xdiff: factor out match_func_rec()

Add match_func_rec(), a helper that wraps accessing a record and calling
the appropriate function for checking if it contains a function line.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

xdiff/xemit.c

@@ -120,6 +120,16 @@ static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
 	return -1;
 }
 
+static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
+			   char *buf, long sz)
+{
+	const char *rec;
+	long len = xdl_get_rec(xdf, ri, &rec);
+	if (!xecfg->find_func)
+		return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
+	return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
+}
+
 struct func_line {
 	long len;
 	char buf[80];
@@ -128,7 +138,6 @@ struct func_line {
 static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
 			  struct func_line *func_line, long start, long limit)
 {
-	find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
 	long l, size, step = (start > limit) ? -1 : 1;
 	char *buf, dummy[1];
 
@@ -136,9 +145,7 @@ static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
 	size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
 
 	for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
-		const char *rec;
-		long reclen = xdl_get_rec(&xe->xdf1, l, &rec);
-		long len = ff(rec, reclen, buf, size, xecfg->find_func_priv);
+		long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
 		if (len >= 0) {
 			if (func_line)
 				func_line->len = len;