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author | Marc-André Lureau <marcandre.lureau@redhat.com> | 2018-04-19 17:01:42 +0200 |
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committer | Markus Armbruster <armbru@redhat.com> | 2018-05-04 08:27:53 +0200 |
commit | 3d3eacaeccaab718ea0e2ddaa578bfae9e311c59 (patch) | |
tree | e0f8f345f94f9de6b203da0e4a8ff06b23e4c5ae | |
parent | 7ee9edfdb117da47c86c9764d90f0be11a648666 (diff) | |
download | qemu-3d3eacaeccaab718ea0e2ddaa578bfae9e311c59.zip qemu-3d3eacaeccaab718ea0e2ddaa578bfae9e311c59.tar.gz qemu-3d3eacaeccaab718ea0e2ddaa578bfae9e311c59.tar.bz2 |
qobject: use a QObjectBase_ struct
By moving the base fields to a QObjectBase_, QObject can be a type
which also has a 'base' field. This allows writing a generic QOBJECT()
macro that will work with any QObject type, including QObject
itself. The container_of() macro ensures that the object to cast has a
QObjectBase_ base field, giving some type safety guarantees. QObject
must have no members but QObjectBase_ base, or else QOBJECT() breaks.
QObjectBase_ is not a typedef and uses a trailing underscore to make
it obvious it is not for normal use and to avoid potential abuse.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180419150145.24795-3-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
-rw-r--r-- | include/qapi/qmp/qbool.h | 2 | ||||
-rw-r--r-- | include/qapi/qmp/qdict.h | 2 | ||||
-rw-r--r-- | include/qapi/qmp/qlist.h | 2 | ||||
-rw-r--r-- | include/qapi/qmp/qnull.h | 2 | ||||
-rw-r--r-- | include/qapi/qmp/qnum.h | 2 | ||||
-rw-r--r-- | include/qapi/qmp/qobject.h | 31 | ||||
-rw-r--r-- | include/qapi/qmp/qstring.h | 2 | ||||
-rw-r--r-- | qobject/qobject.c | 12 | ||||
-rw-r--r-- | tests/check-qdict.c | 6 |
9 files changed, 35 insertions, 26 deletions
diff --git a/include/qapi/qmp/qbool.h b/include/qapi/qmp/qbool.h index b9a44a1..5f61e38 100644 --- a/include/qapi/qmp/qbool.h +++ b/include/qapi/qmp/qbool.h @@ -17,7 +17,7 @@ #include "qapi/qmp/qobject.h" struct QBool { - QObject base; + struct QObjectBase_ base; bool value; }; diff --git a/include/qapi/qmp/qdict.h b/include/qapi/qmp/qdict.h index 2cc3e90..921a28d 100644 --- a/include/qapi/qmp/qdict.h +++ b/include/qapi/qmp/qdict.h @@ -25,7 +25,7 @@ typedef struct QDictEntry { } QDictEntry; struct QDict { - QObject base; + struct QObjectBase_ base; size_t size; QLIST_HEAD(,QDictEntry) table[QDICT_BUCKET_MAX]; }; diff --git a/include/qapi/qmp/qlist.h b/include/qapi/qmp/qlist.h index 5c673ac..8d2c32c 100644 --- a/include/qapi/qmp/qlist.h +++ b/include/qapi/qmp/qlist.h @@ -22,7 +22,7 @@ typedef struct QListEntry { } QListEntry; struct QList { - QObject base; + struct QObjectBase_ base; QTAILQ_HEAD(,QListEntry) head; }; diff --git a/include/qapi/qmp/qnull.h b/include/qapi/qmp/qnull.h index c992ee2..e8ea2c3 100644 --- a/include/qapi/qmp/qnull.h +++ b/include/qapi/qmp/qnull.h @@ -16,7 +16,7 @@ #include "qapi/qmp/qobject.h" struct QNull { - QObject base; + struct QObjectBase_ base; }; extern QNull qnull_; diff --git a/include/qapi/qmp/qnum.h b/include/qapi/qmp/qnum.h index 3e47475..45bf02a 100644 --- a/include/qapi/qmp/qnum.h +++ b/include/qapi/qmp/qnum.h @@ -45,7 +45,7 @@ typedef enum { * convert under the hood. */ struct QNum { - QObject base; + struct QObjectBase_ base; QNumKind kind; union { int64_t i64; diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h index 5206ff9..a713c01 100644 --- a/include/qapi/qmp/qobject.h +++ b/include/qapi/qmp/qobject.h @@ -34,13 +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) +/* this struct must have no other members than base */ +struct QObject { + struct QObjectBase_ base; +}; + +#define QOBJECT(obj) ({ \ + typeof(obj) _obj = (obj); \ + _obj ? container_of(&(_obj)->base, QObject, base) : NULL; \ +}) /* High-level interface for qobject_incref() */ #define QINCREF(obj) \ @@ -68,8 +76,8 @@ QEMU_BUILD_BUG_MSG(QTYPE__MAX != 7, 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; } /** @@ -77,8 +85,9 @@ static inline void qobject_init(QObject *obj, QType type) */ static inline void qobject_incref(QObject *obj) { - if (obj) - obj->refcnt++; + if (obj) { + obj->base.refcnt++; + } } /** @@ -101,8 +110,8 @@ void qobject_destroy(QObject *obj); */ static inline void qobject_decref(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); } } @@ -112,8 +121,8 @@ static inline void qobject_decref(QObject *obj) */ 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; } /** diff --git a/include/qapi/qmp/qstring.h b/include/qapi/qmp/qstring.h index 30ae260..b3b3d44 100644 --- a/include/qapi/qmp/qstring.h +++ b/include/qapi/qmp/qstring.h @@ -16,7 +16,7 @@ #include "qapi/qmp/qobject.h" struct QString { - QObject base; + struct QObjectBase_ base; char *string; size_t length; size_t capacity; diff --git a/qobject/qobject.c b/qobject/qobject.c index 87649c5..cf4b7e2 100644 --- a/qobject/qobject.c +++ b/qobject/qobject.c @@ -37,9 +37,9 @@ static void (*qdestroy[QTYPE__MAX])(QObject *) = { void qobject_destroy(QObject *obj) { - assert(!obj->refcnt); - assert(QTYPE_QNULL < obj->type && obj->type < QTYPE__MAX); - qdestroy[obj->type](obj); + assert(!obj->base.refcnt); + assert(QTYPE_QNULL < obj->base.type && obj->base.type < QTYPE__MAX); + qdestroy[obj->base.type](obj); } @@ -62,11 +62,11 @@ bool qobject_is_equal(const QObject *x, const QObject *y) return true; } - if (!x || !y || x->type != y->type) { + if (!x || !y || x->base.type != y->base.type) { return false; } - assert(QTYPE_NONE < x->type && x->type < QTYPE__MAX); + assert(QTYPE_NONE < x->base.type && x->base.type < QTYPE__MAX); - return qis_equal[x->type](x, y); + return qis_equal[x->base.type](x, y); } diff --git a/tests/check-qdict.c b/tests/check-qdict.c index 08d4303..07bb8f4 100644 --- a/tests/check-qdict.c +++ b/tests/check-qdict.c @@ -570,11 +570,11 @@ static void qdict_join_test(void) } /* Check the references */ - g_assert(qdict_get(dict1, "foo")->refcnt == 1); - g_assert(qdict_get(dict1, "bar")->refcnt == 1); + g_assert(qdict_get(dict1, "foo")->base.refcnt == 1); + g_assert(qdict_get(dict1, "bar")->base.refcnt == 1); if (!overwrite) { - g_assert(qdict_get(dict2, "foo")->refcnt == 1); + g_assert(qdict_get(dict2, "foo")->base.refcnt == 1); } /* Clean up */ |