hirun 0.1.13

A concurrent framework for asynchronous programming based on event-driven, non-blocking I/O mechanism
Documentation 
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use super::{Poll, POLLIN, POLLOUT};
use crate::{Error, Result};
use core::mem::MaybeUninit;
use core::ptr;
use hipool::{Allocator, Boxed, Pool, PoolAlloc};

pub(crate) type BoxedPollImpl<'a, A> = Boxed<'a, PollImpl<'a, A>, A>;

#[repr(C)]
pub(crate) struct PollImpl<'a, A: Allocator = PoolAlloc> {
    fd: i32,
    events: Boxed<'a, [MaybeUninit<libc::epoll_event>], A>,
}

unsafe impl<A: Allocator + Pool> Send for PollImpl<'static, A> {}

impl<'a, A: Allocator + 'a> Drop for PollImpl<'a, A> {
    fn drop(&mut self) {
        unsafe { libc::close(self.fd) };
    }
}

impl<'a, A: Allocator + 'a> PollImpl<'a, A> {
    pub fn new_in(pool: &'a A) -> Result<BoxedPollImpl<'a, A>> {
        let events = Boxed::uninit_slice_in::<libc::epoll_event>(pool, EPOLL_EVENT_MAX)?;
        let uninit = Boxed::uninit_in::<Self>(pool)?;
        let fd = unsafe { libc::epoll_create1(libc::EPOLL_CLOEXEC) };
        if fd >= 0 {
            let poll = uninit.write(Self { fd, events });
            Ok(poll)
        } else {
            Err(Error::last())
        }
    }
}

impl<'a, A: Allocator + 'a> Poll for PollImpl<'a, A> {
    fn add_event(&self, fd: i32, events: u32, e: u64) -> Result<()> {
        let mut event = libc::epoll_event { events, u64: e };
        let ret =
            unsafe { libc::epoll_ctl(self.fd, libc::EPOLL_CTL_ADD, fd, ptr::addr_of_mut!(event)) };
        if ret == 0 {
            Ok(())
        } else {
            Err(Error::last())
        }
    }

    fn mod_event(&self, fd: i32, events: u32, e: u64) -> Result<()> {
        let mut event = libc::epoll_event { events, u64: e };
        let ret =
            unsafe { libc::epoll_ctl(self.fd, libc::EPOLL_CTL_MOD, fd, ptr::addr_of_mut!(event)) };
        if ret == 0 {
            Ok(())
        } else {
            Err(Error::last())
        }
    }

    fn del_event(&self, fd: i32, e: u64) -> Result<()> {
        let mut event = libc::epoll_event { events: 0, u64: e };
        let ret =
            unsafe { libc::epoll_ctl(self.fd, libc::EPOLL_CTL_DEL, fd, ptr::addr_of_mut!(event)) };
        if ret == 0 {
            Ok(())
        } else {
            Err(Error::last())
        }
    }

    fn wait<F>(&mut self, timeout: i32, mut f: F) -> Result<u32>
    where
        F: FnMut(u32, u64),
    {
        let events = self.events.as_ptr().cast::<libc::epoll_event>();
        let cnt = unsafe { libc::epoll_wait(self.fd, events, self.events.len() as i32, timeout) };
        if cnt >= 0 {
            for event in &mut self.events[0..cnt as usize] {
                let event = unsafe { event.assume_init_ref() };
                let mut events = event.events & (POLLIN | POLLOUT);
                if events == 0 {
                    events = POLLIN | POLLOUT;
                }
                f(events, event.u64);
            }
            Ok(cnt as u32)
        } else {
            Err(Error::last())
        }
    }
}

const EPOLL_EVENT_MAX: usize = 512;