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authorPřemysl Janouch <p.janouch@gmail.com>2015-02-11 02:07:52 +0100
committerPřemysl Janouch <p.janouch@gmail.com>2015-02-11 02:07:52 +0100
commitcd1a55a0d1f77aedb078ab9fef96dac94b41c86b (patch)
tree8618c6f854a0f19c87590bdb93f96a4c83566c62 /common.c
parent59b1c5c056269a5151ef7a17cdedf8a3caccfc61 (diff)
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Import option handler from ponymap
Diffstat (limited to 'common.c')
-rw-r--r--common.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/common.c b/common.c
index 8c85b2f..e67f57a 100644
--- a/common.c
+++ b/common.c
@@ -1995,3 +1995,152 @@ call_write_default_config (const char *hint, const struct config_item *table)
print_status ("configuration written to `%s'", filename);
free (filename);
}
+
+// --- Option handler ----------------------------------------------------------
+
+// Simple wrapper for the getopt_long API to make it easier to use and maintain.
+
+#define OPT_USAGE_ALIGNMENT_COLUMN 30 ///< Alignment for option descriptions
+
+enum
+{
+ OPT_OPTIONAL_ARG = (1 << 0), ///< The argument is optional
+ OPT_LONG_ONLY = (1 << 1) ///< Ignore the short name in opt_string
+};
+
+// All options need to have both a short name, and a long name. The short name
+// is what is returned from opt_handler_get(). It is possible to define a value
+// completely out of the character range combined with the OPT_LONG_ONLY flag.
+//
+// When `arg_hint' is defined, the option is assumed to have an argument.
+
+struct opt
+{
+ int short_name; ///< The single-letter name
+ const char *long_name; ///< The long name
+ const char *arg_hint; ///< Option argument hint
+ int flags; ///< Option flags
+ const char *description; ///< Option description
+};
+
+struct opt_handler
+{
+ int argc; ///< The number of program arguments
+ char **argv; ///< Program arguments
+
+ const char *arg_hint; ///< Program arguments hint
+ const char *description; ///< Description of the program
+
+ const struct opt *opts; ///< The list of options
+ size_t opts_len; ///< The length of the option array
+
+ struct option *options; ///< The list of options for getopt
+ char *opt_string; ///< The `optstring' for getopt
+};
+
+static void
+opt_handler_free (struct opt_handler *self)
+{
+ free (self->options);
+ free (self->opt_string);
+}
+
+static void
+opt_handler_init (struct opt_handler *self, int argc, char **argv,
+ const struct opt *opts, const char *arg_hint, const char *description)
+{
+ memset (self, 0, sizeof *self);
+ self->argc = argc;
+ self->argv = argv;
+ self->arg_hint = arg_hint;
+ self->description = description;
+
+ size_t len = 0;
+ for (const struct opt *iter = opts; iter->long_name; iter++)
+ len++;
+
+ self->opts = opts;
+ self->opts_len = len;
+ self->options = xcalloc (len + 1, sizeof *self->options);
+
+ struct str opt_string;
+ str_init (&opt_string);
+
+ for (size_t i = 0; i < len; i++)
+ {
+ const struct opt *opt = opts + i;
+ struct option *mapped = self->options + i;
+
+ mapped->name = opt->long_name;
+ if (!opt->arg_hint)
+ mapped->has_arg = no_argument;
+ else if (opt->flags & OPT_OPTIONAL_ARG)
+ mapped->has_arg = optional_argument;
+ else
+ mapped->has_arg = required_argument;
+ mapped->val = opt->short_name;
+
+ if (opt->flags & OPT_LONG_ONLY)
+ continue;
+
+ str_append_c (&opt_string, opt->short_name);
+ if (opt->arg_hint)
+ {
+ str_append_c (&opt_string, ':');
+ if (opt->flags & OPT_OPTIONAL_ARG)
+ str_append_c (&opt_string, ':');
+ }
+ }
+
+ self->opt_string = str_steal (&opt_string);
+}
+
+static void
+opt_handler_usage (struct opt_handler *self, FILE *stream)
+{
+ struct str usage;
+ str_init (&usage);
+
+ str_append_printf (&usage, "Usage: %s [OPTION]... %s\n",
+ self->argv[0], self->arg_hint ? self->arg_hint : "");
+ str_append_printf (&usage, "%s\n\n", self->description);
+
+ for (size_t i = 0; i < self->opts_len; i++)
+ {
+ struct str row;
+ str_init (&row);
+
+ const struct opt *opt = self->opts + i;
+ if (!(opt->flags & OPT_LONG_ONLY))
+ str_append_printf (&row, " -%c, ", opt->short_name);
+ else
+ str_append (&row, " ");
+ str_append_printf (&row, "--%s", opt->long_name);
+ if (opt->arg_hint)
+ str_append_printf (&row, (opt->flags & OPT_OPTIONAL_ARG)
+ ? " [%s]" : " %s", opt->arg_hint);
+
+ // TODO: keep the indent if there are multiple lines
+ if (row.len + 2 <= OPT_USAGE_ALIGNMENT_COLUMN)
+ {
+ str_append (&row, " ");
+ str_append_printf (&usage, "%-*s%s\n",
+ OPT_USAGE_ALIGNMENT_COLUMN, row.str, opt->description);
+ }
+ else
+ str_append_printf (&usage, "%s\n%-*s%s\n", row.str,
+ OPT_USAGE_ALIGNMENT_COLUMN, "", opt->description);
+
+ str_free (&row);
+ }
+
+ fputs (usage.str, stream);
+ str_free (&usage);
+}
+
+static int
+opt_handler_get (struct opt_handler *self)
+{
+ return getopt_long (self->argc, self->argv,
+ self->opt_string, self->options, NULL);
+}