include/lttng/ref-internal.h

   1 #ifndef LTTNG_REF_INTERNAL_H
   2 #define LTTNG_REF_INTERNAL_H
   3
   4 /*
   5  * LTTng - Non thread-safe reference counting
   6  *
   7  * Copyright 2013, 2014 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8  *
   9  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License, version 2.1 only,
  13  * as published by the Free Software Foundation.
  14  *
  15  * This library is distributed in the hope that it will be useful, but WITHOUT
  16  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  18  * for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this library; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include <assert.h>
  26
  27 typedef void (*lttng_release_func)(void *);
  28
  29 struct lttng_ref {
  30         unsigned long count;
  31         lttng_release_func release;
  32 };
  33
  34 static inline
  35 void lttng_ref_init(struct lttng_ref *ref, lttng_release_func release)
  36 {
  37         assert(ref);
  38         ref->count = 1;
  39         ref->release = release;
  40 }
  41
  42 static inline
  43 void lttng_ref_get(struct lttng_ref *ref)
  44 {
  45         assert(ref);
  46         ref->count++;
  47         /* Overflow check. */
  48         assert(ref->count);
  49 }
  50
  51 static inline
  52 void lttng_ref_put(struct lttng_ref *ref)
  53 {
  54         assert(ref);
  55         /* Underflow check. */
  56         assert(ref->count);
  57         if (caa_unlikely((--ref->count) == 0)) {
  58                 ref->release(ref);
  59         }
  60 }
  61
  62 #endif /* LTTNG_REF_INTERNAL_H */