From: Jeff King <peff@peff.net>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: "René Scharfe" <l.s.r@web.de>, "Git List" <git@vger.kernel.org>,
"Junio C Hamano" <gitster@pobox.com>
Subject: [PATCH 6/8] write_file: add pointer+len variant
Date: Fri, 8 Jul 2016 05:12:22 -0400 [thread overview]
Message-ID: <20160708091222.GF10152@sigill.intra.peff.net> (raw)
In-Reply-To: <20160708090400.GA26594@sigill.intra.peff.net>
There are many callsites which could use write_file, but for
which it is a little awkward because they have a strbuf or
other pointer/len combo. Specifically:
1. write_file() takes a format string, so we have to use
"%s" or "%.*s", which are ugly.
2. Using any form of "%s" does not handle embedded NULs in
the output. That probably doesn't matter for our
call-sites, but it's nicer not to have to worry.
3. It's less efficient; we format into another strbuf
just to do the write. That's probably not measurably
slow for our uses, but it's simply inelegant.
We can fix this by providing a helper to write out the
formatted buffer, and just calling it from write_file().
Note that we don't do the usual "complete with a newline"
that write_file does. If the caller has their own buffer,
there's a reasonable chance they're doing something more
complicated than a single line, and they can call
strbuf_complete_line() themselves.
We could go even further and add strbuf_write_file(), but it
doesn't save much:
- write_file_buf(path, sb.buf, sb.len);
+ strbuf_write_file(&sb, path);
It would also be somewhat asymmetric with strbuf_read_file,
which actually returns errors rather than dying (and the
error handling is most of the benefit of write_file() in the
first place).
Signed-off-by: Jeff King <peff@peff.net>
---
cache.h | 6 ++++++
wrapper.c | 16 +++++++++++-----
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/cache.h b/cache.h
index 3f6c53f..9d6ad4f 100644
--- a/cache.h
+++ b/cache.h
@@ -1745,6 +1745,12 @@ static inline ssize_t write_str_in_full(int fd, const char *str)
return write_in_full(fd, str, strlen(str));
}
+/**
+ * Open (and truncate) the file at path, write the contents of buf to it,
+ * and close it. Dies if any errors are encountered.
+ */
+extern void write_file_buf(const char *path, const char *buf, size_t len);
+
extern void write_file(const char *path, const char *fmt, ...);
/* pager.c */
diff --git a/wrapper.c b/wrapper.c
index 7c126b8..b827206 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -640,22 +640,28 @@ int xsnprintf(char *dst, size_t max, const char *fmt, ...)
return len;
}
+void write_file_buf(const char *path, const char *buf, size_t len)
+{
+ int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+ if (write_in_full(fd, buf, len) != len)
+ die_errno(_("could not write to %s"), path);
+ if (close(fd))
+ die_errno(_("could not close %s"), path);
+}
+
void write_file(const char *path, const char *fmt, ...)
{
va_list params;
struct strbuf sb = STRBUF_INIT;
- int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
va_start(params, fmt);
strbuf_vaddf(&sb, fmt, params);
va_end(params);
strbuf_complete_line(&sb);
- if (write_in_full(fd, sb.buf, sb.len) != sb.len)
- die_errno(_("could not write to %s"), path);
+
+ write_file_buf(path, sb.buf, sb.len);
strbuf_release(&sb);
- if (close(fd))
- die_errno(_("could not close %s"), path);
}
void sleep_millisec(int millisec)
--
2.9.0.393.g704e522
next prev parent reply other threads:[~2016-07-08 9:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-07 20:02 [PATCH] am: ignore return value of write_file() René Scharfe
2016-07-07 20:31 ` Jeff King
2016-07-08 6:37 ` Johannes Schindelin
2016-07-08 6:56 ` Jeff King
2016-07-08 9:04 ` [PATCH 0/8] write_file cleanups Jeff King
2016-07-08 9:06 ` [PATCH 1/8] config: fix bogus fd check when setting up default config Jeff King
2016-07-08 9:08 ` [PATCH 2/8] am: ignore return value of write_file() Jeff King
2016-07-08 9:08 ` [PATCH 3/8] branch: use non-gentle write_file for branch description Jeff King
2016-07-08 9:09 ` [PATCH 4/8] write_file: drop "gently" form Jeff King
2016-07-08 9:10 ` [PATCH 5/8] write_file: use xopen Jeff King
2016-07-08 9:12 ` Jeff King [this message]
2016-07-08 9:12 ` [PATCH 7/8] write_file: add format attribute Jeff King
2016-07-08 9:25 ` Jeff King
2016-07-08 9:25 ` [PATCH 1/2] walker: let walker_say take arbitrary formats Jeff King
2016-07-08 9:25 ` [PATCH 2/2] avoid using sha1_to_hex output as printf format Jeff King
2016-07-08 10:35 ` Jeff King
2016-07-08 17:02 ` Junio C Hamano
2016-07-08 17:09 ` Junio C Hamano
2016-07-08 21:41 ` Jeff King
2016-07-08 9:12 ` [PATCH 8/8] use write_file_buf where applicable Jeff King
2016-07-08 9:16 ` [PATCH 9/8] branch: use write_file_buf instead of write_file Jeff King
2016-07-08 18:44 ` [PATCH 0/8] write_file cleanups René Scharfe
2016-07-09 14:24 ` [PATCH] am: ignore return value of write_file() Johannes Schindelin
2016-07-10 10:53 ` Johannes Schindelin
2016-07-08 6:33 ` Johannes Schindelin
2016-07-08 18:44 ` René Scharfe
2016-07-08 21:51 ` Jeff King
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