use std::fs::DirEntry;

#[derive(Debug)]
struct BlobDesc {
    name: String,
    size: u64,
}

fn convert(entry_result: Result<DirEntry, std::io::Error>) -> Option<BlobDesc> {
    let f = |e: DirEntry| -> Result<BlobDesc, std::io::Error> {
        let name = "foo".to_string()/*e.path().file_name()?.to_str().unwrap_or("xx").to_string()*/;
        let size = e.metadata()?.len();
        Ok(BlobDesc {
            name: name,
            size: size,
        })
    };

    match entry_result {
        Ok(entry) => {
            match f(entry) {
                Ok(blob_desc) => Some(blob_desc),
                Err(_) => None,
            }
        }
        Err(_) => None,
    }
}

fn main() {

}