data_or_ref.rs

use std::rc::Rc;

enum DataOrRef<'a, T> {
    Owned(T),
    Borrowed(&'a T),
}

struct MyStruct<'a, T> {
    data: DataOrRef<'a, T>,
}

impl<'a, T> MyStruct<'a, T> {
    fn new_owned(data: T) -> Self {
        MyStruct {
            data: DataOrRef::Owned(data),
        }
    }

    fn new_borrowed(data: &'a T) -> Self {
        MyStruct {
            data: DataOrRef::Borrowed(data),
        }
    }

    fn as_ref(&self) -> &T {
        match &self.data {
            DataOrRef::Owned(d) => &d,
            DataOrRef::Borrowed(d) => d,
        }
    }

    fn clone(&self) -> Self
    where
        T: Clone,
    {
        match &self.data {
            DataOrRef::Owned(d) => MyStruct::new_owned(d.clone()),
            DataOrRef::Borrowed(d) => MyStruct::new_borrowed(d),
        }
    }

    fn to_owned(&self) -> MyStruct<'static, T>
    where
        T: Clone,
    {
        match &self.data {
            DataOrRef::Owned(d) => MyStruct::new_owned(d.clone()),
            DataOrRef::Borrowed(d) => MyStruct::new_owned(d.clone()),
        }
    }
}