Add Serialize and Deserialize to SortedMap

Summary: ^

Reviewed By: stepancheg

Differential Revision: D50662284

fbshipit-source-id: 88dcc1c41b884c686183c96530cac8ca5d208ab8

starlark_map/src/sorted_map.rs

@@ -20,6 +20,8 @@
 use std::hash::Hash;
 
 use allocative::Allocative;
+use serde::Deserialize;
+use serde::Serialize;
 
 use crate::ordered_map::OrderedMap;
 use crate::small_map;
@@ -183,6 +185,30 @@ impl<'a, K: Ord + Hash, V> IntoIterator for &'a mut SortedMap<K, V> {
     }
 }
 
+impl<K: Serialize, V: Serialize> Serialize for SortedMap<K, V> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        self.map.serialize(serializer)
+    }
+}
+
+impl<'de, K, V> Deserialize<'de> for SortedMap<K, V>
+where
+    K: Deserialize<'de> + Hash + Eq,
+    V: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Ok(Self {
+            map: OrderedMap::deserialize(deserializer)?,
+        })
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::sorted_map::SortedMap;