97f515985d
git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@2 fdac6126-5c0c-442c-9429-916003d36597
133 lines
4.2 KiB
C++
133 lines
4.2 KiB
C++
/*===========================================================================*\
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* *
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* OpenMesh *
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* Copyright (C) 2003 by Computer Graphics Group, RWTH Aachen *
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* www.openmesh.org *
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* *
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*---------------------------------------------------------------------------*
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* *
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* License *
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* *
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* This library is free software; you can redistribute it and/or modify it *
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* under the terms of the GNU Lesser General Public License as published *
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* by the Free Software Foundation, version 2.1. *
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* *
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* This library is distributed in the hope that it will be useful, but *
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* WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
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* Lesser General Public License for more details. *
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* *
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* You should have received a copy of the GNU Lesser General Public *
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* License along with this library; if not, write to the Free Software *
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *
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* *
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\*===========================================================================*/
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//=============================================================================
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//
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// Implements a simple singleton template
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//
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//=============================================================================
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#ifndef __SINGLETON_HH__
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#define __SINGLETON_HH__
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//=== INCLUDES ================================================================
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// OpenMesh
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#include <OpenMesh/Core/System/config.h>
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// STL
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#include <stdexcept>
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#include <iostream>
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//== NAMESPACES ===============================================================
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namespace OpenMesh {
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//=== IMPLEMENTATION ==========================================================
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/** A simple singleton template.
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Encapsulates an arbitrary class and enforces its uniqueness.
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*/
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template <typename T>
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class SingletonT
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{
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public:
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/** Singleton access function.
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Use this function to obtain a reference to the instance of the
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encapsulated class. Note that this instance is unique and created
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on the first call to Instance().
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*/
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static T& Instance()
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{
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if (!pInstance__)
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{
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// check if singleton alive
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if (destroyed__)
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{
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OnDeadReference();
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}
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// first time request -> initialize
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else
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{
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Create();
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}
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}
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return *pInstance__;
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}
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private:
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// Disable constructors/assignment to enforce uniqueness
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SingletonT();
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SingletonT(const SingletonT&);
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SingletonT& operator=(const SingletonT&);
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// Create a new singleton and store its pointer
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static void Create()
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{
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static T theInstance;
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pInstance__ = &theInstance;
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}
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// Will be called if instance is accessed after its lifetime has expired
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static void OnDeadReference()
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{
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throw std::runtime_error("[Singelton error] - Dead reference detected!\n");
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}
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virtual ~SingletonT()
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{
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pInstance__ = 0;
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destroyed__ = true;
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}
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static T* pInstance__;
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static bool destroyed__;
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};
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//=============================================================================
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} // namespace OpenMesh
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//=============================================================================
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#if defined(OM_INCLUDE_TEMPLATES) && !defined(OPENMESH_SINGLETON_C)
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# define OPENMESH_SINGLETON_TEMPLATES
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# include "SingletonT.cc"
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#endif
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//=============================================================================
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#endif // __SINGLETON_HH__
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//=============================================================================
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