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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_CONDITIONALLY_ENABLED_EVENT_HPP
 
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#define BOOST_COROSIO_DETAIL_CONDITIONALLY_ENABLED_EVENT_HPP
 
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#include <boost/corosio/detail/conditionally_enabled_mutex.hpp>
 
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#include <chrono>
 
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#include <condition_variable>
 
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namespace boost::corosio::detail {
 
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/* Condition variable wrapper that becomes a no-op when disabled.
 
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   When enabled, notify/wait delegate to an underlying
 
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   std::condition_variable. When disabled, all operations
 
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   are no-ops. The wait paths are unreachable in
 
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   single-threaded mode because the task sentinel prevents
 
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   the empty-queue state in do_one().
 
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*/
 
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class conditionally_enabled_event
 
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{
 
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    std::condition_variable cond_;
 
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    bool enabled_;
 
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public:
 
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    explicit conditionally_enabled_event(bool enabled = true) noexcept
 
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        : enabled_(enabled)
 
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    {
 
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    }
 
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    conditionally_enabled_event(conditionally_enabled_event const&)            = delete;
 
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    conditionally_enabled_event& operator=(conditionally_enabled_event const&) = delete;
 
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    void set_enabled(bool v) noexcept
 
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    {
 
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        enabled_ = v;
 
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    }
 
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    void notify_one()
 
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    {
 
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        if (enabled_)
 
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            cond_.notify_one();
 
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    }
 
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    void notify_all()
 
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    {
 
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        if (enabled_)
 
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            cond_.notify_all();
 
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    }
 
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    void wait(conditionally_enabled_mutex::scoped_lock& lock)
 
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    {
 
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        if (enabled_)
 
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            cond_.wait(lock.underlying());
 
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    }
 
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    template<class Rep, class Period>
 
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    void wait_for(
 
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        conditionally_enabled_mutex::scoped_lock& lock,
 
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        std::chrono::duration<Rep, Period> const& d)
 
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    {
 
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        if (enabled_)
 
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            cond_.wait_for(lock.underlying(), d);
 
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    }
 
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};
 
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} // namespace boost::corosio::detail
 
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#endif // BOOST_COROSIO_DETAIL_CONDITIONALLY_ENABLED_EVENT_HPP