From dfd206b3a364f488aa43ba612c90556fd3d0f65d Mon Sep 17 00:00:00 2001
From: Asias He <asias@scylladb.com>
Date: Wed, 18 Apr 2018 14:02:40 +0800
Subject: [PATCH] serializer: Add std::optional support

---
 serializer.hh      |  1 +
 serializer_impl.hh | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/serializer.hh b/serializer.hh
index 6b56040927..562c772c08 100644
--- a/serializer.hh
+++ b/serializer.hh
@@ -27,6 +27,7 @@
 #include <seastar/core/sstring.hh>
 #include <unordered_map>
 #include <experimental/optional>
+#include <optional>
 #include "enum_set.hh"
 #include "utils/managed_bytes.hh"
 #include "bytes_ostream.hh"
diff --git a/serializer_impl.hh b/serializer_impl.hh
index d6b8468408..a11b6161bc 100644
--- a/serializer_impl.hh
+++ b/serializer_impl.hh
@@ -540,6 +540,33 @@ void serialize_fragmented(Output& out, FragmentedBuffer&& v) {
     serializer<bytes>::write_fragmented(out, std::forward<FragmentedBuffer>(v));
 }
 
+template<typename T>
+struct serializer<std::optional<T>> {
+    template<typename Input>
+    static std::optional<T> read(Input& in) {
+        std::optional<T> v;
+        auto b = deserialize(in, boost::type<bool>());
+        if (b) {
+            v = deserialize(in, boost::type<T>());
+        }
+        return v;
+    }
+    template<typename Output>
+    static void write(Output& out, const std::optional<T>& v) {
+        serialize(out, bool(v));
+        if (v) {
+            serialize(out, v.value());
+        }
+    }
+    template<typename Input>
+    static void skip(Input& in) {
+        auto present = deserialize(in, boost::type<bool>());
+        if (present) {
+            serializer<T>::skip(in);
+        }
+    }
+};
+
 template<typename T>
 struct serializer<std::experimental::optional<T>> {
     template<typename Input>