qmutex.cpp

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#include <stdio.h>

#include "qglobal.h"

#include "qmutex.h"
#include "qmutex_p.h"

QMutex::QMutex() : d(new QMutexPrivate())
{
}

QMutex::~QMutex()
{
  delete d;
}

void QMutex::lock()
{
    //printf("%p: QMutex::lock(): enter\n",this);
    bool isLocked;
    isLocked = d->contenders.testAndSet(0, 1);
    if (!isLocked)
    {
      isLocked = d->contenders.fetchAndAdd(1)==0;
      if (!isLocked)
      {
        // didn't get the lock, wait for it
        //printf("%p: QMutex::lock(): wait() %d\n",this,(int)d->contenders);
        d->wait();

        // release lock
        d->contenders.fetchAndAdd(-1);
      }
    }
    //printf("%p: QMutex::lock(): leave\n",this);
}

bool QMutex::tryLock()
{
    bool isLocked = d->contenders.testAndSet(0, 1);
    return isLocked;
}

void QMutex::unlock()
{
    //printf("%p: QMutex::unlock(): enter %d\n",this,(int)d->contenders);
    if (!d->contenders.testAndSet(1, 0))
    {
         //printf("%p: QMutex::unlock(): wakeUp()\n",this);
         d->wakeUp();
    }
    //printf("%p: QMutex::unlock(): leave\n",this);
}