Fix a race condition related to service acquisition.

The explanation is in the testcase and in the task.

The reentrancy caused some deadlocks, that's why handleMessage() stops
processing if the refcount has dropped down to zero. Should also save
some CPU cycles at the application shutdown time.

Task-number: QTBUG-15651
Reviewed-by: Trust Me

1 files changed, 10 insertions, 3 deletions

diff --git a/src/dbus/qdbusconnection_p.h b/src/dbus/qdbusconnection_p.h
index 1bd00da..67145b8 100644
--- a/src/dbus/qdbusconnection_p.h
+++ b/src/dbus/qdbusconnection_p.h
@@ -203,6 +203,8 @@ public:
     void disconnectRelay(const QString &service,
                          const QString &path, const QString &interface,
                          QDBusAbstractInterface *receiver, const char *signal);
+    void registerService(const QString &serviceName);
+    void unregisterService(const QString &serviceName);
 
     bool handleMessage(const QDBusMessage &msg);
     void waitForFinished(QDBusPendingCallPrivate *pcall);
@@ -247,9 +249,11 @@ public slots:
     void socketWrite(int);
     void objectDestroyed(QObject *o);
     void relaySignal(QObject *obj, const QMetaObject *, int signalId, const QVariantList &args);
-    void _q_serviceOwnerChanged(const QString &name, const QString &oldOwner, const QString &newOwner);
-    void registerService(const QString &serviceName);
-    void unregisterService(const QString &serviceName);
+
+private slots:
+    void serviceOwnerChangedNoLock(const QString &name, const QString &oldOwner, const QString &newOwner);
+    void registerServiceNoLock(const QString &serviceName);
+    void unregisterServiceNoLock(const QString &serviceName);
 
 signals:
     void serviceOwnerChanged(const QString &name, const QString &oldOwner, const QString &newOwner);
@@ -303,6 +307,9 @@ public:
                             QObject *receiver, const char *signal, int minMIdx,
                             bool buildSignature);
     static DBusHandlerResult messageFilter(DBusConnection *, DBusMessage *, void *);
+    static bool checkReplyForDelivery(QDBusConnectionPrivate *target, QObject *object,
+                                      int idx, const QList<int> &metaTypes,
+                                      const QDBusMessage &msg);
     static QDBusCallDeliveryEvent *prepareReply(QDBusConnectionPrivate *target, QObject *object,
                                                 int idx, const QList<int> &metaTypes,
                                                 const QDBusMessage &msg);