colpetto 0.7.0

Async libinput wrapper
Documentation 
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use std::{
    ffi::{CStr, c_int},
    os::fd::RawFd,
};

use anyhow::Result;
use colpetto::{Error, Libinput, event::AsRawEvent};
use rustix::{
    fd::{FromRawFd, IntoRawFd, OwnedFd},
    fs::{Mode, OFlags, open},
};
use tokio::{
    runtime,
    sync::mpsc::{self, UnboundedReceiver, UnboundedSender},
    task::LocalSet,
};
use tokio_stream::{StreamExt, wrappers::UnboundedReceiverStream};

#[derive(Debug)]
struct Event {
    event_type: &'static str,
    device_name: String,
}

struct ShutdownHandle(UnboundedSender<()>);

impl ShutdownHandle {
    pub fn shutdown(&self) {
        let _ = self.0.send(());
    }
}

#[tokio::main]
async fn main() -> Result<()> {
    let (rx, shutdown_handle) = spawn_libinput_task()?;

    tokio::spawn(async move {
        let _ = tokio::signal::ctrl_c().await;
        // Make sure to shutdown the libinput thread
        shutdown_handle.shutdown();
    });

    let mut stream = UnboundedReceiverStream::new(rx);

    // We can spawn a task no problem despite libinput being neither sync nor send
    let handle = tokio::spawn(async move {
        while let Some(event) = stream.try_next().await? {
            println!(
                "Got \"{}\" event from \"{}\"",
                event.event_type, event.device_name
            );
        }

        anyhow::Ok(())
    });

    handle.await??;

    Ok(())
}

fn open_restricted(path: &CStr, flags: c_int) -> Result<RawFd, c_int> {
    open(path, OFlags::from_bits_retain(flags as u32), Mode::empty())
        .map(IntoRawFd::into_raw_fd)
        .map_err(|err| err.raw_os_error().wrapping_neg())
}

fn close_restricted(fd: RawFd) {
    drop(unsafe { OwnedFd::from_raw_fd(fd) });
}

fn spawn_libinput_task() -> Result<(
    UnboundedReceiver<Result<Event, colpetto::Error>>,
    ShutdownHandle,
)> {
    let (event_sx, event_rx) = mpsc::unbounded_channel();
    let (shutdown_sx, mut shutdown_rx) = mpsc::unbounded_channel();

    let rt = runtime::Builder::new_current_thread()
        .enable_all()
        .build()?;

    std::thread::spawn(move || {
        let local = LocalSet::new();

        local.spawn_local(async move {
            let mut libinput = Libinput::with_tracing(open_restricted, close_restricted)?;

            libinput.udev_assign_seat(c"seat0")?;

            let mut stream = libinput.event_stream()?;

            loop {
                tokio::select! {
                    Some(()) = shutdown_rx.recv() => {
                        println!("shutting down libinput instance...");
                        break;
                    }
                    Some(res) = stream.next() => {
                        if event_sx
                            .send(res.map(|event| Event {
                                event_type: event.event_type(),
                                device_name: event.device().name().to_string_lossy().to_string(),
                            }))
                            .is_err()
                        {
                            break;
                        }
                    }
                    else => break,
                }
            }

            Ok::<_, Error>(())
        });

        rt.block_on(local);
    });

    Ok((event_rx, ShutdownHandle(shutdown_sx)))
}