1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159

use {io, EventSet, PollOpt, Token};
use event::IoEvent;
use nix::sys::epoll::*;
use nix::unistd::close;
use std::os::unix::io::RawFd;

#[derive(Debug)]
pub struct Selector {
    epfd: RawFd
}

impl Selector {
    pub fn new() -> io::Result<Selector> {
        let epfd = try!(epoll_create().map_err(super::from_nix_error));

        Ok(Selector { epfd: epfd })
    }

    /// Wait for events from the OS
    pub fn select(&mut self, evts: &mut Events, timeout_ms: usize) -> io::Result<()> {
        use std::{isize, slice};

        let timeout_ms = if timeout_ms >= isize::MAX as usize {
            isize::MAX
        } else {
            timeout_ms as isize
        };

        let dst = unsafe {
            slice::from_raw_parts_mut(
                evts.events.as_mut_ptr(),
                evts.events.capacity())
        };

        // Wait for epoll events for at most timeout_ms milliseconds
        let cnt = try!(epoll_wait(self.epfd, dst, timeout_ms)
                           .map_err(super::from_nix_error));

        unsafe { evts.events.set_len(cnt); }

        Ok(())
    }

    /// Register event interests for the given IO handle with the OS
    pub fn register(&mut self, fd: RawFd, token: Token, interests: EventSet, opts: PollOpt) -> io::Result<()> {
        let info = EpollEvent {
            events: ioevent_to_epoll(interests, opts),
            data: token.as_usize() as u64
        };

        epoll_ctl(self.epfd, EpollOp::EpollCtlAdd, fd, &info)
            .map_err(super::from_nix_error)
    }

    /// Register event interests for the given IO handle with the OS
    pub fn reregister(&mut self, fd: RawFd, token: Token, interests: EventSet, opts: PollOpt) -> io::Result<()> {
        let info = EpollEvent {
            events: ioevent_to_epoll(interests, opts),
            data: token.as_usize() as u64
        };

        epoll_ctl(self.epfd, EpollOp::EpollCtlMod, fd, &info)
            .map_err(super::from_nix_error)
    }

    /// Deregister event interests for the given IO handle with the OS
    pub fn deregister(&mut self, fd: RawFd) -> io::Result<()> {
        // The &info argument should be ignored by the system,
        // but linux < 2.6.9 required it to be not null.
        // For compatibility, we provide a dummy EpollEvent.
        let info = EpollEvent {
            events: EpollEventKind::empty(),
            data: 0
        };

        epoll_ctl(self.epfd, EpollOp::EpollCtlDel, fd, &info)
            .map_err(super::from_nix_error)
    }
}

fn ioevent_to_epoll(interest: EventSet, opts: PollOpt) -> EpollEventKind {
    let mut kind = EpollEventKind::empty();

    if interest.is_readable() {
        kind.insert(EPOLLIN);
    }

    if interest.is_writable() {
        kind.insert(EPOLLOUT);
    }

    if interest.is_hup() {
        kind.insert(EPOLLRDHUP);
    }

    if opts.is_edge() {
        kind.insert(EPOLLET);
    }

    if opts.is_oneshot() {
        kind.insert(EPOLLONESHOT);
    }

    if opts.is_level() {
        kind.remove(EPOLLET);
    }

    kind
}

impl Drop for Selector {
    fn drop(&mut self) {
        let _ = close(self.epfd);
    }
}

pub struct Events {
    events: Vec<EpollEvent>,
}

impl Events {
    pub fn new() -> Events {
        Events {
            events: Vec::with_capacity(1024),
        }
    }

    #[inline]
    pub fn len(&self) -> usize {
        self.events.len()
    }

    #[inline]
    pub fn get(&self, idx: usize) -> IoEvent {
        let epoll = self.events[idx].events;
        let mut kind = EventSet::none();

        if epoll.contains(EPOLLIN) {
            kind = kind | EventSet::readable();
        }

        if epoll.contains(EPOLLOUT) {
            kind = kind | EventSet::writable();
        }

        // EPOLLHUP - Usually means a socket error happened
        if epoll.contains(EPOLLERR) {
            kind = kind | EventSet::error();
        }

        if epoll.contains(EPOLLRDHUP) | epoll.contains(EPOLLHUP) {
            kind = kind | EventSet::hup();
        }

        let token = self.events[idx].data;

        IoEvent::new(kind, Token(token as usize))
    }
}