build a path list in parallel

utils.rs

use crossbeam_channel as channel;
use ignore::WalkBuilder;
use std::path::{Path, PathBuf};

#[derive(Debug)]
enum Message {
    FoundPath(Result<ignore::DirEntry, ignore::Error>),
    DoneScanning,
}

fn get_search_paths_from_starting_path(starting_path: &Path) -> Vec<PathBuf> {
    let (tx, rx) = channel::unbounded();
    let mut paths: Vec<ignore::DirEntry> = vec![];

    WalkBuilder::new(starting_path).build_parallel().run(|| {
        let tx = tx.clone();
        Box::new(move |result| {
            tx.send(Message::FoundPath(result)).unwrap();
            ignore::WalkState::Continue
        })
    });

    tx.send(Message::DoneScanning).unwrap();

    loop {
        match rx.recv() {
            Ok(Message::DoneScanning) => break,
            Ok(Message::FoundPath(Ok(path))) => paths.push(path),
            _ => (),
        }
    }

    drop(rx);

    paths
        .iter()
        .filter(|f| f.path().is_file())
        .map(|file| file.path().to_owned())
        .collect()
}