date: use strbufs in date-formatting functions

Many of the date functions write into fixed-size buffers.
This is a minor pain, as we have to take special
precautions, and frequently end up copying the result into a
strbuf or heap-allocated buffer anyway (for which we
sometimes use strcpy!).

Let's instead teach parse_date, datestamp, etc to write to a
strbuf. The obvious downside is that we might need to
perform a heap allocation where we otherwise would not need
to. However, it turns out that the only two new allocations
required are:

  1. In test-date.c, where we don't care about efficiency.

  2. In determine_author_info, which is not performance
     critical (and where the use of a strbuf will help later
     refactoring).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 11 insertions, 15 deletions

diff --git a/ident.c b/ident.c
index 1d9b6e770d..9bcc4e11b8 100644
--- a/ident.c
+++ b/ident.c
@@ -9,7 +9,7 @@
 
 static struct strbuf git_default_name = STRBUF_INIT;
 static struct strbuf git_default_email = STRBUF_INIT;
-static char git_default_date[50];
+static struct strbuf git_default_date = STRBUF_INIT;
 
 #define IDENT_NAME_GIVEN 01
 #define IDENT_MAIL_GIVEN 02
@@ -129,9 +129,9 @@ const char *ident_default_email(void)
 
 static const char *ident_default_date(void)
 {
-	if (!git_default_date[0])
-		datestamp(git_default_date, sizeof(git_default_date));
-	return git_default_date;
+	if (!git_default_date.len)
+		datestamp(&git_default_date);
+	return git_default_date.buf;
 }
 
 static int crud(unsigned char c)
@@ -292,7 +292,6 @@ const char *fmt_ident(const char *name, const char *email,
 		      const char *date_str, int flag)
 {
 	static struct strbuf ident = STRBUF_INIT;
-	char date[50];
 	int strict = (flag & IDENT_STRICT);
 	int want_date = !(flag & IDENT_NO_DATE);
 	int want_name = !(flag & IDENT_NO_NAME);
@@ -320,15 +319,6 @@ const char *fmt_ident(const char *name, const char *email,
 		die("unable to auto-detect email address (got '%s')", email);
 	}
 
-	if (want_date) {
-		if (date_str && date_str[0]) {
-			if (parse_date(date_str, date, sizeof(date)) < 0)
-				die("invalid date format: %s", date_str);
-		}
-		else
-			strcpy(date, ident_default_date());
-	}
-
 	strbuf_reset(&ident);
 	if (want_name) {
 		strbuf_addstr_without_crud(&ident, name);
@@ -339,8 +329,14 @@ const char *fmt_ident(const char *name, const char *email,
 			strbuf_addch(&ident, '>');
 	if (want_date) {
 		strbuf_addch(&ident, ' ');
-		strbuf_addstr_without_crud(&ident, date);
+		if (date_str && date_str[0]) {
+			if (parse_date(date_str, &ident) < 0)
+				die("invalid date format: %s", date_str);
+		}
+		else
+			strbuf_addstr(&ident, ident_default_date());
 	}
+
 	return ident.buf;
 }