv)
 {
 	int i;
 
+	/* see date.c, function show_date_relative */
+	char timebuf[(sizeof(long) * 5 / 2 + sizeof(" minutes ago,")) * 2];
+	struct tm tm;
+	struct timeval when = {0, 0};
+	tm.tm_sec  = 0;
+	tm.tm_min  = 0;
+	tm.tm_hour = 12;
+	tm.tm_mday = 1;
+	tm.tm_mon  = 0  /* January */;
+	tm.tm_year = 90 /* 1990 */ ;
+	tm.tm_isdst = -1;
+	when.tv_sec = mktime(&tm);
+
 	for (i = 1; i < argc; i++) {
 		char result[100];
 		time_t t;
@@ -15,6 +28,13 @@ int main(int argc, char **argv)
 
 		t = approxidate(argv[i]);
 		printf("%s -> %s\n", argv[i], ctime(&t));
+
+		t = approxidate_relative(argv[i], &when);
+		printf("relative: %s -> %s", argv[i], ctime(&t));
+
+		printf("relative: %s, out of %s",
+		       show_date_relative(t, 0, &when, timebuf,sizeof(timebuf)),
+		       ctime(&t));
 	}
 	return 0;
 }
-- 
1.6.4.1.294.g16262