X-Git-Url: http://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fargpar%2Fargpar.h;h=43dbd0d56fc1bad4be1f7a8f67c56d53c66c8f33;hp=00334cd6fb9d6f0c14a7fc08f5a21d114e778e65;hb=4624dad0d79b63be45c5c6d7eb2920ba09746f06;hpb=b4b7369fbeb9c037449782132cfcdad1dac435d9

diff --git a/src/common/argpar/argpar.h b/src/common/argpar/argpar.h
index 00334cd6f..43dbd0d56 100644
--- a/src/common/argpar/argpar.h
+++ b/src/common/argpar/argpar.h
@@ -9,6 +9,77 @@
 
 #include <stdbool.h>
 
+/*
+ * 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).
+ */
+
 /* Sentinel for an option descriptor array */
 #define ARGPAR_OPT_DESCR_SENTINEL	{ -1, '\0', NULL, false }
 
@@ -25,6 +96,9 @@
 #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 */
@@ -106,66 +180,20 @@ struct argpar_parse_ret {
 };
 
 /*
- * Parses the arguments `argv` of which the count is `argc` using the
- * sentinel-terminated (use `ARGPAR_OPT_DESCR_SENTINEL`) option
- * descriptor array `descrs`.
- *
- * This function 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 function 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 function accepts duplicate options (the resulting array of items
- * contains one entry for each instance).
+ * Parses arguments in `argv` until the end is reached or an error is
+ * encountered.
  *
  * On success, this function returns an array of items
- * (`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 returned array contains the items 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
- *
- * the function returns an array of four items: two options, one
- * non-option, and one option.
+ * (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
+ * 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
  *
@@ -214,4 +242,73 @@ struct argpar_parse_ret argpar_parse(unsigned int argc,
 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 */