[PATCH] diffcore-pickaxe: simplify has_changes and contains

[PATCH] diffcore-pickaxe: simplify has_changes and contains

[René Scharfe]

Halve the number of callsites of contains() to two using temporary
variables, simplifying the code.  While at it, get rid of the
diff_options parameter, which became unused with 8fa4b09f.

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
---
 diffcore-pickaxe.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index c97ac9b..401eb72 100644
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -131,8 +131,7 @@ static void diffcore_pickaxe_grep(struct diff_options *o)
 	return;
 }
 
-static unsigned int contains(mmfile_t *mf, struct diff_options *o,
-			     regex_t *regexp, kwset_t kws)
+static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws)
 {
 	unsigned int cnt;
 	unsigned long sz;
@@ -176,11 +175,9 @@ static int has_changes(mmfile_t *one, mmfile_t *two,
 		       struct diff_options *o,
 		       regex_t *regexp, kwset_t kws)
 {
-	if (!one)
-		return contains(two, o, regexp, kws) != 0;
-	if (!two)
-		return contains(one, o, regexp, kws) != 0;
-	return contains(one, o, regexp, kws) != contains(two, o, regexp, kws);
+	unsigned int one_contains = one ? contains(one, regexp, kws) : 0;
+	unsigned int two_contains = two ? contains(two, regexp, kws) : 0;
+	return one_contains != two_contains;
 }
 
 static int pickaxe_match(struct diff_filepair *p, struct diff_options *o,
-- 
1.8.3.2

Re: [PATCH] diffcore-pickaxe: simplify has_changes and contains

[Jeff King]

On Sat, Jul 06, 2013 at 03:53:27PM +0200, René Scharfe wrote:

> Halve the number of callsites of contains() to two using temporary
> variables, simplifying the code.  While at it, get rid of the
> diff_options parameter, which became unused with 8fa4b09f.

There is a slight change in behavior, too:

> -	if (!one)
> -		return contains(two, o, regexp, kws) != 0;
> -	if (!two)
> -		return contains(one, o, regexp, kws) != 0;
> -	return contains(one, o, regexp, kws) != contains(two, o, regexp, kws);
> +	unsigned int one_contains = one ? contains(one, regexp, kws) : 0;
> +	unsigned int two_contains = two ? contains(two, regexp, kws) : 0;
> +	return one_contains != two_contains;

Before, if (!one && !two) we would call contains(two, ...), and now we
will simply assume it is zero. Which I think is an improvement, as we
would have segfaulted before. I don't think it is a bug in the current
code (we would not ever feed the function two NULLs), but it is nice to
be more defensive.

Acked-by: Jeff King <peff@peff.net>

-Peff

Re: [PATCH] diffcore-pickaxe: simplify has_changes and contains

[Junio C Hamano]

Jeff King <peff@peff.net> writes:

> Before, if (!one && !two) we would call contains(two, ...), and now we
> will simply assume it is zero. Which I think is an improvement, as we
> would have segfaulted before. I don't think it is a bug in the current
> code (we would not ever feed the function two NULLs), but it is nice to
> be more defensive.
>
> Acked-by: Jeff King <peff@peff.net>

Thanks, both.