src/core/refcnt.c

   1 /*
   2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <stdlib.h>
  22 #include <gpxe/refcnt.h>
  23
  24 /** @file
  25  *
  26  * Reference counting
  27  *
  28  */
  29
  30 /**
  31  * Increment reference count
  32  *
  33  * @v refcnt            Reference counter, or NULL
  34  * @ret refcnt          Reference counter
  35  *
  36  * If @c refcnt is NULL, no action is taken.
  37  */
  38 struct refcnt * ref_get ( struct refcnt *refcnt ) {
  39
  40         if ( refcnt ) {
  41                 refcnt->refcnt++;
  42                 DBGC2 ( refcnt, "REFCNT %p incremented to %d\n",
  43                         refcnt, refcnt->refcnt );
  44         }
  45         return refcnt;
  46 }
  47
  48 /**
  49  * Decrement reference count
  50  *
  51  * @v refcnt            Reference counter, or NULL
  52  *
  53  * If the reference count decreases below zero, the object's free()
  54  * method will be called.
  55  *
  56  * If @c refcnt is NULL, no action is taken.
  57  */
  58 void ref_put ( struct refcnt *refcnt ) {
  59
  60         if ( ! refcnt )
  61                 return;
  62
  63         refcnt->refcnt--;
  64         DBGC2 ( refcnt, "REFCNT %p decremented to %d\n",
  65                 refcnt, refcnt->refcnt );
  66
  67         if ( refcnt->refcnt >= 0 )
  68                 return;
  69
  70         if ( refcnt->free ) {
  71                 DBGC ( refcnt, "REFCNT %p being freed via method %p\n",
  72                        refcnt, refcnt->free );
  73                 refcnt->free ( refcnt );
  74         } else {
  75                 DBGC ( refcnt, "REFCNT %p being freed\n", refcnt );
  76                 free ( refcnt );
  77         }
  78 }
  79
  80 /**
  81  * Do not free reference-counted object
  82  *
  83  * @v refcnt            Reference counter
  84  *
  85  * This is meant for initializing a reference counter structure in a
  86  * statically allocated object.
  87  */
  88 void ref_no_free ( struct refcnt *refcnt __unused ) {
  89         /* Do nothing */
  90 }