[PATCH 1/2] kconfig: add menu_next() function and menu_for_each(_sub)_entry macros

[PATCH 1/2] kconfig: add menu_next() function and menu_for_each(_sub)_entry macros

[Masahiro Yamada]

Several functions require traversing menu entries sequentially. This
commit introduces some helpers to simplify such operations.

The menu_next() function facilitates depth-first traversal:

 1. Descend to the child level if the current menu has one
 2. Move to the next sibling at the same level if available
 3. Ascend to the parent level if there is no more child or sibling

The menu_for_each_sub_entry() macro iterates over all submenu entries
using depth-first traverse.

The menu_for_each_entry() macro is the same, but over all menu entries.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/kconfig/lkc.h  |  5 +++++
 scripts/kconfig/menu.c | 21 +++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index e7cc9e985c4f..cfb7e9ac41a3 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -79,6 +79,11 @@ void str_printf(struct gstr *gs, const char *fmt, ...);
 char *str_get(struct gstr *gs);
 
 /* menu.c */
+struct menu *menu_next(struct menu *menu, struct menu *root);
+#define menu_for_each_sub_entry(menu, root) \
+	for (menu = menu_next(root, root); menu; menu = menu_next(menu, root))
+#define menu_for_each_entry(menu) \
+	menu_for_each_sub_entry(menu, &rootmenu)
 void _menu_init(void);
 void menu_warn(struct menu *menu, const char *fmt, ...);
 struct menu *menu_add_menu(void);
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 3b822cd110f4..fe6af8700622 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -17,6 +17,27 @@ static const char nohelp_text[] = "There is no help available for this option.";
 struct menu rootmenu;
 static struct menu **last_entry_ptr;
 
+/**
+ * menu_next - return the next menu entry with depth-first traversal
+ * @menu: pointer to the current menu
+ * @root: root of the sub-tree to traverse. If NULL is given, the traveral
+ *        continues until it reaches the end of the entire menu tree.
+ * return: the menu to visit next, or NULL when it reaches the end.
+ */
+struct menu *menu_next(struct menu *menu, struct menu *root)
+{
+	if (menu->list)
+		return menu->list;
+
+	while (menu != root && !menu->next)
+		menu = menu->parent;
+
+	if (menu == root)
+		return NULL;
+
+	return menu->next;
+}
+
 void menu_warn(struct menu *menu, const char *fmt, ...)
 {
 	va_list ap;
-- 
2.40.1

[PATCH 2/2] kconfig: use menu_for_each_entry() to traverse menu tree

[Masahiro Yamada]

Use menu_for_each_entry() to traverse the menu tree instead of
implementing similar logic in each function.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/kconfig/confdata.c | 28 +++++-----------------------
 scripts/kconfig/parser.y   | 13 +------------
 2 files changed, 6 insertions(+), 35 deletions(-)

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 0e35c4819cf1..ce0ef417b71b 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -793,23 +793,19 @@ int conf_write_defconfig(const char *filename)
 
 	sym_clear_all_valid();
 
-	/* Traverse all menus to find all relevant symbols */
-	menu = rootmenu.list;
-
-	while (menu != NULL)
-	{
+	menu_for_each_entry(menu) {
 		sym = menu->sym;
 		if (sym && !sym_is_choice(sym)) {
 			sym_calc_value(sym);
 			if (!(sym->flags & SYMBOL_WRITE))
-				goto next_menu;
+				continue;
 			sym->flags &= ~SYMBOL_WRITE;
 			/* If we cannot change the symbol - skip */
 			if (!sym_is_changeable(sym))
-				goto next_menu;
+				continue;
 			/* If symbol equals to default value - skip */
 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)
-				goto next_menu;
+				continue;
 
 			/*
 			 * If symbol is a choice value and equals to the
@@ -827,25 +823,11 @@ int conf_write_defconfig(const char *filename)
 				if (!sym_is_optional(cs) && sym == ds) {
 					if ((sym->type == S_BOOLEAN) &&
 					    sym_get_tristate_value(sym) == yes)
-						goto next_menu;
+						continue;
 				}
 			}
 			print_symbol_for_dotconfig(out, sym);
 		}
-next_menu:
-		if (menu->list != NULL) {
-			menu = menu->list;
-		}
-		else if (menu->next != NULL) {
-			menu = menu->next;
-		} else {
-			while ((menu = menu->parent)) {
-				if (menu->next != NULL) {
-					menu = menu->next;
-					break;
-				}
-			}
-		}
 	}
 	fclose(out);
 	return 0;
diff --git a/scripts/kconfig/parser.y b/scripts/kconfig/parser.y
index 7fb996612c96..8f339b47fe8d 100644
--- a/scripts/kconfig/parser.y
+++ b/scripts/kconfig/parser.y
@@ -517,20 +517,9 @@ void conf_parse(const char *name)
 
 	menu_finalize();
 
-	menu = &rootmenu;
-	while (menu) {
+	menu_for_each_entry(menu) {
 		if (menu->sym && sym_check_deps(menu->sym))
 			yynerrs++;
-
-		if (menu->list) {
-			menu = menu->list;
-			continue;
-		}
-
-		while (!menu->next && menu->parent)
-			menu = menu->parent;
-
-		menu = menu->next;
 	}
 
 	if (yynerrs)
-- 
2.40.1