diff options
Diffstat (limited to 'include/qapi/qmp/qobject.h')
-rw-r--r-- | include/qapi/qmp/qobject.h | 81 |
1 files changed, 46 insertions, 35 deletions
diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h index e022707578..fcfd549220 100644 --- a/include/qapi/qmp/qobject.h +++ b/include/qapi/qmp/qobject.h @@ -15,17 +15,17 @@ * ------------------------------------ * * - 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. + * return it as either a weak or a strong reference. If the + * reference is strong, you are responsible for calling + * qobject_unref() 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. + * should call qobject_ref() 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, + * qobject_unref() 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. */ @@ -34,21 +34,21 @@ #include "qapi/qapi-builtin-types.h" -struct QObject { +/* Not for use outside include/qapi/qmp/ */ +struct QObjectBase_ { 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)) +/* this struct must have no other members than base */ +struct QObject { + struct QObjectBase_ base; +}; -/* High-level interface for qobject_decref() */ -#define QDECREF(obj) \ - qobject_decref(obj ? QOBJECT(obj) : NULL) +#define QOBJECT(obj) ({ \ + typeof(obj) _obj = (obj); \ + _obj ? container_of(&(_obj)->base, QObject, base) : NULL; \ +}) /* Required for qobject_to() */ #define QTYPE_CAST_TO_QNull QTYPE_QNULL @@ -61,25 +61,22 @@ struct QObject { QEMU_BUILD_BUG_MSG(QTYPE__MAX != 7, "The QTYPE_CAST_TO_* list needs to be extended"); -#define qobject_to(type, obj) ({ \ - QObject *_tmp = qobject_check_type(obj, glue(QTYPE_CAST_TO_, type)); \ - _tmp ? container_of(_tmp, type, base) : (type *)NULL; }) +#define qobject_to(type, obj) \ + ((type *)qobject_check_type(obj, glue(QTYPE_CAST_TO_, type))) /* 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; + obj->base.refcnt = 1; + obj->base.type = type; } -/** - * qobject_incref(): Increment QObject's reference count - */ -static inline void qobject_incref(QObject *obj) +static inline void qobject_ref_impl(QObject *obj) { - if (obj) - obj->refcnt++; + if (obj) { + obj->base.refcnt++; + } } /** @@ -96,25 +93,39 @@ bool qobject_is_equal(const QObject *x, const QObject *y); */ void qobject_destroy(QObject *obj); -/** - * qobject_decref(): Decrement QObject's reference count, deallocate - * when it reaches zero - */ -static inline void qobject_decref(QObject *obj) +static inline void qobject_unref_impl(QObject *obj) { - assert(!obj || obj->refcnt); - if (obj && --obj->refcnt == 0) { + assert(!obj || obj->base.refcnt); + if (obj && --obj->base.refcnt == 0) { qobject_destroy(obj); } } /** + * qobject_ref(): Increment QObject's reference count + * + * Returns: the same @obj. The type of @obj will be propagated to the + * return type. + */ +#define qobject_ref(obj) ({ \ + typeof(obj) _o = (obj); \ + qobject_ref_impl(QOBJECT(_o)); \ + _o; \ +}) + +/** + * qobject_unref(): Decrement QObject's reference count, deallocate + * when it reaches zero + */ +#define qobject_unref(obj) qobject_unref_impl(QOBJECT(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; + assert(QTYPE_NONE < obj->base.type && obj->base.type < QTYPE__MAX); + return obj->base.type; } /** |