src/argpar/argpar.h

   1 #ifndef BABELTRACE_ARGPAR_H
   2 #define BABELTRACE_ARGPAR_H
   3
   4 /*
   5  * Copyright 2019 Philippe Proulx <pproulx@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  */
  25
  26 #include <stdbool.h>
  27
  28 /* Sentinel for an option descriptor array */
  29 #define ARGPAR_OPT_DESCR_SENTINEL       { -1, '\0', NULL, false }
  30
  31 /*
  32  * ARGPAR_HIDDEN: if argpar is used in some shared library, we don't want them
  33  * to be exported by that library, so mark them as "hidden".
  34  *
  35  * On Windows, symbols are local unless explicitly exported,
  36  * see https://gcc.gnu.org/wiki/Visibility
  37  */
  38 #if defined(_WIN32) || defined(__CYGWIN__)
  39 #define ARGPAR_HIDDEN
  40 #else
  41 #define ARGPAR_HIDDEN __attribute__((visibility("hidden")))
  42 #endif
  43
  44 /* Option descriptor */
  45 struct argpar_opt_descr {
  46         /* Numeric ID for this option */
  47         const int id;
  48
  49         /* Short option character, or `\0` */
  50         const char short_name;
  51
  52         /* Long option name (without `--`), or `NULL` */
  53         const char * const long_name;
  54
  55         /* True if this option has an argument */
  56         const bool with_arg;
  57 };
  58
  59 /* Item type */
  60 enum argpar_item_type {
  61         /* Option */
  62         ARGPAR_ITEM_TYPE_OPT,
  63
  64         /* Non-option */
  65         ARGPAR_ITEM_TYPE_NON_OPT,
  66 };
  67
  68 /* Base item */
  69 struct argpar_item {
  70         enum argpar_item_type type;
  71 };
  72
  73 /* Option item */
  74 struct argpar_item_opt {
  75         struct argpar_item base;
  76
  77         /* Corresponding descriptor */
  78         const struct argpar_opt_descr *descr;
  79
  80         /* Argument, or `NULL` if none */
  81         const char *arg;
  82 };
  83
  84 /* Non-option item */
  85 struct argpar_item_non_opt {
  86         struct argpar_item base;
  87
  88         /*
  89          * Complete argument, pointing to one of the entries of the
  90          * original arguments (`argv`).
  91          */
  92         const char *arg;
  93
  94         /* Index of this argument amongst all original arguments (`argv`) */
  95         unsigned int orig_index;
  96
  97         /* Index of this argument amongst other non-option arguments */
  98         unsigned int non_opt_index;
  99 };
 100
 101 struct argpar_item_array {
 102         /* Array of `struct argpar_item *`, or `NULL` on error */
 103         struct argpar_item **items;
 104
 105         /* Number of used slots in `items`. */
 106         unsigned int n_items;
 107
 108         /* Number of allocated slots in `items`. */
 109         unsigned int n_alloc;
 110 };
 111
 112 /* What is returned by argpar_parse() */
 113 struct argpar_parse_ret {
 114         /* Array of `struct argpar_item *`, or `NULL` on error */
 115         struct argpar_item_array *items;
 116
 117         /* Error string, or `NULL` if none */
 118         char *error;
 119
 120         /* Number of original arguments (`argv`) ingested */
 121         unsigned int ingested_orig_args;
 122 };
 123
 124 /*
 125  * Parses the arguments `argv` of which the count is `argc` using the
 126  * sentinel-terminated (use `ARGPAR_OPT_DESCR_SENTINEL`) option
 127  * descriptor array `descrs`.
 128  *
 129  * This function considers ALL the elements of `argv`, including the
 130  * first one, so that you would typically pass `argc - 1` and
 131  * `&argv[1]` from what main() receives.
 132  *
 133  * This argument parser supports:
 134  *
 135  * * Short options without an argument, possibly tied together:
 136  *
 137  *       -f -auf -n
 138  *
 139  * * Short options with argument:
 140  *
 141  *       -b 45 -f/mein/file -xyzhello
 142  *
 143  * * Long options without an argument:
 144  *
 145  *       --five-guys --burger-king --pizza-hut --subway
 146  *
 147  * * Long options with arguments:
 148  *
 149  *       --security enable --time=18.56
 150  *
 151  * * Non-option arguments (anything else).
 152  *
 153  * This function does not accept `-` or `--` as arguments. The latter
 154  * means "end of options" for many command-line tools, but this function
 155  * is all about keeping the order of the arguments, so it does not mean
 156  * much to put them at the end. This has the side effect that a
 157  * non-option argument cannot have the form of an option, for example if
 158  * you need to pass the exact relative path `--component`. In that case,
 159  * you would need to pass `./--component`. There's no generic way to
 160  * escape `-` for the moment.
 161  *
 162  * This function accepts duplicate options (the resulting array of items
 163  * contains one entry for each instance).
 164  *
 165  * On success, this function returns an array of items
 166  * (`struct argpar_item *`). Each item is to be casted to the
 167  * appropriate type (`struct argpar_item_opt *` or
 168  * `struct argpar_item_non_opt *`) depending on its type.
 169  *
 170  * The returned array contains the items in the same order that the
 171  * arguments were parsed, including non-option arguments. This means,
 172  * for example, that for
 173  *
 174  *     --hello --meow=23 /path/to/file -b
 175  *
 176  * the function returns an array of four items: two options, one
 177  * non-option, and one option.
 178  *
 179  * In the returned structure, `ingested_orig_args` is the number of
 180  * ingested arguments within `argv` to produce the resulting array of
 181  * items. If `fail_on_unknown_opt` is true, then on success
 182  * `ingested_orig_args` is equal to `argc`. Otherwise,
 183  * `ingested_orig_args` contains the number of original arguments until
 184  * an unknown _option_ occurs. For example, with
 185  *
 186  *     --great --white contact nuance --shark nuclear
 187  *
 188  * if `--shark` is not described within `descrs` and
 189  * `fail_on_unknown_opt` is false, then `ingested_orig_args` is 4 (two
 190  * options, two non-options), whereas `argc` is 6.
 191  *
 192  * This makes it possible to know where a command name is, for example.
 193  * With those arguments:
 194  *
 195  *     --verbose --stuff=23 do-something --specific-opt -f -b
 196  *
 197  * and the descriptors for `--verbose` and `--stuff` only, the function
 198  * returns the `--verbose` and `--stuff` option items, the
 199  * `do-something` non-option item, and that three original arguments
 200  * were ingested. This means you can start the next argument parsing
 201  * stage, with option descriptors depending on the command name, at
 202  * `&argv[3]`.
 203  *
 204  * Note that `ingested_orig_args` is not always equal to the number of
 205  * returned items, as
 206  *
 207  *     --hello -fdw
 208  *
 209  * for example contains two ingested original arguments, but four
 210  * resulting items.
 211  *
 212  * On failure, the returned structure's `items` member is `NULL`, and
 213  * the `error` string member contains details about the error.
 214  *
 215  * You can finalize the returned structure with
 216  * argpar_parse_ret_fini().
 217  */
 218 ARGPAR_HIDDEN
 219 struct argpar_parse_ret argpar_parse(unsigned int argc,
 220                 const char * const *argv,
 221                 const struct argpar_opt_descr *descrs,
 222                 bool fail_on_unknown_opt);
 223
 224 /*
 225  * Finalizes what is returned by argpar_parse().
 226  *
 227  * It is safe to call argpar_parse() multiple times with the same
 228  * structure.
 229  */
 230 ARGPAR_HIDDEN
 231 void argpar_parse_ret_fini(struct argpar_parse_ret *ret);
 232
 233 #endif /* BABELTRACE_ARGPAR_H */