data: add unlink function

This patch adds unlink function from libyang to allow
proper node cleanup procedure.

Fixes: #84
Signed-off-by: Stefan Gula <steweg@gmail.com>
Signed-off-by: Samuel Gauthier <samuel.gauthier@6wind.com>

Author: steweg

cffi/cdefs.h

@@ -267,6 +267,8 @@ LY_ERR lys_set_implemented(struct lys_module *,	const char **);
 #define LYD_NEW_PATH_CANON_VALUE ...
 LY_ERR lyd_new_path(struct lyd_node *, const struct ly_ctx *, const char *, const char *, uint32_t, struct lyd_node **);
 LY_ERR lyd_find_xpath(const struct lyd_node *, const char *, struct ly_set **);
+void lyd_unlink_siblings(struct lyd_node *node);
+void lyd_unlink_tree(struct lyd_node *node);
 void lyd_free_all(struct lyd_node *node);
 void lyd_free_tree(struct lyd_node *node);
 

libyang/data.py

@@ -868,6 +868,12 @@ def merge_data_dict(
             rpcreply=rpcreply,
         )
 
+    def unlink(self, with_siblings: bool = False) -> None:
+        if with_siblings:
+            lib.lyd_unlink_siblings(self.cdata)
+        else:
+            lib.lyd_unlink_tree(self.cdata)
+
     def free_internal(self, with_siblings: bool = True) -> None:
         if with_siblings:
             lib.lyd_free_all(self.cdata)

tests/test_data.py

@@ -881,3 +881,19 @@ def test_dnode_double_free(self):
         dnode = self.ctx.parse_data_mem(self.JSON_CONFIG, "json", validate_present=True)
         dnode.free()
         dnode.free()
+
+    def test_dnode_unlink(self):
+        dnode = self.ctx.parse_data_mem(self.JSON_CONFIG, "json", validate_present=True)
+        self.assertIsInstance(dnode, DContainer)
+        try:
+            child = dnode.find_one("hostname")
+            self.assertIsInstance(child, DNode)
+            child.unlink(with_siblings=False)
+            self.assertIsNone(dnode.find_one("hostname"))
+            child = next(dnode.children(), None)
+            self.assertIsNot(child, None)
+            child.unlink(with_siblings=True)
+            child = next(dnode.children(), None)
+            self.assertIsNone(child, None)
+        finally:
+            dnode.free()