From: "Torsten Bögershausen" <tboegi@web.de>
To: Paul Tan <pyokagan@gmail.com>, git@vger.kernel.org
Cc: Johannes Schindelin <johannes.schindelin@gmx.de>,
Stefan Beller <sbeller@google.com>
Subject: Re: [PATCH v4 01/44] wrapper: implement xopen()
Date: Mon, 29 Jun 2015 06:48:16 +0200 [thread overview]
Message-ID: <5590CE10.3020104@web.de> (raw)
In-Reply-To: <1435500366-31700-2-git-send-email-pyokagan@gmail.com>
On 06/28/2015 04:05 PM, Paul Tan wrote:
> A common usage pattern of open() is to check if it was successful, and
> die() if it was not:
>
> int fd = open(path, O_WRONLY | O_CREAT, 0777);
> if (fd < 0)
> die_errno(_("Could not open '%s' for writing."), path);
>
> Implement a wrapper function xopen() that does the above so that we can
> save a few lines of code, and make the die() messages consistent.
>
> Helped-by: Torsten Bögershausen <tboegi@web.de>
> Helped-by: Jeff King <peff@peff.net>
> Signed-off-by: Paul Tan <pyokagan@gmail.com>
> ---
> git-compat-util.h | 1 +
> wrapper.c | 25 +++++++++++++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/git-compat-util.h b/git-compat-util.h
> index c6d391f..e168dfd 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -717,6 +717,7 @@ extern void *xrealloc(void *ptr, size_t size);
> extern void *xcalloc(size_t nmemb, size_t size);
> extern void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
> extern void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
> +extern int xopen(const char *path, int flags, ...);
> extern ssize_t xread(int fd, void *buf, size_t len);
> extern ssize_t xwrite(int fd, const void *buf, size_t len);
> extern ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
> diff --git a/wrapper.c b/wrapper.c
> index ff49807..7e13ae0 100644
> --- a/wrapper.c
> +++ b/wrapper.c
> @@ -189,6 +189,31 @@ void *xcalloc(size_t nmemb, size_t size)
> # endif
> #endif
>
> +/**
> + * xopen() is the same as open(), but it die()s if the open() fails.
> + */
> +int xopen(const char *path, int oflag, ...)
> +{
> + mode_t mode = 0;
> + va_list ap;
> +
> + va_start(ap, oflag);
> + if (oflag & O_CREAT)
> + mode = va_arg(ap, mode_t);
> + va_end(ap);
> +
> + assert(path);
> +
2 remarks:
- I don't know if and why we need the assert() here (but don't know if
we have a strategie in Git for assert())
- Having xopen() with 2 or 3 parameter is good, but the current may need
some tweaks for better portability:
int xopen(const char *path, int oflag, ...)
{
mode_t mode = 0;
if (oflag & O_CREAT) {
va_list ap;
va_start(ap, oflag);
mode = va_arg(ap, int);
va_end(ap);
}
See e.g.
<http://blitiri.com.ar/git/r/libfiu/c/37f6a98110e3bb59bbb4971241baa3a385c3f724/>
why va_arg(ap, int) should be used:
+
+ /* va_arg() can only take fully promoted types, and mode_t
+ * sometimes is smaller than an int, so we should always pass
+ * int to it, and not mode_t. Not doing so would may result in
+ * a compile-time warning and run-time error. We asume that it
+ * is never bigger than an int, which holds in practise. */
+ mode = va_arg(l, int);
+
next prev parent reply other threads:[~2015-06-29 4:48 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-28 14:05 [PATCH v4 00/44] Make git-am a builtin Paul Tan
2015-06-28 14:05 ` [PATCH v4 01/44] wrapper: implement xopen() Paul Tan
2015-06-29 4:48 ` Torsten Bögershausen [this message]
2015-06-29 5:04 ` Stefan Beller
2015-06-29 17:18 ` Junio C Hamano
2015-07-01 6:05 ` Paul Tan
2015-07-01 6:04 ` Paul Tan
2015-06-28 14:05 ` [PATCH v4 02/44] wrapper: implement xfopen() Paul Tan
2015-06-28 14:05 ` [PATCH v4 03/44] builtin-am: implement skeletal builtin am Paul Tan
2015-06-28 14:05 ` [PATCH v4 04/44] builtin-am: implement patch queue mechanism Paul Tan
2015-06-29 5:08 ` Stefan Beller
2015-07-07 12:50 ` Paul Tan
2015-06-28 14:05 ` [PATCH v4 05/44] builtin-am: split out mbox/maildir patches with git-mailsplit Paul Tan
2015-06-28 14:05 ` [PATCH v4 06/44] builtin-am: auto-detect mbox patches Paul Tan
2015-06-28 14:05 ` [PATCH v4 07/44] builtin-am: extract patch and commit info with git-mailinfo Paul Tan
2015-06-28 14:05 ` [PATCH v4 08/44] builtin-am: apply patch with git-apply Paul Tan
2015-06-28 14:05 ` [PATCH v4 09/44] builtin-am: implement committing applied patch Paul Tan
2015-06-28 14:05 ` [PATCH v4 10/44] builtin-am: refuse to apply patches if index is dirty Paul Tan
2015-06-28 14:05 ` [PATCH v4 11/44] builtin-am: implement --resolved/--continue Paul Tan
2015-06-28 14:05 ` [PATCH v4 12/44] builtin-am: implement --skip Paul Tan
2015-06-28 14:05 ` [PATCH v4 13/44] builtin-am: implement --abort Paul Tan
2015-06-28 14:05 ` [PATCH v4 14/44] builtin-am: reject patches when there's a session in progress Paul Tan
2015-06-28 14:05 ` [PATCH v4 15/44] builtin-am: implement -q/--quiet, GIT_QUIET Paul Tan
2015-06-28 14:05 ` [PATCH v4 16/44] builtin-am: exit with user friendly message on failure Paul Tan
2015-06-28 14:05 ` [PATCH v4 17/44] builtin-am: implement -s/--signoff Paul Tan
2015-06-28 14:05 ` [PATCH v4 18/44] cache-tree: introduce write_index_as_tree() Paul Tan
2015-06-28 14:05 ` [PATCH v4 19/44] builtin-am: implement --3way, am.threeway Paul Tan
2015-06-30 0:18 ` Stefan Beller
2015-06-28 14:05 ` [PATCH v4 20/44] builtin-am: implement --rebasing mode Paul Tan
2015-06-28 14:05 ` [PATCH v4 21/44] builtin-am: bypass git-mailinfo when --rebasing Paul Tan
2015-06-28 14:05 ` [PATCH v4 22/44] builtin-am: handle stray state directory Paul Tan
2015-06-28 14:05 ` [PATCH v4 23/44] builtin-am: implement -u/--utf8 Paul Tan
2015-06-28 14:05 ` [PATCH v4 24/44] builtin-am: implement -k/--keep, --keep-non-patch Paul Tan
2015-06-28 14:05 ` [PATCH v4 25/44] builtin-am: implement --[no-]message-id, am.messageid Paul Tan
2015-06-28 14:05 ` [PATCH v4 26/44] builtin-am: support --keep-cr, am.keepcr Paul Tan
2015-06-28 14:05 ` [PATCH v4 27/44] builtin-am: implement --[no-]scissors Paul Tan
2015-07-07 8:23 ` Paul Tan
2015-06-28 14:05 ` [PATCH v4 28/44] builtin-am: pass git-apply's options to git-apply Paul Tan
2015-06-29 23:56 ` Stefan Beller
2015-07-01 10:22 ` Paul Tan
2015-07-01 17:01 ` Stefan Beller
2015-06-28 14:05 ` [PATCH v4 29/44] builtin-am: implement --ignore-date Paul Tan
2015-06-28 14:05 ` [PATCH v4 30/44] builtin-am: implement --committer-date-is-author-date Paul Tan
2015-06-28 14:05 ` [PATCH v4 31/44] builtin-am: implement -S/--gpg-sign, commit.gpgsign Paul Tan
2015-06-29 23:51 ` Stefan Beller
2015-07-01 8:01 ` Paul Tan
2015-07-01 16:43 ` Stefan Beller
2015-06-28 14:05 ` [PATCH v4 32/44] builtin-am: invoke post-rewrite hook Paul Tan
2015-06-28 14:05 ` [PATCH v4 33/44] builtin-am: support automatic notes copying Paul Tan
2015-06-28 14:05 ` [PATCH v4 34/44] builtin-am: invoke applypatch-msg hook Paul Tan
2015-06-28 14:05 ` [PATCH v4 35/44] builtin-am: invoke pre-applypatch hook Paul Tan
2015-06-28 14:05 ` [PATCH v4 36/44] builtin-am: invoke post-applypatch hook Paul Tan
2015-06-28 14:05 ` [PATCH v4 37/44] builtin-am: rerere support Paul Tan
2015-06-28 14:06 ` [PATCH v4 38/44] builtin-am: support and auto-detect StGit patches Paul Tan
2015-06-29 20:42 ` Stefan Beller
2015-06-29 20:51 ` Eric Sunshine
2015-06-29 21:39 ` Junio C Hamano
2015-07-01 7:25 ` Paul Tan
2015-06-28 14:06 ` [PATCH v4 39/44] builtin-am: support and auto-detect StGit series files Paul Tan
2015-06-28 14:06 ` [PATCH v4 40/44] builtin-am: support and auto-detect mercurial patches Paul Tan
2015-06-29 20:32 ` Stefan Beller
2015-06-29 20:32 ` Stefan Beller
2015-07-01 9:07 ` Paul Tan
2015-07-01 8:48 ` Paul Tan
2015-06-28 14:06 ` [PATCH v4 41/44] builtin-am: implement -i/--interactive Paul Tan
2015-06-28 14:06 ` [PATCH v4 42/44] builtin-am: implement legacy -b/--binary option Paul Tan
2015-06-29 20:05 ` Stefan Beller
[not found] ` <CABPQNSakaoyNRuNz=bcDYWdy4e2O3M4UuYoOT5JAV1mt-BiAOw@mail.gmail.com>
2015-07-14 10:09 ` Paul Tan
2015-06-28 14:06 ` [PATCH v4 43/44] builtin-am: check for valid committer ident Paul Tan
2015-06-29 20:02 ` Stefan Beller
2015-07-01 6:43 ` Paul Tan
2015-06-28 14:06 ` [PATCH v4 44/44] builtin-am: remove redirection to git-am.sh Paul Tan
2015-06-29 5:01 ` [PATCH v4 00/44] Make git-am a builtin Stefan Beller
2015-06-30 0:19 ` Stefan Beller
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