s3fs-fuse/src/psemaphore.h

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/*
* s3fs - FUSE-based file system backed by Amazon S3
*
* Copyright(C) 2007 Randy Rizun <rrizun@gmail.com>
*
* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
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#ifndef S3FS_SEMAPHORE_H_
#define S3FS_SEMAPHORE_H_
// portability wrapper for sem_t since macOS does not implement it
#ifdef __APPLE__
#include <dispatch/dispatch.h>
class Semaphore
{
public:
explicit Semaphore(int value) : value(value), sem(dispatch_semaphore_create(value)) {}
~Semaphore() {
// macOS cannot destroy a semaphore with posts less than the initializer
for(int i = 0; i < get_value(); ++i){
post();
}
dispatch_release(sem);
}
void wait() { dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER); }
void post() { dispatch_semaphore_signal(sem); }
int get_value() const { return value; }
private:
const int value;
dispatch_semaphore_t sem;
};
#else
#include <errno.h>
#include <semaphore.h>
class Semaphore
{
public:
explicit Semaphore(int value) : value(value) { sem_init(&mutex, 0, value); }
~Semaphore() { sem_destroy(&mutex); }
void wait()
{
int r;
do {
r = sem_wait(&mutex);
} while (r == -1 && errno == EINTR);
}
void post() { sem_post(&mutex); }
int get_value() const { return value; }
private:
const int value;
sem_t mutex;
};
#endif
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#endif // S3FS_SEMAPHORE_H_