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[Qemu-devel] [PULL 02/10] qobject: Ensure base is at offset 0
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL 02/10] qobject: Ensure base is at offset 0 |
Date: |
Fri, 4 May 2018 10:04:46 +0200 |
From: Marc-André Lureau <address@hidden>
All QObject types have the base QObject as their first field. This
allows the simplification of qobject_to().
Signed-off-by: Marc-André Lureau <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Markus Armbruster <address@hidden>
[Commit message paragraph on type casts dropped, to avoid giving the
impression type casting would be okay]
Signed-off-by: Markus Armbruster <address@hidden>
---
include/qapi/qmp/qobject.h | 5 ++---
qobject/qobject.c | 9 +++++++++
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h
index e022707578..5206ff9ee1 100644
--- a/include/qapi/qmp/qobject.h
+++ b/include/qapi/qmp/qobject.h
@@ -61,9 +61,8 @@ 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)
diff --git a/qobject/qobject.c b/qobject/qobject.c
index 23600aa1c1..87649c5be5 100644
--- a/qobject/qobject.c
+++ b/qobject/qobject.c
@@ -16,6 +16,15 @@
#include "qapi/qmp/qlist.h"
#include "qapi/qmp/qstring.h"
+QEMU_BUILD_BUG_MSG(
+ offsetof(QNull, base) != 0 ||
+ offsetof(QNum, base) != 0 ||
+ offsetof(QString, base) != 0 ||
+ offsetof(QDict, base) != 0 ||
+ offsetof(QList, base) != 0 ||
+ offsetof(QBool, base) != 0,
+ "base qobject must be at offset 0");
+
static void (*qdestroy[QTYPE__MAX])(QObject *) = {
[QTYPE_NONE] = NULL, /* No such object exists */
[QTYPE_QNULL] = NULL, /* qnull_ is indestructible */
--
2.13.6
- [Qemu-devel] [PULL 00/10] QAPI patches for 2018-05-04, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 07/10] qapi: add SysEmuTarget to "common.json", Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 08/10] qapi: change the type of TargetInfo.arch from string to enum SysEmuTarget, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 03/10] qobject: use a QObjectBase_ struct, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 06/10] qapi: fill in CpuInfoFast.arch in query-cpus-fast, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 02/10] qobject: Ensure base is at offset 0,
Markus Armbruster <=
- [Qemu-devel] [PULL 09/10] qapi: discriminate CpuInfoFast on SysEmuTarget, not CpuInfoArch, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 05/10] qobject: Modify qobject_ref() to return obj, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 01/10] qobject: Use qobject_to() instead of type cast, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 10/10] qapi: deprecate CpuInfoFast.arch, Markus Armbruster, 2018/05/04
- [Qemu-devel] [PULL 04/10] qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF, Markus Armbruster, 2018/05/04
- Re: [Qemu-devel] [PULL 00/10] QAPI patches for 2018-05-04, Peter Maydell, 2018/05/04