ApplicationStateStack.hpp

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/*
 * =====================================================================================
 *
 *       Filename:  ApplicationStateStack.hpp
 *
 *    Description:
 *
 *        Created:  14/12/2014 13:48:48
 *
 *         Author:  Quentin Bazin, <quent42340@gmail.com>
 *
 * =====================================================================================
 */
#ifndef GK_APPLICATIONSTATESTACK_HPP_
#define GK_APPLICATIONSTATESTACK_HPP_

#include <memory>
#include <stack>

#include "gk/core/ApplicationState.hpp"

namespace gk {

class ApplicationStateStack {
    public:
        template<typename T, typename... Args>
        auto push(Args &&...args) -> typename std::enable_if<std::is_base_of<ApplicationState, T>::value, T&>::type {
            m_states.emplace(std::make_shared<T>(std::forward<Args>(args)...));
            m_states.top()->setStateStack(this);
            return static_cast<T&>(top());
        }

        void pop();

        void clear() { while(!empty()) pop(); }

        void clearDeletedStates();

        ApplicationState &top() const { return *m_states.top().get(); }

        bool empty() const { return m_states.empty(); }

        std::size_t size() const { return m_states.size(); }

        static ApplicationStateStack &getInstance() {
            return *s_instance;
        }

        static void setInstance(ApplicationStateStack &instance) {
            s_instance = &instance;
        }

    private:
        // Member data
        static ApplicationStateStack *s_instance;               

        std::stack<std::shared_ptr<ApplicationState>> m_states; 
        std::stack<std::shared_ptr<ApplicationState>> m_trash;  
};

} // namespace gk

#endif // GK_APPLICATIONSTATESTACK_HPP_