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//
 
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// Copyright (c) 2026 Michael Vandeberg
 
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//
 
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
 
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
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//
 
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// Official repository: https://github.com/cppalliance/corosio
 
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//
 
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#ifndef BOOST_COROSIO_DETAIL_OP_BASE_HPP
 
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#define BOOST_COROSIO_DETAIL_OP_BASE_HPP
 
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#include <boost/capy/io_result.hpp>
 
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#include <boost/capy/ex/executor_ref.hpp>
 
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#include <boost/capy/ex/io_env.hpp>
 
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#include <coroutine>
 
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#include <cstddef>
 
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#include <stop_token>
 
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#include <system_error>
 
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namespace boost::corosio::detail {
 
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/* CRTP base for awaitables that return io_result<std::size_t>.
 
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   Derived classes must provide:
 
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     std::coroutine_handle<> dispatch(
 
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         std::coroutine_handle<> h,
 
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         capy::executor_ref ex) const;
 
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   which forwards to the backend implementation method, passing
 
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   token_, &ec_, and &bytes_ as the cancellation/output parameters.
 
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*/
 
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template<class Derived>
 
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class bytes_op_base
 
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{
 
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    friend Derived;
 
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    bytes_op_base() = default;
 
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public:
 
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    std::stop_token token_;
 
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    mutable std::error_code ec_;
 
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    mutable std::size_t bytes_ = 0;
 
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    bool await_ready() const noexcept
 
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    {
 
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        return token_.stop_requested();
 
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    }
 
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    capy::io_result<std::size_t> await_resume() const noexcept
 
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    {
 
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        if (token_.stop_requested())
 
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            return {make_error_code(std::errc::operation_canceled), 0};
 
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        return {ec_, bytes_};
 
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    }
 
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    auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
 
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        -> std::coroutine_handle<>
 
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    {
 
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        token_ = env->stop_token;
 
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        return static_cast<Derived const*>(this)->dispatch(
 
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            h, env->executor);
 
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    }
 
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};
 
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/* CRTP base for awaitables that return io_result<>.
 
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   Derived classes must provide:
 
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     std::coroutine_handle<> dispatch(
 
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         std::coroutine_handle<> h,
 
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         capy::executor_ref ex) const;
 
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   which forwards to the backend implementation method, passing
 
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   token_ and &ec_ as the cancellation/output parameters.
 
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*/
 
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template<class Derived>
 
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class void_op_base
 
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{
 
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    friend Derived;
 
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    void_op_base() = default;
 
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public:
 
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    std::stop_token token_;
 
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    mutable std::error_code ec_;
 
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    bool await_ready() const noexcept
 
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    {
 
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        return token_.stop_requested();
 
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    }
 
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    capy::io_result<> await_resume() const noexcept
 
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    {
 
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        if (token_.stop_requested())
 
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            return {make_error_code(std::errc::operation_canceled)};
 
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        return {ec_};
 
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    }
 
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    auto await_suspend(std::coroutine_handle<> h, capy::io_env const* env)
 
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        -> std::coroutine_handle<>
 
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    {
 
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        token_ = env->stop_token;
 
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        return static_cast<Derived const*>(this)->dispatch(
 
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            h, env->executor);
 
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    }
 
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};
 
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} // namespace boost::corosio::detail
 
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#endif // BOOST_COROSIO_DETAIL_OP_BASE_HPP