qgsoptional.h

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/***************************************************************************
  qgsoptional.h - QgsOptional
 
 ---------------------
 begin                : 7.9.2016
 copyright            : (C) 2016 by Matthias Kuhn
 email                : matthias@opengis.ch
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
#ifndef QGSOPTIONAL_H
#define QGSOPTIONAL_H
 
#include "qgis_core.h"
 
 
template<typename T>
class CORE_EXPORT QgsOptional
{
  public:
 
    QgsOptional() = default;
 
    QgsOptional( const T &data )
      : mEnabled( true )
      , mData( data )
    {
    }
 
    QgsOptional( const T &data, bool enabled )
      : mEnabled( enabled )
      , mData( data )
    {
    }
 
    bool operator== ( const QgsOptional<T> &other ) const
    {
      return mEnabled == other.mEnabled && mData == other.mData;
    }
 
    operator bool() const
    {
      return mEnabled;
    }
 
    bool enabled() const
    {
      return mEnabled;
    }
 
    void setEnabled( bool enabled )
    {
      mEnabled = enabled;
    }
 
    const T *operator->() const
    {
      return &mData;
    }
 
    T data() const
    {
      return mData;
    }
 
    void setData( const T &data )
    {
      mData = data;
    }
 
  private:
    bool mEnabled = false;
    T mData;
};
 
#endif // QGSOPTIONAL_H