lib: northbound cli support to end config nodes

Some more complex CLI usages will require northbound to support
signalizing a custom configuration node end.

For an example:

```
router bgp 100
 bgp router-id 10.254.254.1
 neighbor 10.0.0.100 remote-as 200
 !
 address-family ipv4 unicast
  network 10.0.1.0/24
  network 10.0.2.0/24
  network 10.0.3.0/24
 exit-address-family
 !
 address-family ipv6 unicast
  neighbor 10.0.0.100 activate
 exit-address-family
!
```

This commit implements a new callback called `cli_show_end` which
complements `cli_show` and is only called at the end of processing the
yang configuration node. It will be used to write the configuration
node termination like: "!" or "exit-address-family".

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

diff --git a/lib/northbound.h b/lib/northbound.h
index 8f6753506b9de2cf3c942511291e4e5416197097..69d7c8e0ee68e5ce19bb0bb8eab80cc6b3553b2e 100644 (file)
--- a/lib/northbound.h
+++ b/lib/northbound.h
@@ -337,6 +337,27 @@ struct nb_callbacks {
         */
        void (*cli_show)(struct vty *vty, struct lyd_node *dnode,
                         bool show_defaults);
+
+       /*
+        * Optional callback to show the CLI node end for lists or containers.
+        *
+        * vty
+        *    The vty terminal to dump the configuration to.
+        *
+        * dnode
+        *    libyang data node that should be shown in the form of a CLI
+        *    command.
+        *
+        * show_defaults
+        *    Specify whether to display default configuration values or not.
+        *    This parameter can be ignored most of the time since the
+        *    northbound doesn't call this callback for default leaves or
+        *    non-presence containers that contain only default child nodes.
+        *    The exception are commands associated to multiple configuration
+        *    nodes, in which case it might be desirable to hide one or more
+        *    parts of the command when this parameter is set to false.
+        */
+       void (*cli_show_end)(struct vty *vty, struct lyd_node *dnode);
 };
 
 /*

diff --git a/lib/northbound_cli.c b/lib/northbound_cli.c
index 7b7b526af02a52a64f66b98b3f1454341d1c182a..c96bfbdb9193f36dba0c13469112d3c6e835dc74 100644 (file)
--- a/lib/northbound_cli.c
+++ b/lib/northbound_cli.c
@@ -434,10 +434,29 @@ static int nb_cli_candidate_load_transaction(struct vty *vty,
        return CMD_SUCCESS;
 }
 
+/*
+ * ly_iter_next_is_up: detects when iterating up on the yang model.
+ *
+ * This function detects whether next node in the iteration is upwards,
+ * then return the node otherwise return NULL.
+ */
+static struct lyd_node *ly_iter_next_up(struct lyd_node *elem)
+{
+       /* Are we going downwards? Is this still not a leaf? */
+       if (!(elem->schema->nodetype & (LYS_LEAF | LYS_LEAFLIST | LYS_ANYDATA)))
+               return NULL;
+
+       /* Are there still leaves in this branch? */
+       if (elem->next != NULL)
+               return NULL;
+
+       return elem->parent;
+}
+
 void nb_cli_show_dnode_cmds(struct vty *vty, struct lyd_node *root,
                            bool with_defaults)
 {
-       struct lyd_node *next, *child;
+       struct lyd_node *next, *child, *parent;
 
        LY_TREE_DFS_BEGIN (root, next, child) {
                struct nb_node *nb_node;
@@ -452,6 +471,19 @@ void nb_cli_show_dnode_cmds(struct vty *vty, struct lyd_node *root,
 
                (*nb_node->cbs.cli_show)(vty, child, with_defaults);
        next:
+               /*
+                * When transiting upwards in the yang model we should
+                * give the previous container/list node a chance to
+                * print its close vty output (e.g. "!" or "end-family"
+                * etc...).
+                */
+               parent = ly_iter_next_up(child);
+               if (parent != NULL) {
+                       nb_node = parent->schema->priv;
+                       if (nb_node->cbs.cli_show_end)
+                               (*nb_node->cbs.cli_show_end)(vty, parent);
+               }
+
                LY_TREE_DFS_END(root, next, child);
        }
 }