Utils.hpp

/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 athre0z
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#ifndef UTILS_HPP
#define UTILS_HPP

#include <QString>
#include <QDir>

namespace Utils
{

// ============================================================================================== //
// [NonCopyable]                                                                                  //
// ============================================================================================== //

/**
 * @brief Makes derived classes non-copyable.
 */
class NonCopyable
{
    NonCopyable(const NonCopyable&); // not implemented
    NonCopyable& operator = (const NonCopyable&); // not implemented
public:
    NonCopyable() {}
    virtual ~NonCopyable() {}
};

// ============================================================================================== //
// [Singleton]                                                                                    //
// ============================================================================================== //

template<typename T>
class Singleton : public NonCopyable
{
    static T *m_instance;
protected:
    Singleton() {}
    virtual ~Singleton() {}
public:
    static T& instance();
    static void freeInstance();
    static bool isInstantiated();
};

// ============================================================================================== //
// Implementation of inline methods [Singleton]                                                   //
// ============================================================================================== //

template<typename T> T *Singleton<T>::m_instance = nullptr;

template<typename T> inline
T& Singleton<T>::instance()
{
    if (!m_instance)
        m_instance = new T;
    return *m_instance;
}

template<typename T> inline
void Singleton<T>::freeInstance()
{
    if (m_instance)
    {
        delete m_instance;
        m_instance = nullptr;
    }
}

template<typename T> inline
bool Singleton<T>::isInstantiated()
{
    return m_instance != nullptr;
}

// ============================================================================================== //

}

#endif