[libcxx] Handle changing of fr_FR locale thousand sep in Windows libcxx tests

libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp

@@ -54,7 +54,7 @@ class my_facetw
 };
 
 static std::wstring convert_thousands_sep(std::wstring const& in) {
-  return LocaleHelpers::convert_thousands_sep_fr_FR(in);
+  return LocaleHelpers::convert_mon_thousands_sep_fr_FR(in);
 }
 #endif // TEST_HAS_NO_WIDE_CHARACTERS
 

libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp

@@ -54,7 +54,7 @@ class my_facetw
 };
 
 static std::wstring convert_thousands_sep(std::wstring const& in) {
-  return LocaleHelpers::convert_thousands_sep_fr_FR(in);
+  return LocaleHelpers::convert_mon_thousands_sep_fr_FR(in);
 }
 #endif // TEST_HAS_NO_WIDE_CHARACTERS
 

libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp

@@ -29,6 +29,10 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
+#if defined(_WIN32) && !defined(TEST_HAS_NO_WIDE_CHARACTERS)
+#  include "locale_helpers.h"
+#endif
+
 class Fnf
     : public std::moneypunct_byname<char, false>
 {
@@ -115,7 +119,11 @@ int main(int, char**)
 #if defined(_CS_GNU_LIBC_VERSION)
     const wchar_t fr_sep = glibc_version_less_than("2.27") ? L' ' : L'\u202F';
 #elif defined(_WIN32)
-    const wchar_t fr_sep = L'\u00A0';
+    // Windows has changed it's fr thousands sep between releases.
+    // Fetch the host's separator in order to know what to expect from the test results.
+    const std::wstring fr_sep_s = LocaleHelpers::get_locale_mon_thousands_sep(LOCALE_fr_FR_UTF_8);
+    assert(fr_sep_s.size() == 1);
+    const wchar_t fr_sep = fr_sep_s[0];
 #elif defined(_AIX)
     const wchar_t fr_sep = L'\u202F';
 #else

libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp

@@ -28,6 +28,10 @@
 #include "test_macros.h"
 #include "platform_support.h" // locale name macros
 
+#if defined(_WIN32) && !defined(TEST_HAS_NO_WIDE_CHARACTERS)
+#  include "locale_helpers.h"
+#endif
+
 int main(int, char**)
 {
     {
@@ -78,7 +82,11 @@ int main(int, char**)
 #if defined(_CS_GNU_LIBC_VERSION)
             const wchar_t wsep = glibc_version_less_than("2.27") ? L' ' : L'\u202f';
 #elif defined(_WIN32)
-            const wchar_t wsep = L'\u00A0';
+          // Windows has changed it's fr thousands sep between releases.
+          // Fetch the host's separator in order to know what to expect from the test results.
+          const std::wstring wsep_s = LocaleHelpers::get_locale_mon_thousands_sep(LOCALE_fr_FR_UTF_8);
+          assert(wsep_s.size() == 1);
+          const wchar_t wsep = wsep_s[0];
 #else
             const wchar_t wsep = L',';
 #endif

libcxx/test/std/time/time.duration/time.duration.nonmember/ostream.pass.cpp

@@ -36,6 +36,10 @@
 #include "platform_support.h" // locale name macros
 #include "test_macros.h"
 
+#if defined(_WIN32) && !defined(TEST_HAS_NO_WIDE_CHARACTERS)
+#  include "locale_helpers.h"
+#endif
+
 #define SV(S) MAKE_STRING_VIEW(CharT, S)
 
 template <class CharT, class Rep, class Period>
@@ -89,10 +93,16 @@ static void test_values() {
 #endif
   } else {
 #ifdef _WIN32
-    assert(stream_fr_FR_locale<CharT>(-1'000'000s) == SV("-1\u00A0000\u00A0000s"));
-    assert(stream_fr_FR_locale<CharT>(1'000'000s) == SV("1\u00A0000\u00A0000s"));
-    assert(stream_fr_FR_locale<CharT>(-1'000.123456s) == SV("-1\u00A0000,1235s"));
-    assert(stream_fr_FR_locale<CharT>(1'000.123456s) == SV("1\u00A0000,1235s"));
+    std::wstring expected_sep = LocaleHelpers::get_locale_thousands_sep(LOCALE_fr_FR_UTF_8);
+    assert(expected_sep.size() == 1);
+    assert(stream_fr_FR_locale<CharT>(-1'000'000s) ==
+           LocaleHelpers::convert_thousands_sep(L"-1 000 000s", expected_sep[0]));
+    assert(stream_fr_FR_locale<CharT>(1'000'000s) ==
+           LocaleHelpers::convert_thousands_sep(L"1 000 000s", expected_sep[0]));
+    assert(stream_fr_FR_locale<CharT>(-1'000.123456s) ==
+           LocaleHelpers::convert_thousands_sep(L"-1 000,1235s", expected_sep[0]));
+    assert(stream_fr_FR_locale<CharT>(1'000.123456s) ==
+           LocaleHelpers::convert_thousands_sep(L"1 000,1235s", expected_sep[0]));
 #elif defined(__APPLE__)
     assert(stream_fr_FR_locale<CharT>(-1'000'000s) == SV("-1000000s"));
     assert(stream_fr_FR_locale<CharT>(1'000'000s) == SV("1000000s"));

libcxx/test/support/locale_helpers.h

@@ -41,20 +41,103 @@ std::wstring convert_thousands_sep(std::wstring const& in, wchar_t sep) {
   return out;
 }
 
+#  if defined(_WIN32)
+// This implementation is similar to the locale_guard in the private libcxx implementation headers
+// but exists here for usability from the libcxx/test/std conformance test suites.
+class LocaleGuard {
+public:
+  explicit LocaleGuard(const char* locale_in) : status_(_configthreadlocale(_ENABLE_PER_THREAD_LOCALE)) {
+    assert(status_ != -1);
+    // Setting the locale can be expensive even when the locale given is
+    // already the current locale, so do an explicit check to see if the
+    // current locale is already the one we want.
+    const char* curr_locale = set_locale_asserts(nullptr);
+    // If every category is the same, the locale string will simply be the
+    // locale name, otherwise it will be a semicolon-separated string listing
+    // each category.  In the second case, we know at least one category won't
+    // be what we want, so we only have to check the first case.
+    if (std::strcmp(locale_in, curr_locale) != 0) {
+      locale_all_ = _strdup(curr_locale);
+      assert(locale_all_ != nullptr);
+      set_locale_asserts(locale_in);
+    }
+  }
+
+  ~LocaleGuard() {
+    // The CRT documentation doesn't explicitly say, but setlocale() does the
+    // right thing when given a semicolon-separated list of locale settings
+    // for the different categories in the same format as returned by
+    // setlocale(LC_ALL, nullptr).
+    if (locale_all_ != nullptr) {
+      set_locale_asserts(locale_all_);
+      free(locale_all_);
+    }
+    _configthreadlocale(status_);
+  }
+
+private:
+  static const char* set_locale_asserts(const char* locale_in) {
+    const char* new_locale = setlocale(LC_ALL, locale_in);
+    assert(new_locale != nullptr);
+    return new_locale;
+  }
+
+  int status_;
+  char* locale_all_ = nullptr;
+};
+
+template <typename T>
+std::wstring get_locale_lconv_cstr_member(const char* locale, T lconv::*cstr_member) {
+  // Store and later restore current locale
+  LocaleGuard g(locale);
+
+  char* locale_set = setlocale(LC_ALL, locale);
+  assert(locale_set != nullptr);
+  lconv* lc            = localeconv();
+  const char* selected = lc->*cstr_member;
+  if (selected == nullptr) {
+    // member is empty string on the locale
+    return std::wstring();
+  }
+
+  std::size_t len = std::mbsrtowcs(nullptr, &selected, 0, nullptr);
+  assert(len != static_cast<std::size_t>(-1));
+
+  std::wstring ws_out(len, L'\0');
+  std::mbstate_t mb = {};
+  std::size_t ret   = std::mbsrtowcs(&ws_out[0], &selected, len, &mb);
+  assert(ret != static_cast<std::size_t>(-1));
+
+  return ws_out;
+}
+
+std::wstring get_locale_mon_thousands_sep(const char* locale) {
+  return get_locale_lconv_cstr_member(locale, &lconv::mon_thousands_sep);
+}
+
+std::wstring get_locale_thousands_sep(const char* locale) {
+  return get_locale_lconv_cstr_member(locale, &lconv::thousands_sep);
+}
+#  endif // _WIN32
+
 // GLIBC 2.27 and newer use U+202F NARROW NO-BREAK SPACE as a thousands separator.
 // This function converts the spaces in string inputs to U+202F if need
 // be. FreeBSD's locale data also uses U+202F, since 2018.
-// Windows uses U+00A0 NO-BREAK SPACE.
-std::wstring convert_thousands_sep_fr_FR(std::wstring const& in) {
-#if defined(_CS_GNU_LIBC_VERSION)
+// Windows may use U+00A0 NO-BREAK SPACE or U+0202F NARROW NO-BREAK SPACE.
+std::wstring convert_mon_thousands_sep_fr_FR(std::wstring const& in) {
+#  if defined(_CS_GNU_LIBC_VERSION)
   if (glibc_version_less_than("2.27"))
     return in;
   else
     return convert_thousands_sep(in, L'\u202F');
 #elif defined(__FreeBSD__)
   return convert_thousands_sep(in, L'\u202F');
 #elif defined(_WIN32)
-  return convert_thousands_sep(in, L'\u00A0');
+  // Windows has changed it's fr thousands sep between releases,
+  // so we find the host's separator instead of hard-coding it.
+  std::wstring fr_sep_s = get_locale_mon_thousands_sep(LOCALE_fr_FR_UTF_8);
+  assert(fr_sep_s.size() == 1);
+  return convert_thousands_sep(in, fr_sep_s[0]);
 #else
   return in;
 #endif