Dependency tool

DependencyTools.h

#pragma once

#include <cassert>
#include <functional>

template <typename T>
class Injection final
{
    static T* s_ptr;

public:
    class Scope final
    {
        std::function<void()> m_finalizer;

    public:
        Scope(Scope&& other) = default;
        Scope& operator=(Scope&&) = default;

        Scope(const Scope&) = delete;
        Scope& operator=(const Scope&) = delete;

        explicit Scope(T* ptr)
            : m_finalizer([]{ s_ptr = nullptr; })
        {
            assert(ptr && "injecting object is null");
            assert(!s_ptr && "object is already injected");

            s_ptr = ptr;
        }

        ~Scope()
        {
            if (m_finalizer)
                m_finalizer();
        }
    };

    T* operator->() const { return s_ptr; }
};


template <typename T>
T* Injection<T>::s_ptr = nullptr;