From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49685) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f9B4S-0006gV-Ts for qemu-devel@nongnu.org; Thu, 19 Apr 2018 11:02:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f9B4P-00027g-Sn for qemu-devel@nongnu.org; Thu, 19 Apr 2018 11:02:00 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54908 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f9B4P-00025h-Ju for qemu-devel@nongnu.org; Thu, 19 Apr 2018 11:01:57 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 14BCA4023155 for ; Thu, 19 Apr 2018 15:01:54 +0000 (UTC) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Thu, 19 Apr 2018 17:01:42 +0200 Message-Id: <20180419150145.24795-3-marcandre.lureau@redhat.com> In-Reply-To: <20180419150145.24795-1-marcandre.lureau@redhat.com> References: <20180419150145.24795-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v6 2/5] qobject: use a QObjectBase_ struct List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: eblake@redhat.com, berrange@redhat.com, armbru@redhat.com, pbonzini@redhat.com, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= 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-Andr=C3=A9 Lureau Reviewed-by: Eric Blake --- include/qapi/qmp/qbool.h | 2 +- include/qapi/qmp/qdict.h | 2 +- include/qapi/qmp/qlist.h | 2 +- include/qapi/qmp/qnull.h | 2 +- include/qapi/qmp/qnum.h | 2 +- include/qapi/qmp/qobject.h | 31 ++++++++++++++++++++----------- include/qapi/qmp/qstring.h | 2 +- qobject/qobject.c | 12 ++++++------ 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 b9a44a1bfe..5f61e38e64 100644 --- a/include/qapi/qmp/qbool.h +++ b/include/qapi/qmp/qbool.h @@ -17,7 +17,7 @@ #include "qapi/qmp/qobject.h" =20 struct QBool { - QObject base; + struct QObjectBase_ base; bool value; }; =20 diff --git a/include/qapi/qmp/qdict.h b/include/qapi/qmp/qdict.h index 2cc3e906f7..921a28d2d3 100644 --- a/include/qapi/qmp/qdict.h +++ b/include/qapi/qmp/qdict.h @@ -25,7 +25,7 @@ typedef struct QDictEntry { } QDictEntry; =20 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 5c673acb06..8d2c32ca28 100644 --- a/include/qapi/qmp/qlist.h +++ b/include/qapi/qmp/qlist.h @@ -22,7 +22,7 @@ typedef struct QListEntry { } QListEntry; =20 struct QList { - QObject base; + struct QObjectBase_ base; QTAILQ_HEAD(,QListEntry) head; }; =20 diff --git a/include/qapi/qmp/qnull.h b/include/qapi/qmp/qnull.h index c992ee2ae1..e8ea2c315a 100644 --- a/include/qapi/qmp/qnull.h +++ b/include/qapi/qmp/qnull.h @@ -16,7 +16,7 @@ #include "qapi/qmp/qobject.h" =20 struct QNull { - QObject base; + struct QObjectBase_ base; }; =20 extern QNull qnull_; diff --git a/include/qapi/qmp/qnum.h b/include/qapi/qmp/qnum.h index 3e47475b2c..45bf02a036 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 5206ff9ee1..a713c0165b 100644 --- a/include/qapi/qmp/qobject.h +++ b/include/qapi/qmp/qobject.h @@ -34,13 +34,21 @@ =20 #include "qapi/qapi-builtin-types.h" =20 -struct QObject { +/* Not for use outside include/qapi/qmp/ */ +struct QObjectBase_ { QType type; size_t refcnt; }; =20 -/* 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 =3D (obj); \ + _obj ? container_of(&(_obj)->base, QObject, base) : NULL; \ +}) =20 /* High-level interface for qobject_incref() */ #define QINCREF(obj) \ @@ -68,8 +76,8 @@ QEMU_BUILD_BUG_MSG(QTYPE__MAX !=3D 7, static inline void qobject_init(QObject *obj, QType type) { assert(QTYPE_NONE < type && type < QTYPE__MAX); - obj->refcnt =3D 1; - obj->type =3D type; + obj->base.refcnt =3D 1; + obj->base.type =3D type; } =20 /** @@ -77,8 +85,9 @@ static inline void qobject_init(QObject *obj, QType typ= e) */ static inline void qobject_incref(QObject *obj) { - if (obj) - obj->refcnt++; + if (obj) { + obj->base.refcnt++; + } } =20 /** @@ -101,8 +110,8 @@ void qobject_destroy(QObject *obj); */ static inline void qobject_decref(QObject *obj) { - assert(!obj || obj->refcnt); - if (obj && --obj->refcnt =3D=3D 0) { + assert(!obj || obj->base.refcnt); + if (obj && --obj->base.refcnt =3D=3D 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; } =20 /** diff --git a/include/qapi/qmp/qstring.h b/include/qapi/qmp/qstring.h index 30ae260a7f..b3b3d444d2 100644 --- a/include/qapi/qmp/qstring.h +++ b/include/qapi/qmp/qstring.h @@ -16,7 +16,7 @@ #include "qapi/qmp/qobject.h" =20 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 87649c5be5..cf4b7e229e 100644 --- a/qobject/qobject.c +++ b/qobject/qobject.c @@ -37,9 +37,9 @@ static void (*qdestroy[QTYPE__MAX])(QObject *) =3D { =20 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); } =20 =20 @@ -62,11 +62,11 @@ bool qobject_is_equal(const QObject *x, const QObject= *y) return true; } =20 - if (!x || !y || x->type !=3D y->type) { + if (!x || !y || x->base.type !=3D y->base.type) { return false; } =20 - assert(QTYPE_NONE < x->type && x->type < QTYPE__MAX); + assert(QTYPE_NONE < x->base.type && x->base.type < QTYPE__MAX); =20 - 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 2e73c2f86e..029b6b15b9 100644 --- a/tests/check-qdict.c +++ b/tests/check-qdict.c @@ -570,11 +570,11 @@ static void qdict_join_test(void) } =20 /* Check the references */ - g_assert(qdict_get(dict1, "foo")->refcnt =3D=3D 1); - g_assert(qdict_get(dict1, "bar")->refcnt =3D=3D 1); + g_assert(qdict_get(dict1, "foo")->base.refcnt =3D=3D 1); + g_assert(qdict_get(dict1, "bar")->base.refcnt =3D=3D 1); =20 if (!overwrite) { - g_assert(qdict_get(dict2, "foo")->refcnt =3D=3D 1); + g_assert(qdict_get(dict2, "foo")->base.refcnt =3D=3D 1); } =20 /* Clean up */ --=20 2.17.0.253.g3dd125b46d