torcadminthread.cpp

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/* Class TorcAdminThread
*
* This file is part of the Torc project.
*
* Copyright (C) Mark Kendall 2012-18
*
* 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.
*/

// Qt
#include <QMutex>

// Torc
#include "torclocalcontext.h"
#include "torclogging.h"
#include "torcadminthread.h"

TorcAdminThread::TorcAdminThread()
  : TorcQThread(TORC_ADMIN_THREAD)
{
}

void TorcAdminThread::Start(void)
{
    LOG(VB_GENERAL, LOG_INFO, QStringLiteral("Admin thread starting"));

    // create objects that will run in the admin thread
    TorcAdminObject::CreateObjects();
}

void TorcAdminThread::Finish(void)
{
    TorcAdminObject::DestroyObjects();
    LOG(VB_GENERAL, LOG_INFO, QStringLiteral("Admin thread stopping"));
}

QList<TorcAdminObject*> TorcAdminObject::gTorcAdminObjects;
TorcAdminObject* TorcAdminObject::gTorcAdminObject = nullptr;
QMutex* TorcAdminObject::gTorcAdminObjectsLock = new QMutex(QMutex::Recursive);

TorcAdminObject::TorcAdminObject(int Priority)
  : m_nextTorcAdminObject(nullptr),
    m_priority(Priority)
{
    QMutexLocker lock(gTorcAdminObjectsLock);
    m_nextTorcAdminObject = gTorcAdminObject;
    gTorcAdminObject = this;
}

int TorcAdminObject::Priority(void) const
{
    return m_priority;
}

TorcAdminObject* TorcAdminObject::GetNextObject(void)
{
    return m_nextTorcAdminObject;
}

bool TorcAdminObject::HigherPriority(const TorcAdminObject *Object1, const TorcAdminObject *Object2)
{
    return Object1->Priority() > Object2->Priority();
}

void TorcAdminObject::CreateObjects(void)
{
    QMutexLocker lock(gTorcAdminObjectsLock);

    // guard against multiple concurrent use
    if (!gTorcAdminObjects.isEmpty())
    {
        LOG(VB_GENERAL, LOG_CRIT, QStringLiteral("Trying to create admin objects but they already exist!"));
        return;
    }

    // create a list of static objects that can be sorted by priority.
    // Dynamically created objects will be appended to this list.
    TorcAdminObject* object = gTorcAdminObject;
    while (object)
    {
        gTorcAdminObjects.append(object);
        object = object->GetNextObject();
    }

    if (gTorcAdminObjects.isEmpty())
        return;

    qSort(gTorcAdminObjects.begin(), gTorcAdminObjects.end(), TorcAdminObject::HigherPriority);

    QList<TorcAdminObject*>::const_iterator it = gTorcAdminObjects.constBegin();
    for ( ; it != gTorcAdminObjects.constEnd(); ++it)
        (*it)->Create();
}

void TorcAdminObject::DestroyObjects(void)
{
    QMutexLocker lock(gTorcAdminObjectsLock);

    // destroy in the reverse order of creation
    QList<TorcAdminObject*>::const_iterator it = gTorcAdminObjects.constEnd();
    while (it != gTorcAdminObjects.constBegin())
    {
        --it;
        (*it)->Destroy();
    }
    gTorcAdminObjects.clear();
}