Chapter 4 code complete

Chapter04/serialize.rs

@@ -1,21 +1,43 @@
 #[macro_use] extern crate serde_derive;
 extern crate serde;
 extern crate serde_json;
+use serde::{Serialize, Serializer, Deserialize, Deserializer};
+use std::fmt;
+use serde::de::{self, Visitor};
 
 struct Foo
 {
    bar: Box<u64>
 }
 
-trait T {}
+#[derive(Clone,Serialize,Deserialize)]
+enum T_Enum
+{
+   S1(S1),
+   S2(S2),
+}
 
-#[derive(Serialize,Deserialize)]
+trait T {
+   fn as_enum(&self) -> T_Enum;
+}
+
+#[derive(Clone,Serialize,Deserialize)]
 struct S1;
-impl T for S1 {}
+impl T for S1 {
+   fn as_enum(&self) -> T_Enum
+   {
+      T_Enum::S1(self.clone())
+   }
+}
 
-#[derive(Serialize,Deserialize)]
+#[derive(Clone,Serialize,Deserialize)]
 struct S2;
-impl T for S2 {}
+impl T for S2 {
+   fn as_enum(&self) -> T_Enum
+   {
+      T_Enum::S2(self.clone())
+   }
+}
 
 #[derive(Serialize,Deserialize)]
 struct Container
@@ -23,6 +45,35 @@ struct Container
    field: Box<T>
 }
 
+impl Serialize for Box<T> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
+        self.as_enum().serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for Box<T> {
+    fn deserialize<D>(deserializer: D) -> Result<Box<T>, D::Error>
+        where D: Deserializer<'de>
+    {
+        let result = T_Enum::deserialize(deserializer);
+        match result
+        {
+           Result::Ok(te) => {
+              match te {
+                 T_Enum::S1(s1) => Result::Ok(Box::new(s1.clone())),
+                 T_Enum::S2(s2) => Result::Ok(Box::new(s2.clone()))
+              }
+           }
+           Result::Err(err) => Result::Err(err)
+        }
+    }
+}
+
 fn main()
 {
+   let bt: Box<T> = Box::new(S1);
+   let s = serde_json::to_string(&bt).unwrap();
+   let bt: Box<T> = serde_json::from_str(s.as_str()).unwrap();
 }