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conky/src/semaphore.hh

116 lines
2.6 KiB
C++

/*
*
* Conky, a system monitor, based on torsmo
*
* Please see COPYING for details
*
* Copyright (C) 2010 Pavel Labath et al.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef SEMAPHORE_HH
#define SEMAPHORE_HH
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <stdexcept>
#if defined(__APPLE__) && defined(__MACH__)
/*
* On Darwin, unnamed semaphores are not supported!
* The only close equivalent to unnamed semaphores is using
* GCD!
*/
#include <dispatch/dispatch.h>
class semaphore {
dispatch_semaphore_t sem;
semaphore(const semaphore &) = delete;
semaphore &operator=(const semaphore &) = delete;
public:
semaphore(unsigned int value = 0) {
sem = dispatch_semaphore_create(value);
if (!sem) throw std::logic_error(strerror(errno));
}
~semaphore() { dispatch_release(sem); }
void post() { dispatch_semaphore_signal(sem); }
void wait() { dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER); }
bool trywait() {
/* XXX Quick patch */
#define DISPATCH_EAGAIN 49
int ret = dispatch_semaphore_wait(sem, DISPATCH_TIME_NOW);
while (ret > 0) {
if (ret == DISPATCH_EAGAIN)
return false;
else if (errno != EINTR)
abort();
}
return true;
}
};
#else
#include <semaphore.h>
class semaphore {
sem_t sem;
semaphore(const semaphore &) = delete;
semaphore &operator=(const semaphore &) = delete;
public:
semaphore(unsigned int value = 0) {
if (sem_init(&sem, 0, value)) throw std::logic_error(strerror(errno));
}
~semaphore() { sem_destroy(&sem); }
void post() {
if (sem_post(&sem)) throw std::overflow_error(strerror(errno));
}
void wait() {
while (sem_wait(&sem)) {
if (errno != EINTR) abort();
}
}
bool trywait() {
while (sem_trywait(&sem)) {
if (errno == EAGAIN)
return false;
else if (errno != EINTR)
abort();
}
return true;
}
};
#endif /* defined(__APPLE__) && defined(__MACH__) */
#endif