/* $Id: commonio.h,v 1.7 2001/08/14 21:09:54 malekith Exp $ */

/*
 * Linked list entry.
 */
struct commonio_entry {
	char *line;
	void *eptr;  /* struct passwd, struct spwd, ... */
	struct commonio_entry *prev, *next;
	int changed:1;
};

/*
 * Operations depending on database type: passwd, group, shadow etc.
 */
struct commonio_ops {
	/*
	 * Make a copy of the object (for example, struct passwd)
	 * and all strings pointed by it, in malloced memory.
	 */
	void *(*dup)(const void *);

	/*
	 * free() the object including any strings pointed by it.
	 */
	void (*free)(void *);

	/*
	 * Return the name of the object (for example, pw_name
	 * for struct passwd).
	 */
	const char *(*getname)(const void *);

	/*
	 * Parse a string, return object (in static area -
	 * should be copied using the dup operation above).
	 */
	void *(*parse)(const char *);

	/*
	 * Write the object to the file (this calls putpwent()
	 * for struct passwd, for example).
	 */
	int (*put)(const void *, FILE *);

	/*
	 * fgets and fputs (can be replaced by versions that
	 * understand line continuation conventions).
	 */
	char *(*fgets)(char *, int, FILE *);
	int (*fputs)(const char *, FILE *);
};

/*
 * Database structure.
 */
struct commonio_db {
	/*
	 * Name of the data file.
	 */
	char filename[1024];

	/*
	 * Operations from above.
	 */
	struct commonio_ops *ops;

	/*
	 * Currently open file stream.
	 */
	FILE *fp;

	/*
	 * Head, tail, current position in linked list.
	 */
	struct commonio_entry *head, *tail, *cursor;

	/*
	 * Various flags.
	 */
	int changed:1;
	int isopen:1;
	int locked:1;
	int readonly:1;
};

extern int commonio_setname(struct commonio_db *, const char *);
extern int commonio_present(const struct commonio_db *);
extern int commonio_lock(struct commonio_db *);
extern int commonio_lock_nowait(struct commonio_db *);
extern int commonio_open(struct commonio_db *, int);
extern const void *commonio_locate(struct commonio_db *, const char *);
extern int commonio_update(struct commonio_db *, const void *);
extern int commonio_remove(struct commonio_db *, const char *);
extern int commonio_rewind(struct commonio_db *);
extern const void *commonio_next(struct commonio_db *);
extern int commonio_close(struct commonio_db *);
extern int commonio_unlock(struct commonio_db *);
extern void commonio_del_entry(struct commonio_db *, const struct commonio_entry *);
extern int commonio_sort_wrt(struct commonio_db *shadow, struct commonio_db *passwd);
extern int commonio_sort(struct commonio_db *db, int (*cmp)(const void *, const void *));