refactor(i18n): char* -> std::string_view

Prefer std::string_view over char* so make it clear that null
terminators are not required.

src/quick-lint-js/i18n/locale.cpp

@@ -70,10 +70,11 @@ Locale_Parts parse_locale(std::string_view locale_name) {
 }
 
 template <class Func>
-void locale_name_combinations(const char* locale_name, Func&& callback);
+void locale_name_combinations(std::string_view locale_name, Func&& callback);
 }
 
-std::optional<int> find_locale(const char* locales, const char* locale_name) {
+std::optional<int> find_locale(const char* locales,
+                               std::string_view locale_name) {
   // NOTE[locale-list-null-terminator]: The code generator guarantees that there
   // is an empty string at the end of the list (i.e. two null bytes at the end).
   C_String_List_View locales_list(locales);
@@ -94,7 +95,7 @@ std::optional<int> find_locale(const char* locales, const char* locale_name) {
 }
 
 void enumerate_locale_name_combinations(
-    const char* locale_name,
+    std::string_view locale_name,
     Temporary_Function_Ref<bool(std::string_view locale)> callback) {
   return locale_name_combinations<
       Temporary_Function_Ref<bool(std::string_view locale)>>(
@@ -106,11 +107,11 @@ QLJS_WARNING_PUSH
 QLJS_WARNING_IGNORE_GCC("-Wzero-as-null-pointer-constant")
 
 template <class Func>
-void locale_name_combinations(const char* locale_name, Func&& callback) {
+void locale_name_combinations(std::string_view locale_name, Func&& callback) {
   Locale_Parts parts = parse_locale(locale_name);
 
   std::vector<char> locale;
-  std::size_t max_locale_size = std::strlen(locale_name);
+  std::size_t max_locale_size = locale_name.size();
   locale.reserve(max_locale_size);
   locale.insert(locale.end(), parts.language().begin(), parts.language().end());
 

src/quick-lint-js/i18n/locale.h

@@ -13,11 +13,12 @@ namespace quick_lint_js {
 //
 // If locales is "en_US\0fr_FR\0de_DE\0", and locale_name is "fr_FR", then the
 // result will be 1.
-std::optional<int> find_locale(const char* locales, const char* locale_name);
+std::optional<int> find_locale(const char* locales,
+                               std::string_view locale_name);
 
 // For testing only.
 void enumerate_locale_name_combinations(
-    const char* locale_name,
+    std::string_view locale_name,
     Temporary_Function_Ref<bool(std::string_view locale)>);
 }
 

src/quick-lint-js/i18n/translation.cpp

@@ -22,8 +22,8 @@ namespace quick_lint_js {
 Translator qljs_messages;
 
 namespace {
-std::vector<std::string> split_on(const char* s, char separator) {
-  std::vector<std::string> locales;
+std::vector<std::string_view> split_on(const char* s, char separator) {
+  std::vector<std::string_view> locales;
   for (;;) {
     const char* sep = std::strchr(s, separator);
     if (sep) {
@@ -37,7 +37,7 @@ std::vector<std::string> split_on(const char* s, char separator) {
   return locales;
 }
 
-std::vector<std::string> get_user_locale_preferences() {
+std::vector<std::string_view> get_user_locale_preferences() {
   // This lookup order roughly mimics GNU gettext.
 
   int category =
@@ -74,7 +74,7 @@ void initialize_locale() {
 void initialize_translations_from_environment() {
   initialize_locale();
   if (!qljs_messages.use_messages_from_locales(
-          Span<const std::string>(get_user_locale_preferences()))) {
+          Span<const std::string_view>(get_user_locale_preferences()))) {
     qljs_messages.use_messages_from_source_code();
   }
 }
@@ -91,7 +91,7 @@ void Translator::use_messages_from_source_code() {
   this->locale_index_ = translation_table_locale_count;
 }
 
-bool Translator::use_messages_from_locale(const char* locale_name) {
+bool Translator::use_messages_from_locale(std::string_view locale_name) {
   std::optional<int> locale_index =
       find_locale(translation_data.locale_table, locale_name);
   if (locale_index.has_value()) {
@@ -102,13 +102,13 @@ bool Translator::use_messages_from_locale(const char* locale_name) {
 }
 
 bool Translator::use_messages_from_locales(
-    Span<const std::string> locale_names) {
-  for (const std::string& locale : locale_names) {
-    if (locale == "C" || locale == "POSIX") {
+    Span<const std::string_view> locale_names) {
+  for (const std::string_view& locale : locale_names) {
+    if (locale == "C"sv || locale == "POSIX"sv) {
       // Stop seaching. C/POSIX locale takes priority. See GNU gettext.
       break;
     }
-    bool found_messages = this->use_messages_from_locale(locale.c_str());
+    bool found_messages = this->use_messages_from_locale(locale);
     if (found_messages) {
       return true;
     }

src/quick-lint-js/i18n/translation.h

@@ -27,8 +27,8 @@ class Translator {
   explicit Translator() = default;
 
   void use_messages_from_source_code();
-  bool use_messages_from_locale(const char* locale_name);
-  bool use_messages_from_locales(Span<const std::string> locale_names);
+  bool use_messages_from_locale(std::string_view locale_name);
+  bool use_messages_from_locales(Span<const std::string_view> locale_names);
 
   const Char8* translate(const Translatable_Message& message);