Introducing QArrayDataPointer

This class provides RAII functionality for handling QArrayData pointers.

Together with QArrayDataHeader and QArrayDataOps, this offers common
boilerplate code for implementing a container which, itself, defines its
own interface.

Change-Id: If38eba22fbe8f69038a06fff4acb50af434d229e
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h
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+++ b/src/corelib/tools/qarraydatapointer.h
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+/****************************************************************************
+**
+** Copyright (C) 2011 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QARRAYDATAPOINTER_H
+#define QARRAYDATAPOINTER_H
+
+#include <QtCore/qarraydataops.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Core)
+
+template <class T>
+struct QArrayDataPointer
+{
+private:
+    typedef QTypedArrayData<T> Data;
+    typedef QArrayDataOps<T> DataOps;
+
+public:
+    QArrayDataPointer()
+        : d(Data::sharedNull())
+    {
+    }
+
+    QArrayDataPointer(const QArrayDataPointer &other)
+        : d((other.d->ref.ref(), other.d))
+    {
+    }
+
+    explicit QArrayDataPointer(QTypedArrayData<T> *ptr)
+        : d(ptr)
+    {
+    }
+
+    QArrayDataPointer &operator=(const QArrayDataPointer &other)
+    {
+        QArrayDataPointer tmp(other);
+        this->swap(tmp);
+        return *this;
+    }
+
+    DataOps &operator*() const
+    {
+        Q_ASSERT(d);
+        return *static_cast<DataOps *>(d);
+    }
+
+    DataOps *operator->() const
+    {
+        Q_ASSERT(d);
+        return static_cast<DataOps *>(d);
+    }
+
+    ~QArrayDataPointer()
+    {
+        if (!d->ref.deref()) {
+            (*this)->destroyAll();
+            Data::deallocate(d);
+        }
+    }
+
+    bool isNull() const
+    {
+        return d == Data::sharedNull();
+    }
+
+    Data *data() const
+    {
+        return d;
+    }
+
+    void swap(QArrayDataPointer &other)
+    {
+        qSwap(d, other.d);
+    }
+
+    void clear()
+    {
+        QArrayDataPointer tmp(d);
+        d = Data::sharedEmpty();
+    }
+
+private:
+    Data *d;
+};
+
+template <class T>
+inline bool operator==(const QArrayDataPointer<T> &lhs, const QArrayDataPointer<T> &rhs)
+{
+    return lhs.data() == rhs.data();
+}
+
+template <class T>
+inline bool operator!=(const QArrayDataPointer<T> &lhs, const QArrayDataPointer<T> &rhs)
+{
+    return lhs.data() != rhs.data();
+}
+
+template <class T>
+inline void qSwap(QArrayDataPointer<T> &p1, QArrayDataPointer<T> &p2)
+{
+    p1.swap(p2);
+}
+
+QT_END_NAMESPACE
+
+namespace std
+{
+    template <class T>
+    inline void swap(
+            QT_PREPEND_NAMESPACE(QArrayDataPointer)<T> &p1,
+            QT_PREPEND_NAMESPACE(QArrayDataPointer)<T> &p2)
+    {
+        p1.swap(p2);
+    }
+}
+
+QT_END_HEADER
+
+#endif // include guard