text-based mount.nfs: Fix po_rightmost() enum return values

Neil observed that po_rightmost() now returns enum values from both

enum {
	PO_NOT_FOUND = 0,
	PO_FOUND = 1,
}

and

enum {
	PO_KEY2_RIGHTMOST = 1,
	PO_KEY1_RIGHTMOST = -1,
}

It would be cleaner to use a single enum for po_rightmost()'s return value.

We take the next logical step and create specific types for the return
values in order to ensure we don't mix the enum values, and to document
explicitly what return values callers can expect.

This could have been a simpler patch, but I think the end result is a
cleaner overall parser API.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 13 insertions, 12 deletions

diff --git a/utils/mount/parse_opt.h b/utils/mount/parse_opt.h
index 6b9fb5e..e7924dd 100644
--- a/utils/mount/parse_opt.h
+++ b/utils/mount/parse_opt.h
@@ -21,31 +21,32 @@
  *
  */
 
-enum {
+typedef enum {
 	PO_FAILED = 0,
 	PO_SUCCEEDED = 1,
-};
+} po_return_t;
 
-enum {
+typedef enum {
 	PO_NOT_FOUND = 0,
 	PO_FOUND = 1,
-};
+} po_found_t;
 
-enum {
-	PO_KEY2_RIGHTMOST = 1,
+typedef enum {
 	PO_KEY1_RIGHTMOST = -1,
-};
+	PO_NEITHER_FOUND = 0,
+	PO_KEY2_RIGHTMOST = 1,
+} po_rightmost_t;
 
 struct mount_options;
 
 struct mount_options *	po_split(char *);
 void			po_replace(struct mount_options *,
 				   struct mount_options *);
-int			po_join(struct mount_options *, char **);
+po_return_t		po_join(struct mount_options *, char **);
 
-int			po_append(struct mount_options *, char *);
-int			po_contains(struct mount_options *, char *);
+po_return_t		po_append(struct mount_options *, char *);
+po_found_t		po_contains(struct mount_options *, char *);
 char *			po_get(struct mount_options *, char *);
-int			po_rightmost(struct mount_options *, char *, char *);
-int			po_remove_all(struct mount_options *, char *);
+po_rightmost_t		po_rightmost(struct mount_options *, char *, char *);
+po_found_t		po_remove_all(struct mount_options *, char *);
 void			po_destroy(struct mount_options *);