ref_option_to_cow.rs

use std::borrow::Cow;

trait FromRefOpt<'a, T> {
    fn from_ref_opt(option: Option<&'a T>) -> Self;
}


impl<'a, T: Clone + Default> FromRefOpt<'a, T> for Cow<'a, T> {
    fn from_ref_opt(option: Option<&'a T>) -> Cow<'a, T> {
        if let Some(x) = option {
            Cow::Borrowed(x)
        } else {
            Cow::Owned(T::default())
        }
    }
}