diff options
author | Jędrzej Nowacki <jedrzej.nowacki@nokia.com> | 2011-10-26 11:09:29 +0200 |
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committer | Qt by Nokia <qt-info@nokia.com> | 2011-11-09 10:11:14 +0100 |
commit | 2b39be6dd5d111482e5df06ac6dea18ca338d9f0 (patch) | |
tree | 13f9b75bdb796db88330f6b67e38e0619254adaf /src/corelib/kernel/qmetatypeswitcher_p.h | |
parent | eda469d3a093b488d3cff64e0f8e3c69d34bf84a (diff) |
Implement QMetaTypeSwitcher.
Currently one of the most common coding pattern, when working with
QMetaType types, is to switch over all types ids to convert a given
type id to a real c++ type. The pattern is not perfect, because of:
- code duplication - to convert type id to a real type a user has to
write own switch case
- maintenance - adding new type to QMetaType::Types doesn't propagate
to other parts of code.
Proposed type switcher can solve the issue by switching type id and
delegating found c++ type.
The class is created for internal use only and was created to simplify
common problems in QtDeclarative, QtScript and QVariant.
Change-Id: I0567ef908024b3b05ee18126f98a73a74748fbd2
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Diffstat (limited to 'src/corelib/kernel/qmetatypeswitcher_p.h')
-rw-r--r-- | src/corelib/kernel/qmetatypeswitcher_p.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/corelib/kernel/qmetatypeswitcher_p.h b/src/corelib/kernel/qmetatypeswitcher_p.h new file mode 100644 index 0000000000..2a443aa60e --- /dev/null +++ b/src/corelib/kernel/qmetatypeswitcher_p.h @@ -0,0 +1,101 @@ +/**************************************************************************** +** +** 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 QMETATYPESWITCHER_P_H +#define QMETATYPESWITCHER_P_H + +#include "qmetatype.h" + +// +// 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. +// + +class QMetaTypeSwitcher { +public: + + typedef void *UnknownType; + template<class ReturnType, class DelegateObject> + static ReturnType switcher(DelegateObject &logic, int type, const void *data); +}; + + +#define QT_METATYPE_SWICHER_CASE_PRIMITIVE(TypeName, TypeId, Name)\ + case QMetaType::TypeName: return logic.delegate(static_cast<const Name *>(data)); + +#define QT_METATYPE_SWICHER_CASE_PRIMITIVE_POINTER(TypeName, TypeId, Name)\ + case QMetaType::TypeName: return logic.delegate(static_cast< Name * const *>(data)); + +#define QT_METATYPE_SWICHER_CASE_POINTER(TypeName, TypeId, Name)\ + case QMetaType::TypeName: return logic.delegate(static_cast< QT_PREPEND_NAMESPACE(Name) * const *>(data)); + +#define QT_METATYPE_SWICHER_CASE_QCLASS(TypeName, TypeId, Name)\ + case QMetaType::TypeName: return logic.delegate(static_cast<const QT_PREPEND_NAMESPACE(Name) *>(data)); + +template<class ReturnType, class DelegateObject> +ReturnType QMetaTypeSwitcher::switcher(DelegateObject &logic, int type, const void *data) +{ + switch (QMetaType::Type(type)) { + QT_FOR_EACH_STATIC_PRIMITIVE_TYPE(QT_METATYPE_SWICHER_CASE_PRIMITIVE) + QT_FOR_EACH_STATIC_PRIMITIVE_POINTER(QT_METATYPE_SWICHER_CASE_PRIMITIVE_POINTER) + QT_FOR_EACH_STATIC_CORE_POINTER(QT_METATYPE_SWICHER_CASE_POINTER) + QT_FOR_EACH_STATIC_CORE_CLASS(QT_METATYPE_SWICHER_CASE_QCLASS) + QT_FOR_EACH_STATIC_CORE_TEMPLATE(QT_METATYPE_SWICHER_CASE_QCLASS) + QT_FOR_EACH_STATIC_GUI_CLASS(QT_METATYPE_SWICHER_CASE_QCLASS) + QT_FOR_EACH_STATIC_WIDGETS_CLASS(QT_METATYPE_SWICHER_CASE_QCLASS) + + default: + return logic.delegate(static_cast<const UnknownType *>(data)); + } +} + +#undef QT_METATYPE_SWICHER_CASE_PRIMITIVE +#undef QT_METATYPE_SWICHER_CASE_PRIMITIVE_POINTER +#undef QT_METATYPE_SWICHER_CASE_QCLASS +#undef QT_METATYPE_SWICHER_CASE_POINTER + +#endif // QMETATYPESWITCHER_P_H |