test_type_object.cc

#include "define.h"

//! An example type descriptor that is also an object.
struct t_type : t_object<t_type>
{
	//! Called by the collector to scan object members.
	void (*f_scan)(t_object<t_type>*, t_scan<t_type>);
	//! Called by the collector to finalize this.
	/*!
	  It is necessary to scan object members as in f_scan.
	  This is where to destruct native part.
	 */
	void (*f_finalize)(t_object<t_type>*, t_scan<t_type>);
};

template<typename T>
struct t_type_of : t_type
{
	T* f_new(auto&&... a_xs)
	{
		f_epoch_point<t_type>();
		auto p = static_cast<T*>(f_engine<t_type>()->f_allocate(sizeof(T)));
		new(p) T(std::forward<decltype(a_xs)>(a_xs)...);
		// Finishes object construction.
		p->f_be(this);
		return p;
	}
};

template<>
struct t_type_of<t_type> : t_type
{
	//! Constructs t_type_of<t_type>.
	static t_type_of* f_initialize()
	{
		f_epoch_point<t_type>();
		auto p = static_cast<t_type_of*>(f_engine<t_type>()->f_allocate(sizeof(t_type_of)));
		p->f_scan = p->f_finalize = [](auto, auto)
		{
		};
		// t_type_of<t_type> is also an instance of t_type_of<t_type>.
		p->f_be(p);
		return p;
	}

	//! Constructs t_type_of<T>.
	template<typename T>
	t_type_of<T>* f_new()
	{
		f_epoch_point<t_type>();
		auto p = static_cast<t_type_of<T>*>(f_engine<t_type>()->f_allocate(sizeof(t_type_of<T>)));
		p->f_scan = [](auto a_this, auto a_scan)
		{
			// Just delegates to a_this.
			static_cast<T*>(a_this)->f_scan(a_scan);
		};
		p->f_finalize = [](auto a_this, auto a_scan)
		{
			// Just delegates to a_this.
			auto p = static_cast<T*>(a_this);
			p->f_scan(a_scan);
			std::destroy_at(p);
		};
		// t_type_of<T> is an instance of t_type_of<t_type>.
		p->f_be(this);
		return p;
	}
};

struct t_pair : t_object<t_type>
{
	t_slot_of<t_object<t_type>> v_head;
	t_slot_of<t_object<t_type>> v_tail;

	//! Called by t_type_of<t_pair>::f_new(...).
	t_pair(t_object<t_type>* RECYCLONE__SPILL a_head = nullptr, t_object<t_type>* RECYCLONE__SPILL a_tail = nullptr) : v_head(a_head), v_tail(a_tail)
	{
		f_epoch_point<t_type>();
	}
	//! Called by t_type_of<t_pair>::f_scan(...).
	void f_scan(t_scan<t_type> a_scan)
	{
		a_scan(v_head);
		a_scan(v_tail);
	}
};

int main(int argc, char* argv[])
{
	t_engine<t_type>::t_options options;
	if (argc > 1) std::sscanf(argv[1], "%zu", &options.v_collector__threshold);
	options.v_verbose = true;
	t_engine<t_type> engine(options);
	return []() RECYCLONE__NOINLINE
	{
		auto RECYCLONE__SPILL type_type = t_type_of<t_type>::f_initialize();
		assert(type_type->f_type() == type_type);
		auto RECYCLONE__SPILL type_pair = type_type->f_new<t_pair>();
		assert(type_pair->f_type() == type_type);
		assert(type_pair->f_new(type_pair->f_new(), type_pair->f_new())->f_type() == type_pair);
		return 0;
	}();
}