/* NEW CODE implementing a simple system like "drive letters" but longer names,
 * Copyright (C) 2024 Zak Fenton
 * NO WARRANTY USE AT YOUR OWN RISK etc. under terms of UNLICENSE or MIT license
 */

#ifndef _DRIVES_H
#define _DRIVES_H

// The logic for managing filesystem instances themselves is separate
// to the management of the drives structure, but the drives system acts
// as a convenience wrapper over the filesystem logic.
#include "fsinstance.h"
#include "syscdefs.h"

#define DRIVES_HANDLER_NONE 0
#define DRIVES_HANDLER_FS   1

/* The maximum number of drives. */
#define DRIVES_MAX      10

/* The maximum length of a drive name. */
#define DRIVES_NAMEMAX  24

/* An entry for a single drive. */
struct drives_entry {
  int handler;
  int nusers;
  void* handlerdata;
  char name[DRIVES_NAMEMAX];
};

/* The drives structure. */
struct drives {
  sched_spinlock_t lock;
  struct drives_entry entries[DRIVES_MAX];
};

/* Allocates and initialises a new drives structure. Note that functions for
 * dealing with multiple drives structures will be dealt with later!
 */
struct drives* drives_alloc();

/* Allocates a drive in the drives structure with the given data, returning the
 * drive number on success or -1 on failure.
 */
int drives_setup(struct drives* drives, int handlertype, void* handlerdata, const char* name);

/* Finds the corresponding drive and retrieves the fields. This should lock the
 * structure while operating, incrementing nusers before releasing the lock.
 *
 * Returns the drive number on success or -1 on failure.
 */
int drives_open(struct drives* drives, const char* name, int* handlertype, void** handlerdata);

/* Safely decrements the user count of the given drive number, returning -1. */
int drives_close(struct drives* drives, int driven);

/* Safely increments the user count of the given drive number, returning the number. */
int drives_dup(struct drives* drives, int driven);

/* Looks up the (filesystem-specific) inode structure for a given path, storing
 * the filesystem type in a variable at the given pointer (0 on failure).
 */
void* drives_fsnode(struct drives* drives, int hint, char* path, int* fstypevar);
void* drives_fsparent(struct drives* drives, int hint, char* path, int* fstypevar, char* namevar, int namelen);

/* Begin/end a filesystem operation, also returning the appropriate fsinstance for the hint drive and/or path. */
fsinstance_t* drives_fsbegin(struct drives* drives, int hint, char* path);
void drives_fsend(struct drives* drives, fsinstance_t* instance);

/* Gets information about a drive, filling a structure with information about the drive. */
int drives_getinfo(struct drives* drives, int drivenumber, struct __syscdefs_driveinfo* structure);

/* From ifndef at top of file: */
#endif