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

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