pcsx2/common/Darwin/DarwinSemaphore.cpp

72 lines
1.9 KiB
C++

// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
// SPDX-License-Identifier: LGPL-3.0+
#if defined(__APPLE__)
#include <cstdio>
#include <cassert> // assert
#include <pthread.h> // pthread_setcancelstate()
#include <sys/time.h> // gettimeofday()
#include <mach/mach.h>
#include <mach/task.h> // semaphore_create() and semaphore_destroy()
#include <mach/semaphore.h> // semaphore_*()
#include <mach/mach_error.h> // mach_error_string()
#include <mach/mach_time.h> // mach_absolute_time()
#include "common/Threading.h"
// --------------------------------------------------------------------------------------
// Semaphore Implementation for Darwin/OSX
//
// Sadly, Darwin/OSX needs its own implementation of Semaphores instead of
// relying on phtreads, because OSX unnamed semaphore (the best kind)
// support is very poor.
//
// This implementation makes use of Mach primitives instead. These are also
// what Grand Central Dispatch (GCD) is based on, as far as I understand:
// http://newosxbook.com/articles/GCD.html.
//
// --------------------------------------------------------------------------------------
static void MACH_CHECK(kern_return_t mach_retval)
{
if (mach_retval != KERN_SUCCESS)
{
fprintf(stderr, "mach error: %s", mach_error_string(mach_retval));
assert(mach_retval == KERN_SUCCESS);
}
}
Threading::KernelSemaphore::KernelSemaphore()
{
MACH_CHECK(semaphore_create(mach_task_self(), &m_sema, SYNC_POLICY_FIFO, 0));
}
Threading::KernelSemaphore::~KernelSemaphore()
{
MACH_CHECK(semaphore_destroy(mach_task_self(), m_sema));
}
void Threading::KernelSemaphore::Post()
{
MACH_CHECK(semaphore_signal(m_sema));
}
void Threading::KernelSemaphore::Wait()
{
MACH_CHECK(semaphore_wait(m_sema));
}
bool Threading::KernelSemaphore::TryWait()
{
mach_timespec_t time = {};
kern_return_t res = semaphore_timedwait(m_sema, time);
if (res == KERN_OPERATION_TIMED_OUT)
return false;
MACH_CHECK(res);
return true;
}
#endif