mdw@git.distorted.org.uk Git - fwd/blob - reffd.h

   1 /* -*-c-*-
   2  *
   3  * $Id: reffd.h,v 1.1 1999/07/26 23:33:01 mdw Exp $
   4  *
   5  * Reference counted file descriptors
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: reffd.h,v $
  32  * Revision 1.1  1999/07/26 23:33:01  mdw
  33  * Infrastructure for the new design.
  34  *
  35  */
  36
  37 #ifndef REFFD_H
  38 #define REFFD_H
  39
  40 #ifdef __cplusplus
  41   extern "C" {
  42 #endif
  43
  44 /*----- Header files ------------------------------------------------------*/
  45
  46 #include <unistd.h>
  47
  48 #include <mLib/sub.h>
  49
  50 /*----- Data structures ---------------------------------------------------*/
  51
  52 typedef struct reffd {
  53   int fd;
  54   unsigned ref;
  55   void (*proc)(void */*p*/);
  56   void *p;
  57 } reffd;
  58
  59 /*----- Functions provided ------------------------------------------------*/
  60
  61 /* --- @reffd_init@ --- *
  62  *
  63  * Arguments:   @int fd@ = file descriptor
  64  *
  65  * Returns:     Reference-counted file descriptor object.
  66  *
  67  * Use:         Creates a refcounted file descriptor.
  68  */
  69
  70 extern reffd *reffd_init(int /*fd*/);
  71
  72 /* --- @reffd_handler@ --- *
  73  *
  74  * Arguments:   @reffd *r@ = pointer to reference counted filehandle
  75  *              @void (*proc)(void *p)@ = procedure to call
  76  *              @void *p@
  77  *
  78  * Returns:     ---
  79  *
  80  * Use:         Sets the reference counted file descriptor to call @proc@
  81  *              when it is no longer required.
  82  */
  83
  84 extern void reffd_handler(reffd */*r*/, void (*/*proc*/)(void */*p*/),
  85                           void */*p*/);
  86
  87 /* --- @reffd_inc@ --- *
  88  *
  89  * Arguments:   @reffd *r@ = pointer to reference counted filehandle
  90  *
  91  * Returns:     ---
  92  *
  93  * Use:         Increments the reference count for a file descriptor.
  94  */
  95
  96 #define REFFD_INC(r) do { (r)->ref++; } while (0)
  97
  98 extern void reffd_inc(reffd */*r*/);
  99
 100 /* --- @reffd_dec@ --- *
 101  *
 102  * Arguments:   @reffd *r@ = pointer to reference counted filehandle
 103  *
 104  * Returns:     ---
 105  *
 106  * Use:         Decrements the reference count for a file descriptor.
 107  */
 108
 109 #define REFFD_DEC(r) do {                                               \
 110   reffd *_r = (r);                                                      \
 111   _r->ref--;                                                            \
 112   if (_r->ref == 0) {                                                   \
 113     close(_r->fd);                                                      \
 114     if (_r->proc)                                                       \
 115       _r->proc(_r->p);                                                  \
 116     DESTROY(_r);                                                        \
 117   }                                                                     \
 118 } while (0)
 119
 120 extern void reffd_dec(reffd */*r*/);
 121
 122 /*----- That's all, folks -------------------------------------------------*/
 123
 124 #ifdef __cplusplus
 125   }
 126 #endif
 127
 128 #endif