#ifndef _INCL_TRANS_H

/*
    Basic structs for the DB transaction engine.
*/


/* This holds a datum for any of the transaction types */
typedef union {
  char *name;                   /* Name of an object to delete */
  /* Or link to */
  struct {
    Obj *obj;                   /* Object to insert */
    char *name;                 /* its name */
  } object;
  struct {
    char *this;                 /* Name of thing to insert/remove */
    char *there;                /* from here.  */
  } insdel;

  struct {
    char *to;
    char *from;
    char *who;                  /* from here.  */
  } linkchk;
} tr_opdata;



/* String these together to make a program for tr_exec() */
typedef struct tr_op {
  int (*handler) ();
  tr_opdata parm;
  struct tr_op *next;
} tr_op;



/* This points to a list of tr_ops, of course. Geez. */
typedef struct {
  tr_op *first;                 /* First operation of the program */
  tr_op *last;                  /* Last operation of the program */
} tr_prog;



/* Flags for the various transaction handlers.  */
#define TR_VALIDATE 0
#define TR_EXEC     1
#define TR_ABORT    2


/* The functions YOU use to get at transact.c */
extern tr_prog *tr_newprog(void);
extern void tr_addop ();
extern void tr_exec(tr_prog *prog);
extern void tr_abort(tr_prog *prog);
extern int tr_validate(tr_prog *prog);
extern void tr_addop(tr_prog *prog, tr_op *op);



/* The handlers for the various DB transactions */
extern int tr_newobj(tr_opdata *data, int flag);
extern int tr_delobj(tr_opdata *data, int flag);
extern int tr_zeroobj(tr_opdata *data, int flag);
extern int tr_insply(tr_opdata *data, int flag);
extern int tr_remply(tr_opdata *data, int flag);
extern int tr_addlink(tr_opdata *data, int flag);


#define _INCL_TRANS_H
#endif