Singleton.h

Go to the documentation of this file.

//
//C++ Template: Singleton<T>
//
#ifndef __SINGLETON_H__INCLUDED__
#define __SINGLETON_H__INCLUDED__

namespace InitializationFunctors
{
template < typename T >
class DefaultConstructor
{
public:
    T*operator()() const
    {
        return new T();
    }
};
};

template < typename T, typename INIT = InitializationFunctors::DefaultConstructor< T > >
class Singleton
{
protected:
    static T *_singletonInstance;

    static void initializeSingleton()
    {
        if (_singletonInstance != 0)
            delete _singletonInstance;
        //GCC 3.3 errors out if you do '(INIT())()'
        INIT singletonConstructor;
        _singletonInstance = singletonConstructor();
    }

    static void deinitializeSingleton()
    {
        _singletonInstance = 0;
    }

    ~Singleton()
    {
        if (_singletonInstance == this)
            deinitializeSingleton();
    }

public:
    static T * getSingleton()
    {
        if (_singletonInstance == 0)
            initializeSingleton();
        return _singletonInstance;
    }
};

#endif //__SINGLETON_H__INCLUDED__