From 0766d839fe52eb12ac7ecd34bc39a76399cfde41 Mon Sep 17 00:00:00 2001
From: qicosmos <qicosmos@linux.alibaba.com>
Date: Mon, 23 Sep 2024 16:34:23 +0800
Subject: [PATCH] [struct_json][feat]support custom optional(struct_pack
 compatible) (#781)

---
 include/ylt/standalone/iguana/dynamic.hpp     |  7 +++++++
 include/ylt/standalone/iguana/json_writer.hpp | 10 ++++++----
 include/ylt/standalone/iguana/util.hpp        |  3 +--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/ylt/standalone/iguana/dynamic.hpp b/include/ylt/standalone/iguana/dynamic.hpp
index 47cf20154..5b134baf6 100644
--- a/include/ylt/standalone/iguana/dynamic.hpp
+++ b/include/ylt/standalone/iguana/dynamic.hpp
@@ -159,6 +159,13 @@ struct base_impl : public base {
   virtual ~base_impl() {}
 
   mutable size_t cache_size = 0;
+
+ private:
+  virtual void dummy() {
+    // make sure init T before main, and can register_type before main.
+    [[maybe_unused]] static auto t =
+        ylt::reflection::internal::wrapper<T>::value;
+  }
 };
 
 IGUANA_INLINE std::shared_ptr<base> create_instance(std::string_view name) {
diff --git a/include/ylt/standalone/iguana/json_writer.hpp b/include/ylt/standalone/iguana/json_writer.hpp
index 1901d565b..75d4a70e9 100644
--- a/include/ylt/standalone/iguana/json_writer.hpp
+++ b/include/ylt/standalone/iguana/json_writer.hpp
@@ -12,8 +12,9 @@ template <bool Is_writing_escape = true, typename Stream, typename T,
           std::enable_if_t<ylt_refletable_v<T>, int> = 0>
 IGUANA_INLINE void to_json(T &&t, Stream &s);
 namespace detail {
-template <bool Is_writing_escape = true, typename Stream, typename T>
-IGUANA_INLINE void to_json_impl(Stream &ss, const std::optional<T> &val);
+template <bool Is_writing_escape = true, typename Stream, typename T,
+          std::enable_if_t<optional_v<T>, int> = 0>
+IGUANA_INLINE void to_json_impl(Stream &ss, const T &val);
 
 template <bool Is_writing_escape = true, typename Stream, typename T,
           std::enable_if_t<fixed_array_v<T>, int> = 0>
@@ -151,8 +152,9 @@ IGUANA_INLINE void to_json_impl(Stream &ss, T val) {
   }
 }
 
-template <bool Is_writing_escape, typename Stream, typename T>
-IGUANA_INLINE void to_json_impl(Stream &ss, const std::optional<T> &val) {
+template <bool Is_writing_escape, typename Stream, typename T,
+          std::enable_if_t<optional_v<T>, int>>
+IGUANA_INLINE void to_json_impl(Stream &ss, const T &val) {
   if (!val) {
     ss.append("null");
   }
diff --git a/include/ylt/standalone/iguana/util.hpp b/include/ylt/standalone/iguana/util.hpp
index 614040cc0..8c3fca9e2 100644
--- a/include/ylt/standalone/iguana/util.hpp
+++ b/include/ylt/standalone/iguana/util.hpp
@@ -47,8 +47,7 @@ template <typename T>
 inline constexpr bool enum_v = std::is_enum_v<std::decay_t<T>>;
 
 template <typename T>
-constexpr inline bool optional_v =
-    is_template_instant_of<std::optional, std::remove_cvref_t<T>>::value;
+constexpr inline bool optional_v = ylt::reflection::optional<T>;
 
 template <class, class = void>
 struct is_container : std::false_type {};