TclThreadList.h

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/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *                    > www.orxonox.net <
 *
 *
 *   License notice:
 *
 *   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 2
 *   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 this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 *   Author:
 *      Fabian 'x3n' Landau
 *   Co-authors:
 *      ...
 *
 */

#ifndef _TclThreadList_H__
#define _TclThreadList_H__

#include "core/CorePrereqs.h"

#include <list>

#include <boost/thread/condition_variable.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <boost/thread/locks.hpp>

namespace orxonox
{
    template <class T>
    class TclThreadList
    {
        public:
            void push_front(const T& value);
            void push_back(const T& value);
            template <class InputIterator> void insert(typename std::list<T>::iterator position, InputIterator begin, InputIterator end);

            void wait_and_pop_front(T* value);
            void wait_and_pop_back(T* value);
            bool try_pop_front(T* value);
            bool try_pop_back(T* value);
            void clear();

            size_t size() const;
            bool empty() const;
            bool is_in(const T& value) const;

            inline std::list<T>& getList()
                { return this->list_; }

            inline const std::list<T>& getList() const
                { return this->list_; }

            inline boost::shared_mutex& getMutex() const
                { return this->mutex_; }

        private:
            std::list<T>                  list_;        
            mutable boost::shared_mutex   mutex_;       
            boost::condition_variable_any condition_;   
    };

    template <class T>
    void TclThreadList<T>::push_front(const T& value)
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);
        this->list_.push_front(value);
        lock.unlock();                  // unlock the mutex...
        this->condition_.notify_all();  // ...then call notify_all to wake threads waiting in wait_and_pop_front/back
    }

    template <class T>
    void TclThreadList<T>::push_back(const T& value)
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);
        this->list_.push_back(value);
        lock.unlock();                  // unlock the mutex...
        this->condition_.notify_all();  // ...then call notify_all to wake threads waiting in wait_and_pop_front/back
    }

    template <class T>
    template <class InputIterator> void TclThreadList<T>::insert(typename std::list<T>::iterator position, InputIterator begin, InputIterator end)
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);
        this->list_.insert(position, begin, end);
        lock.unlock();                  // unlock the mutex...
        this->condition_.notify_all();  // ...then call notify_all to wake threads waiting in wait_and_pop_front/back
    }

    template <class T>
    void TclThreadList<T>::wait_and_pop_front(T* value)
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);

        while (this->list_.empty())       // check if there's an element in the list
            this->condition_.wait(lock);  // wait until the condition becomes true (a notification comes from push_front, push_back or insert

        *value = this->list_.front();
        this->list_.pop_front();
    }

    template <class T>
    void TclThreadList<T>::wait_and_pop_back(T* value)
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);

        while (this->list_.empty())       // check if there's an element in the list
            this->condition_.wait(lock);  // wait until the condition becomes true (a notification comes from push_front, push_back or insert

        *value = this->list_.back();
        this->list_.pop_back();
    }

    template <class T>
    bool TclThreadList<T>::try_pop_front(T* value)
    {
        boost::upgrade_lock<boost::shared_mutex> lock(this->mutex_); // gain shared lock

        if (this->list_.empty())
        {
            // No elements - return immediately
            return false;
        }
        else
        {
            // At least one element - write it into the passed variable and pop it from the list
            boost::upgrade_to_unique_lock<boost::shared_mutex> unique_lock(lock); // upgrade to unique lock to modify the list
            *value = this->list_.front();
            this->list_.pop_front();
        }
        return true;
    }

    template <class T>
    bool TclThreadList<T>::try_pop_back(T* value)
    {
        boost::upgrade_lock<boost::shared_mutex> lock(this->mutex_); // gain shared lock

        if (this->list_.empty())
        {
            // No elements - return immediately
            return false;
        }
        else
        {
            // At least one element - write it into the passed variable and pop it from the list
            boost::upgrade_to_unique_lock<boost::shared_mutex> unique_lock(lock); // upgrade to unique lock to modify the list
            *value = this->list_.back();
            this->list_.pop_back();
        }
        return true;
    }

    template <class T>
    void TclThreadList<T>::clear()
    {
        boost::unique_lock<boost::shared_mutex> lock(this->mutex_);
        this->list_.clear();
    }

    template <class T>
    size_t TclThreadList<T>::size() const
    {
        boost::shared_lock<boost::shared_mutex> lock(this->mutex_);
        return this->list_.size();
    }

    template <class T>
    bool TclThreadList<T>::empty() const
    {
        boost::shared_lock<boost::shared_mutex> lock(this->mutex_);
        return this->list_.empty();
    }

    template <class T>
    bool TclThreadList<T>::is_in(const T& value) const
    {
        boost::shared_lock<boost::shared_mutex> lock(this->mutex_);

        for (const T& element : this->list_)
            if (element == value)
                return true;

        return false;
    }
}

#endif /* _TclThreadList_H__ */