include/optutils: add err_exclusive_options()

This is improved implementation of exclusive_option(). The new
implementation:

  - uses regular struct option to compose error messages
  - relationships between options are described in one const static array
  - the current status is stored in one int array

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/include/optutils.h b/include/optutils.h
index fae28fd0d..7819ab360 100644
--- a/include/optutils.h
+++ b/include/optutils.h
@@ -17,6 +17,8 @@ static inline const char *option_to_longopt(int c, const struct option *opts)
 #ifndef OPTUTILS_EXIT_CODE
 # define OPTUTILS_EXIT_CODE EXIT_FAILURE
 #endif
+
+/* deprecated */
 static inline void exclusive_option(int *what, const int how,
 				    const char *errmesg)
 {
@@ -30,5 +32,78 @@ static inline void exclusive_option(int *what, const int how,
 	     _("options %s are mutually exclusive"), errmesg);
 }
 
+/*
+ * Check collisions between options.
+ *
+ * The conflicts between options are described in ul_excl_t array. The
+ * array contains groups of mutually exclusive options. For example
+ *
+ *	static const ul_excl_t excl[] = {
+ *		{ 'Z','b','c' },		// first group
+ *		{ 'b','x' },			// second group
+ *		{ 0 }
+ *	};
+ *
+ *	int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
+ *
+ *	while ((c = getopt_long(argc, argv, "Zbcx", longopts, NULL)) != -1) {
+ *
+ *		err_exclusive_options(c, longopts, excl, excl_st);
+ *
+ *		switch (c) {
+ *		case 'Z':
+ *		   ....
+ *		}
+ *	}
+ *
+ * The array excl[] defines two groups of the mutually exclusive options. The
+ * option '-b' is in the both groups.
+ *
+ * Note that the options in the group have to be in ASCII order (ABC..abc..) and
+ * groups have to be also in ASCII order.
+ *
+ * The current status of options is stored in excl_st array. The size of the array
+ * must be the same as number of the groups in the ul_excl_t array.
+ *
+ * If you're unsure then see sys-utils/mount.c or misc-utils/findmnt.c.
+ */
+#define UL_EXCL_STATUS_INIT	{ 0 }
+typedef int ul_excl_t[16];
+
+static inline void err_exclusive_options(
+			int c,
+			const struct option *opts,
+			const ul_excl_t *excl,
+			int *status)
+{
+	int e;
+
+	for (e = 0; excl[e][0] && excl[e][0] <= c; e++) {
+		const int *op = excl[e];
+
+		for (; *op && *op <= c; op++) {
+			if (*op != c)
+				continue;
+			if (status[e] == 0)
+				status[e] = c;
+			else if (status[e] != c) {
+				fprintf(stderr, _("%s: options "),
+						program_invocation_short_name);
+				for (op = excl[e]; *op; op++) {
+					if (opts)
+						fprintf(stderr, "--%s ",
+							option_to_longopt(*op, opts));
+					else
+						fprintf(stderr, "-%c ", *op);
+				}
+				fprintf(stderr, _("are mutually exclusive."));
+				fputc('\n', stderr);
+				exit(OPTUTILS_EXIT_CODE);
+			}
+			break;
+		}
+	}
+}
+
 #endif