[reflection] fix type_string that lose const (#874)

Author: miyanyan

include/ylt/reflection/template_string.hpp

@@ -31,18 +31,11 @@ constexpr std::string_view get_raw_name() {
 template <typename T>
 inline constexpr std::string_view type_string() {
   constexpr std::string_view sample = get_raw_name<int>();
-  constexpr size_t pos = sample.find("int");
+  constexpr size_t prefix_length = sample.find("int");
+  constexpr size_t suffix_length = sample.size() - prefix_length - 3;
+
   constexpr std::string_view str = get_raw_name<T>();
-  constexpr auto next1 = str.rfind(sample[pos + 3]);
-#if defined(_MSC_VER)
-  constexpr std::size_t npos = str.find_first_of(" ", pos);
-  if constexpr (npos != std::string_view::npos)
-    return str.substr(npos + 1, next1 - npos - 1);
-  else
-    return str.substr(pos, next1 - pos);
-#else
-  return str.substr(pos, next1 - pos);
-#endif
+  return str.substr(prefix_length, str.size() - prefix_length - suffix_length);
 }
 
 template <auto T>

src/reflection/tests/test_reflection.cpp

@@ -3,6 +3,7 @@
 
 #include "ylt/reflection/member_value.hpp"
 #include "ylt/reflection/private_visitor.hpp"
+#include "ylt/reflection/template_string.hpp"
 #include "ylt/reflection/template_switch.hpp"
 #include "ylt/reflection/user_reflect_macro.hpp"
 
@@ -465,6 +466,62 @@ TEST_CASE("test visit private") {
   auto name = bank.*(std::get<1>(tp));  // ok
 }
 
+namespace test_type_string {
+struct struct_test {};
+class class_test {};
+union union_test {};
+}  // namespace test_type_string
+
+TEST_CASE("test type_string") {
+  CHECK(type_string<int>() == "int");
+  CHECK(type_string<const int>() == "const int");
+  CHECK(type_string<volatile int>() == "volatile int");
+
+#if defined(__clang__)
+  CHECK(type_string<int&>() == "int &");
+  CHECK(type_string<int&&>() == "int &&");
+  CHECK(type_string<const int&>() == "const int &");
+  CHECK(type_string<const int&&>() == "const int &&");
+  CHECK(type_string<volatile int&>() == "volatile int &");
+  CHECK(type_string<volatile int&&>() == "volatile int &&");
+#else
+  CHECK(type_string<int&>() == "int&");
+  CHECK(type_string<int&&>() == "int&&");
+  CHECK(type_string<const int&>() == "const int&");
+  CHECK(type_string<const int&&>() == "const int&&");
+  CHECK(type_string<volatile int&>() == "volatile int&");
+  CHECK(type_string<volatile int&&>() == "volatile int&&");
+#endif
+
+#if defined(_MSC_VER) && !defined(__clang__)
+  CHECK(type_string<test_type_string::struct_test>() ==
+        "struct test_type_string::struct_test");
+  CHECK(type_string<const test_type_string::struct_test>() ==
+        "const struct test_type_string::struct_test");
+  CHECK(type_string<test_type_string::class_test>() ==
+        "class test_type_string::class_test");
+  CHECK(type_string<const test_type_string::class_test>() ==
+        "const class test_type_string::class_test");
+  CHECK(type_string<test_type_string::union_test>() ==
+        "union test_type_string::union_test");
+  CHECK(type_string<const test_type_string::union_test>() ==
+        "const union test_type_string::union_test");
+#else
+  CHECK(type_string<test_type_string::struct_test>() ==
+        "test_type_string::struct_test");
+  CHECK(type_string<const test_type_string::struct_test>() ==
+        "const test_type_string::struct_test");
+  CHECK(type_string<test_type_string::class_test>() ==
+        "test_type_string::class_test");
+  CHECK(type_string<const test_type_string::class_test>() ==
+        "const test_type_string::class_test");
+  CHECK(type_string<test_type_string::union_test>() ==
+        "test_type_string::union_test");
+  CHECK(type_string<const test_type_string::union_test>() ==
+        "const test_type_string::union_test");
+#endif
+}
+
 DOCTEST_MSVC_SUPPRESS_WARNING_WITH_PUSH(4007)
 int main(int argc, char** argv) { return doctest::Context(argc, argv).run(); }
 DOCTEST_MSVC_SUPPRESS_WARNING_POP