libspinscale/include/spinscale/co/returnValues.h

#ifndef RETURN_VALUES_H
#define RETURN_VALUES_H

#include <config.h>
#include <exception>
#include <iostream>
#include <thread>
#include <type_traits>

namespace sscl::co {

template <typename T, bool IsVoid = std::is_void_v<T>>
struct ReturnValueStorage;

template <typename T>
struct ReturnValueStorage<T, false>
{
	T myReturnValue{};
};

template <typename T>
struct ReturnValueStorage<T, true>
{
};

template <typename T>
struct ReturnValues
: public ReturnValueStorage<T>
{
	ReturnValues() noexcept
	: myExceptionPtr(myMemberExceptionPtr)
	{}

	explicit ReturnValues(std::exception_ptr &callerExceptionPtr) noexcept
	: myExceptionPtr(callerExceptionPtr)
	{}

	~ReturnValues() noexcept
	{
#ifdef CONFIG_LIBSSCL_DEBUG_CO
		std::cout << __func__ << ": " << std::this_thread::get_id()
			<< " Destructing.\n";
#endif
	}

	/**	EXPLANATION:
	 * The exception_ptr ref here can either point to the exception_ptr
	 * a non-viral coroutine supplied to us as its storage space for
	 * where we should store any exception that is thrown;
	 *
	 * Or it could point to the member exception_ptr in this very class,
	 * which is used for viral coroutines that can bubble their exception
	 * up and automatically via the language runtime.
	 */
	std::exception_ptr &myExceptionPtr;
	std::exception_ptr myMemberExceptionPtr = nullptr;
};

} // namespace sscl::co

#endif // RETURN_VALUES_H