tec_signal.hpp

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// Time-stamp: <Last changed 2026-02-20 16:02:26 by magnolia>
/*----------------------------------------------------------------------
------------------------------------------------------------------------
Copyright (c) 2020-2026 The Emacs Cat (https://github.com/olddeuteronomy/tec).
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
 
     http://www.apache.org/licenses/LICENSE-2.0
 
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
------------------------------------------------------------------------
----------------------------------------------------------------------*/
#pragma once
 
#include <mutex>
#include <condition_variable>
 
#include "tec/tec_def.hpp" // IWYU pragma: keep
 
 
namespace tec {
 
class Signal {
private:
    using Lock = std::lock_guard<std::mutex>; 
    using ULock = std::unique_lock<std::mutex>; 
 
    mutable std::mutex m_; 
    mutable std::condition_variable cv_; 
    mutable bool flag_; 
 
public:
    Signal()
        : flag_(false)
    {}
 
    Signal(const Signal&) = delete;
    Signal(Signal&&) = delete;
 
    virtual ~Signal() = default;
 
    void set() {
        {
            Lock lock(m_);
            flag_ = true;
        }
        cv_.notify_all();
    }
 
    void wait() const {
        ULock ulock(m_);
        cv_.wait(ulock, [this] { return flag_; });
    }
 
    template <typename Duration>
    bool wait_for(Duration dur) const {
        ULock ulock(m_);
        return cv_.wait_for(ulock, dur, [this] { return flag_; });
    }
 
    struct OnExit {
    private:
        Signal* sig_; 
 
    public:
        explicit OnExit(Signal* sig) : sig_{sig} {}
 
        ~OnExit() { sig_->set(); }
    };
}; // class Signal
 
} // namespace tec