add ord and partialOrd to Timestamp

prost-types/src/lib.rs

@@ -395,6 +395,15 @@ impl std::hash::Hash for Timestamp {
     }
 }
 
+impl Ord for Timestamp {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        match self.seconds.cmp(&other.seconds) {
+            std::cmp::Ordering::Equal => self.nanos.cmp(&other.nanos),
+            ordering => ordering,
+        }
+    }
+}
+
 #[cfg(feature = "std")]
 impl From<std::time::SystemTime> for Timestamp {
     fn from(system_time: std::time::SystemTime) -> Timestamp {
@@ -907,4 +916,20 @@ mod tests {
         // Must contain at least one "/" character.
         assert_eq!(TypeUrl::new("google.protobuf.Duration"), None);
     }
+
+    #[test]
+    fn check_timestamp_ord() {
+        let earlier_timestamp = Timestamp { seconds: 10, nanos: 500 };
+        let later_timestamp = Timestamp { seconds: 10, nanos: 700 };
+        let equal_timestamp = Timestamp { seconds: 10, nanos: 500 };
+
+        assert!(earlier_timestamp < later_timestamp);
+        assert!(earlier_timestamp <= later_timestamp);
+        assert!(later_timestamp > earlier_timestamp);
+        assert!(later_timestamp >= earlier_timestamp);
+
+        assert_eq!(earlier_timestamp.cmp(&later_timestamp), std::cmp::Ordering::Less);
+        assert_eq!(later_timestamp.cmp(&earlier_timestamp), std::cmp::Ordering::Greater);
+        assert_eq!(equal_timestamp.cmp(&earlier_timestamp), std::cmp::Ordering::Equal);
+    }
 }

prost-types/src/protobuf.rs

@@ -2293,7 +2293,7 @@ impl NullValue {
 /// the time format spec '%Y-%m-%dT%H:%M:%S.%fZ'. Likewise, in Java, one can use
 /// the Joda Time's [`ISODateTimeFormat.dateTime()`](<http://www.joda.org/joda-time/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTime%2D%2D>) to obtain a formatter capable of generating timestamps in this format.
 #[allow(clippy::derive_partial_eq_without_eq)]
-#[derive(Clone, PartialEq, ::prost::Message)]
+#[derive(Clone, PartialEq, PartialOrd,::prost::Message)]
 pub struct Timestamp {
     /// Represents seconds of UTC time since Unix epoch
     /// 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to