/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* 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 Lesser General Public License
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#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)) {
OFAcquireMemoryBarrier();
function();
OFAtomicIntIncrease(control);
OFReleaseMemoryBarrier();
} 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
}