semaphore.hpp

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#ifndef JOIN_CORE_SEMAPHORE_HPP
#define JOIN_CORE_SEMAPHORE_HPP
 
// libjoin.
#include <join/error.hpp>
#include <join/utils.hpp>
 
// C++.
#include <chrono>
 
// C.
#include <semaphore.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <climits>
 
namespace join
{
    class Semaphore
    {
    public:
        Semaphore (size_t value = 0);
 
        Semaphore (const std::string& name, size_t value = 0, int oflag = O_CREAT, mode_t mode = 0644);
 
        Semaphore (const Semaphore& other) = delete;
 
        Semaphore& operator= (const Semaphore& other) = delete;
 
        ~Semaphore () noexcept;
 
        void post () noexcept;
 
        void wait () noexcept;
 
        bool tryWait () noexcept;
 
        template <class Rep, class Period>
        bool timedWait (std::chrono::duration<Rep, Period> timeout)
        {
            struct timespec ts = toTimespec (std::chrono::system_clock::now () + timeout);
            if (((_named) ? ::sem_timedwait (_named_handle, &ts) : ::sem_timedwait (&_unnamed_handle, &ts)) == -1)
            {
                lastError = std::error_code (errno, std::generic_category ());
                return false;
            }
 
            return true;
        }
 
        int value () noexcept;
 
    private:
        union
        {
            sem_t* _named_handle;
            sem_t _unnamed_handle;
        };
 
        bool _named = false;
    };
 
    class SharedSemaphore
    {
    public:
        SharedSemaphore (size_t value = 0);
 
        SharedSemaphore (const SharedSemaphore& other) = delete;
 
        SharedSemaphore& operator= (const SharedSemaphore& other) = delete;
 
        ~SharedSemaphore () noexcept;
 
        void post () noexcept;
 
        void wait () noexcept;
 
        bool tryWait () noexcept;
 
        template <class Rep, class Period>
        bool timedWait (std::chrono::duration<Rep, Period> timeout)
        {
            struct timespec ts = toTimespec (std::chrono::system_clock::now () + timeout);
            if (sem_timedwait (&_handle, &ts) == -1)
            {
                lastError = std::error_code (errno, std::generic_category ());
                return false;
            }
 
            return true;
        }
 
        int value () noexcept;
 
    private:
        sem_t _handle;
    };
}
 
#endif