diff options
Diffstat (limited to 'common.c')
| -rw-r--r-- | common.c | 149 |
1 files changed, 149 insertions, 0 deletions
@@ -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); +} |