intrusive_ptr を楽に定義する

template<class Derived>
class intrusive_ptr_facade
{
    friend Derived;
    std::size_t ref_;
    friend inline void intrusive_ptr_add_ref(Derived* p)
    {
        ++static_cast<intrusive_ptr_facade<Derived>*>(p)->ref_;
    }
    friend inline void intrusive_ptr_release(Derived* p)
    {
        if (--static_cast<intrusive_ptr_facade<Derived>*>(p)->ref_ == 0)
        {
            delete p;
        }
    }
    intrusive_ptr_facade() : ref_(0) { }
};

class hoge : public intrusive_ptr_facade<hoge> { };

intrusive_ptr<hoge> h(new hoge());

public 継承なのがダサすぎる……。