kconfig: Document the 'menu' struct

Understanding what it represents helps a lot when reading the code, and it's not obvious, so document it.

The ROOT_MENU flag is only set and tested by the gconf and qconf front ends, so leave it undocumented here. The obvious guess for what it means is correct.

Signed-off-by Ulf Magnusson <[email protected]>

---
 scripts/kconfig/expr.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

scripts/kconfig/expr.h +45 -1

index a73f762..ae7583c 100644
@@ -166,22 +166,67 @@ struct property {
        for (st = sym->prop; st; st = st->next) \
                if (st->text)
 
+/*
+ * Represents a node in the menu tree, as seen in e.g. menuconfig (though used
+ * for all front ends). Each symbol, menu, etc. defined in the Kconfig files
+ * gets a node. A symbol defined in multiple locations gets one node at each
+ * location.
+ */
 struct menu {
+       /* The next menu node at the same level */
        struct menu *next;
+
+       /* The parent menu node, corresponding to e.g. a menu or choice */
        struct menu *parent;
+
+       /* The first child menu node, for e.g. menus and choices */
        struct menu *list;
+
+       /*
+        * The symbol associated with the menu node. Choices are implemented as
+        * a special kind of symbol. NULL for menus, comments, and ifs.
+        */
        struct symbol *sym;
+
+       /*
+        * The prompt associated with the node. This holds the prompt for a
+        * symbol as well as the text for a menu or comment, along with the
+        * type (P_PROMPT, P_MENU, etc.)
+        */
        struct property *prompt;
+
+       /*
+        * 'visible if' dependencies. If more than one is given, they will be
+        * ANDed together.
+        */
        struct expr *visibility;
+
+       /*
+        * Ordinary dependencies from e.g. 'depends on' and 'if', ANDed
+        * together
+        */
        struct expr *dep;
+
+       /* MENU_* flags */
        unsigned int flags;
+
+       /* Any help text associated with the node */
        char *help;
+
+       /* The location where the menu node appears in the Kconfig files */
        struct file *file;
        int lineno;
+
+       /* For use by front ends that need to store auxiliary data */
        void *data;
 };
 
+/*
+ * Set on a menu node when the corresponding symbol changes state in some way.
+ * Can be checked by front ends.
+ */
 #define MENU_CHANGED           0x0001
+
 #define MENU_ROOT              0x0002
 
 struct jump_key {
--

2.7.4

Understanding what it represents helps a lot when reading the code, and it's not obvious, so document it.

The ROOT_MENU flag is only set and tested by the gconf and qconf front ends, so leave it undocumented here. The obvious guess for what it means is correct.

Signed-off-by Ulf Magnusson <[email protected]>