move contents of taskchampion repo to tc/

rust/taskchampion/src/utils.rs

@@ -0,0 +1,61 @@
+use std::convert::TryInto;
+use uuid::Uuid;
+
+/// A representation of a UUID as a key.  This is just a newtype wrapping the 128-bit packed form
+/// of a UUID.
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub(crate) struct Key(uuid::Bytes);
+
+impl From<&[u8]> for Key {
+    fn from(bytes: &[u8]) -> Key {
+        Key(bytes.try_into().expect("expected 16 bytes"))
+    }
+}
+
+impl From<&Uuid> for Key {
+    fn from(uuid: &Uuid) -> Key {
+        let key = Key(*uuid.as_bytes());
+        key
+    }
+}
+
+impl From<Uuid> for Key {
+    fn from(uuid: Uuid) -> Key {
+        let key = Key(*uuid.as_bytes());
+        key
+    }
+}
+
+impl From<Key> for Uuid {
+    fn from(key: Key) -> Uuid {
+        Uuid::from_bytes(key.0)
+    }
+}
+
+impl AsRef<[u8]> for Key {
+    fn as_ref(&self) -> &[u8] {
+        &self.0[..]
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use pretty_assertions::assert_eq;
+
+    #[test]
+    fn test_from_bytes() {
+        let k: Key = (&[1u8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16][..]).into();
+        let u: Uuid = k.into();
+        assert_eq!(
+            u,
+            Uuid::parse_str("01020304-0506-0708-090a-0b0c0d0e0f10").unwrap()
+        );
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_from_bytes_bad_len() {
+        let _: Key = (&[1u8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11][..]).into();
+    }
+}