xordirs.rs

extern crate crossbeam_utils;

use std::{
    collections::HashSet,
    env,
    error::Error,
    fs,
    sync::{Arc, Mutex},
};

fn main() -> Result<(), Box<dyn Error>> {
    let args: Vec<String> = env::args().collect();
    let n = args.len() - 1;
    let maps_list = Arc::new(Mutex::new(Vec::with_capacity(n)));

    crossbeam_utils::thread::scope(|scope| {
        for i in 1..(n + 1) {
            let file = &args[i][..];
            println!("listing: {}", file);
            let maps_list = maps_list.clone();

            scope.spawn(move || match get_set(file) {
                Ok(s) => maps_list.lock().unwrap().push(s),
                Err(e) => eprintln!("error encountered collecting files: {} \n {}", file, e),
            });
        }
    });

    let maps = maps_list.lock().unwrap();
    let xor = maps.iter().fold(HashSet::new(), |acc, set| &acc ^ &set);
    println!("{:?}", xor);

    Ok(())
}

fn get_set<S>(file: S) -> Result<HashSet<String>, Box<dyn Error>>
where
    S: AsRef<str>,
{
    let mut set = HashSet::new();
    let contents = fs::read_dir(file.as_ref())?;
    for entry in contents {
        let dir = entry?;
        if let Some(name) = dir.path().file_name() {
            set.insert(name.to_str().unwrap().to_string());
        }
    }
    Ok(set)
}