qt5base-lts/src/dbus/qdbusabstractinterface_p.h
Thiago Macieira 58d9b42c03 Fix deadlock on disconnectNotify() called from ~QObject
Normally, disconnectNotify() is called at the end of QObject::disconnect
and all the locks have been dropped. That is not the case for the
QObject destructor, so we need to deal with the fact that it there may
be some locks held.

I didn't catch this issue during testing because it depends on the
pointer addresses of the object being destroyed and that of the
QDBusAbstractInterface sender object, as we use one global, non-
recursive mutex pool. For the same reason, this patch is not testable.

The fix is simple: we don't need to remove the relay rules immediately.
It's ok for them to happen later, since the worst case scenario is that
we'll receive a few more signals than we have objects to deliver them
to. If that happens, we'll do a little more work than we have to. But in
the normal case, the amount of work is the same and we get the benefit
of returning more quickly from the destructor. What's more, if the
QDBusAbstractInterface object also gets destroyed, the events are
deleted and QDBusConnectionPrivate will clean everything up.

Task-number: QTBUG-48410
Change-Id: I42e7ef1a481840699a8dffff1406b789ba5217b3
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
2015-09-25 07:45:06 +00:00

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3.5 KiB
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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Copyright (C) 2015 Intel Corporation.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtDBus module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** a written agreement between you and The Qt Company. For licensing terms
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** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
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** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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** $QT_END_LICENSE$
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****************************************************************************/
//
// W A R N I N G
// -------------
//
// This file is not part of the public API. This header file may
// change from version to version without notice, or even be
// removed.
//
// We mean it.
//
//
#ifndef QDBUSABSTRACTINTERFACE_P_H
#define QDBUSABSTRACTINTERFACE_P_H
#include <qdbusabstractinterface.h>
#include <qdbusconnection.h>
#include <qdbuserror.h>
#include "qdbusconnection_p.h"
#include "private/qobject_p.h"
#define ANNOTATION_NO_WAIT "org.freedesktop.DBus.Method.NoReply"
#ifndef QT_NO_DBUS
QT_BEGIN_NAMESPACE
class QDBusAbstractInterfacePrivate : public QObjectPrivate
{
public:
Q_DECLARE_PUBLIC(QDBusAbstractInterface)
mutable QDBusConnection connection; // mutable because we want to make calls from const functions
QString service;
QString currentOwner;
QString path;
QString interface;
mutable QDBusError lastError;
int timeout;
// this is set during creation and never changed
// it can't be const because QDBusInterfacePrivate has one more check
bool isValid;
QDBusAbstractInterfacePrivate(const QString &serv, const QString &p,
const QString &iface, const QDBusConnection& con, bool dynamic);
virtual ~QDBusAbstractInterfacePrivate() { }
void initOwnerTracking();
bool canMakeCalls() const;
// these functions do not check if the property is valid
bool property(const QMetaProperty &mp, void *returnValuePtr) const;
bool setProperty(const QMetaProperty &mp, const QVariant &value);
// return conn's d pointer
inline QDBusConnectionPrivate *connectionPrivate() const
{ return QDBusConnectionPrivate::d(connection); }
void _q_serviceOwnerChanged(const QString &name, const QString &oldOwner, const QString &newOwner);
static void finishDisconnectNotify(QDBusAbstractInterface *iface, int signalId);
};
QT_END_NAMESPACE
#endif // QT_NO_DBUS
#endif