rec_smolist.h

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/* BLURB gpl
 
                           Coda File System
                              Release 8
 
          Copyright (c) 1987-2025 Carnegie Mellon University
                  Additional copyrights listed below
 
This  code  is  distributed "AS IS" without warranty of any kind under
the terms of the GNU General Public Licence Version 2, as shown in the
file  LICENSE.  The  technical and financial  contributors to Coda are
listed in the file CREDITS.
 
                        Additional copyrights
                           none currently
 
#*/
 
/*
 *
 * rec_smolist.h -- Specification of a recoverable singly-linked list type
 * where list elements can be on only one list at a time.
 *
 * NOTE (Satya, 5/31/95)
 * ---------------------
 * The files util/rec_smolist.[ch] were originally called vol/recolist.[ch].
 * The original data structures  recolink and recolist are now
 * called rec_smolink and rec_smolist (for "small" olist and olink).
 * No functional code changes have been made --- just systematic renaming.
 *
 * This change was made to reduce confusion with rec_olist and rec_olink.
 * The rec_smo* data structures are very similar to the rec_o* data structures
 * except that the recoverable structures are smaller.
 * rec_smolist occupies the size of one long  (pointer to the last element)
 * while rec_olist is 12 bytes long.
 * These data structures were defined as part of a fix to the
 * server a long time ago, avoiding re-initialization.
 * rec_smolist was designed to convert each volume's vnode array from an
 * array of pointers (each to a single vnode) to an array of lists of
 * vnodes without having to reinitialize the servers.  It is now
 * possible to have multiple vnodes with the same vnode number because
 * resolution can recreate a previously deleted vnode.
 *
 */
 
#ifndef _UTIL_REC_SMOLIST_H_
#define _UTIL_REC_SMOLIST_H_ 1
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <stdio.h>
 
#ifdef __cplusplus
}
#endif
 
#include <coda_tsa.h>
 
class rec_smolist;
class rec_smolist_iterator;
struct rec_smolink;
 
class rec_smolist {
    friend class rec_smolist_iterator;
    struct rec_smolink *last; // last->next is head of list
 
public:
    rec_smolist();
    ~rec_smolist();
    void
    insert(struct rec_smolink *) REQUIRES_TRANSACTION; // add at head of list
    void
    append(struct rec_smolink *) REQUIRES_TRANSACTION; // add at tail of list
    struct rec_smolink *
    remove(struct rec_smolink *) REQUIRES_TRANSACTION; // remove specified entry
    struct rec_smolink *
    get(void) REQUIRES_TRANSACTION; // return and remove head of list
    int IsEmpty(void); // 1 if list is empty
    void print(void);
    void print(FILE *);
    void print(int);
};
 
class rec_smolist_iterator {
    rec_smolist *clist; // current olist
    struct rec_smolink *clink; // current olink
    struct rec_smolink *nlink; // next olink (in case they remove the object)
 
public:
    rec_smolist_iterator(rec_smolist &);
    rec_smolink *operator()(); // return next object or 0
    // Support safe deletion of currently
    // returned entry.  See dlist.h also.
};
 
struct rec_smolink {
    struct rec_smolink *next;
};
void rec_smolink_print(struct rec_smolink *l, int fd);
 
#endif /* _UTIL_REC_SMOLIST_H_ */