src/corelib/kernel/qobjectcleanuphandler.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/corelib/kernel/qobjectcleanuphandler.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,148 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qobjectcleanuphandler.h"
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QObjectCleanupHandler
+    \brief The QObjectCleanupHandler class watches the lifetime of multiple QObjects.
+
+    \ingroup objectmodel
+
+    A QObjectCleanupHandler is useful whenever you need to know when a
+    number of \l{QObject}s that are owned by someone else have been
+    deleted. This is important, for example, when referencing memory
+    in an application that has been allocated in a shared library.
+
+    To keep track of some \l{QObject}s, create a
+    QObjectCleanupHandler, and add() the objects you are interested
+    in. If you are no longer interested in tracking a particular
+    object, use remove() to remove it from the cleanup handler. If an
+    object being tracked by the cleanup handler gets deleted by
+    someone else it will automatically be removed from the cleanup
+    handler. You can delete all the objects in the cleanup handler
+    with clear(), or by destroying the cleanup handler. isEmpty()
+    returns true if the QObjectCleanupHandler has no objects to keep
+    track of.
+
+    \sa QPointer
+*/
+
+/*!
+    Constructs an empty QObjectCleanupHandler.
+*/
+QObjectCleanupHandler::QObjectCleanupHandler()
+{
+}
+
+/*!
+    Destroys the cleanup handler. All objects in this cleanup handler
+    will be deleted.
+
+    \sa clear()
+*/
+QObjectCleanupHandler::~QObjectCleanupHandler()
+{
+    clear();
+}
+
+/*!
+    Adds \a object to this cleanup handler and returns the pointer to
+    the object.
+
+    \sa remove()
+*/
+QObject *QObjectCleanupHandler::add(QObject* object)
+{
+    if (!object)
+        return 0;
+
+    connect(object, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed(QObject*)));
+    cleanupObjects.insert(0, object);
+    return object;
+}
+
+/*!
+    Removes the \a object from this cleanup handler. The object will
+    not be destroyed.
+
+    \sa add()
+*/
+void QObjectCleanupHandler::remove(QObject *object)
+{
+    int index;
+    if ((index = cleanupObjects.indexOf(object)) != -1) {
+        cleanupObjects.removeAt(index);
+        disconnect(object, SIGNAL(destroyed(QObject*)), this, SLOT(objectDestroyed(QObject*)));
+    }
+}
+
+/*!
+    Returns true if this cleanup handler is empty or if all objects in
+    this cleanup handler have been destroyed; otherwise return false.
+
+    \sa add() remove() clear()
+*/
+bool QObjectCleanupHandler::isEmpty() const
+{
+    return cleanupObjects.isEmpty();
+}
+
+/*!
+    Deletes all objects in this cleanup handler. The cleanup handler
+    becomes empty.
+
+    \sa isEmpty()
+*/
+void QObjectCleanupHandler::clear()
+{
+    while (!cleanupObjects.isEmpty())
+        delete cleanupObjects.takeFirst();
+}
+
+void QObjectCleanupHandler::objectDestroyed(QObject *object)
+{
+    remove(object);
+}
+
+QT_END_NAMESPACE