blob: b8ddbca405cf37e1f54cbbedab4c3f0d3caa7706 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
/*
* QEMU Object Model.
*
* Based on ideas by Avi Kivity <avi@redhat.com>
*
* Copyright (C) 2009, 2015 Red Hat Inc.
*
* Authors:
* Luiz Capitulino <lcapitulino@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
* QObject Reference Counts Terminology
* ------------------------------------
*
* - Returning references: A function that returns an object may
* return it as either a weak or a strong reference. If the reference
* is strong, you are responsible for calling QDECREF() on the reference
* when you are done.
*
* If the reference is weak, the owner of the reference may free it at
* any time in the future. Before storing the reference anywhere, you
* should call QINCREF() to make the reference strong.
*
* - Transferring ownership: when you transfer ownership of a reference
* by calling a function, you are no longer responsible for calling
* QDECREF() when the reference is no longer needed. In other words,
* when the function returns you must behave as if the reference to the
* passed object was weak.
*/
#ifndef QOBJECT_H
#define QOBJECT_H
#include "qapi-types.h"
struct QObject {
QType type;
size_t refcnt;
};
/* Get the 'base' part of an object */
#define QOBJECT(obj) (&(obj)->base)
/* High-level interface for qobject_incref() */
#define QINCREF(obj) \
qobject_incref(QOBJECT(obj))
/* High-level interface for qobject_decref() */
#define QDECREF(obj) \
qobject_decref(obj ? QOBJECT(obj) : NULL)
/* Initialize an object to default values */
static inline void qobject_init(QObject *obj, QType type)
{
assert(QTYPE_NONE < type && type < QTYPE__MAX);
obj->refcnt = 1;
obj->type = type;
}
/**
* qobject_incref(): Increment QObject's reference count
*/
static inline void qobject_incref(QObject *obj)
{
if (obj)
obj->refcnt++;
}
/**
* qobject_destroy(): Free resources used by the object
*/
void qobject_destroy(QObject *obj);
/**
* qobject_decref(): Decrement QObject's reference count, deallocate
* when it reaches zero
*/
static inline void qobject_decref(QObject *obj)
{
assert(!obj || obj->refcnt);
if (obj && --obj->refcnt == 0) {
qobject_destroy(obj);
}
}
/**
* qobject_type(): Return the QObject's type
*/
static inline QType qobject_type(const QObject *obj)
{
assert(QTYPE_NONE < obj->type && obj->type < QTYPE__MAX);
return obj->type;
}
extern QObject qnull_;
static inline QObject *qnull(void)
{
qobject_incref(&qnull_);
return &qnull_;
}
#endif /* QOBJECT_H */
|
