removed unused code again

#include "geo/CityNode.hpp"

#include "geo/GeographicNode.hpp"

#include "topo/Graph.hpp"

#include "util/ConcurrentQueue.hpp"

#include <lemon/list_graph.h>

#include <map>

#include <utility>

/*

 * Copyright (c) 2013-2014, Michael Grey and Markus Theil

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holder nor the names of its

 *    contributors may be used to endorse or promote products derived

 *    from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS

 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <mutex>

#include <queue>

#include <condition_variable>

// http://www.justsoftwaresolutions.co.uk/threading/implementing-a-thread-safe-queue-using-condition-variables.html

template <typename Data>

class ConcurrentQueue {

   private:

    std::queue<Data> the_queue;

    mutable std::mutex the_mutex;

    std::condition_variable the_condition_variable;

   public:

    void push(Data const& data) {

        std::unique_lock<std::mutex> lock(the_mutex);

        the_queue.push(data);

        lock.unlock();

        the_condition_variable.notify_one();

    }

    void push(Data const&& data) {

        std::unique_lock<std::mutex> lock(the_mutex);

        the_queue.push(data);

        lock.unlock();

        the_condition_variable.notify_one();

    }

    bool empty() const {

        std::unique_lock<std::mutex> lock(the_mutex);

        return the_queue.empty();

    }

    bool try_pop(Data& popped_value) {

        std::unique_lock<std::mutex> lock(the_mutex);

        if (the_queue.empty()) {

            return false;

        }

        popped_value = the_queue.front();

        the_queue.pop();

        return true;

    }

    void wait_and_pop(Data& popped_value) {

        std::unique_lock<std::mutex> lock(the_mutex);

        while (the_queue.empty()) {

            the_condition_variable.wait(lock);

        }

        popped_value = the_queue.front();

        the_queue.pop();

    }

};