[PATCH] strbuf: avoid redundant reset in strbuf_getwholeline()

[PATCH] strbuf: avoid redundant reset in strbuf_getwholeline()

[René Scharfe]

The HAVE_GETDELIM variant of strbuf_getwholeline() calls strbuf_reset()
on the strbuf before handing it over to getdelim(3).  This is
unnecessary:

  - getdelim(3) doesn't care whether the old buffer contents is
    NUL-terminated and has no access to ->len,
  - on success getdelim(3) NUL-terminates the buffer and we set ->len,
  - on error we either call strbuf_init() or strbuf_reset().

Remove the superfluous preparatory call.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 strbuf.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/strbuf.c b/strbuf.c
index 764b629927..44955669e8 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -646,8 +646,6 @@ int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
 	if (feof(fp))
 		return EOF;
 
-	strbuf_reset(sb);
-
 	/* Translate slopbuf to NULL, as we cannot call realloc on it */
 	if (!sb->alloc)
 		sb->buf = NULL;
-- 
2.55.0

Re: [PATCH] strbuf: avoid redundant reset in strbuf_getwholeline()

[Junio C Hamano]

René Scharfe <l.s.r@web.de> writes:

> The HAVE_GETDELIM variant of strbuf_getwholeline() calls strbuf_reset()
> on the strbuf before handing it over to getdelim(3).  This is
> unnecessary:
>
>   - getdelim(3) doesn't care whether the old buffer contents is
>     NUL-terminated and has no access to ->len,
>   - on success getdelim(3) NUL-terminates the buffer and we set ->len,
>   - on error we either call strbuf_init() or strbuf_reset().
>
> Remove the superfluous preparatory call.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
>  strbuf.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/strbuf.c b/strbuf.c
> index 764b629927..44955669e8 100644
> --- a/strbuf.c
> +++ b/strbuf.c
> @@ -646,8 +646,6 @@ int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
>  	if (feof(fp))
>  		return EOF;
>  
> -	strbuf_reset(sb);
> -

This is well explained and makes perfect sense.

Thanks.  Will apply and mark for 'next'.

>  	/* Translate slopbuf to NULL, as we cannot call realloc on it */
>  	if (!sb->alloc)
>  		sb->buf = NULL;