src/xmlpatterns/api/qreferencecountedvalue_p.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/api/qreferencecountedvalue_p.h	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,106 @@
+/****************************************************************************
+**
+** 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 QtXmlPatterns 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+
+#ifndef QPatternist_ReferenceCountedValue_p_h
+#define QPatternist_ReferenceCountedValue_p_h
+
+QT_BEGIN_HEADER
+QT_BEGIN_NAMESPACE
+
+namespace QPatternist
+{
+/*!
+   \class ReferenceCountedValue
+   \internal
+   \since 4.4
+   \brief A template class that reference counts a value.
+
+   This class is useful when an instance needs to have ownership semantics
+   as if it was value based. A typical examples is a QObject pointer, which
+   doesn't have a single owner.
+
+   This is achieved through storing a copy of the object as
+   a member inside ReferenceCountedValue, which never is copied. It will
+   stay in scope until the last reference to the ReferenceCountedValue instance
+   is removed, and subsequently ReferenceCountedValue is deleted and hence also
+   the contained value. One should use ReferenceCountedValue by passing around
+   copies of Ptr, which is a typedef for the QExplicitlySharedDataPointer
+   smart pointer.
+*/
+    template<typename T>
+    class ReferenceCountedValue : public QSharedData
+    {
+    public:
+        typedef QExplicitlySharedDataPointer<ReferenceCountedValue<T> > Ptr;
+
+        inline ReferenceCountedValue(T *const v) : value(v)
+        {
+        }
+
+        inline ~ReferenceCountedValue()
+        {
+            delete value;
+        }
+
+        T *const value;
+    private:
+        /*!
+          Disabled, no implementation provided.
+         */
+        inline ReferenceCountedValue();
+        Q_DISABLE_COPY(ReferenceCountedValue)
+    };
+}
+
+QT_END_NAMESPACE
+QT_END_HEADER
+
+#endif