[PATCH 1/4, V3, libnftnl] rule: Implement internal expression iterator

["Carlos Falgueras García" <carlosfg@riseup.net>]

Introduce nftnl_expr_iter_init() to allow stack allocated iterators for
internal use.

Signed-off-by: Carlos Falgueras García <carlosfg@riseup.net>
---
 src/rule.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/rule.c b/src/rule.c
index 11fceca..69ffc7e 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -29,6 +29,14 @@
 #include <libnftnl/set.h>
 #include <libnftnl/expr.h>
 
+struct nftnl_expr_iter {
+	const struct nftnl_rule	*r;
+	struct nftnl_expr	*cur;
+};
+
+static void nftnl_expr_iter_init(const struct nftnl_rule *r,
+				 struct nftnl_expr_iter *iter);
+
 struct nftnl_rule {
 	struct list_head head;
 
@@ -1025,10 +1033,16 @@ int nftnl_expr_foreach(struct nftnl_rule *r,
 }
 EXPORT_SYMBOL_ALIAS(nftnl_expr_foreach, nft_rule_expr_foreach);
 
-struct nftnl_expr_iter {
-	const struct nftnl_rule	*r;
-	struct nftnl_expr	*cur;
-};
+static void nftnl_expr_iter_init(const struct nftnl_rule *r,
+				 struct nftnl_expr_iter *iter)
+{
+	iter->r = r;
+	if (list_empty(&r->expr_list))
+		iter->cur = NULL;
+	else
+		iter->cur = list_entry(r->expr_list.next, struct nftnl_expr,
+				       head);
+}
 
 struct nftnl_expr_iter *nftnl_expr_iter_create(const struct nftnl_rule *r)
 {
@@ -1037,13 +1051,7 @@ struct nftnl_expr_iter *nftnl_expr_iter_create(const struct nftnl_rule *r)
 	iter = calloc(1, sizeof(struct nftnl_expr_iter));
 	if (iter == NULL)
 		return NULL;
-
-	iter->r = r;
-	if (list_empty(&r->expr_list))
-		iter->cur = NULL;
-	else
-		iter->cur = list_entry(r->expr_list.next, struct nftnl_expr,
-				       head);
+	nftnl_expr_iter_init(r, iter);
 
 	return iter;
 }
-- 
2.8.3