Add impls for Cow

serde/src/de/impls.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::hash::Hash;
 use std::marker::PhantomData;
@@ -854,3 +855,13 @@ impl<T: Deserialize> Deserialize for Rc<T> {
         Ok(Rc::new(val))
     }
 }
+
+impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deserialize, {
+    #[inline]
+    fn deserialize<D>(deserializer: &mut D) -> Result<Cow<'a, T>, D::Error>
+        where D: Deserializer,
+    {
+        let val = try!(Deserialize::deserialize(deserializer));
+        Ok(Cow::Owned(val))
+    }
+}

serde/src/ser/impls.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::hash::Hash;
 use std::path;
@@ -518,6 +519,15 @@ impl<T> Serialize for Arc<T> where T: Serialize, {
     }
 }
 
+impl<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned, {
+    #[inline]
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+        where S: Serializer,
+    {
+        (**self).serialize(serializer)
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 impl Serialize for path::Path {