SynchronizedList.h

/*
╔══════════════════════════════════════════════════════════════════════════════╗
║                       SIMPLY POWERFUL TOOLKIT (SPTK)                         ║
╟──────────────────────────────────────────────────────────────────────────────╢
║  copyright            © 1999-2022 Alexey Parshin. All rights reserved.       ║
║  email                alexeyp@gmail.com                                      ║
╚══════════════════════════════════════════════════════════════════════════════╝
┌──────────────────────────────────────────────────────────────────────────────┐
│   This library is free software; you can redistribute it and/or modify it    │
│   under the terms of the GNU Library General Public License as published by  │
│   the Free Software Foundation; either version 2 of the License, or (at your │
│   option) any later version.                                                 │
│                                                                              │
│   This library 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 Library   │
│   General Public License for more details.                                   │
│                                                                              │
│   You should have received a copy of the GNU Library General Public License  │
│   along with this library; if not, write to the Free Software Foundation,    │
│   Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.               │
│                                                                              │
│   Please report all bugs and problems to alexeyp@gmail.com.                  │
└──────────────────────────────────────────────────────────────────────────────┘
*/
 
#pragma once
 
#include <functional>
#include <list>
#include <mutex>
#include <sptk5/sptk.h>
#include <sptk5/threads/Semaphore.h>
 
namespace sptk {
 
template<class T>
class SynchronizedList
{
public:
    using CallbackFunction = std::function<bool(T& item)>;
 
    SynchronizedList() = default;
 
    SynchronizedList(const SynchronizedList&) = delete;
 
    SynchronizedList(SynchronizedList&&) noexcept = default;
 
    SynchronizedList& operator=(const SynchronizedList&) = delete;
 
    SynchronizedList& operator=(SynchronizedList&&) noexcept = default;
 
    virtual ~SynchronizedList() = default;
 
    virtual void push_front(const T& data)
    {
        std::scoped_lock lock(m_mutex);
        m_list.push_front(data);
        m_semaphore.post();
    }
 
    virtual bool pop_front(T& item, std::chrono::milliseconds timeout)
    {
        if (m_semaphore.sleep_for(timeout))
        {
            std::scoped_lock lock(m_mutex);
            if (!m_list.empty())
            {
                item = m_list.front();
                m_list.pop_front();
                return true;
            }
        }
        return false;
    }
 
    virtual void push_back(const T& data)
    {
        std::scoped_lock lock(m_mutex);
        m_list.push_back(data);
        m_semaphore.post();
    }
 
    virtual bool pop_back(T& item, std::chrono::milliseconds timeout)
    {
        if (m_semaphore.sleep_for(timeout))
        {
            std::scoped_lock lock(m_mutex);
            if (!m_list.empty())
            {
                item = m_list.back();
                m_list.pop_back();
                return true;
            }
        }
        return false;
    }
 
    virtual void remove(T& item)
    {
        std::scoped_lock lock(m_mutex);
        m_list.remove(item);
    }
 
    virtual void wakeup()
    {
        m_semaphore.post();
    }
 
    bool empty() const
    {
        std::scoped_lock lock(m_mutex);
        return m_list.empty();
    }
 
    size_t size() const
    {
        std::scoped_lock lock(m_mutex);
        return m_list.size();
    }
 
    void clear()
    {
        std::scoped_lock lock(m_mutex);
        m_list.clear();
    }
 
    bool each(const CallbackFunction& callbackFunction)
    {
        std::scoped_lock lock(m_mutex);
        for (auto itor = m_list.begin(); itor != m_list.end(); ++itor)
        {
            if (!callbackFunction(*itor))
            {
                return false;
            }
        }
        return true;
    }
 
private:
    mutable std::mutex m_mutex; 
    Semaphore m_semaphore;      
    std::list<T> m_list;        
};
 
}