data: adding ability to get target_nodes

This patch introduces target_nodes API, which allows user
to get all target data nodes that current leafref node is pointing
to

Signed-off-by: Stefan Gula <steweg@gmail.com>

Author: steweg

libyang/data.py

@@ -1015,7 +1015,7 @@ def leafref_link_node_tree(self) -> None:
 
     def leafref_nodes(self) -> Iterator["DNode"]:
         """
-        Gets the leafref links record for given node.
+        Gets the nodes that are referring to this node.
 
         Requires leafref_linking to be set on the libyang context.
         """
@@ -1026,6 +1026,19 @@ def leafref_nodes(self) -> Iterator["DNode"]:
         for n in ly_array_iter(out[0].leafref_nodes):
             yield DNode.new(self.context, n)
 
+    def target_nodes(self) -> Iterator["DNode"]:
+        """
+        Gets the target nodes that are referred by this node.
+
+        Requires leafref_linking to be set on the libyang context.
+        """
+        term_node = ffi.cast("struct lyd_node_term *", self.cdata)
+        out = ffi.new("const struct lyd_leafref_links_rec **")
+        if lib.lyd_leafref_get_links(term_node, out) != lib.LY_SUCCESS:
+            return
+        for n in ly_array_iter(out[0].target_nodes):
+            yield DNode.new(self.context, n)
+
     def __repr__(self):
         cls = self.__class__
         return "<%s.%s: %s>" % (cls.__module__, cls.__name__, str(self))

tests/test_data.py

@@ -1092,6 +1092,9 @@ def test_dnode_leafref_linking(self):
         dnode4 = next(dnode3.leafref_nodes())
         self.assertIsInstance(dnode4, DLeaf)
         self.assertEqual(dnode4.cdata, dnode2.cdata)
+        dnode5 = next(dnode4.target_nodes())
+        self.assertIsInstance(dnode5, DLeaf)
+        self.assertEqual(dnode5.cdata, dnode3.cdata)
         dnode1.free()
 
     def test_dnode_store_only(self):