[PATCH net-next v2 2/6] tools: ynl: convert enum selector to string for sub-message parsing

[Hangbin Liu <hangbin.liu@linux.dev>]

From: Hangbin Liu <liuhangbin@kylinos.cn>

YNL sub-message parsing expects a string selector for strcmp(). So for
non-external enum selectors, convert the integer value to its string form
via the family's {enum}_str() helper. This enables correct decoding of
sub-messages keyed by enum values.

After change, the new generated code looks like

	const char *encap_type_str;
	encap_type_str = rt_route_encap_type_str(dst->encap_type);
	if (!encap_type_str)
		return ynl_submsg_failed(yarg, "encap", "encap-type");
	if (rt_route_encap_data_parse(&parg, encap_type_str, attr))
		return YNL_PARSE_CB_ERROR;

Signed-off-by: Hangbin Liu <liuhangbin@kylinos.cn>
---
 tools/net/ynl/pyynl/ynl_gen_c.py | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index 2b3483db1b60..785e747e5865 100755
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -951,10 +951,22 @@ class TypeSubMessage(TypeNest):
             sel_var = f"_sel_{sel}"
         else:
             sel_var = f"{var}->{sel}"
-        get_lines = [f'if (!{sel_var})',
-                     f'return ynl_submsg_failed(yarg, "{self.name}", "{selector}");',
-                     f"if ({self.nested_render_name}_parse(&parg, {sel_var}, attr))",
-                     "return YNL_PARSE_CB_ERROR;"]
+
+        parse_sel = sel_var
+        get_lines = []
+        if not self.selector.is_external() and self.selector.attr and \
+           "enum" in self.selector.attr.attr:
+            enum_name = self.selector.attr.attr["enum"]
+            str_fn = c_lower(self.family.ident_name + "-" + enum_name) + "_str"
+            sel_str_var = f"{sel}_str"
+            get_lines += [f'const char *{sel_str_var};',
+                          f'{sel_str_var} = {str_fn}({sel_var});']
+            parse_sel = sel_str_var
+
+        get_lines += [f'if (!{parse_sel})',
+                      f'return ynl_submsg_failed(yarg, "{self.name}", "{selector}");',
+                      f"if ({self.nested_render_name}_parse(&parg, {parse_sel}, attr))",
+                      "return YNL_PARSE_CB_ERROR;"]
         init_lines = [f"parg.rsp_policy = &{self.nested_render_name}_nest;",
                       f"parg.data = &{var}->{self.c_name};"]
         return get_lines, init_lines, None

-- 
2.55.0