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+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU LGPLv2.
+ See the file COPYING.LIB.
+*/
+
+#ifndef _FUSE_OPT_H_
+#define _FUSE_OPT_H_
+
+/** @file
+ *
+ * This file defines the option parsing interface of FUSE
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Option description
+ *
+ * This structure describes a single option, and and action associated
+ * with it, in case it matches.
+ *
+ * More than one such match may occur, in which case the action for
+ * each match is executed.
+ *
+ * There are three possible actions in case of a match:
+ *
+ * i) An integer (int or unsigned) variable determined by 'offset' is
+ * set to 'value'
+ *
+ * ii) The processing function is called, with 'value' as the key
+ *
+ * iii) An integer (any) or string (char *) variable determined by
+ * 'offset' is set to the value of an option parameter
+ *
+ * 'offset' should normally be either set to
+ *
+ * - 'offsetof(struct foo, member)' actions i) and iii)
+ *
+ * - -1 action ii)
+ *
+ * The 'offsetof()' macro is defined in the <stddef.h> header.
+ *
+ * The template determines which options match, and also have an
+ * effect on the action. Normally the action is either i) or ii), but
+ * if a format is present in the template, then action iii) is
+ * performed.
+ *
+ * The types of templates are:
+ *
+ * 1) "-x", "-foo", "--foo", "--foo-bar", etc. These match only
+ * themselves. Invalid values are "--" and anything beginning
+ * with "-o"
+ *
+ * 2) "foo", "foo-bar", etc. These match "-ofoo", "-ofoo-bar" or
+ * the relevant option in a comma separated option list
+ *
+ * 3) "bar=", "--foo=", etc. These are variations of 1) and 2)
+ * which have a parameter
+ *
+ * 4) "bar=%s", "--foo=%lu", etc. Same matching as above but perform
+ * action iii).
+ *
+ * 5) "-x ", etc. Matches either "-xparam" or "-x param" as
+ * two separate arguments
+ *
+ * 6) "-x %s", etc. Combination of 4) and 5)
+ *
+ * If the format is "%s", memory is allocated for the string unlike
+ * with scanf().
+ */
+struct fuse_opt {
+ /** Matching template and optional parameter formatting */
+ const char *templ;
+
+ /**
+ * Offset of variable within 'data' parameter of fuse_opt_parse()
+ * or -1
+ */
+ unsigned long offset;
+
+ /**
+ * Value to set the variable to, or to be passed as 'key' to the
+ * processing function. Ignored if template has a format
+ */
+ int value;
+};
+
+/**
+ * Key option. In case of a match, the processing function will be
+ * called with the specified key.
+ */
+#define FUSE_OPT_KEY(templ, key) { templ, -1U, key }
+
+/**
+ * Last option. An array of 'struct fuse_opt' must end with a NULL
+ * template value
+ */
+#define FUSE_OPT_END { NULL, 0, 0 }
+
+/**
+ * Argument list
+ */
+struct fuse_args {
+ /** Argument count */
+ int argc;
+
+ /** Argument vector. NULL terminated */
+ char **argv;
+
+ /** Is 'argv' allocated? */
+ int allocated;
+};
+
+/**
+ * Initializer for 'struct fuse_args'
+ */
+#define FUSE_ARGS_INIT(argc, argv) { argc, argv, 0 }
+
+/**
+ * Key value passed to the processing function if an option did not
+ * match any template
+ */
+#define FUSE_OPT_KEY_OPT -1
+
+/**
+ * Key value passed to the processing function for all non-options
+ *
+ * Non-options are the arguments beginning with a charater other than
+ * '-' or all arguments after the special '--' option
+ */
+#define FUSE_OPT_KEY_NONOPT -2
+
+/**
+ * Special key value for options to keep
+ *
+ * Argument is not passed to processing function, but behave as if the
+ * processing function returned 1
+ */
+#define FUSE_OPT_KEY_KEEP -3
+
+/**
+ * Special key value for options to discard
+ *
+ * Argument is not passed to processing function, but behave as if the
+ * processing function returned zero
+ */
+#define FUSE_OPT_KEY_DISCARD -4
+
+/**
+ * Processing function
+ *
+ * This function is called if
+ * - option did not match any 'struct fuse_opt'
+ * - argument is a non-option
+ * - option did match and offset was set to -1
+ *
+ * The 'arg' parameter will always contain the whole argument or
+ * option including the parameter if exists. A two-argument option
+ * ("-x foo") is always converted to single arguemnt option of the
+ * form "-xfoo" before this function is called.
+ *
+ * Options of the form '-ofoo' are passed to this function without the
+ * '-o' prefix.
+ *
+ * The return value of this function determines whether this argument
+ * is to be inserted into the output argument vector, or discarded.
+ *
+ * @param data is the user data passed to the fuse_opt_parse() function
+ * @param arg is the whole argument or option
+ * @param key determines why the processing function was called
+ * @param outargs the current output argument list
+ * @return -1 on error, 0 if arg is to be discarded, 1 if arg should be kept
+ */
+typedef int (*fuse_opt_proc_t)(void *data, const char *arg, int key,
+ struct fuse_args *outargs);
+
+/**
+ * Option parsing function
+ *
+ * If 'args' was returned from a previous call to fuse_opt_parse() or
+ * it was constructed from
+ *
+ * A NULL 'args' is equivalent to an empty argument vector
+ *
+ * A NULL 'opts' is equivalent to an 'opts' array containing a single
+ * end marker
+ *
+ * A NULL 'proc' is equivalent to a processing function always
+ * returning '1'
+ *
+ * @param args is the input and output argument list
+ * @param data is the user data
+ * @param opts is the option description array
+ * @param proc is the processing function
+ * @return -1 on error, 0 on success
+ */
+int fuse_opt_parse(struct fuse_args *args, void *data,
+ const struct fuse_opt opts[], fuse_opt_proc_t proc);
+
+/**
+ * Add an option to a comma separated option list
+ *
+ * @param opts is a pointer to an option list, may point to a NULL value
+ * @param opt is the option to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_opt(char **opts, const char *opt);
+
+/**
+ * Add an option, escaping commas, to a comma separated option list
+ *
+ * @param opts is a pointer to an option list, may point to a NULL value
+ * @param opt is the option to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_opt_escaped(char **opts, const char *opt);
+
+/**
+ * Add an argument to a NULL terminated argument vector
+ *
+ * @param args is the structure containing the current argument list
+ * @param arg is the new argument to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_add_arg(struct fuse_args *args, const char *arg);
+
+/**
+ * Add an argument at the specified position in a NULL terminated
+ * argument vector
+ *
+ * Adds the argument to the N-th position. This is useful for adding
+ * options at the beggining of the array which must not come after the
+ * special '--' option.
+ *
+ * @param args is the structure containing the current argument list
+ * @param pos is the position at which to add the argument
+ * @param arg is the new argument to add
+ * @return -1 on allocation error, 0 on success
+ */
+int fuse_opt_insert_arg(struct fuse_args *args, int pos, const char *arg);
+
+/**
+ * Free the contents of argument list
+ *
+ * The structure itself is not freed
+ *
+ * @param args is the structure containing the argument list
+ */
+void fuse_opt_free_args(struct fuse_args *args);
+
+
+/**
+ * Check if an option matches
+ *
+ * @param opts is the option description array
+ * @param opt is the option to match
+ * @return 1 if a match is found, 0 if not
+ */
+int fuse_opt_match(const struct fuse_opt opts[], const char *opt);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _FUSE_OPT_H_ */