[PATCH 1/2] btrfs-progs: Make option parsing more robust to code modifications

[Hugo Mills <hugo@carfax.org.uk>]

The current approach to option parsing, where long-only options are
selected on the basis of their position in the long_options array is
fragile and painful to modify if options are to be inserted into the
list, rather than appended.

Instead, use the last field of struct option to return a value which
cannot be a char (and hence a short option), and simply switch on those
within the case statement.

Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
---
 cmds-check.c | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/cmds-check.c b/cmds-check.c
index f06e029..a1226c6 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -8403,13 +8403,15 @@ out:
 	return bad_roots;
 }
 
+enum { OPT_REPAIR = 257, OPT_INIT_CSUM, OPT_INIT_EXTENT, OPT_CHECK_CSUM };
+
 static struct option long_options[] = {
 	{ "super", 1, NULL, 's' },
-	{ "repair", 0, NULL, 0 },
-	{ "init-csum-tree", 0, NULL, 0 },
-	{ "init-extent-tree", 0, NULL, 0 },
-	{ "check-data-csum", 0, NULL, 0 },
-	{ "backup", 0, NULL, 0 },
+	{ "repair", 0, NULL, OPT_REPAIR },
+	{ "init-csum-tree", 0, NULL, OPT_INIT_CSUM },
+	{ "init-extent-tree", 0, NULL, OPT_INIT_EXTENT },
+	{ "check-data-csum", 0, NULL, OPT_CHECK_CSUM },
+	{ "backup", 0, NULL, 'b' },
 	{ "subvol-extents", 1, NULL, 'E' },
 	{ "qgroup-report", 0, NULL, 'Q' },
 	{ "tree-root", 1, NULL, 'r' },
@@ -8483,23 +8485,26 @@ int cmd_check(int argc, char **argv)
 			case '?':
 			case 'h':
 				usage(cmd_check_usage);
-		}
-		if (option_index == 1) {
-			printf("enabling repair mode\n");
-			repair = 1;
-			ctree_flags |= OPEN_CTREE_WRITES;
-		} else if (option_index == 2) {
-			printf("Creating a new CRC tree\n");
-			init_csum_tree = 1;
-			repair = 1;
-			ctree_flags |= OPEN_CTREE_WRITES;
-		} else if (option_index == 3) {
-			init_extent_tree = 1;
-			ctree_flags |= (OPEN_CTREE_WRITES |
-					OPEN_CTREE_NO_BLOCK_GROUPS);
-			repair = 1;
-		} else if (option_index == 4) {
-			check_data_csum = 1;
+			case OPT_REPAIR:
+				printf("enabling repair mode\n");
+				repair = 1;
+				ctree_flags |= OPEN_CTREE_WRITES;
+				break;
+			case OPT_INIT_CSUM:
+				printf("Creating a new CRC tree\n");
+				init_csum_tree = 1;
+				repair = 1;
+				ctree_flags |= OPEN_CTREE_WRITES;
+				break;
+			case OPT_INIT_EXTENT:
+				init_extent_tree = 1;
+				ctree_flags |= (OPEN_CTREE_WRITES |
+						OPEN_CTREE_NO_BLOCK_GROUPS);
+				repair = 1;
+				break;
+			case OPT_CHECK_CSUM:
+				check_data_csum = 1;
+				break;
 		}
 	}
 	argc = argc - optind;
-- 
2.1.4