112 lines
3.0 KiB
C
112 lines
3.0 KiB
C
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/*
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* s3fs - FUSE-based file system backed by Amazon S3
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*
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* Copyright(C) 2007 Randy Rizun <rrizun@gmail.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef S3FS_SEMAPHORE_H_
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#define S3FS_SEMAPHORE_H_
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//-------------------------------------------------------------------
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// Class Semaphore
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//-------------------------------------------------------------------
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// portability wrapper for sem_t since macOS does not implement it
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#ifdef __APPLE__
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#include <dispatch/dispatch.h>
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class Semaphore
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{
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public:
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explicit Semaphore(int value) : value(value), sem(dispatch_semaphore_create(value)) {}
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~Semaphore()
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{
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// macOS cannot destroy a semaphore with posts less than the initializer
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for(int i = 0; i < get_value(); ++i){
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post();
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}
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dispatch_release(sem);
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}
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Semaphore(const Semaphore&) = delete;
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Semaphore(Semaphore&&) = delete;
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Semaphore& operator=(const Semaphore&) = delete;
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Semaphore& operator=(Semaphore&&) = delete;
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void wait() { dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER); }
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bool try_wait()
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{
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if(0 == dispatch_semaphore_wait(sem, DISPATCH_TIME_NOW)){
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return true;
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}else{
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return false;
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}
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}
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void post() { dispatch_semaphore_signal(sem); }
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int get_value() const { return value; }
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private:
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const int value;
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dispatch_semaphore_t sem;
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};
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#else
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#include <errno.h>
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#include <semaphore.h>
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class Semaphore
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{
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public:
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explicit Semaphore(int value) : value(value) { sem_init(&mutex, 0, value); }
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~Semaphore() { sem_destroy(&mutex); }
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void wait()
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{
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int r;
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do {
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r = sem_wait(&mutex);
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} while (r == -1 && errno == EINTR);
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}
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bool try_wait()
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{
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int result;
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do{
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result = sem_trywait(&mutex);
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}while(result == -1 && errno == EINTR);
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return (0 == result);
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}
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void post() { sem_post(&mutex); }
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int get_value() const { return value; }
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private:
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const int value;
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sem_t mutex;
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};
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#endif
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#endif // S3FS_SEMAPHORE_H_
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/*
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* Local variables:
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* tab-width: 4
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* c-basic-offset: 4
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* End:
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* vim600: expandtab sw=4 ts=4 fdm=marker
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* vim<600: expandtab sw=4 ts=4
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*/
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