main.rs

use evdev::{self, EventType, InputEventKind};
use mio::unix::SourceFd;
use mio::{Events, Interest, Poll, Token};
use std::io;
use std::os::unix::io::AsRawFd;

fn main() -> io::Result<()> {
    let devices = evdev::enumerate().collect::<Vec<_>>();
    // for d in devices {
    //     println!(
    //         "Name: {:?}, path: {:?}, events: {:?}",
    //         d.name(),
    //         d.physical_path(),
    //         d.supported_events()
    //     );
    // }
    let mut devices = devices
        .into_iter()
        .filter(|d| {
            let types = d.supported_events();
            // TODO: consider a better heuristic for keyboards than "things with
            // key repeat and no mouse or scroll wheel". maybe use `properties`?
            // on the other hand we could just be conservative and accept more
            // devices and throw out their events when they're not key presses
            types.contains(EventType::KEY)
                && types.contains(EventType::REPEAT)
                && !types.contains(EventType::RELATIVE)
        })
        .collect::<Vec<_>>();
    let fds = devices.iter().map(|d| d.as_raw_fd()).collect::<Vec<_>>();
    let mut sources = fds.iter().map(|d| SourceFd(&d)).collect::<Vec<_>>();

    let mut poll = Poll::new()?;
    let mut events = Events::with_capacity(1024);
    for (i, source) in sources.iter_mut().enumerate() {
        poll.registry()
            .register(source, Token(i), Interest::READABLE)?;
    }

    loop {
        poll.poll(&mut events, None)?;

        for event in &events {
            let idx = event.token().0;
            for ev in devices[idx].fetch_events().unwrap() {
                if let InputEventKind::Key(k) = ev.kind() {
                    println!(
                        "{:?} - {}",
                        k,
                        if ev.value() == 0 {
                            "released"
                        } else {
                            "pressed"
                        }
                    );
                }
            }
        }
    }
}