unicorn/qemu/include/qapi/qmp/qobject.h
Eric Blake 805c803298
qobject: Rename qtype_code to QType
The name QType matches our CODING_STYLE conventions for type names
in CamelCase. It also matches the fact that we are already naming
all the enum members with a prefix of QTYPE, not QTYPE_CODE. And
doing the rename will also make it easier for the next patch to use
QAPI for providing the enum, which also wants CamelCase type names.

Backports commit 1310a3d3bd9301ff5a825287638cfab24c2c6689 from qemu
2018-02-19 21:41:52 -05:00

123 lines
2.9 KiB
C

/*
* 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 <stddef.h>
#include <assert.h>
typedef enum {
QTYPE_NONE,
QTYPE_QNULL,
QTYPE_QINT,
QTYPE_QSTRING,
QTYPE_QDICT,
QTYPE_QLIST,
QTYPE_QFLOAT,
QTYPE_QBOOL,
QTYPE_QERROR,
QTYPE_MAX,
} QType;
typedef struct QObject {
QType type;
size_t refcnt;
} QObject;
/* Objects definitions must include this */
#define QObject_HEAD \
QObject base
/* 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 */