source: trunk/yat/utility/Queue.h @ 3751

#ifndef theplu_yat_utility_queue
#define theplu_yat_utility_queue

// $Id: Queue.h 3751 2018-10-17 01:49:41Z peter $
//
// Copyright (C) 2013, 2014, 2016, 2017 Peter Johansson
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with yat. If not, see <http://www.gnu.org/licenses/>.

#include "config_public.h"

#include "BasicQueue.h"
#include "utility.h"
#include "yat_assert.h"

#include <boost/thread.hpp>

#include <deque>
#include <utility>

namespace theplu {
namespace yat {
namespace utility {

  /**
     \brief Multi-thread safe queue

     This class provides a multi-thread safe queue. The Queue is
     typically shared by multiple threads such that some threads push
     elements and some pop elements. The Queue is a "first in first
     out" container and holds the same functionality as the similar
     <a href="http://www.sgi.com/tech/stl/queue.html">std::queue</a>. The
     difference is that Queue is multi-thread safe, in other words,
     when one thread access the Queue, other threads are locked out
     from access so that only one thread touches the Queue at a time
     and its behaviour is well defined. In a single-thread application
     there is no point in using the class as std::queue should be
     prefereble.

     \note Copy constructor and assignment are available but they are
     not thread safe in the current implementation.

     \since New in yat 0.11

     \see Boost Library provides a
     <a href="http://www.boost.org/doc/libs/1_55_0/doc/html/lockfree.html">
     lock-free queue</a>
   */
  template<typename T>
  class Queue :
    public detail::BasicQueue<Queue<T>, T, std::deque<T> >
  {
    friend class detail::BasicQueue<Queue<T>, T, std::deque<T> >;
    typedef detail::BasicQueue<Queue<T>, T, std::deque<T> > Base;
  public:
    /**
       \brief Create a Queue with no elements
    */
    Queue(void) {}

    /**
       \brief Copy constructor
    */
    Queue(const Queue& other)
      : Base(other) {}

    /**
       \brief assignment operator
     */
    Queue& operator=(const Queue& lhs)
    {
      this->assign(lhs);
      return *this;
    }

  private:
    void pop_impl(T& value, boost::unique_lock<boost::mutex>& lock)
    {
      YAT_ASSERT(this->q_.size());
      value = YAT_MOVE_IF_NOEXCEPT(this->q_.front());
      this->q_.pop_front();
    }


    void push_impl(const T& value, boost::unique_lock<boost::mutex>& lock)
    {
      this->q_.push_back(value);
    }


#ifdef YAT_HAVE_RVALUE
    void push_impl(T&& value, boost::unique_lock<boost::mutex>& lock)
    {
      this->q_.push_back(std::move(value));
    }
#endif
  };

}}}
#endif