*: change the signature of the northbound callbacks to be more flexible

Having a fixed set of parameters for each northbound callback isn't a
good idea since it makes it difficult to add new parameters whenever
that becomes necessary, as several hundreds or thousands of existing
callbacks need to be updated accordingly.

To remediate this issue, this commit changes the signature of all
northbound callbacks to have a single parameter: a pointer to a
'nb_cb_x_args' structure (where x is different for each type
of callback). These structures encapsulate all real parameters
(both input and output) the callbacks need to have access to. And
adding a new parameter to a given callback is as simple as adding
a new field to the corresponding 'nb_cb_x_args' structure, without
needing to update any instance of that callback in any daemon.

This commit includes a .cocci semantic patch that can be used to
update old code to the new format automatically.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 25 insertions, 28 deletions

diff --git a/lib/vrf.c b/lib/vrf.c
index 79195453e..f8702973b 100644
--- a/lib/vrf.c
+++ b/lib/vrf.c
@@ -1053,31 +1053,30 @@ vrf_id_t vrf_generate_id(void)
 /*
  * XPath: /frr-vrf:lib/vrf
  */
-static int lib_vrf_create(enum nb_event event, const struct lyd_node *dnode,
-			  union nb_resource *resource)
+static int lib_vrf_create(struct nb_cb_create_args *args)
 {
 	const char *vrfname;
 	struct vrf *vrfp;
 
-	vrfname = yang_dnode_get_string(dnode, "./name");
+	vrfname = yang_dnode_get_string(args->dnode, "./name");
 
-	if (event != NB_EV_APPLY)
+	if (args->event != NB_EV_APPLY)
 		return NB_OK;
 
 	vrfp = vrf_get(VRF_UNKNOWN, vrfname);
 
-	nb_running_set_entry(dnode, vrfp);
+	nb_running_set_entry(args->dnode, vrfp);
 
 	return NB_OK;
 }
 
-static int lib_vrf_destroy(enum nb_event event, const struct lyd_node *dnode)
+static int lib_vrf_destroy(struct nb_cb_destroy_args *args)
 {
 	struct vrf *vrfp;
 
-	switch (event) {
+	switch (args->event) {
 	case NB_EV_VALIDATE:
-		vrfp = nb_running_get_entry(dnode, NULL, true);
+		vrfp = nb_running_get_entry(args->dnode, NULL, true);
 		if (CHECK_FLAG(vrfp->status, VRF_ACTIVE)) {
 			zlog_debug("%s Only inactive VRFs can be deleted",
 				   __func__);
@@ -1088,7 +1087,7 @@ static int lib_vrf_destroy(enum nb_event event, const struct lyd_node *dnode)
 	case NB_EV_ABORT:
 		break;
 	case NB_EV_APPLY:
-		vrfp = nb_running_unset_entry(dnode);
+		vrfp = nb_running_unset_entry(args->dnode);
 
 		/* Clear configured flag and invoke delete. */
 		UNSET_FLAG(vrfp->status, VRF_CONFIGURED);
@@ -1099,12 +1098,11 @@ static int lib_vrf_destroy(enum nb_event event, const struct lyd_node *dnode)
 	return NB_OK;
 }
 
-static const void *lib_vrf_get_next(const void *parent_list_entry,
-				    const void *list_entry)
+static const void *lib_vrf_get_next(struct nb_cb_get_next_args *args)
 {
-	struct vrf *vrfp = (struct vrf *)list_entry;
+	struct vrf *vrfp = (struct vrf *)args->list_entry;
 
-	if (list_entry == NULL) {
+	if (args->list_entry == NULL) {
 		vrfp = RB_MIN(vrf_name_head, &vrfs_by_name);
 	} else {
 		vrfp = RB_NEXT(vrf_name_head, vrfp);
@@ -1113,20 +1111,19 @@ static const void *lib_vrf_get_next(const void *parent_list_entry,
 	return vrfp;
 }
 
-static int lib_vrf_get_keys(const void *list_entry, struct yang_list_keys *keys)
+static int lib_vrf_get_keys(struct nb_cb_get_keys_args *args)
 {
-	struct vrf *vrfp = (struct vrf *)list_entry;
+	struct vrf *vrfp = (struct vrf *)args->list_entry;
 
-	keys->num = 1;
-	strlcpy(keys->key[0], vrfp->name, sizeof(keys->key[0]));
+	args->keys->num = 1;
+	strlcpy(args->keys->key[0], vrfp->name, sizeof(args->keys->key[0]));
 
 	return NB_OK;
 }
 
-static const void *lib_vrf_lookup_entry(const void *parent_list_entry,
-					const struct yang_list_keys *keys)
+static const void *lib_vrf_lookup_entry(struct nb_cb_lookup_entry_args *args)
 {
-	const char *vrfname = keys->key[0];
+	const char *vrfname = args->keys->key[0];
 
 	struct vrf *vrf = vrf_lookup_by_name(vrfname);
 
@@ -1136,25 +1133,25 @@ static const void *lib_vrf_lookup_entry(const void *parent_list_entry,
 /*
  * XPath: /frr-vrf:lib/vrf/id
  */
-static struct yang_data *lib_vrf_state_id_get_elem(const char *xpath,
-						   const void *list_entry)
+static struct yang_data *
+lib_vrf_state_id_get_elem(struct nb_cb_get_elem_args *args)
 {
-	struct vrf *vrfp = (struct vrf *)list_entry;
+	struct vrf *vrfp = (struct vrf *)args->list_entry;
 
-	return yang_data_new_uint32(xpath, vrfp->vrf_id);
+	return yang_data_new_uint32(args->xpath, vrfp->vrf_id);
 }
 
 /*
  * XPath: /frr-vrf:lib/vrf/active
  */
-static struct yang_data *lib_vrf_state_active_get_elem(const char *xpath,
-						       const void *list_entry)
+static struct yang_data *
+lib_vrf_state_active_get_elem(struct nb_cb_get_elem_args *args)
 {
-	struct vrf *vrfp = (struct vrf *)list_entry;
+	struct vrf *vrfp = (struct vrf *)args->list_entry;
 
 	if (vrfp->status == VRF_ACTIVE)
 		return yang_data_new_bool(
-			xpath, vrfp->status == VRF_ACTIVE ? true : false);
+			args->xpath, vrfp->status == VRF_ACTIVE ? true : false);
 
 	return NULL;
 }