/* IRCfs - IRC FileServ for *nix.
 * Copyright (C) 2002  Nick 'Zaf' Clifford <zaf@nrc.co.nz>
 * For licensing details, refer to the LICENSE file in the source 
 * code directory.
 */
#ifndef __file_h__
#define __file_h__

#include <unistd.h>
#include <ctype.h>
#include <sys/types.h>

struct file_handler;
struct file;
struct fileset;
struct dir_handler;
struct dir;

int register_file_handler(struct file_handler *fh);
int register_dir_handler(struct dir_handler *fh);

struct file_handler *find_file_handler(const char *name);
struct dir_handler *find_dir_handler(const char *name);


struct fileset {
	const char *name;
	struct dir *root_dir;
};

struct file {
	int unqid;
	struct file_handler *handler;
	void *appdata;
	void *data;
};

struct dir {
	int unqid;
	struct dir_handler *handler;
	void *appdata;
	void *data;
};

typedef int (*dir_traverse_files_t)(struct dir *, const char *, void *);
typedef int (*dir_traverse_dirs_t)(struct dir *, const char *, void *);
struct dir_handler {
	/* name of the directory handler */
	const char *name;

	/* Returns a string representing the dir name, not including
	 * full path
	 */
	const char *(*get_name)(struct dir *file);
	/* Returns a string representing the dirs full name and path 
	 * in the system.
	 */
	const char *(*get_full_name)(struct dir *file);

	/* Returns a string representing the dirs relative name and path 
	 * Relative to the root of the virtual file system
	 */
	const char *(*get_relative_name)(struct dir *file);


	struct dir *(*create)(struct dir *parent, const char *name);
	struct dir *(*open)(struct dir *parent, const char *name);
	int (*close)(struct dir *dir);

	int (*list_files)(struct dir *dir, dir_traverse_files_t, void *data);
	int (*list_dirs)(struct dir *dir, dir_traverse_dirs_t, void *data);

	/* Gets and sets application specific data. Does NOT
	 * free this data in any way when the file is closed
	 */
	void (*set_app_data)(struct dir *,void *appdata);
	void *(*get_app_data)(struct dir *);
	
};


enum file_callback_type { file_can_read, file_can_write };
typedef int (*file_callback_t)(struct file *, enum file_callback_type type);

enum file_flags { 
	file_flag_none = 0x00, 
	/* The file is opened for read only */
	file_flag_readonly = 0x01, 
	/* The file is opened for reading and writing.
	 * If neither nosmash nor smash have been supplied, then
	 * the file position is set the the beginning of the file, but
	 * the contents remain intact
	 */
	file_flag_readwrite = 0x02, 
	/* Don't overwrite an existing file.
	 * If creating a file with this flag, then don't overwrite
	 * a file that already exists.
	 */
	file_flag_nosmash = 0x04, 
	/* Overwrite any existing file.
	 * If opening an existing file for write, set the file size to 0 
	 * first.
	 * If creating a file, overwrite any existing file.
	 * Not valid with readonly (makes no sense)
	 */
	file_flag_smash = 0x08, 
	/* Create the file if it doesn't exist. Doesn't need to be
	 * passed to create
	 */
	file_flag_create = 0x10
};

struct file_handler {
	/* name of the file handler */
	const char *name;

	/* Returns a string representing the files name, not including
	 * full path
	 */
	const char *(*get_name)(struct file *file);
	/* Returns a string representing the files full name and path 
	 * in the system.
	 */
	const char *(*get_full_name)(struct file *file);
	/* Returns a string representing the files relative name and path 
	 * Relative to the root of the virtual file system
	 */
	const char *(*get_relative_name)(struct file *file);

	/* Gets and sets application specific data. Does NOT
	 * free this data in any way when the file is closed
	 */
	void (*set_app_data)(struct file *,void *appdata);
	void *(*get_app_data)(struct file *);
	
	/* Returns 0 if given filename is a valid name consisting of
	 * valid charactesr for this filehandlers.
	 * Returns -1 otherwise
	 */
	int (*validate_name)(const char *filename);
	
	/* Create a file inside the specified dir, named "name"
	 * You must supply atleast either flag_flag_readonly or 
	 * file_flag_readwrite.
	 */
	struct file *(*create)(struct dir *dir, const char *name, 
			enum file_flags flags);
	/* Open a file in the current directory named "name"
	 * You must supply atleast either flag_flag_readonly or 
	 * file_flag_readwrite.
	 */
	struct file *(*open)(struct dir *dir, const char *name, 
			enum file_flags flags);

	int (*exists)(struct dir *dir, const char *name);
	
	/* Close the file. Don't refer to file * again after this
	 */
	int (*close)(struct file *);

	/* Returns 1 if the file position is at the end of file */
	int (*eof)(struct file *);
	
	/* Get/Set a string statistic for a file */
	int (*set_str_statistic)(struct file *file, const char *name,
		const char *value);
	int (*get_str_statistic)(struct file *file, const char *name,
			char *buffer, size_t buff_size);

	/* Get/Set an integer statistic for a file */
	int (*set_int_statistic)(struct file *file, const char *name,
			int value);
	int (*get_int_statistic)(struct file *file, int *buffer);

	size_t (*get_size)(struct file *file);
	
	/* Read from the file.
	 * Returns -1 on error.
	 * Returns 0 if at EOF or if action would block.
	 * Returns number of bytes read otherwise.
	 */
	int (*read)(struct file *file, char *buffer, size_t size);
	/* Write to the file
	 * Returns -1 on error.
	 * Returns 0 if action would block, or size == 0
	 * Returns number of bytes written otherwise (may be less than size!)
	 */
	int (*write)(struct file *file, char *buffer, size_t size);
	
	/* Sets the current position in the file.
	 * Whence can be one of:
	 * SEEK_SET: position is absolute
	 * SEEK_END: position is from the end of file
	 * SEEK_CUR: position is relative to current position
	 */
	int (*lseek)(struct file *file, int whence, u_int32_t position);

	/* Register a callback on this file waiting util it can read/write
	 * When the file is ready, it calls the specified function.
	 * multiple callback handlers for the same type are NOT supported.
	 */
	int (*set_callback)(struct file *file, enum file_callback_type type,
			file_callback_t func);
	
};

void file_set_app_data(struct file *f, void *appdata);
void *file_get_app_data(struct file *f);
void dir_set_app_data(struct dir *f, void *appdata);
void *dir_get_app_data(struct dir *f);


#endif