queuemanager.cpp

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/
 
#include "queuemanager.h"
#include <QTimer>
 
namespace LC
{
namespace Util
{
    QueueManager::QueueManager (int timeout, QObject *parent)
    : QObject (parent)
    , Timeout_ (timeout)
    , ReqTimer_ (new QTimer (this))
    , Paused_ (false)
    {
        ReqTimer_->setSingleShot (true);
        connect (ReqTimer_,
                SIGNAL (timeout ()),
                this,
                SLOT (exec ()));
    }
 
    void QueueManager::Schedule (std::function<void ()> f, QObject *dep, QueuePriority prio)
    {
        const auto& now = QDateTime::currentDateTime ();
 
        if (prio == QueuePriority::High)
            Queue_.prepend ({ f, dep ? OptionalTracker_t { dep } : OptionalTracker_t () });
        else
            Queue_.append ({ f, dep ? OptionalTracker_t { dep } : OptionalTracker_t () });
 
        const auto diff = LastRequest_.msecsTo (now);
        if (diff >= Timeout_)
            exec ();
        else if (Queue_.size () == 1)
            ReqTimer_->start (Timeout_ - diff);
    }
 
    void QueueManager::Clear ()
    {
        Queue_.clear ();
    }
 
    void QueueManager::Pause ()
    {
        Paused_ = true;
        ReqTimer_->stop ();
    }
 
    bool QueueManager::IsPaused () const
    {
        return Paused_;
    }
 
    void QueueManager::Resume ()
    {
        Paused_ = false;
        ReqTimer_->start (Timeout_);
    }
 
    void QueueManager::exec ()
    {
        if (Queue_.isEmpty ())
            return;
 
        if (Paused_)
            return;
 
        const auto& pair = Queue_.takeFirst ();
        if (pair.second && !*pair.second)
        {
            exec ();
            return;
        }
 
        pair.first ();
        LastRequest_ = QDateTime::currentDateTime ();
 
        if (!Queue_.isEmpty ())
            ReqTimer_->start (Timeout_);
    }
}
}