coroutine_handle.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2021 Tobias Hienzsch
 
#ifndef TETL_COROUTINE_COROUTINE_HANDLE_HPP
#define TETL_COROUTINE_COROUTINE_HANDLE_HPP
 
#include <etl/_cstddef/nullptr_t.hpp>
#include <etl/_functional/hash.hpp>
 
#if defined(__cpp_coroutines)
 
namespace etl {
 
/// \ingroup coroutine
template <typename Promise = void>
struct coroutine_handle;
 
/// \ingroup coroutine
template <>
struct coroutine_handle<void> {
    constexpr coroutine_handle() noexcept = default;
 
    constexpr coroutine_handle(nullptr_t handle) noexcept
        : _handle(handle)
    {
    }
 
    constexpr auto operator=(nullptr_t) noexcept -> coroutine_handle&
    {
        _handle = nullptr;
        return *this;
    }
 
    [[nodiscard]] constexpr auto address() const noexcept -> void*
    {
        return _handle;
    }
 
    [[nodiscard]] static constexpr auto from_address(void* addr) noexcept -> coroutine_handle
    {
        auto self    = coroutine_handle{};
        self._handle = addr;
        return self;
    }
 
    [[nodiscard]] constexpr explicit operator bool() const noexcept
    {
        return _handle != nullptr;
    }
 
    [[nodiscard]] auto done() const noexcept -> bool
    {
        return __builtin_coro_done(_handle);
    }
 
    auto operator()() const -> void
    {
        resume();
    }
 
    auto resume() const -> void
    {
        __builtin_coro_resume(_handle);
    }
 
    auto destroy() const -> void
    {
        __builtin_coro_destroy(_handle);
    }
 
protected:
    void* _handle{nullptr};
};
 
/// \relates coroutine_handle
/// \ingroup coroutine
template <typename T>
struct hash<coroutine_handle<T>> {
    [[nodiscard]] auto operator()(coroutine_handle<T> const& v) const noexcept -> size_t
    {
        return hash<void*>()(v.address());
    }
};
 
} // namespace etl
 
#endif // defined(__cpp_coroutines)
 
#endif // TETL_COROUTINE_COROUTINE_HANDLE_HPP