Re: [PATCH 2/2] commit: don't check for space twice when looking for header

["Jakub Narębski" <jnareb@gmail.com>]

W dniu 25.02.2017 o 20:27, René Scharfe pisze:
> Both standard_header_field() and excluded_header_field() check if
> there's a space after the buffer that's handed to them.  We already
> check in the caller if that space is present.  Don't bother calling
> the functions if it's missing, as they are guaranteed to return 0 in
> that case, and remove the now redundant checks from them.
> 
> Signed-off-by: Rene Scharfe <l.s.r@web.de>
> ---
>  commit.c | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/commit.c b/commit.c
> index 173c6d3818..fab8269731 100644
> --- a/commit.c
> +++ b/commit.c
> @@ -1308,11 +1308,11 @@ void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
>  
>  static inline int standard_header_field(const char *field, size_t len)
>  {
> -	return ((len == 4 && !memcmp(field, "tree ", 5)) ||
> -		(len == 6 && !memcmp(field, "parent ", 7)) ||
> -		(len == 6 && !memcmp(field, "author ", 7)) ||
> -		(len == 9 && !memcmp(field, "committer ", 10)) ||
> -		(len == 8 && !memcmp(field, "encoding ", 9)));
> +	return ((len == 4 && !memcmp(field, "tree", 4)) ||
> +		(len == 6 && !memcmp(field, "parent", 6)) ||
> +		(len == 6 && !memcmp(field, "author", 6)) ||
> +		(len == 9 && !memcmp(field, "committer", 9)) ||
> +		(len == 8 && !memcmp(field, "encoding", 8)));

I agree (for what it is worth from me) with the rest of changes,
but I think current code is better self-documenting for this
function.

>  }
>  
>  static int excluded_header_field(const char *field, size_t len, const char **exclude)
> @@ -1322,8 +1322,7 @@ static int excluded_header_field(const char *field, size_t len, const char **exc
>  
>  	while (*exclude) {
>  		size_t xlen = strlen(*exclude);
> -		if (len == xlen &&
> -		    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
> +		if (len == xlen && !memcmp(field, *exclude, xlen))
>  			return 1;
>  		exclude++;
>  	}
> @@ -1357,9 +1356,8 @@ static struct commit_extra_header *read_commit_extra_header_lines(
>  		eof = memchr(line, ' ', next - line);
>  		if (!eof)
>  			eof = next;
> -
> -		if (standard_header_field(line, eof - line) ||
> -		    excluded_header_field(line, eof - line, exclude))
> +		else if (standard_header_field(line, eof - line) ||
> +			 excluded_header_field(line, eof - line, exclude))
>  			continue;
>  
>  		it = xcalloc(1, sizeof(*it));
>