Rust struct where user decides who owns the data.

main.rs

#![forbid(missing_debug_implementations, missing_copy_implementations)]
#![deny(rust_2018_idioms)]
#![deny(clippy::pedantic)]
#![allow(dead_code)]

use std::borrow::Cow;

struct YouDecide<'a> {
    s: Cow<'a, str>
}

impl<'a> YouDecide<'a> {
    fn new<S: Into<Cow<'a, str>>>(value: S) -> Self {
        Self{
            s: value.into()
        }
    }

    fn value(& self) -> &str {
        self.s.as_ref()
    }
}

fn main() {
    let reference = "static";
    let owned = String::from("owned");
    let a = YouDecide::new(reference);
    let b = YouDecide::new(owned.clone());
    let c = YouDecide::new(&owned);
    println!("{}", a.value());
    println!("{}", b.value());
    println!("{}", c.value());
}