readdir.rs

#![feature(conservative_impl_trait)]

use std::{io, fs, ffi};

#[derive(Debug)]
enum ReadDirErrors {
  IOError(io::Error),
  OSString(ffi::OsString),
}

impl From<io::Error> for ReadDirErrors {
  fn from(err: io::Error) -> ReadDirErrors {
    ReadDirErrors::IOError(err)
  }
}

impl From<ffi::OsString> for ReadDirErrors {
  fn from(err: ffi::OsString) -> ReadDirErrors {
    ReadDirErrors::OSString(err)
  }
}

fn get_dir_contents(path: &str) -> Result<Vec<String>, ReadDirErrors> {
  let contents = fs::read_dir(path)?
    .map(|entry| Ok(entry?.file_name().into_string()?))
    .collect::<Result<Vec<String>, ReadDirErrors>>()?;
  Ok(contents)
}

fn single_run(path: &str) {
  let contents = get_dir_contents(path);
  for entry in contents.unwrap() {
    println!("{:?}", entry);
  }
}

extern crate rayon;
use rayon::prelude::*;
fn multi_run(paths: Vec<&str>) {
  match paths.len() {
    1 => single_run(paths[0]),
    _ => paths.par_iter().for_each(|&path| single_run(&path)),
  }
}

fn readdir_closure<'a>(path: &'a str) -> impl Fn() -> Result<Vec<String>, ReadDirErrors>  {
  move || {
    let contents = fs::read_dir(path)?
      .map(|entry| Ok(entry?.file_name().into_string()?))
      .collect::<Result<Vec<String>, ReadDirErrors>>()?;
    Ok(contents)
  }
}

fn main() {
  let mut path = "./";
  let contents = readdir_closure(path)();
  println!("{:?}", contents);
}