1/* Base class of intrusively reference-counted objects.
2   Copyright (C) 2017-2020 Free Software Foundation, Inc.
3
4   This file is part of GDB.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
18
19#ifndef COMMON_REFCOUNTED_OBJECT_H
20#define COMMON_REFCOUNTED_OBJECT_H
21
22/* Base class of intrusively reference-countable objects.
23   Incrementing and decrementing the reference count is an external
24   responsibility.  */
25
26class refcounted_object
27{
28public:
29  refcounted_object () = default;
30
31  /* Increase the refcount.  */
32  void incref ()
33  {
34    gdb_assert (m_refcount >= 0);
35    m_refcount++;
36  }
37
38  /* Decrease the refcount.  */
39  void decref ()
40  {
41    m_refcount--;
42    gdb_assert (m_refcount >= 0);
43  }
44
45  int refcount () const { return m_refcount; }
46
47private:
48  DISABLE_COPY_AND_ASSIGN (refcounted_object);
49
50  /* The reference count.  */
51  int m_refcount = 0;
52};
53
54/* A policy class to interface gdb::ref_ptr with a
55   refcounted_object.  */
56
57struct refcounted_object_ref_policy
58{
59  static void incref (refcounted_object *ptr)
60  {
61    ptr->incref ();
62  }
63
64  static void decref (refcounted_object *ptr)
65  {
66    ptr->decref ();
67  }
68};
69
70#endif /* COMMON_REFCOUNTED_OBJECT_H */
71