--- /dev/null
+#ifndef BABELTRACE_ARGPAR_H
+#define BABELTRACE_ARGPAR_H
+
+/*
+ * Copyright 2019 Philippe Proulx <pproulx@efficios.com>
+ *
+ * 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 <stdbool.h>
+
+/* 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 */
projects / lttng-tools.git / blobdiff