move-only: Detail_CheckNumFormatSpecifiers and G_TRANSLATION_FUN

This is required for a future commit. Can be reviewed via the git
options --color-moved=dimmed-zebra --color-moved-ws=ignore-all-space

Also move util::detail::Hex to a proper namespace instead of an inline
namespace so it doesn't conflict with the new util::detail namespace, and
won't create other problems for callers trying to use the inline namespaces.

Also fix a misleading comment in util_string_tests.cpp.

Co-Authored-By: Ryan Ofsky <ryan@ofsky.org>

src/test/util_string_tests.cpp

@@ -16,13 +16,13 @@ BOOST_AUTO_TEST_SUITE(util_string_tests)
 template <unsigned NumArgs>
 inline void PassFmt(util::ConstevalFormatString<NumArgs> fmt)
 {
-    // This was already executed at compile-time, but is executed again at run-time to avoid -Wunused.
+    // Execute compile-time check again at run-time to get code coverage stats
-    decltype(fmt)::Detail_CheckNumFormatSpecifiers(fmt.fmt);
+    util::detail::CheckNumFormatSpecifiers<NumArgs>(fmt.fmt);
 }
 template <unsigned WrongNumArgs>
 inline void FailFmtWithError(const char* wrong_fmt, std::string_view error)
 {
-    BOOST_CHECK_EXCEPTION(util::ConstevalFormatString<WrongNumArgs>::Detail_CheckNumFormatSpecifiers(wrong_fmt), const char*, HasReason(error));
+    BOOST_CHECK_EXCEPTION(util::detail::CheckNumFormatSpecifiers<WrongNumArgs>(wrong_fmt), const char*, HasReason{error});
 }
 
 BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)

src/util/strencodings.h

@@ -377,6 +377,24 @@ consteval uint8_t ConstevalHexDigit(const char c)
     throw "Only lowercase hex digits are allowed, for consistency";
 }
 
+namespace detail {
+template <size_t N>
+struct Hex {
+    std::array<std::byte, N / 2> bytes{};
+    consteval Hex(const char (&hex_str)[N])
+        // 2 hex digits required per byte + implicit null terminator
+        requires(N % 2 == 1)
+    {
+        if (hex_str[N - 1]) throw "null terminator required";
+        for (std::size_t i = 0; i < bytes.size(); ++i) {
+            bytes[i] = static_cast<std::byte>(
+                (ConstevalHexDigit(hex_str[2 * i]) << 4) |
+                 ConstevalHexDigit(hex_str[2 * i + 1]));
+        }
+    }
+};
+} // namespace detail
+
 /**
  * ""_hex is a compile-time user-defined literal returning a
  * `std::array<std::byte>`, equivalent to ParseHex(). Variants provided:
@@ -407,25 +425,6 @@ consteval uint8_t ConstevalHexDigit(const char c)
  *   time/runtime barrier.
  */
 inline namespace hex_literals {
-namespace detail {
-
-template <size_t N>
-struct Hex {
-    std::array<std::byte, N / 2> bytes{};
-    consteval Hex(const char (&hex_str)[N])
-        // 2 hex digits required per byte + implicit null terminator
-        requires(N % 2 == 1)
-    {
-        if (hex_str[N - 1]) throw "null terminator required";
-        for (std::size_t i = 0; i < bytes.size(); ++i) {
-            bytes[i] = static_cast<std::byte>(
-                (ConstevalHexDigit(hex_str[2 * i]) << 4) |
-                 ConstevalHexDigit(hex_str[2 * i + 1]));
-        }
-    }
-};
-
-} // namespace detail
 
 template <util::detail::Hex str>
 constexpr auto operator""_hex() { return str.bytes; }

src/util/string.h

@@ -17,19 +17,9 @@
 #include <vector>
 
 namespace util {
-/**
+namespace detail {
- * @brief A wrapper for a compile-time partially validated format string
- *
- * This struct can be used to enforce partial compile-time validation of format
- * strings, to reduce the likelihood of tinyformat throwing exceptions at
- * run-time. Validation is partial to try and prevent the most common errors
- * while avoiding re-implementing the entire parsing logic.
- */
 template <unsigned num_params>
-struct ConstevalFormatString {
+constexpr static void CheckNumFormatSpecifiers(const char* str)
-    const char* const fmt;
-    consteval ConstevalFormatString(const char* str) : fmt{str} { Detail_CheckNumFormatSpecifiers(fmt); }
-    constexpr static void Detail_CheckNumFormatSpecifiers(const char* str)
 {
     unsigned count_normal{0}; // Number of "normal" specifiers, like %s
     unsigned count_pos{0};    // Max number in positional specifier, like %8$s
@@ -88,6 +78,20 @@ struct ConstevalFormatString {
     unsigned count{count_normal | count_pos};
     if (num_params != count) throw "Format specifier count must match the argument count!";
 }
+} // namespace detail
+
+/**
+ * @brief A wrapper for a compile-time partially validated format string
+ *
+ * This struct can be used to enforce partial compile-time validation of format
+ * strings, to reduce the likelihood of tinyformat throwing exceptions at
+ * run-time. Validation is partial to try and prevent the most common errors
+ * while avoiding re-implementing the entire parsing logic.
+ */
+template <unsigned num_params>
+struct ConstevalFormatString {
+    const char* const fmt;
+    consteval ConstevalFormatString(const char* str) : fmt{str} { detail::CheckNumFormatSpecifiers<num_params>(fmt); }
 };
 
 void ReplaceAll(std::string& in_out, const std::string& search, const std::string& substitute);

src/util/translation.h

@@ -10,6 +10,9 @@
 #include <functional>
 #include <string>
 
+/** Translate a message to the native language of the user. */
+const extern std::function<std::string(const char*)> G_TRANSLATION_FUN;
+
 /**
  * Bilingual messages:
  *   - in GUI: user's native language + untranslated (i.e. English)
@@ -64,9 +67,6 @@ bilingual_str format(const bilingual_str& fmt, const Args&... args)
 }
 } // namespace tinyformat
 
-/** Translate a message to the native language of the user. */
-const extern std::function<std::string(const char*)> G_TRANSLATION_FUN;
-
 struct ConstevalStringLiteral {
     const char* const lit;
     consteval ConstevalStringLiteral(const char* str) : lit{str} {}