parse-options.c

   1 #include "git-compat-util.h"
   2 #include "parse-options.h"
   3
   4 #define OPT_SHORT 1
   5 #define OPT_UNSET 2
   6
   7 struct optparse_t {
   8         const char **argv;
   9         int argc;
  10         const char *opt;
  11 };
  12
  13 static inline const char *get_arg(struct optparse_t *p)
  14 {
  15         if (p->opt) {
  16                 const char *res = p->opt;
  17                 p->opt = NULL;
  18                 return res;
  19         }
  20         p->argc--;
  21         return *++p->argv;
  22 }
  23
  24 static inline const char *skip_prefix(const char *str, const char *prefix)
  25 {
  26         size_t len = strlen(prefix);
  27         return strncmp(str, prefix, len) ? NULL : str + len;
  28 }
  29
  30 static int opterror(const struct option *opt, const char *reason, int flags)
  31 {
  32         if (flags & OPT_SHORT)
  33                 return error("switch `%c' %s", opt->short_name, reason);
  34         if (flags & OPT_UNSET)
  35                 return error("option `no-%s' %s", opt->long_name, reason);
  36         return error("option `%s' %s", opt->long_name, reason);
  37 }
  38
  39 static int get_value(struct optparse_t *p,
  40                      const struct option *opt, int flags)
  41 {
  42         const char *s;
  43
  44         if (p->opt && (flags & OPT_UNSET))
  45                 return opterror(opt, "takes no value", flags);
  46
  47         switch (opt->type) {
  48         case OPTION_BOOLEAN:
  49                 if (!(flags & OPT_SHORT) && p->opt)
  50                         return opterror(opt, "takes no value", flags);
  51                 if (flags & OPT_UNSET)
  52                         *(int *)opt->value = 0;
  53                 else
  54                         (*(int *)opt->value)++;
  55                 return 0;
  56
  57         case OPTION_STRING:
  58                 if (flags & OPT_UNSET) {
  59                         *(const char **)opt->value = (const char *)NULL;
  60                         return 0;
  61                 }
  62                 if (!p->opt && p->argc <= 1)
  63                         return opterror(opt, "requires a value", flags);
  64                 *(const char **)opt->value = get_arg(p);
  65                 return 0;
  66
  67         case OPTION_INTEGER:
  68                 if (flags & OPT_UNSET) {
  69                         *(int *)opt->value = 0;
  70                         return 0;
  71                 }
  72                 if (!p->opt && p->argc <= 1)
  73                         return opterror(opt, "requires a value", flags);
  74                 *(int *)opt->value = strtol(get_arg(p), (char **)&s, 10);
  75                 if (*s)
  76                         return opterror(opt, "expects a numerical value", flags);
  77                 return 0;
  78
  79         default:
  80                 die("should not happen, someone must be hit on the forehead");
  81         }
  82 }
  83
  84 static int parse_short_opt(struct optparse_t *p, const struct option *options)
  85 {
  86         for (; options->type != OPTION_END; options++) {
  87                 if (options->short_name == *p->opt) {
  88                         p->opt = p->opt[1] ? p->opt + 1 : NULL;
  89                         return get_value(p, options, OPT_SHORT);
  90                 }
  91         }
  92         return error("unknown switch `%c'", *p->opt);
  93 }
  94
  95 static int parse_long_opt(struct optparse_t *p, const char *arg,
  96                           const struct option *options)
  97 {
  98         for (; options->type != OPTION_END; options++) {
  99                 const char *rest;
 100                 int flags = 0;
 101
 102                 if (!options->long_name)
 103                         continue;
 104
 105                 rest = skip_prefix(arg, options->long_name);
 106                 if (!rest) {
 107                         if (strncmp(arg, "no-", 3))
 108                                 continue;
 109                         flags |= OPT_UNSET;
 110                         rest = skip_prefix(arg + 3, options->long_name);
 111                         if (!rest)
 112                                 continue;
 113                 }
 114                 if (*rest) {
 115                         if (*rest != '=')
 116                                 continue;
 117                         p->opt = rest + 1;
 118                 }
 119                 return get_value(p, options, flags);
 120         }
 121         return error("unknown option `%s'", arg);
 122 }
 123
 124 int parse_options(int argc, const char **argv, const struct option *options,
 125                   const char * const usagestr[], int flags)
 126 {
 127         struct optparse_t args = { argv + 1, argc - 1, NULL };
 128         int j = 0;
 129
 130         for (; args.argc; args.argc--, args.argv++) {
 131                 const char *arg = args.argv[0];
 132
 133                 if (*arg != '-' || !arg[1]) {
 134                         argv[j++] = args.argv[0];
 135                         continue;
 136                 }
 137
 138                 if (arg[1] != '-') {
 139                         args.opt = arg + 1;
 140                         do {
 141                                 if (*args.opt == 'h')
 142                                         usage_with_options(usagestr, options);
 143                                 if (parse_short_opt(&args, options) < 0)
 144                                         usage_with_options(usagestr, options);
 145                         } while (args.opt);
 146                         continue;
 147                 }
 148
 149                 if (!arg[2]) { /* "--" */
 150                         if (!(flags & PARSE_OPT_KEEP_DASHDASH)) {
 151                                 args.argc--;
 152                                 args.argv++;
 153                         }
 154                         break;
 155                 }
 156
 157                 if (!strcmp(arg + 2, "help"))
 158                         usage_with_options(usagestr, options);
 159                 if (parse_long_opt(&args, arg + 2, options))
 160                         usage_with_options(usagestr, options);
 161         }
 162
 163         memmove(argv + j, args.argv, args.argc * sizeof(*argv));
 164         argv[j + args.argc] = NULL;
 165         return j + args.argc;
 166 }
 167
 168 #define USAGE_OPTS_WIDTH 24
 169 #define USAGE_GAP         2
 170
 171 void usage_with_options(const char * const *usagestr,
 172                         const struct option *opts)
 173 {
 174         fprintf(stderr, "usage: %s\n", *usagestr++);
 175         while (*usagestr && **usagestr)
 176                 fprintf(stderr, "   or: %s\n", *usagestr++);
 177         while (*usagestr)
 178                 fprintf(stderr, "    %s\n", *usagestr++);
 179
 180         if (opts->type != OPTION_GROUP)
 181                 fputc('\n', stderr);
 182
 183         for (; opts->type != OPTION_END; opts++) {
 184                 size_t pos;
 185                 int pad;
 186
 187                 if (opts->type == OPTION_GROUP) {
 188                         fputc('\n', stderr);
 189                         if (*opts->help)
 190                                 fprintf(stderr, "%s\n", opts->help);
 191                         continue;
 192                 }
 193
 194                 pos = fprintf(stderr, "    ");
 195                 if (opts->short_name)
 196                         pos += fprintf(stderr, "-%c", opts->short_name);
 197                 if (opts->long_name && opts->short_name)
 198                         pos += fprintf(stderr, ", ");
 199                 if (opts->long_name)
 200                         pos += fprintf(stderr, "--%s", opts->long_name);
 201
 202                 switch (opts->type) {
 203                 case OPTION_INTEGER:
 204                         pos += fprintf(stderr, " <n>");
 205                         break;
 206                 case OPTION_STRING:
 207                         if (opts->argh)
 208                                 pos += fprintf(stderr, " <%s>", opts->argh);
 209                         else
 210                                 pos += fprintf(stderr, " ...");
 211                         break;
 212                 default:
 213                         break;
 214                 }
 215
 216                 if (pos <= USAGE_OPTS_WIDTH)
 217                         pad = USAGE_OPTS_WIDTH - pos;
 218                 else {
 219                         fputc('\n', stderr);
 220                         pad = USAGE_OPTS_WIDTH;
 221                 }
 222                 fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
 223         }
 224         fputc('\n', stderr);
 225
 226         exit(129);
 227 }