X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fargpar%2Fargpar.h;fp=src%2Fcommon%2Fargpar%2Fargpar.h;h=1442f5183f30d7906386c9853923cc2b58624336;hp=0000000000000000000000000000000000000000;hb=2463b7879c00298daa79744cdaae82ac061a4ed8;hpb=3a4595c2469472dee1656cde5f8882c2123efd3c diff --git a/src/common/argpar/argpar.h b/src/common/argpar/argpar.h new file mode 100644 index 000000000..1442f5183 --- /dev/null +++ b/src/common/argpar/argpar.h @@ -0,0 +1,330 @@ +#ifndef BABELTRACE_ARGPAR_H +#define BABELTRACE_ARGPAR_H + +/* + * Copyright 2019 Philippe Proulx + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +/* + * argpar is a library that provides facilities for argument parsing. + * + * Two APIs are available: + * + * - The iterator-style API, where you initialize a state object with + * `argpar_state_create`, then repeatedly call `argpar_state_parse_next` to + * get the arguments, until (1) there are no more arguments, (2) the parser + * encounters an error (e.g. unknown option) or (3) you get bored. This + * API gives you more control on when to stop parsing the arguments. + * + * - The parse-everything-in-one-shot-API, where you call `argpar_parse`, + * which parses the arguments until (1) there are not more arguments or + * (2) it encounters a parser error. It returns you a list of all the + * arguments it was able to parse, which you can consult at your leisure. + * + * The following describes how arguments are parsed, and applies to both APIs. + * + * argpar parses the arguments `argv` of which the count is `argc` using the + * sentinel-terminated (use `ARGPAR_OPT_DESCR_SENTINEL`) option + * descriptor array `descrs`. + * + * argpar considers ALL the elements of `argv`, including the* first one, so + * that you would typically pass `argc - 1` and `&argv[1]` from what main() + * receives. + * + * This argument parser supports: + * + * * Short options without an argument, possibly tied together: + * + * -f -auf -n + * + * * Short options with argument: + * + * -b 45 -f/mein/file -xyzhello + * + * * Long options without an argument: + * + * --five-guys --burger-king --pizza-hut --subway + * + * * Long options with arguments: + * + * --security enable --time=18.56 + * + * * Non-option arguments (anything else). + * + * This parser does not accept `-` or `--` as arguments. The latter + * means "end of options" for many command-line tools, but this function + * is all about keeping the order of the arguments, so it does not mean + * much to put them at the end. This has the side effect that a + * non-option argument cannot have the form of an option, for example if + * you need to pass the exact relative path `--component`. In that case, + * you would need to pass `./--component`. There's no generic way to + * escape `-` for the moment. + * + * This parser accepts duplicate options (it will output one item for each + * instance). + * + * The returned items are of the type `struct argpar_item *`. Each item + * is to be casted to the appropriate type (`struct argpar_item_opt *` or + * `struct argpar_item_non_opt *`) depending on its type. + * + * The items are returned in the same order that the arguments were parsed, + * including non-option arguments. This means, for example, that for + * + * --hello --meow=23 /path/to/file -b + * + * found items are returned in this order: option item (--hello), option item + * (--meow=23), non-option item (/path/to/file) and option item (-b). + */ + +#include + +/* Sentinel for an option descriptor array */ +#define ARGPAR_OPT_DESCR_SENTINEL { -1, '\0', NULL, false } + +/* + * ARGPAR_HIDDEN: if argpar is used in some shared library, we don't want them + * to be exported by that library, so mark them as "hidden". + * + * On Windows, symbols are local unless explicitly exported, + * see https://gcc.gnu.org/wiki/Visibility + */ +#if defined(_WIN32) || defined(__CYGWIN__) +#define ARGPAR_HIDDEN +#else +#define ARGPAR_HIDDEN __attribute__((visibility("hidden"))) +#endif + +/* Forward-declaration for the opaque type. */ +struct argpar_state; + +/* Option descriptor */ +struct argpar_opt_descr { + /* Numeric ID for this option */ + const int id; + + /* Short option character, or `\0` */ + const char short_name; + + /* Long option name (without `--`), or `NULL` */ + const char * const long_name; + + /* True if this option has an argument */ + const bool with_arg; +}; + +/* Item type */ +enum argpar_item_type { + /* Option */ + ARGPAR_ITEM_TYPE_OPT, + + /* Non-option */ + ARGPAR_ITEM_TYPE_NON_OPT, +}; + +/* Base item */ +struct argpar_item { + enum argpar_item_type type; +}; + +/* Option item */ +struct argpar_item_opt { + struct argpar_item base; + + /* Corresponding descriptor */ + const struct argpar_opt_descr *descr; + + /* Argument, or `NULL` if none */ + const char *arg; +}; + +/* Non-option item */ +struct argpar_item_non_opt { + struct argpar_item base; + + /* + * Complete argument, pointing to one of the entries of the + * original arguments (`argv`). + */ + const char *arg; + + /* Index of this argument amongst all original arguments (`argv`) */ + unsigned int orig_index; + + /* Index of this argument amongst other non-option arguments */ + unsigned int non_opt_index; +}; + +struct argpar_item_array { + /* Array of `struct argpar_item *`, or `NULL` on error */ + struct argpar_item **items; + + /* Number of used slots in `items`. */ + unsigned int n_items; + + /* Number of allocated slots in `items`. */ + unsigned int n_alloc; +}; + +/* What is returned by argpar_parse() */ +struct argpar_parse_ret { + /* Array of `struct argpar_item *`, or `NULL` on error */ + struct argpar_item_array *items; + + /* Error string, or `NULL` if none */ + char *error; + + /* Number of original arguments (`argv`) ingested */ + unsigned int ingested_orig_args; +}; + +/* + * Parses arguments in `argv` until the end is reached or an error is + * encountered. + * + * On success, this function returns an array of items + * (field `items` of `struct argpar_parse_ret`) corresponding to each parsed + * argument. + * + * In the returned structure, `ingested_orig_args` is the number of + * ingested arguments within `argv` to produce the resulting array of + * items. + * + * If `fail_on_unknown_opt` is true, then on success `ingested_orig_args` is + * equal to `argc`. Otherwise, `ingested_orig_args` contains the number of + * original arguments until an unknown _option_ occurs. For example, with + * + * --great --white contact nuance --shark nuclear + * + * if `--shark` is not described within `descrs` and + * `fail_on_unknown_opt` is false, then `ingested_orig_args` is 4 (two + * options, two non-options), whereas `argc` is 6. + * + * This makes it possible to know where a command name is, for example. + * With those arguments: + * + * --verbose --stuff=23 do-something --specific-opt -f -b + * + * and the descriptors for `--verbose` and `--stuff` only, the function + * returns the `--verbose` and `--stuff` option items, the + * `do-something` non-option item, and that three original arguments + * were ingested. This means you can start the next argument parsing + * stage, with option descriptors depending on the command name, at + * `&argv[3]`. + * + * Note that `ingested_orig_args` is not always equal to the number of + * returned items, as + * + * --hello -fdw + * + * for example contains two ingested original arguments, but four + * resulting items. + * + * On failure, the returned structure's `items` member is `NULL`, and + * the `error` string member contains details about the error. + * + * You can finalize the returned structure with + * argpar_parse_ret_fini(). + */ +ARGPAR_HIDDEN +struct argpar_parse_ret argpar_parse(unsigned int argc, + const char * const *argv, + const struct argpar_opt_descr *descrs, + bool fail_on_unknown_opt); + +/* + * Finalizes what is returned by argpar_parse(). + * + * It is safe to call argpar_parse() multiple times with the same + * structure. + */ +ARGPAR_HIDDEN +void argpar_parse_ret_fini(struct argpar_parse_ret *ret); + +/* + * Creates an instance of `struct argpar_state`. + * + * This sets up the argpar_state structure, but does not actually + * start parsing the arguments. + * + * When you are done with it, the state must be freed with + * `argpar_state_destroy`. + */ +ARGPAR_HIDDEN +struct argpar_state *argpar_state_create( + unsigned int argc, + const char * const *argv, + const struct argpar_opt_descr * const descrs); + +/* + * Destroys an instance of `struct argpar_state`. + */ +ARGPAR_HIDDEN +void argpar_state_destroy(struct argpar_state *state); + + +enum argpar_state_parse_next_status { + ARGPAR_STATE_PARSE_NEXT_STATUS_OK, + ARGPAR_STATE_PARSE_NEXT_STATUS_END, + ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT, + ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR, +}; + +/* + * Parses and returns the next argument from `state`. + * + * On success, an item describing the argument is returned in `*item` and + * ARGPAR_STATE_PARSE_NEXT_STATUS_OK is returned. The item must be freed with + * `argpar_item_destroy`. + * + * If there are no more arguments to parse, ARGPAR_STATE_PARSE_NEXT_STATUS_END + * is returned. + * + * On failure (status codes ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR_UNKNOWN_OPT and + * ARGPAR_STATE_PARSE_NEXT_STATUS_ERROR), an error string is returned in `*error`. + * This string must be freed with `free`. + */ +enum argpar_state_parse_next_status argpar_state_parse_next( + struct argpar_state *state, + struct argpar_item **item, + char **error); + +/* + * Return the number of ingested elements from argv that were required to + * produce the previously returned items. + */ +ARGPAR_HIDDEN +int argpar_state_get_ingested_orig_args(struct argpar_state *state); + +/* + * Destroy an instance of `struct argpar_item`, as returned by + * argpar_state_parse_next. + */ +ARGPAR_HIDDEN +void argpar_item_destroy(struct argpar_item *item); + +#define ARGPAR_ITEM_DESTROY_AND_RESET(_item) \ + { \ + argpar_item_destroy(_item); \ + _item = NULL; \ + } + + +#endif /* BABELTRACE_ARGPAR_H */