Return vector of Files in Directory

[AhmedSalih3d]

Hello!

Googling I found this example:

read_dir in std::fs - Rust

use std::io;
use std::fs::{self, DirEntry};
use std::path::Path;

// one possible implementation of walking a directory only visiting files
fn visit_dirs(dir: &Path, cb: &dyn Fn(&DirEntry)) -> io::Result<()> {
    if dir.is_dir() {
        for entry in fs::read_dir(dir)? {
            let entry = entry?;
            let path = entry.path();
            if path.is_dir() {
                visit_dirs(&path, cb)?;
            } else {
                cb(&entry);
            }
        }
    }
    Ok(())
}

But I cannot figure out how to use it - what is "cb"? I have never seen the "&dyn Fn.." syntax before ( new user). And how would I alter the function so that it would keep error checking but actually also output a vector of the files in the directory?

Kind regards

[2e71828]

cb here is a callback: code privided by the caller to be run once for each file found during the search. Fn(...) is special syntax for a closure trait which, in this case, is being passed as a reference to a trait object.

Similar code to build a vector might look like this (untested):

fn collect_files_from_dir(dir: &Path) -> io::Result<Vec<PathBuf>> {
    let mut result: Vec<PathBuf> = vec![];
    if dir.is_dir() {
        for entry in fs::read_dir(dir)? {
            let entry = entry?;
            let path = entry.path();
            if path.is_dir() {
                result.extend(collect_files_from_dir(&path)?);
            } else {
                result.push(path);
            }
        }
    }
    Ok(result)
}

[AhmedSalih3d]

Thanks for the explanation! Ended up using "glob", but that also makes sense what you did.
Kind regards