lib: rework the yang schema node iteration functions

* Rename yang_snodes_iterate() to yang_snodes_iterate_subtree() and
  expose it in the public API.
* Rename yang_module_snodes_iterate() to yang_snodes_iterate_module().
* Rename yang_all_snodes_iterate() to yang_snodes_iterate_all().
* Make it possible to stop the iteration at any time by returning
  YANG_ITER_STOP in the iteration callbacks.
* Make the iteration callbacks accept only one user argument and not
  two.

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

1 files changed, 59 insertions, 27 deletions

diff --git a/lib/yang.h b/lib/yang.h
index aa08654ab..940f5d38e 100644
--- a/lib/yang.h
+++ b/lib/yang.h
@@ -86,14 +86,26 @@ enum yang_path_type {
 	YANG_PATH_DATA,
 };
 
-/* Filter non-presence containers. */
-#define YANG_ITER_FILTER_NPCONTAINERS 0x0001
-/* Filter list keys (leafs). */
-#define YANG_ITER_FILTER_LIST_KEYS 0x0002
-/* Filter RPC input/output nodes. */
-#define YANG_ITER_FILTER_INPUT_OUTPUT 0x0004
-/* Filter implicitely created nodes. */
-#define YANG_ITER_FILTER_IMPLICIT 0x0008
+enum yang_iter_flags {
+	/* Filter non-presence containers. */
+	YANG_ITER_FILTER_NPCONTAINERS = (1<<0),
+
+	/* Filter list keys (leafs). */
+	YANG_ITER_FILTER_LIST_KEYS = (1<<1),
+
+	/* Filter RPC input/output nodes. */
+	YANG_ITER_FILTER_INPUT_OUTPUT = (1<<2),
+
+	/* Filter implicitely created nodes. */
+	YANG_ITER_FILTER_IMPLICIT = (1<<3),
+};
+
+/* Callback used by the yang_snodes_iterate_*() family of functions. */
+typedef int (*yang_iterate_cb)(const struct lys_node *snode, void *arg);
+
+/* Return values of the 'yang_iterate_cb' callback. */
+#define YANG_ITER_CONTINUE 0
+#define YANG_ITER_STOP -1
 
 /* Global libyang context for native FRR models. */
 extern struct ly_ctx *ly_native_ctx;
@@ -141,46 +153,66 @@ extern struct yang_module *yang_module_find(const char *module_name);
 extern void yang_module_embed(struct yang_module_embed *embed);
 
 /*
+ * Iterate recursively over all children of a schema node.
+ *
+ * snode
+ *    YANG schema node to operate on.
+ *
+ * cb
+ *    Function to call with each schema node.
+ *
+ * flags
+ *    YANG_ITER_* flags to control how the iteration is performed.
+ *
+ * arg
+ *    Arbitrary argument passed as the second parameter in each call to 'cb'.
+ *
+ * Returns:
+ *    The return value of the last called callback.
+ */
+extern int yang_snodes_iterate_subtree(const struct lys_node *snode,
+				       yang_iterate_cb cb, uint16_t flags,
+				       void *arg);
+
+/*
  * Iterate over all libyang schema nodes from the given YANG module.
  *
  * module
  *    YANG module to operate on.
  *
- * func
+ * cb
  *    Function to call with each schema node.
  *
  * flags
- *    YANG_ITER_FILTER_* flags to specify node types that should be filtered.
+ *    YANG_ITER_* flags to control how the iteration is performed.
  *
- * arg1
- *    Arbitrary argument passed as the second parameter in each call to 'func'.
+ * arg
+ *    Arbitrary argument passed as the second parameter in each call to 'cb'.
  *
- * arg2
- *    Arbitrary argument passed as the third parameter in each call to 'func'.
+ * Returns:
+ *    The return value of the last called callback.
  */
-extern void yang_module_snodes_iterate(const struct lys_module *module,
-				       void (*func)(const struct lys_node *,
-						    void *, void *),
-				       uint16_t flags, void *arg1, void *arg2);
+extern int yang_snodes_iterate_module(const struct lys_module *module,
+				      yang_iterate_cb cb, uint16_t flags,
+				      void *arg);
 
 /*
  * Iterate over all libyang schema nodes from all loaded YANG modules.
  *
- * func
+ * cb
  *    Function to call with each schema node.
  *
  * flags
- *    YANG_ITER_FILTER_* flags to specify node types that should be filtered.
+ *    YANG_ITER_* flags to control how the iteration is performed.
  *
- * arg1
- *    Arbitrary argument passed as the second parameter in each call to 'func'.
+ * arg
+ *    Arbitrary argument passed as the second parameter in each call to 'cb'.
  *
- * arg2
- *    Arbitrary argument passed as the third parameter in each call to 'func'.
+ * Returns:
+ *    The return value of the last called callback.
  */
-extern void yang_all_snodes_iterate(void (*func)(const struct lys_node *,
-						 void *, void *),
-				    uint16_t flags, void *arg1, void *arg2);
+extern int yang_snodes_iterate_all(yang_iterate_cb cb, uint16_t flags,
+				   void *arg);
 
 /*
  * Build schema path or data path of the schema node.