git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
From: "Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: "Johannes Schindelin" <johannes.schindelin@gmx.de>,
	"Matthias Aßhauer" <mha1993@live.de>
Subject: [PATCH] mingw: use modern strftime implementation if possible
Date: Wed, 08 Apr 2020 17:58:49 +0000	[thread overview]
Message-ID: <pull.753.git.git.1586368729890.gitgitgadget@gmail.com> (raw)

From: =?UTF-8?q?Matthias=20A=C3=9Fhauer?= <mha1993@live.de>

Microsoft introduced a new "Universal C Runtime Library" (UCRT) with
Visual Studio 2015. The UCRT comes with a new strftime() implementation
that supports more date formats. We link git against the older
"Microsoft Visual C Runtime Library" (MSVCRT), so to use the UCRT
strftime() we need to load it from ucrtbase.dll using
DECLARE_PROC_ADDR()/INIT_PROC_ADDR().

Most supported Windows systems should have recieved the UCRT via Windows
update, but in some cases only MSVCRT might be available. In that case
we fall back to using that implementation.

With this change, it is possible to use e.g. the `%g` and `%V` date
format specifiers, e.g.

	git show -s --format=%cd --date=format:‘%g.%V’ HEAD

Without this change, the user would see this error message on Windows:

	fatal: invalid strftime format: '‘%g.%V’'

This fixes https://github.com/git-for-windows/git/issues/2495

Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
    Use a modern strftime() on Windows when available
    
    This is another contribution that came in via Git for Windows.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-753%2Fdscho%2Fmingw-modern-strftime-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-753/dscho/mingw-modern-strftime-v1
Pull-Request: https://github.com/git/git/pull/753

 compat/mingw.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index d14065d60ec..2136744af35 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -964,7 +964,16 @@ int mingw_utime (const char *file_name, const struct utimbuf *times)
 size_t mingw_strftime(char *s, size_t max,
 		      const char *format, const struct tm *tm)
 {
-	size_t ret = strftime(s, max, format, tm);
+	/* a pointer to the original strftime in case we can't find the UCRT version */
+	static size_t (*fallback)(char *, size_t, const char *, const struct tm *) = strftime;
+	size_t ret;
+	DECLARE_PROC_ADDR(ucrtbase.dll, size_t, strftime, char *, size_t,
+		const char *, const struct tm *);
+
+	if (INIT_PROC_ADDR(strftime))
+		ret = strftime(s, max, format, tm);
+	else
+		ret = fallback(s, max, format, tm);
 
 	if (!ret && errno == EINVAL)
 		die("invalid strftime format: '%s'", format);

base-commit: 9fadedd637b312089337d73c3ed8447e9f0aa775
-- 
gitgitgadget

             reply	other threads:[~2020-04-08 17:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-08 17:58 Johannes Schindelin via GitGitGadget [this message]
2020-04-08 19:14 ` Junio C Hamano
2020-04-10 14:39   ` Johannes Schindelin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=pull.753.git.git.1586368729890.gitgitgadget@gmail.com \
    --to=gitgitgadget@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=johannes.schindelin@gmx.de \
    --cc=mha1993@live.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).