95 lines
2.9 KiB
C++
95 lines
2.9 KiB
C++
/*
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* Copyright 2006-2007 Aaron Seigo <aseigo@kde.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Library General Public License as
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* published by the Free Software Foundation; either version 2, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef PLASMA_DATAENGINEMANAGER_H
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#define PLASMA_DATAENGINEMANAGER_H
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#include <QtCore/QHash>
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#include <plasma/dataengine.h>
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namespace Plasma
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{
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class DataEngineManagerPrivate;
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/**
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* @class DataEngineManager plasma/dataenginemanager.h <Plasma/DataEngineManager>
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*
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* @short DataEngine loader and life time manager
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*
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* Plasma::DataEngineManager provides facilities for listing, loading and
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* according to reference count unloading of DataEngines.
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**/
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class PLASMA_EXPORT DataEngineManager: public QObject
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{
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Q_OBJECT
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public:
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/**
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* Singleton pattern accessor.
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*/
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static DataEngineManager *self();
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/**
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* Returns a data engine object if one is loaded and available.
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* On failure, the fallback NullEngine (which does nothing and
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* !isValid()) is returned.
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*
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* @param name the name of the engine
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*/
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Plasma::DataEngine *engine(const QString &name) const;
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/**
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* Loads a data engine and increases the reference count on it.
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* This should be called once per object (or set of objects) using the
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* DataEngine. Afterwards, dataEngine should be used or the return
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* value cached. Call unloadDataEngine when finished with the engine.
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*
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* @param name the name of the engine
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* @return the data engine that was loaded, or the NullEngine on failure.
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*/
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Plasma::DataEngine *loadEngine(const QString &name);
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/**
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* Decreases the reference count on the engine. If the count reaches
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* zero, then the engine is deleted to save resources.
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*/
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void unloadEngine(const QString &name);
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/**
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* Returns a listing of all known engines by name
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*/
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static QStringList listAllEngines();
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private:
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/**
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* Default constructor. The singleton method self() is the
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* preferred access mechanism.
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*/
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DataEngineManager();
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~DataEngineManager();
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DataEngineManagerPrivate *const d;
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friend class DataEngineManagerSingleton;
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};
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} // namespace Plasma
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#endif // multiple inclusion guard
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