[PATCH 6/8] write_file: add pointer+len variant
- From
Jeff King <peff@peff.net>
- Date
- Jul 8, 2016, 09:12 UTC
- Message-ID
- <20160708091222.GF10152@sigill.intra.peff.net>
- 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