feat: Added readme and forgotten id.rs

crates/iced-video/src/id.rs

@@ -0,0 +1,55 @@
+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, PartialOrd, Ord)]
+pub struct Id(Internal);
+
+impl Id {
+    /// Creates a new [`Id`] from a static `str`.
+    pub const fn new(id: &'static str) -> Self {
+        Self(Internal::Custom(borrow::Cow::Borrowed(id)))
+    }
+
+    /// 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))
+    }
+}
+
+impl From<&'static str> for Id {
+    fn from(value: &'static str) -> Self {
+        Self::new(value)
+    }
+}
+
+impl From<String> for Id {
+    fn from(value: String) -> Self {
+        Self(Internal::Custom(borrow::Cow::Owned(value)))
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+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);
+    }
+}