On 30/04/19 16:06 +0100, Jonathan Wakely wrote:
Fix several bugs in the encoding conversions for filesystem::path that prevent conversion of Unicode characters outside the Basic Multilingual Plane, and prevent returning basic_string specializations with alternative allocator types.The std::codecvt_utf8 class template is not suitable for UTF-16 conversions because it uses UCS-2 instead. For conversions between UTF-8 and UTF-16 either std::codecvt<C, char, mbstate> or codecvt_utf8_utf16<C> must be used. The __str_codecvt_in and __str_codecvt_out utilities do not return false on a partial conversion (e.g. for invalid or incomplete Unicode input). Add new helpers that treat partial conversions as errors, and use them for all filesystem::path conversions. PR libstdc++/90281 Fix string conversions for filesystem::path * include/bits/fs_path.h (u8path) [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use codecvt_utf8_utf16 instead of codecvt_utf8. Use __str_codecvt_in_all to fail for partial conversions and throw on error. [!_GLIBCXX_FILESYSTEM_IS_WINDOWS && _GLIBCXX_USE_CHAR8_T] (path::_Cvt<char8_t>): Add explicit specialization. [_GLIBCXX_FILESYSTEM_IS_WINDOWS] (path::_Cvt::_S_wconvert): Remove overloads. [_GLIBCXX_FILESYSTEM_IS_WINDOWS] (path::_Cvt::_S_convert): Use if-constexpr instead of dispatching to _S_wconvert. Use codecvt instead of codecvt_utf8. Use __str_codecvt_in_all and __str_codecvt_out_all. [!_GLIBCXX_FILESYSTEM_IS_WINDOWS] (path::_Cvt::_S_convert): Use codecvt instead of codecvt_utf8. Use __str_codecvt_out_all. (path::_S_str_convert) [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use codecvt_utf8_utf16 instead of codecvt_utf8. Construct return values with allocator. Use __str_codecvt_out_all. Fallthrough to POSIX code after converting to UTF-8. (path::_S_str_convert): Use codecvt instead of codecvt_utf8. Use __str_codecvt_in_all. (path::string): Fix initialization of string types with different allocators. (path::u8string) [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use codecvt_utf8_utf16 instead of codecvt_utf8. Use __str_codecvt_out_all. * include/bits/locale_conv.h (__do_str_codecvt): Reorder static and runtime conditions. (__str_codecvt_out_all, __str_codecvt_in_all): New functions that return false for partial conversions. * include/experimental/bits/fs_path.h (u8path): [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Implement correctly for mingw. [_GLIBCXX_FILESYSTEM_IS_WINDOWS] (path::_Cvt::_S_wconvert): Add missing handling for char8_t. Use codecvt and codecvt_utf8_utf16 instead of codecvt_utf8. Use __str_codecvt_in_all and __str_codecvt_out_all. [!_GLIBCXX_FILESYSTEM_IS_WINDOWS] (path::_Cvt::_S_convert): Use codecvt instead of codecvt_utf8. Use __str_codecvt_out_all. (path::string) [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use codecvt_utf8_utf16 instead of codecvt_utf8. Construct return values with allocator. Use __str_codecvt_out_all and __str_codecvt_in_all. (path::string) [!_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use __str_codecvt_in_all. (path::u8string) [_GLIBCXX_FILESYSTEM_IS_WINDOWS]: Use codecvt_utf8_utf16 instead of codecvt_utf8. Use __str_codecvt_out_all. * src/c++17/fs_path.cc (path::_S_convert_loc): Use __str_codecvt_in_all. * src/filesystem/path.cc (path::_S_convert_loc): Likewise. * testsuite/27_io/filesystem/path/construct/90281.cc: New test. * testsuite/27_io/filesystem/path/factory/u8path.cc: New test. * testsuite/27_io/filesystem/path/native/string.cc: Test with empty strings and with Unicode characters outside the basic multilingual plane. * testsuite/27_io/filesystem/path/native/alloc.cc: New test. * testsuite/experimental/filesystem/path/construct/90281.cc: New test. * testsuite/experimental/filesystem/path/factory/u8path.cc: New test. * testsuite/experimental/filesystem/path/native/alloc.cc: New test. * testsuite/experimental/filesystem/path/native/string.cc: Test with empty strings and with Unicode characters outside the basic multilingual plane. Tested powerpc64le-linux and x86_64-w64-mingw32. As this ended up being a large patch I'll wait until after 9.1.0 is released to commit this (and then will backport a simpler version).
I forgot to commit the patch after the release. It's now on trunk, as r272385, and I'll backport it soon.
