stopwatch/src/main.rs

//! stopwatch is a simple CLI stopwatch

use crossbeam_channel::tick;
use std::io::{stdout, Write};
use std::time::{Duration, Instant};

#[macro_use]
extern crate crossbeam_channel;

fn main() {
    let out = stdout();
    let mut out = out.lock();

    // 30 fps should be enough
    let step_duration = Duration::from_millis(1000 / 30);
    let start = Instant::now();
    let ticker = tick(step_duration);

    loop {
        select! {
            recv(ticker) -> now => {
                let elapsed = now.unwrap().duration_since(start);
                let secs = elapsed.as_secs();
                let millis = elapsed.subsec_millis();
                write!(out, "\r[2K").unwrap();
                write!(out, "{:02}:{:02}:{:03}", secs/60, secs % 60, millis).unwrap();
                out.flush().unwrap();
            }
        }
    }
}