main.rs

#![allow(unused_variables)]
use futures::future::LocalBoxFuture;
use futures::prelude::*;
use std::path::Path;
use tokio::fs::*;

fn walkdir<'a, C>(path: &'a Path, cb: &'a mut C) -> LocalBoxFuture<'a, ()>
where
    C: Fn(&DirEntry),
{
    async move {
        let mut dir = read_dir(path).await.unwrap();
        while let Some(dentry) = dir.next().await {
            let dentry = dentry.unwrap();
            cb(&dentry);
            if dentry.file_type().await.unwrap().is_dir() {
                let dentry_path = dentry.path();
                walkdir(dentry_path.as_path(), cb).await;
            }
        }
    }
    .boxed_local()
}

#[tokio::main]
async fn main() {
    walkdir(Path::new(".").as_ref(), &mut |d: &DirEntry| {
        println!("{}", d.file_name().into_string().unwrap());
    })
    .await;
}