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use std::borrow;
use std::sync::atomic::{self, AtomicUsize};
static NEXT_ID: AtomicUsize = AtomicUsize::new(0);
/// The identifier of a generic widget.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Id(Internal);
impl Id {
/// Creates a custom [`Id`].
pub fn new(id: impl Into<borrow::Cow<'static, str>>) -> Self {
Self(Internal::Custom(id.into()))
}
/// Creates a unique [`Id`].
///
/// This function produces a different [`Id`] every time it is called.
pub fn unique() -> Self {
let id = NEXT_ID.fetch_add(1, atomic::Ordering::Relaxed);
Self(Internal::Unique(id))
}
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
enum Internal {
Unique(usize),
Custom(borrow::Cow<'static, str>),
}
#[cfg(test)]
mod tests {
use super::Id;
#[test]
fn unique_generates_different_ids() {
let a = Id::unique();
let b = Id::unique();
assert_ne!(a, b);
}
}
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