/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This file is part of ObjFW. It may be distributed under the terms of the
* Q Public License 1.0, which can be found in the file LICENSE.QPL included in
* the packaging of this file.
*
* Alternatively, it may be distributed under the terms of the GNU General
* Public License, either version 2 or 3, which can be found in the file
* LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
* file.
*/
#include "config.h"
#include <stdbool.h>
#import "OFOnce.h"
#if defined(OF_HAVE_THREADS) && defined(OF_HAVE_ATOMIC_OPS)
# import "OFAtomic.h"
# import "OFPlainMutex.h"
#endif
#ifdef OF_AMIGAOS
# define Class IntuitionClass
# include <proto/exec.h>
# undef Class
#endif
void
OFOnce(OFOnceControl *control, void (*function)(void))
{
#if !defined(OF_HAVE_THREADS)
if (*control == 0) {
function();
*control = 1;
}
#elif defined(OF_HAVE_PTHREADS)
pthread_once(control, function);
#elif defined(OF_HAVE_ATOMIC_OPS)
/* Avoid atomic operations in case it's already done. */
if (*control == 2)
return;
if (OFAtomicIntCompareAndSwap(control, 0, 1)) {
function();
OFMemoryBarrier();
OFAtomicIntIncrease(control);
} else
while (*control == 1)
OFYieldThread();
#elif defined(OF_AMIGAOS)
bool run = false;
/* Avoid Forbid() in case it's already done. */
if (*control == 2)
return;
Forbid();
switch (*control) {
case 0:
*control = 1;
run = true;
break;
case 1:
while (*control == 1) {
Permit();
Forbid();
}
}
Permit();
if (run) {
function();
*control = 2;
}
#else
# error No OFOnce available
#endif
}