libstdc++: Fix filesystem::u8path for mingw targets (PR 95392)

When I refactored filesystem::path string conversions in
r11-587-584d52b088f9fcf78704b504c3f1f07e17c1cded I failed to update the
mingw-specific code in filesystem::u8path, causing a bootstrap failure.

This fixes it, and further refactors the mingw-specific code along the
same lines as the previous commit. All conversions from UTF-8 strings to
wide strings now use the same helper function, __wstr_from_utf8.

	PR libstdc++/95392
	* include/bits/fs_path.h (path::_S_to_string): Move to
	namespace-scope and rename to ...
	(__detail::__string_from_range): ... this.
	[WINDOWS] (__detail::__wstr_from_utf8): New function template to
	convert a char sequence containing UTF-8 to wstring.
	(path::_S_convert(Iter, Iter)): Adjust call to _S_to_string.
	(path::_S_convert_loc(Iter, Iter, const locale&)): Likewise.
	(u8path(InputIterator, InputIterator)) [WINDOWS]: Use
	__string_from_range to obtain a contiguous range and
	__wstr_from_utf8 to obtain a wide string.
	(u8path(const Source&)) [WINDOWS]: Use __effective_range to
	obtain a contiguous range and __wstr_from_utf8 to obtain a wide
	string.
	(path::_S_convert(const _EcharT*, const _EcharT)) [WINDOWS]:
	Use __wstr_from_utf8.

diff --git a/libstdc++-v3/include/bits/fs_path.h b/libstdc++-v3/include/bits/fs_path.h
index 2d2766ec62e5e10a5416b5135f79e5d95236bc81..26ddf0afec41c78ddc5341c09ef1d0b920486fef 100644 (file)
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -211,6 +211,51 @@ namespace __detail
 #endif
                         , _Val>;
 
+  // Create a string or string view from an iterator range.
+  template<typename _InputIterator>
+    inline auto
+    __string_from_range(_InputIterator __first, _InputIterator __last)
+    {
+      using _EcharT
+       = typename std::iterator_traits<_InputIterator>::value_type;
+      static_assert(__is_encoded_char<_EcharT>);
+
+#if __cpp_lib_concepts
+      constexpr bool __contiguous = std::contiguous_iterator<_InputIterator>;
+#else
+      constexpr bool __contiguous
+       = is_pointer_v<decltype(std::__niter_base(__first))>;
+#endif
+      if constexpr (__contiguous)
+       {
+         // For contiguous iterators we can just return a string view.
+         const auto* __f = std::__to_address(std::__niter_base(__first));
+         const auto* __l = std::__to_address(std::__niter_base(__last));
+         return basic_string_view<_EcharT>(__f, __l - __f);
+       }
+      else
+       // Conversion requires contiguous characters, so create a string.
+       return basic_string<_EcharT>(__first, __last);
+    }
+
+#ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
+  template<typename _Tp>
+    inline std::wstring
+    __wstr_from_utf8(const _Tp& __str)
+    {
+      static_assert(std::is_same_v<typename _Tp::value_type, char>);
+      std::wstring __wstr;
+      // XXX This assumes native wide encoding is UTF-16.
+      std::codecvt_utf8_utf16<wchar_t> __wcvt;
+      const auto __p = __str.data();
+      if (!__str_codecvt_in_all(__p, __p + __str.size(), __wstr, __wcvt))
+       _GLIBCXX_THROW_OR_ABORT(filesystem_error(
+             "Cannot convert character sequence",
+             std::make_error_code(errc::illegal_byte_sequence)));
+      return __wstr;
+    }
+#endif
+
 } // namespace __detail
   /// @endcond
 
@@ -542,33 +587,6 @@ namespace __detail
 
     pair<const string_type*, size_t> _M_find_extension() const noexcept;
 
-    // Create a string or string view from an iterator range.
-    template<typename _InputIterator>
-      static auto
-      _S_to_string(_InputIterator __first, _InputIterator __last)
-      {
-       using _EcharT
-         = typename std::iterator_traits<_InputIterator>::value_type;
-       static_assert(__detail::__is_encoded_char<_EcharT>);
-
-#if __cpp_lib_concepts
-       constexpr bool __contiguous = std::contiguous_iterator<_InputIterator>;
-#else
-       constexpr bool __contiguous
-         = is_pointer_v<decltype(std::__niter_base(__first))>;
-#endif
-       if constexpr (__contiguous)
-         {
-           // For contiguous iterators we can just return a string view.
-           const auto* __f = std::__to_address(std::__niter_base(__first));
-           const auto* __l = std::__to_address(std::__niter_base(__last));
-           return basic_string_view<_EcharT>(__f, __l - __f);
-         }
-       else
-         // Conversion requires contiguous characters, so create a string.
-         return basic_string<_EcharT>(__first, __last);
-      }
-
     // path::_S_convert creates a basic_string<value_type> or
     // basic_string_view<value_type> from a range (either the effective
     // range of a Source parameter, or a pair of InputIterator parameters),
@@ -602,7 +620,7 @@ namespace __detail
     template<typename _Iter>
       static auto
       _S_convert(_Iter __first, _Iter __last)
-      { return _S_convert(_S_to_string(__first, __last)); }
+      { return _S_convert(__detail::__string_from_range(__first, __last)); }
 
     static string_type
     _S_convert_loc(const char* __first, const char* __last,
@@ -612,7 +630,7 @@ namespace __detail
       static string_type
       _S_convert_loc(_Iter __first, _Iter __last, const std::locale& __loc)
       {
-       const auto __s = _S_to_string(__first, __last);
+       const auto __s = __detail::__string_from_range(__first, __last);
        return _S_convert_loc(__s.data(), __s.data() + __s.size(), __loc);
       }
 
@@ -738,28 +756,10 @@ namespace __detail
     {
 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
       if constexpr (is_same_v<_CharT, char>)
-       {
-         // XXX This assumes native wide encoding is UTF-16.
-         std::codecvt_utf8_utf16<path::value_type> __cvt;
-         path::string_type __tmp;
-         if constexpr (is_pointer_v<_InputIterator>)
-           {
-             if (__str_codecvt_in_all(__first, __last, __tmp, __cvt))
-               return path{ __tmp };
-           }
-         else
-           {
-             const std::string __u8str{__first, __last};
-             const char* const __p = __u8str.data();
-             if (__str_codecvt_in_all(__p, __p + __u8str.size(), __tmp, __cvt))
-               return path{ __tmp };
-           }
-         _GLIBCXX_THROW_OR_ABORT(filesystem_error(
-             "Cannot convert character sequence",
-             std::make_error_code(errc::illegal_byte_sequence)));
-       }
+       return path{ __detail::__wstr_from_utf8(
+           __detail::__string_from_range(__first, __last)) };
       else
-       return path{ __first, __last };
+       return path{ __first, __last }; // constructor handles char8_t
 #else
       // This assumes native normal encoding is UTF-8.
       return path{ __first, __last };
@@ -778,21 +778,12 @@ namespace __detail
     {
 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
       if constexpr (is_same_v<_CharT, char>)
-       {
-         if constexpr (is_convertible_v<const _Source&, std::string_view>)
-           {
-             const std::string_view __s = __source;
-             return filesystem::u8path(__s.data(), __s.data() + __s.size());
-           }
-         else
-           {
-             std::string __s = path::_S_string_from_iter(__source);
-             return filesystem::u8path(__s.data(), __s.data() + __s.size());
-           }
-       }
+       return path{ __detail::__wstr_from_utf8(
+           __detail::__effective_range(__source)) };
       else
-       return path{ __source };
+       return path{ __source }; // constructor handles char8_t
 #else
+      // This assumes native normal encoding is UTF-8.
       return path{ __source };
 #endif
     }
@@ -836,11 +827,8 @@ namespace __detail
 #ifdef _GLIBCXX_USE_CHAR8_T
          else if constexpr (is_same_v<_EcharT, char8_t>)
            {
-             const char* __f2 = (const char*)__f;
-             const char* __l2 = (const char*)__l;
-             std::codecvt_utf8_utf16<wchar_t> __wcvt;
-             if (__str_codecvt_in_all(__f2, __l2, __wstr, __wcvt))
-               return __wstr;
+             const auto __f2 = reinterpret_cast<const char*>(__f);
+             return __detail::__wstr_from_utf8(string_view(__f2, __l - __f));
            }
 #endif
          else // char16_t or char32_t
@@ -849,13 +837,7 @@ namespace __detail
              { } __cvt;
              std::string __str;
              if (__str_codecvt_out_all(__f, __l, __str, __cvt))
-               {
-                 const char* __f2 = __str.data();
-                 const char* __l2 = __f2 + __str.size();
-                 std::codecvt_utf8_utf16<wchar_t> __wcvt;
-                 if (__str_codecvt_in_all(__f2, __l2, __wstr, __wcvt))
-                   return __wstr;
-               }
+               return __detail::__wstr_from_utf8(__str);
            }
 #else // ! windows
          struct _UCvt : std::codecvt<_EcharT, char, std::mbstate_t>