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[PATCH 3/3] introduce "format" date-mode

From
Jeff King <peff@peff.net>
Date
Jun 25, 2015, 16:55 UTC
Message-ID
<20150625165545.GC23503@peff.net>
In-Reply-To
<20150625165341.GA21949@peff.net>

This feeds the format directly to strftime. Besides being a little more flexible, the main advantage is that your system strftime may know more about your locale's preferred format (e.g., how to spell the days of the week).

Signed-off-by: Jeff King <peff@peff.net>
---
 Documentation/rev-list-options.txt |  5 +++++
 builtin/blame.c                    |  3 +++
 cache.h                            |  2 ++
 date.c                             |  9 ++++++++-
 gettext.c                          |  1 +
 strbuf.c                           | 29 +++++++++++++++++++++++++++++
 strbuf.h                           |  5 +++++
 t/t6300-for-each-ref.sh            |  8 ++++++++
 8 files changed, 61 insertions(+), 1 deletion(-)
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 77ac439..a9b808f 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -727,6 +727,11 @@ format, often found in email messages.
 +
 `--date=raw` shows the date in the internal raw Git format `%s %z` format.
 +
+`--date=format:...` feeds the format `...` to your system `strftime`.
+Use `--date=format:%c` to show the date in your system locale's
+preferred format.  See the `strftime` manual for a complete list of
+format placeholders.
++
 `--date=default` shows timestamps in the original time zone
 (either committer's or author's).
 
diff --git a/builtin/blame.c b/builtin/blame.c
index 43e8473..e2e3e75 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2596,6 +2596,9 @@ parse_done:
 	case DATE_NORMAL:
 		blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
 		break;
+	case DATE_STRFTIME:
+		blame_date_width = strlen(show_date(0, 0, &blame_date_mode)) + 1; /* add the null */
+		break;
 	}
 	blame_date_width -= 1; /* strip the null */
 
diff --git a/cache.h b/cache.h
index 1759011..bb63a58 100644
--- a/cache.h
+++ b/cache.h
@@ -1105,8 +1105,10 @@ struct date_mode {
 		DATE_ISO8601,
 		DATE_ISO8601_STRICT,
 		DATE_RFC2822,
+		DATE_STRFTIME,
 		DATE_RAW
 	} type;
+	const char *strftime_fmt;
 };
 
 /*
diff --git a/date.c b/date.c
index cdad4db..8f91569 100644
--- a/date.c
+++ b/date.c
@@ -163,6 +163,8 @@ void show_date_relative(unsigned long time, int tz,
 struct date_mode *date_mode_from_type(enum date_mode_type type)
 {
 	static struct date_mode mode;
+	if (type == DATE_STRFTIME)
+		die("BUG: cannot create anonymous strftime date_mode struct");
 	mode.type = type;
 	return &mode;
 }
@@ -221,6 +223,8 @@ const char *show_date(unsigned long time, int tz, const struct 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->type == DATE_STRFTIME)
+		strbuf_addftime(&timebuf, mode->strftime_fmt, tm);
 	else
 		strbuf_addf(&timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
 				weekday_names[tm->tm_wday],
@@ -787,7 +791,10 @@ void parse_date_format(const char *format, struct date_mode *mode)
 		mode->type = DATE_NORMAL;
 	else if (!strcmp(format, "raw"))
 		mode->type = DATE_RAW;
-	else
+	else if (skip_prefix(format, "format:", &format)) {
+		mode->type = DATE_STRFTIME;
+		mode->strftime_fmt = xstrdup(format);
+	} else
 		die("unknown date format %s", format);
 }
 
diff --git a/gettext.c b/gettext.c
index 7378ba2..a268a2c 100644
--- a/gettext.c
+++ b/gettext.c
@@ -162,6 +162,7 @@ void git_setup_gettext(void)
 		podir = GIT_LOCALE_PATH;
 	bindtextdomain("git", podir);
 	setlocale(LC_MESSAGES, "");
+	setlocale(LC_TIME, "");
 	init_gettext_charset("git");
 	textdomain("git");
 }
diff --git a/strbuf.c b/strbuf.c
index 0d4f4e5..a7ba028 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -709,3 +709,32 @@ char *xstrfmt(const char *fmt, ...)
 
 	return ret;
 }
+
+void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
+{
+	size_t len;
+
+	/*
+	 * strftime reports "0" if it could not fit the result in the buffer.
+	 * Unfortunately, it also reports "0" if the requested time string
+	 * takes 0 bytes. So if we were to probe and grow, we have to choose
+	 * some arbitrary cap beyond which we guess that the format probably
+	 * just results in a 0-length output. Since we have to choose some
+	 * reasonable cap anyway, and since it is not that big, we may
+	 * as well just grow to their in the first place.
+	 */
+	strbuf_grow(sb, 128);
+	len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
+
+	if (!len) {
+		/*
+		 * Either we failed, or the format actually produces a 0-length
+		 * output. There's not much we can do, so we leave it blank.
+		 * However, the output array is left in an undefined state, so
+		 * we must re-assert our NUL terminator.
+		 */
+		sb->buf[sb->len] = '\0';
+	} else {
+		sb->len += len;
+	}
+}
diff --git a/strbuf.h b/strbuf.h
index 01c5c63..8c8f8d5 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -345,6 +345,11 @@ __attribute__((format (printf,2,0)))
 extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
 
 /**
+ * Add the time specified by `tm`, as formatted by `strftime`.
+ */
+extern void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm);
+
+/**
  * Read a given size of data from a FILE* pointer to the buffer.
  *
  * NOTE: The buffer is rewound if the read fails. If -1 is returned,
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index 24fc2ba..c7f368c 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -227,6 +227,14 @@ test_expect_success 'Check format "rfc2822" date fields output' '
 	test_cmp expected actual
 '
 
+test_expect_success 'Check format of strftime date fields' '
+	echo "my date is 2006-07-03" >expected &&
+	git for-each-ref \
+	  --format="%(authordate:format:my date is %Y-%m-%d)" \
+	  refs/heads >actual &&
+	test_cmp expected actual
+'
+
 cat >expected <<\EOF
 refs/heads/master
 refs/remotes/origin/master

-- 
2.4.4.742.g862750c
Previous: Junio C HamanoNext: Eric Sunshine
Message 14 of 31 in “several date related issues”
  1. H.Merijn BrandJun 25, 2015
  2. Jeff KingJun 25, 2015
  3. H.Merijn BrandJun 25, 2015
  4. 0/3 localized date formatJeff King, Jun 25, 2015
  5. 1/3 show-branch: use DATE_RELATIVE instead of magic numberJeff King, Jun 25, 2015
  6. 2/3 convert "enum date_mode" into a structJeff King, Jun 25, 2015
  7. John KeepingJun 25, 2015
  8. Jeff KingJun 25, 2015
  9. Junio C HamanoJul 7, 2015
  10. Jeff KingJul 7, 2015
  11. Junio C HamanoJul 7, 2015
  12. Jeff KingJul 7, 2015
  13. Junio C HamanoJul 7, 2015
  14. 3/3 introduce "format" date-modeJeff King, Jun 25, 2015
  15. Eric SunshineJun 29, 2015
  16. Jeff KingJun 30, 2015
  17. Junio C HamanoJun 30, 2015
  18. Jeff KingJun 30, 2015
  19. Junio C HamanoJun 30, 2015
  20. Jeff KingJun 30, 2015
  21. Eric SunshineJun 30, 2015
  22. Jeff KingJun 30, 2015
  23. Eric SunshineJun 30, 2015
  24. Jeff KingJun 30, 2015
  25. Junio C HamanoJun 30, 2015
  26. Eric SunshineJun 30, 2015
  27. Jeff KingJun 30, 2015
  28. Jeff KingJun 30, 2015
  29. Eric SunshineJun 30, 2015
  30. Eric SunshineJul 21, 2015
  31. Jeff KingJul 21, 2015

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