From 219fdf2ab8905618e25b426e1844a67367f0c073 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Mon, 18 Jun 2018 08:43:10 +0200
Subject: [PATCH 012/268] qobject: use a QObjectBase_ struct
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <20180618084330.30009-4-armbru@redhat.com>
Patchwork-id: 80742
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 03/23] qobject: use a QObjectBase_ struct
Bugzilla: 1557995
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
From: Marc-André Lureau <marcandre.lureau@redhat.com>
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>
(cherry picked from commit 3d3eacaeccaab718ea0e2ddaa578bfae9e311c59)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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 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 */
--
1.8.3.1