torcrunlooposx.cpp

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/* Class TorcRunLoopOSX
*
* 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 <QTimer>
#include <QAtomicInt>

// Torc
#include "torclocalcontext.h"
#include "torclogging.h"
#include "torccocoa.h"
#include "torcqthread.h"
#include "torcadminthread.h"
#include "torcrunlooposx.h"

CFRunLoopRef gAdminRunLoop = 0;
QAtomicInt   gAdminRunLoopRunning(0);

TorcOSXCallbackThread::TorcOSXCallbackThread()
  : TorcQThread(QStringLiteral("OSXRunLoop")),
    m_object(nullptr)
{
}

TorcOSXCallbackThread::~TorcOSXCallbackThread()
{
    delete m_object;
}

void TorcOSXCallbackThread::Start(void)
{
    LOG(VB_GENERAL, LOG_INFO, QStringLiteral("OSX callback thread starting"));
    gAdminRunLoop = CFRunLoopGetCurrent();
    m_object = new CallbackObject();
}

void TorcOSXCallbackThread::Finish(void)
{
    if (m_object)
        m_object->disconnect();
    delete m_object;
    m_object = nullptr;
    gAdminRunLoop = 0;
    LOG(VB_GENERAL, LOG_INFO, QStringLiteral("OSX callback thread stopping"));
}

CallbackObject::CallbackObject()
{
    // schedule the run loop to start
    QTimer::singleShot(10, Qt::CoarseTimer, this, SLOT(Run()));
}

void CallbackObject::Run(void)
{
    // start the run loop
    if (gAdminRunLoopRunning.fetchAndAddOrdered(0))
        CFRunLoopRun();

    // if it exits, schedule it to start again. This usually means there is nothing
    // setup using a callback, so don't waste cycles and wait a while before restarting.
    if (gAdminRunLoopRunning.fetchAndAddOrdered(0))
        QTimer::singleShot(100, Qt::CoarseTimer, this, SLOT(Run()));
}

static class TorcRunLoopOSX : public TorcAdminObject
{
  public:
    TorcRunLoopOSX()
      : TorcAdminObject(TORC_ADMIN_CRIT_PRIORITY + 10),
        m_thread(nullptr),
        m_createdThread(false)
    {
    }

    ~TorcRunLoopOSX()
    {
        Destroy();
    }

    void Create(void)
    {
        Destroy();

        // we no longer use a separate admin thread - this code is retained just in case...
        if (true)
        {
            gAdminRunLoop = CFRunLoopGetMain();
            return;
        }

        m_createdThread = true;
        gAdminRunLoopRunning.ref();

        m_thread = new TorcOSXCallbackThread();
        m_thread->start();

        int count = 0;
        while (count++ < 10 && !m_thread->isRunning())
            QThread::msleep(count < 2 ? 10 : 100);

        if (!m_thread->isRunning())
            LOG(VB_GENERAL, LOG_WARNING, QStringLiteral("OS X callback thread not started yet!"));
    }

    void Destroy(void)
    {
        if (!m_createdThread)
            return;

        m_createdThread = false;
        gAdminRunLoopRunning.deref();

        if (gAdminRunLoop)
            CFRunLoopStop(gAdminRunLoop);

        if (m_thread)
        {
            m_thread->quit();
            m_thread->wait();
        }

        delete m_thread;
        m_thread = nullptr;
    }

  private:
    TorcOSXCallbackThread *m_thread;
    bool                   m_createdThread;
} TorcRunLoopOSX;