[struct_pb][fix and feat]1. fix当成员是std::variant类型时.get_fields_name 会有…

…重复字段名bug;2.添加get_field_any接口,具体类型转换延迟到用户端代码 (#698)

include/ylt/standalone/iguana/pb_util.hpp

@@ -3,6 +3,7 @@
 #include <cstddef>
 #include <cstring>
 #include <map>
+#include <set>
 #include <stdexcept>
 #include <string>
 #include <string_view>
@@ -76,20 +77,49 @@ struct base_impl : public base {
     return info;
   }
 
-  std::vector<std::string_view> get_fields_name() override {
+  std::vector<std::string_view> get_fields_name() const override {
     static constexpr auto map = iguana::get_members<T>();
+
     std::vector<std::string_view> vec;
-    for (auto [no, val] : map) {
+    std::set<std::string_view> sets;
+
+    for (auto const& [no, val] : map) {
       std::visit(
-          [&](auto& field) {
-            vec.push_back(std::string_view(field.field_name.data(),
-                                           field.field_name.size()));
+          [&](auto const& field) {
+            if (auto it = sets.emplace(field.field_name.data(),
+                                       field.field_name.size());
+                it.second) {
+              vec.push_back(*it.first);
+            }
           },
           val);
     }
     return vec;
   }
 
+  std::any get_field_any(std::string_view name) const override {
+    static constexpr auto map = iguana::get_members<T>();
+    std::any result;
+
+    for (auto [no, field] : map) {
+      if (result.has_value()) {
+        break;
+      }
+      std::visit(
+          [&](auto val) {
+            if (val.field_name == name) {
+              using value_type = typename decltype(val)::value_type;
+              auto const offset = member_offset((T*)this, val.member_ptr);
+              auto ptr = (((char*)this) + offset);
+              result = {*((value_type*)ptr)};
+            }
+          },
+          field);
+    }
+
+    return result;
+  }
+
   virtual ~base_impl() {}
 
   size_t cache_size = 0;

include/ylt/standalone/iguana/reflection.hpp

@@ -4,6 +4,7 @@
 
 #ifndef IGUANA_REFLECTION_HPP
 #define IGUANA_REFLECTION_HPP
+#include <any>
 #include <array>
 #include <functional>
 #include <iomanip>
@@ -563,7 +564,8 @@ struct field_info {
 struct base {
   virtual void to_pb(std::string &str) {}
   virtual void from_pb(std::string_view str) {}
-  virtual std::vector<std::string_view> get_fields_name() { return {}; }
+  virtual std::vector<std::string_view> get_fields_name() const { return {}; }
+  virtual std::any get_field_any(std::string_view name) const { return {}; }
   virtual iguana::detail::field_info get_field_info(std::string_view name) {
     return {};
   }

src/struct_pb/examples/main.cpp

@@ -18,8 +18,9 @@ struct nest : struct_pb::base_impl<nest> {
   std::string name;
   my_struct value;
   int var;
+  std::variant<int, double> mv;
 };
-REFLECTION(nest, name, value, var);
+REFLECTION(nest, name, value, var, mv);
 
 struct person {
   int id;
@@ -52,17 +53,31 @@ int main() {
   // dynamic reflection
   auto t = struct_pb::create_instance("nest");
   auto names = t->get_fields_name();
-  bool r = (names == std::vector<std::string_view>{"name", "value", "var"});
+  bool r =
+      (names == std::vector<std::string_view>{"name", "value", "var", "mv"});
   assert(r);
 
+  t->set_field_value("mv", std::variant<int, double>{1});
+  auto mv = t->get_field_value<std::variant<int, double>>("mv");
+  auto const temp = std::variant<int, double>{1};
+  assert(mv == temp);
+
   t->set_field_value("name", std::string("tom"));
   auto name = t->get_field_value<std::string>("name");
   assert(name == "tom");
 
-  auto d = dynamic_cast<nest *>(t.get());
+  auto d = dynamic_cast<nest*>(t.get());
   assert(d->name == "tom");
 
   t->set_field_value<std::string>("name", "hello");
-  auto &field_name = t->get_field_value<std::string>("name");
+  auto& field_name = t->get_field_value<std::string>("name");
   assert(field_name == "hello");
+
+  // dynamic any
+  auto const& any_name = t->get_field_any("name");
+  assert(std::any_cast<std::string>(any_name) == "hello");
+
+  auto const& mvar_any = t->get_field_any("mv");
+  auto const& mvar = std::any_cast<std::variant<int, double>>(mvar_any);
+  assert(mvar == temp);
 }