third_party/rust_crates/vendor/notify/examples/monitor_raw.rs

use notify::{RecommendedWatcher, RecursiveMode, Watcher};
use std::path::Path;

fn watch<P: AsRef<Path>>(path: P) -> notify::Result<()> {
    let (tx, rx) = std::sync::mpsc::channel();

    // Automatically select the best implementation for your platform.
    // You can also access each implementation directly e.g. INotifyWatcher.
    let mut watcher: RecommendedWatcher = Watcher::new_immediate(move |res| tx.send(res).unwrap())?;

    // Add a path to be watched. All files and directories at that path and
    // below will be monitored for changes.
    watcher.watch(path, RecursiveMode::Recursive)?;

    for res in rx {
        match res {
            Ok(event) => println!("changed: {:?}", event),
            Err(e) => println!("watch error: {:?}", e),
        }
    }

    Ok(())
}

fn main() {
    let path = std::env::args()
        .nth(1)
        .expect("Argument 1 needs to be a path");
    println!("watching {}", path);
    if let Err(e) = watch(path) {
        println!("error: {:?}", e)
    }
}