forked from artemp/MapQuest-Render-Stack
/
null_handle.hpp
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/
null_handle.hpp
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/*------------------------------------------------------------------------------
*
* Null handle - a handle which doesn't exist, hasn't been
* modified, has no data, etc...
*
* Author: matt.amos@mapquest.com
*
* Copyright 2011 Mapquest, Inc. All Rights reserved.
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*-----------------------------------------------------------------------------*/
#ifndef RENDERMQ_NULL_HANDLE_HPP
#define RENDERMQ_NULL_HANDLE_HPP
#include <string>
#include <ctime>
#include "tile_storage.hpp"
namespace rendermq {
/* Null handle doesn't exist. This is a useful class to have
* around so that the storage classes can reference it and
* return a null handle when they hit an error, or don't have
* the
*/
class null_handle : public tile_storage::handle
{
public:
null_handle();
~null_handle();
virtual bool exists() const;
virtual std::time_t last_modified() const;
virtual bool data(std::string &) const;
virtual bool expired() const;
};
}
#endif // RENDERMQ_NULL_HANDLE_HPP