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♻️ Extract return_void & return_value to their own classes #52

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Merged
kammce merged 1 commit into from
Jan 14, 2026
Merged

♻️ Extract return_void & return_value to their own classes #52

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68 changes: 22 additions & 46 deletions modules/async_context.cppm
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Original file line number Diff line number Diff line change
Expand Up @@ -819,29 +819,9 @@ struct final_awaiter
}
};

export template<typename T>
class promise : public promise_base
template<typename T>
struct promise_return_base
{
public:
using promise_base::promise_base; // Inherit constructors
using promise_base::operator new;
using promise_base::operator delete;
using our_handle = std::coroutine_handle<promise<T>>;

friend class future<T>;

constexpr final_awaiter<promise<T>> final_suspend() noexcept
{
return {};
}

void unhandled_exception() noexcept
{
*m_future_state = std::current_exception();
}

constexpr future<T> get_return_object() noexcept;

template<typename U>
void return_value(U&& p_value) noexcept
requires std::is_constructible_v<T, U&&>
Expand All @@ -850,40 +830,44 @@ public:
m_future_state->template emplace<T>(std::forward<U>(p_value));
}

protected:
future_state<T>* m_future_state;
};

export template<>
class promise<void> : public promise_base
template<>
struct promise_return_base<void>
{
void return_void() noexcept
{
*m_future_state = std::monostate{};
}

future_state<void>* m_future_state;
};

export template<typename T>
class promise
: public promise_base
, public promise_return_base<T>
{
public:
using promise_base::promise_base; // Inherit constructors
using promise_base::operator new;
using promise_base::operator delete;
using our_handle = std::coroutine_handle<promise<void>>;
using our_handle = std::coroutine_handle<promise<T>>;

friend class future<void>;
friend class future<T>;

constexpr final_awaiter<promise<void>> final_suspend() noexcept
constexpr final_awaiter<promise<T>> final_suspend() noexcept
{
return {};
}

constexpr future<void> get_return_object() noexcept;

void unhandled_exception() noexcept
{
*m_future_state = std::current_exception();
}

void return_void() noexcept
{
*m_future_state = std::monostate{};
*promise_return_base<T>::m_future_state = std::current_exception();
}

protected:
future_state<void>* m_future_state;
constexpr future<T> get_return_object() noexcept;
};

export template<typename T>
Expand Down Expand Up @@ -1101,14 +1085,6 @@ constexpr future<T> promise<T>::get_return_object() noexcept
return future<T>{ handle };
}

constexpr future<void> promise<void>::get_return_object() noexcept
{
using future_handle = std::coroutine_handle<promise<void>>;
auto handle = future_handle::from_promise(*this);
m_context->active_handle(handle);
return future<void>{ handle };
}

void context::unsafe_cancel()
{
// TODO(#38): Consider if a safe variant of cancel is achievable
Expand Down