[PATCH/RFC] New date format: local_original

[PATCH/RFC] New date format: local_original

[Tuomas Suutari]

Formats date and time with local and original timezone representation
in same string. They both can be useful at the same time: local
timezone for relating timestamp to local events, and original timezone
to see the author's time of the day.

The format is ISO-8601 timestamp with weekday in local timezone
followed by weekday and time in original timezone in parentheses. The
weekday part makes it easier to understand the timestamps when the
days differ. For example, if local timezone is +0800, then timestamp
2009-10-04T19:37:03+0300 would be formatted as
"Mon 2009-10-05 00:37:03 (Sun 19:37:03 +0300)".

Signed-off-by: Tuomas Suutari <tuomas.suutari@gmail.com>
---

It was hard to decide whether to use --date=local or --date=iso
with git log, so I though that maybe I could have them both.

Hardest part was to decide the actual format string, especially
because they tend to get so long. My solution for that,
is to drop the date part out from the other timestamp and use
weekday as a way to relate them to each other.

So, what do you think? Could this be useful for anyone else?
Any better ideas for the format string?

ps. I tried to find the relevant parts of the documentation
and tests by grepping the names of the other formats (iso8601
and rfc2822) and updated them, but I could have easily missed
something. Tests did not show any new problems, but the
cvsimport tests (t960?) didn't seem to work before or after
my changes.

 Documentation/git-for-each-ref.txt     |    4 ++--
 Documentation/rev-list-options.txt     |    4 +++-
 builtin-blame.c                        |    3 +++
 cache.h                                |    3 ++-
 contrib/completion/git-completion.bash |    5 ++++-
 date.c                                 |   23 +++++++++++++++++++++++
 t/t6300-for-each-ref.sh                |   15 ++++++++++++++-
 7 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 8dc873f..00525c2 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -114,8 +114,8 @@ returns an empty string instead.
 
 As a special case for the date-type fields, you may specify a format for
 the date by adding one of `:default`, `:relative`, `:short`, `:local`,
-`:iso8601` or `:rfc2822` to the end of the fieldname; e.g.
-`%(taggerdate:relative)`.
+`:iso8601`, `:rfc2822`, or `:local_original`, to the end of the
+fieldname; e.g. `%(taggerdate:relative)`.
 
 
 EXAMPLES
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index bf66116..e007244 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -13,7 +13,7 @@ include::pretty-options.txt[]
 
 	Synonym for `--date=relative`.
 
---date={relative,local,default,iso,rfc,short,raw}::
+--date={relative,local,default,iso,rfc,short,raw,local_original}::
 
 	Only takes effect for dates shown in human-readable format, such
 	as when using "--pretty". `log.date` config variable sets a default
@@ -35,6 +35,8 @@ format, often found in E-mail messages.
 +
 `--date=default` shows timestamps in the original timezone
 (either committer's or author's).
++
+`--date=local_original` shows timestamps in local and original timezone.
 
 ifdef::git-rev-list[]
 --header::
diff --git a/builtin-blame.c b/builtin-blame.c
index 7512773..4766dd5 100644
--- a/builtin-blame.c
+++ b/builtin-blame.c
@@ -2290,6 +2290,9 @@ parse_done:
 	case DATE_NORMAL:
 		blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
 		break;
+	case DATE_LOCAL_ORIGINAL:
+		blame_date_width = sizeof("Thu 2006-10-19 16:00:04 (Thu 16:00:04 -0700)");
+		break;
 	}
 	blame_date_width -= 1; /* strip the null */
 
diff --git a/cache.h b/cache.h
index a5eeead..89c3c12 100644
--- a/cache.h
+++ b/cache.h
@@ -729,7 +729,8 @@ enum date_mode {
 	DATE_LOCAL,
 	DATE_ISO8601,
 	DATE_RFC2822,
-	DATE_RAW
+	DATE_RAW,
+	DATE_LOCAL_ORIGINAL
 };
 
 const char *show_date(unsigned long time, int timezone, enum date_mode mode);
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 2c2a0d4..4f4ca53 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1152,7 +1152,10 @@ __git_log_shortlog_options="
 "
 
 __git_log_pretty_formats="oneline short medium full fuller email raw format:"
-__git_log_date_formats="relative iso8601 rfc2822 short local default raw"
+__git_log_date_formats="
+	relative iso8601 rfc2822 short local default raw
+	local_original
+"
 
 _git_log ()
 {
diff --git a/date.c b/date.c
index 5d05ef6..b34a735 100644
--- a/date.c
+++ b/date.c
@@ -151,6 +151,7 @@ const char *show_date(unsigned long time, int tz, enum date_mode mode)
 {
 	struct tm *tm;
 	static char timebuf[200];
+	int n;
 
 	if (mode == DATE_RAW) {
 		snprintf(timebuf, sizeof(timebuf), "%lu %+05d", time, tz);
@@ -185,6 +186,26 @@ const char *show_date(unsigned long time, int tz, enum date_mode mode)
 			weekday_names[tm->tm_wday], tm->tm_mday,
 			month_names[tm->tm_mon], tm->tm_year + 1900,
 			tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
+	else if (mode == DATE_LOCAL_ORIGINAL) {
+		/* Use local timezone first... */
+		tm = time_to_tm(time, local_tzoffset(time));
+		if (!tm)
+			return NULL;
+		n = sprintf(timebuf, "%.3s %04d-%02d-%02d %02d:%02d:%02d",
+			weekday_names[tm->tm_wday],
+			tm->tm_year + 1900,
+			tm->tm_mon + 1,
+			tm->tm_mday,
+			tm->tm_hour, tm->tm_min, tm->tm_sec);
+		/* ...and then original timezone. */
+		tm = time_to_tm(time, tz);
+		if (!tm)
+			return NULL;
+		sprintf(timebuf + n, " (%.3s %02d:%02d:%02d %+05d)",
+			weekday_names[tm->tm_wday],
+			tm->tm_hour, tm->tm_min, tm->tm_sec,
+			tz);
+	}
 	else
 		sprintf(timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 				weekday_names[tm->tm_wday],
@@ -656,6 +677,8 @@ enum date_mode parse_date_format(const char *format)
 		return DATE_NORMAL;
 	else if (!strcmp(format, "raw"))
 		return DATE_RAW;
+	else if (!strcmp(format, "local_original"))
+		return DATE_LOCAL_ORIGINAL;
 	else
 		die("unknown date format %s", format);
 }
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index 8052c86..1c91b21 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -122,7 +122,8 @@ test_expect_success 'Check valid format specifiers for date fields' '
 	git for-each-ref --format="%(authordate:short)" refs/heads &&
 	git for-each-ref --format="%(authordate:local)" refs/heads &&
 	git for-each-ref --format="%(authordate:iso8601)" refs/heads &&
-	git for-each-ref --format="%(authordate:rfc2822)" refs/heads
+	git for-each-ref --format="%(authordate:rfc2822)" refs/heads &&
+	git for-each-ref --format="%(authordate:local_original)" refs/heads
 '
 
 test_expect_success 'Check invalid format specifiers are errors' '
@@ -211,6 +212,18 @@ test_expect_success 'Check format "rfc2822" date fields output' '
 '
 
 cat >expected <<\EOF
+'refs/heads/master' 'Mon 2006-07-03 15:18:43 (Mon 17:18:43 +0200)' 'Mon 2006-07-03 15:18:44 (Mon 17:18:44 +0200)'
+'refs/tags/testtag' 'Mon 2006-07-03 15:18:45 (Mon 17:18:45 +0200)'
+EOF
+
+test_expect_success 'Check format "local_original" date fields output' '
+	f=local_original &&
+	(git for-each-ref --shell --format="%(refname) %(committerdate:$f) %(authordate:$f)" refs/heads &&
+	git for-each-ref --shell --format="%(refname) %(taggerdate:$f)" refs/tags) >actual &&
+	test_cmp expected actual
+'
+
+cat >expected <<\EOF
 refs/heads/master
 refs/remotes/origin/master
 refs/tags/testtag
-- 
1.6.4.1

Re: [PATCH/RFC] New date format: local_original

[Jeff King]

On Tue, Oct 06, 2009 at 10:09:47PM +0300, Tuomas Suutari wrote:

> Formats date and time with local and original timezone representation
> in same string. They both can be useful at the same time: local
> timezone for relating timestamp to local events, and original timezone
> to see the author's time of the day.
>
> [...]
>
> It was hard to decide whether to use --date=local or --date=iso
> with git log, so I though that maybe I could have them both.

It's not clear to me. Do you really _like_ seeing them both, or did you
simply want to see local dates in the iso format, but those two options
(which are conceptually orthogonal) could not be used at the same time?

If the latter, then maybe we should resurrect the patch that allows
"--date=local --date=iso" to do what you want. From this thread:

  http://thread.gmane.org/gmane.comp.version-control.git/112026

If the former, then should the options be orthogonal? That is, should it
be a new format combining the two, or should it be an option to show, in
your preferred format, the time in both local and original time zones?
E.g., something like:

  $ git log --date=iso --local-dates-too
  commit bf01a69ed40e1afcf56aff143f7523da2ce263ed
  Author: Johannes Schindelin <Johannes.Schindelin@gmx.de>
  Date:   2009-10-04 00:41:55 +0200
  Local:  2009-10-03 17:41:55 -0500

And then you can use it with "normal" dates, iso dates, rfc2822 dates,
etc.

I dunno. I have to admit I never personally really wanted anything
except the default date format, unless I was parsing it for something
special.

-Peff

Re: [PATCH/RFC] New date format: local_original

[Junio C Hamano]

Jeff King <peff@peff.net> writes:

> If the former, then should the options be orthogonal? That is, should it
> be a new format combining the two, or should it be an option to show, in
> your preferred format, the time in both local and original time zones?
> E.g., something like:
>
>   $ git log --date=iso --local-dates-too
>   commit bf01a69ed40e1afcf56aff143f7523da2ce263ed
>   Author: Johannes Schindelin <Johannes.Schindelin@gmx.de>
>   Date:   2009-10-04 00:41:55 +0200
>   Local:  2009-10-03 17:41:55 -0500
>
> And then you can use it with "normal" dates, iso dates, rfc2822 dates,
> etc.

Thanks for comments.

I think "--date=iso --local-dates-too" is still not orthogonal enough, let
alone "local_original" which invites "Why is this combination supported
and not this, that, and 47 others?" questions.

I however do not think it is so bad an idea to allow something like:

	git log --date='custom:%Y-%m-%d ...'
	git log --date=custom	;# looks at "date.custom" config

You (not Peff, but figuratively whoever wants to implement it) can add a
mechanism to specify in which timezone (original or local) you would want
the timestring to be given, and make what Tuomas's RFC patch does a mere
special case.  For example, we could reuse 'date "+format"' string with
our own extension %{magic}, with two magic tokens initially defined:

    %{local}	interpret timestamp in local zone from now on
    %{original}	interpret timestamp in the original zone from now on

With such a mechanism Tuomas can define:

	[date]
            custom=%{local}%a %Y-%m-%d %H:%M:%S %{original}(%a %H:%M:%S %z)

and ask "git log --date=custom" to get what his patch does.

Re: [PATCH/RFC] New date format: local_original

[Jeff King]

On Wed, Oct 07, 2009 at 01:01:05PM -0700, Junio C Hamano wrote:

> I think "--date=iso --local-dates-too" is still not orthogonal enough, let
> alone "local_original" which invites "Why is this combination supported
> and not this, that, and 47 others?" questions.
> 
> I however do not think it is so bad an idea to allow something like:
> 
> 	git log --date='custom:%Y-%m-%d ...'
> 	git log --date=custom	;# looks at "date.custom" config

Thanks, that (and the %{local} bit) is a much better suggestion than
mine, I think.

-Peff