tec_queue.hpp

Go to the documentation of this file.

// Time-stamp: <Last changed 2026-02-20 16:01:22 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 <cstddef>
#include <queue>
#include <mutex>
#include <condition_variable>
 
#include "tec/tec_def.hpp" // IWYU pragma: keep
 
 
namespace tec {
 
template <class T>
class SafeQueue {
private:
    std::queue<T> q_; 
    mutable std::mutex m_; 
    mutable std::condition_variable c_; 
 
public:
    SafeQueue(void)
        : q_{}
        , m_{}
        , c_{}
    {}
 
    ~SafeQueue(void) = default;
 
    void enqueue(T&& t) {
        std::lock_guard<std::mutex> lock(m_);
        q_.push(std::move(t));
        c_.notify_one();
    }
 
    T dequeue(void) {
        std::unique_lock<std::mutex> lock(m_);
        while (q_.empty()) {
            // Release lock during wait and reacquire it afterwards.
            c_.wait(lock);
        }
        T val = q_.front();
        q_.pop();
        return val;
    }
 
    std::size_t size() const {
        std::unique_lock<std::mutex> lock(m_);
        return q_.size();
    }
}; // class SafeQueue
 
} // namespace tec