epoll.h

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#include <exception>
#include <qb/utility/branch_hints.h>
#include <sys/epoll.h>
#include "../helper.h"
 
#ifdef __WIN__SYSTEM__
#error "epoll is not available on windows"
#endif
 
#ifndef QB_IO_EPOLL_H
#define QB_IO_EPOLL_H
 
namespace qb {
namespace io {
namespace epoll {

class Proxy {
protected:
    int _epoll; 
 
public:
    Proxy() = default;

    Proxy(const int epoll)
        : _epoll(epoll) {}
 
public:
    using item_type = epoll_event;

    Proxy(Proxy const &) = default;

    inline int
    ctl(item_type &item) const {
        return epoll_ctl(_epoll, EPOLL_CTL_MOD, item.data.fd, &item);
    }

    inline int
    add(item_type &item) const {
        return epoll_ctl(_epoll, EPOLL_CTL_ADD, item.data.fd, &item);
    }

    inline int
    remove(item_type const &item) {
        return epoll_ctl(_epoll, EPOLL_CTL_DEL, item.data.fd, nullptr);
    }
};

template <std::size_t _MAX_EVENTS = 4096>
class Poller : public Proxy {
    epoll_event _epvts[_MAX_EVENTS]; 
 
public:
    Poller()
        : Proxy(epoll_create(_MAX_EVENTS)) {
        if (unlikely(_epoll < 0))
            throw std::runtime_error("failed to init epoll::Poller");
    }

    Poller(Poller const &) = delete;

    ~Poller() {
        ::close(_epoll);
    }

    template <typename _Func>
    inline void
    wait(_Func const &func, int const timeout = 0) {
        const int ret = epoll_wait(_epoll, _epvts, _MAX_EVENTS, timeout);
        if (unlikely(ret < 0)) {
            std::cerr << "epoll::Poller polling has failed " << std::endl;
            return;
        }
        for (int i = 0; i < ret; ++i) {
            func(_epvts[i]);
        }
    }
};
 
} // namespace epoll
} // namespace io
} // namespace qb
 
#endif // QB_IO_EPOLL_H