[libc++] Split sources for <filesystem>

[ldionne]

Summary

The operations.cpp file contained the implementation of a ton of
functionality unrelated to just the filesystem operations. Splitting
this up into more files will make it possible in the future to support
parts of <filesystem> (e.g. path) on systems where there is no notion
of a filesystem.

[philnik]

LGTM with green CI. Do you plant to update this to the current style in a follow-up patch?

[ldionne]

In D152377#4403580, @philnik wrote:

LGTM with green CI. Do you plant to update this to the current style in a follow-up patch?

I didn't plan to, but I could. It looks like there aren't that many changes required to make it comply to our clang-format. I'll look into it later but I'd like to avoid doing this before landing my stack of changes cause I want to avoid rebase nightmares.

[ldionne]

Add files to ignore-format list.

[Mordante]

LGTM, when the CI is happy. On small comment.

libcxx/src/filesystem/directory_entry.cpp

10

Please also check the other new files.

[ldionne]

Add -Wunused-function workaround to header files and rebase.

[ldionne]

Fix CI.

[ldionne]

Try to fix circular header dependency

[ldionne]

It seems like I have to roll up D152379 and D152381 into this patch for anything to work, unfortunately.

[ldionne]

Add missing include.

[ldionne]

Add missing include. This is annoying!

[ldionne]

Poke CI

[ldionne]

Remove temporary CI changes and rebase.

[ldionne]

Fix formatting.

[ldionne]

Fix generated files

[ldionne]

Poke CI

[ldionne]

Fix GCC issues.

[paulkirth]

We're seeing some failures in our CI that seem related to this patch. I think either some CMAKE needs adjusting or maybe there is a stale path in the preprocessor directives that cause something to be missed.

Bot: https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-linux-xarm64/b8777855578345589777/overview

Error Message:

FAILED: libcxx/src/CMakeFiles/cxx_shared.dir/filesystem/operations.cpp.obj 
/b/s/w/ir/x/w/staging/llvm_build/./bin/clang++ --target=x86_64-unknown-fuchsia --sysroot=/b/s/w/ir/x/w/sdk/arch/x64/sysroot -DLIBCXX_BUILDING_LIBCXXABI -D_GLIBCXX_ASSERTIONS -D_LIBCPP_BUILDING_LIBRARY -D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS -D_LIBCPP_ENABLE_ASSERTIONS -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -D_LIBCPP_REMOVE_TRANSITIVE_INCLUDES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src -I/b/s/w/ir/x/w/staging/llvm_build/tools/clang/stage2-bins/include/c++/v1 -I/b/s/w/ir/x/w/staging/llvm_build/tools/clang/stage2-bins/include/x86_64-unknown-fuchsia/c++/v1 -I/b/s/w/ir/x/w/llvm-llvm-project/libcxxabi/include -resource-dir=/b/s/w/ir/x/w/staging/llvm_build/tools/clang/stage2-bins/./lib/clang/17 --target=x86_64-unknown-fuchsia -I/b/s/w/ir/x/w/sdk/pkg/sync/include -I/b/s/w/ir/x/w/sdk/pkg/fdio/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -ffunction-sections -fdata-sections -ffile-prefix-map=/b/s/w/ir/x/w/staging/llvm_build/tools/clang/stage2-bins/runtimes/runtimes-x86_64-unknown-fuchsia-bins=../staging/llvm_build/tools/clang/stage2-bins/runtimes/runtimes-x86_64-unknown-fuchsia-bins -ffile-prefix-map=/b/s/w/ir/x/w/llvm-llvm-project/= -no-canonical-prefixes -O2 -g -DNDEBUG -std=c++20 -fPIC -UNDEBUG -faligned-allocation -nostdinc++ -fvisibility-inlines-hidden -fvisibility=hidden -Wall -Wextra -Wnewline-eof -Wshadow -Wwrite-strings -Wno-unused-parameter -Wno-long-long -Werror=return-type -Wextra-semi -Wundef -Wunused-template -Wformat-nonliteral -Wno-user-defined-literals -Wno-covered-switch-default -Wno-suggest-override -Wno-error -MD -MT libcxx/src/CMakeFiles/cxx_shared.dir/filesystem/operations.cpp.obj -MF libcxx/src/CMakeFiles/cxx_shared.dir/filesystem/operations.cpp.obj.d -o libcxx/src/CMakeFiles/cxx_shared.dir/filesystem/operations.cpp.obj -c /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/operations.cpp
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/operations.cpp:25:
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/time_utils.h:263:16: error: incomplete result type 'TimeVal' (aka 'std::filesystem::detail::(anonymous namespace)::timeval') in function definition
  263 | inline TimeVal make_timeval(TimeSpec const& ts) {
      |                ^
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/posix_compat.h:119:24: note: forward declaration of 'std::filesystem::detail::(anonymous namespace)::timeval'
  119 | using TimeVal = struct timeval;
      |                        ^
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/operations.cpp:25:
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/time_utils.h:266:54: error: member access into incomplete type 'std::filesystem::detail::(anonymous namespace)::timeval'
  266 |     using int_type = decltype(std::declval<TimeVal>().tv_usec);
      |                                                      ^
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/posix_compat.h:119:24: note: forward declaration of 'std::filesystem::detail::(anonymous namespace)::timeval'
  119 | using TimeVal = struct timeval;
      |                        ^
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/operations.cpp:25:
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/time_utils.h:268:24: error: unknown type name 'int_type'
  268 |     return static_cast<int_type>(dur);
      |                        ^
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/time_utils.h:270:11: error: variable has incomplete type 'TimeVal' (aka 'std::filesystem::detail::(anonymous namespace)::timeval')
  270 |   TimeVal TV = {};
      |           ^
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/posix_compat.h:119:24: note: forward declaration of 'std::filesystem::detail::(anonymous namespace)::timeval'
  119 | using TimeVal = struct timeval;
      |                        ^
In file included from /b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/operations.cpp:25:
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/time_utils.h:278:11: error: variable has incomplete type 'TimeVal' (aka 'std::filesystem::detail::(anonymous namespace)::timeval')
  278 |   TimeVal ConvertedTS[2] = {make_timeval(TS[0]), make_timeval(TS[1])};
      |           ^
/b/s/w/ir/x/w/llvm-llvm-project/libcxx/src/filesystem/posix_compat.h:119:24: note: forward declaration of 'std::filesystem::detail::(anonymous namespace)::timeval'
  119 | using TimeVal = struct timeval;
      |                        ^
5 errors generated.

[paulkirth]

Chatted w/ @phosek offline and he thinks this may require some changes to the Fuchsia headers as the failure is happening in Fuchsia targets. Sorry for the noise on this, as I thought this was happening in the normal Linux part of the toolchain build. If we find that there will be some changes required on the libcxx side we'll let you know, but you can ignore my previous comments for now.

[phosek]

In D152377#4435584, @paulkirth wrote:

Chatted w/ @phosek offline and he thinks this may require some changes to the Fuchsia headers as the failure is happening in Fuchsia targets. Sorry for the noise on this, as I thought this was happening in the normal Linux part of the toolchain build. If we find that there will be some changes required on the libcxx side we'll let you know, but you can ignore my previous comments for now.

This should be addressed by D153384.

[sylvestre.ledru]

it also caused:
https://github.com/llvm/llvm-project/issues/63613

/usr/include/sys/statvfs.h:47:1: error: unknown type name '__BEGIN_DECLS'
   47 | __BEGIN_DECLS

libcxx/src/CMakeLists.txt

list(APPEND LIBCXX_SOURCES
     support/ibm/mbsnrtowcs.cpp
     support/ibm/wcsnrtombs.cpp
     support/ibm/xlocale_zos.cpp
     )
 endif()
 
 if (LIBCXX_ENABLE_FILESYSTEM)
   list(APPEND LIBCXX_SOURCES
-    filesystem/filesystem_common.h
-    filesystem/operations.cpp
+    filesystem/directory_entry.cpp
     filesystem/directory_iterator.cpp
+    filesystem/file_descriptor.h
+    filesystem/filesystem_clock.cpp
+    filesystem/filesystem_error.cpp
+    filesystem/operations.cpp
+    filesystem/path_parser.h
+    filesystem/path.cpp
     filesystem/posix_compat.h
+    filesystem/time_utils.h
     )
   # Filesystem uses __int128_t, which requires a definition of __muloi4 when
   # compiled with UBSAN. This definition is not provided by libgcc_s, but is
   # provided by compiler-rt. So we need to disable it to avoid having multiple
   # definitions. See filesystem/int128_builtins.cpp.
   if (NOT LIBCXX_USE_COMPILER_RT)
     list(APPEND LIBCXX_SOURCES
       filesystem/int128_builtins.cpp

libcxx/src/filesystem/directory_entry.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+#include <cstdint>
+#include <filesystem>
+#include <system_error>
+
+#include "file_descriptor.h"
+#include "posix_compat.h"
+#include "time_utils.h"
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+error_code directory_entry::__do_refresh() noexcept {
+  __data_.__reset();
+  error_code failure_ec;
+
+  detail::StatT full_st;
+  file_status st = detail::posix_lstat(__p_, full_st, &failure_ec);
+  if (!status_known(st)) {
+    __data_.__reset();
+    return failure_ec;
+  }
+
+  if (!_VSTD_FS::exists(st) || !_VSTD_FS::is_symlink(st)) {
+    __data_.__cache_type_ = directory_entry::_RefreshNonSymlink;
+    __data_.__type_ = st.type();
+    __data_.__non_sym_perms_ = st.permissions();
+  } else { // we have a symlink
+    __data_.__sym_perms_ = st.permissions();
+    // Get the information about the linked entity.
+    // Ignore errors from stat, since we don't want errors regarding symlink
+    // resolution to be reported to the user.
+    error_code ignored_ec;
+    st = detail::posix_stat(__p_, full_st, &ignored_ec);
+
+    __data_.__type_ = st.type();
+    __data_.__non_sym_perms_ = st.permissions();
+
+    // If we failed to resolve the link, then only partially populate the
+    // cache.
+    if (!status_known(st)) {
+      __data_.__cache_type_ = directory_entry::_RefreshSymlinkUnresolved;
+      return error_code{};
+    }
+    // Otherwise, we resolved the link, potentially as not existing.
+    // That's OK.
+    __data_.__cache_type_ = directory_entry::_RefreshSymlink;
+  }
+
+  if (_VSTD_FS::is_regular_file(st))
+    __data_.__size_ = static_cast<uintmax_t>(full_st.st_size);
+
+  if (_VSTD_FS::exists(st)) {
+    __data_.__nlink_ = static_cast<uintmax_t>(full_st.st_nlink);
+
+    // Attempt to extract the mtime, and fail if it's not representable using
+    // file_time_type. For now we ignore the error, as we'll report it when
+    // the value is actually used.
+    error_code ignored_ec;
+    __data_.__write_time_ =
+        detail::__extract_last_write_time(__p_, full_st, &ignored_ec);
+  }
+
+  return failure_ec;
+}
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM

libcxx/src/filesystem/directory_iterator.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <__assert>
 #include <__config>
 #include <errno.h>
 #include <filesystem>
 #include <stack>
+#include <utility>
 
-#include "filesystem_common.h"
+#include "error.h"
+#include "file_descriptor.h"
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h>
+#else
+# include <dirent.h>   // for DIR & friends
+#endif
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
 using detail::ErrorHandler;
 
 #if defined(_LIBCPP_WIN32API)
 class __dir_stream {
 public:

libcxx/src/filesystem/error.h

+//===----------------------------------------------------------------------===////
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef FILESYSTEM_ERROR_H
+#define FILESYSTEM_ERROR_H
+
+#include <__assert>
+#include <__config>
+#include <cerrno>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdint>
+#include <filesystem>
+#include <string>
+#include <system_error>
+#include <utility> // __libcpp_unreachable
+
+#include "format_string.h"
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h> // ERROR_* macros
+#endif
+
+// TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+namespace {
+
+#if defined(_LIBCPP_WIN32API)
+
+errc __win_err_to_errc(int err) {
+  constexpr struct {
+    DWORD win;
+    errc errc;
+  } win_error_mapping[] = {
+      {ERROR_ACCESS_DENIED, errc::permission_denied},
+      {ERROR_ALREADY_EXISTS, errc::file_exists},
+      {ERROR_BAD_NETPATH, errc::no_such_file_or_directory},
+      {ERROR_BAD_PATHNAME, errc::no_such_file_or_directory},
+      {ERROR_BAD_UNIT, errc::no_such_device},
+      {ERROR_BROKEN_PIPE, errc::broken_pipe},
+      {ERROR_BUFFER_OVERFLOW, errc::filename_too_long},
+      {ERROR_BUSY, errc::device_or_resource_busy},
+      {ERROR_BUSY_DRIVE, errc::device_or_resource_busy},
+      {ERROR_CANNOT_MAKE, errc::permission_denied},
+      {ERROR_CANTOPEN, errc::io_error},
+      {ERROR_CANTREAD, errc::io_error},
+      {ERROR_CANTWRITE, errc::io_error},
+      {ERROR_CURRENT_DIRECTORY, errc::permission_denied},
+      {ERROR_DEV_NOT_EXIST, errc::no_such_device},
+      {ERROR_DEVICE_IN_USE, errc::device_or_resource_busy},
+      {ERROR_DIR_NOT_EMPTY, errc::directory_not_empty},
+      {ERROR_DIRECTORY, errc::invalid_argument},
+      {ERROR_DISK_FULL, errc::no_space_on_device},
+      {ERROR_FILE_EXISTS, errc::file_exists},
+      {ERROR_FILE_NOT_FOUND, errc::no_such_file_or_directory},
+      {ERROR_HANDLE_DISK_FULL, errc::no_space_on_device},
+      {ERROR_INVALID_ACCESS, errc::permission_denied},
+      {ERROR_INVALID_DRIVE, errc::no_such_device},
+      {ERROR_INVALID_FUNCTION, errc::function_not_supported},
+      {ERROR_INVALID_HANDLE, errc::invalid_argument},
+      {ERROR_INVALID_NAME, errc::no_such_file_or_directory},
+      {ERROR_INVALID_PARAMETER, errc::invalid_argument},
+      {ERROR_LOCK_VIOLATION, errc::no_lock_available},
+      {ERROR_LOCKED, errc::no_lock_available},
+      {ERROR_NEGATIVE_SEEK, errc::invalid_argument},
+      {ERROR_NOACCESS, errc::permission_denied},
+      {ERROR_NOT_ENOUGH_MEMORY, errc::not_enough_memory},
+      {ERROR_NOT_READY, errc::resource_unavailable_try_again},
+      {ERROR_NOT_SAME_DEVICE, errc::cross_device_link},
+      {ERROR_NOT_SUPPORTED, errc::not_supported},
+      {ERROR_OPEN_FAILED, errc::io_error},
+      {ERROR_OPEN_FILES, errc::device_or_resource_busy},
+      {ERROR_OPERATION_ABORTED, errc::operation_canceled},
+      {ERROR_OUTOFMEMORY, errc::not_enough_memory},
+      {ERROR_PATH_NOT_FOUND, errc::no_such_file_or_directory},
+      {ERROR_READ_FAULT, errc::io_error},
+      {ERROR_REPARSE_TAG_INVALID, errc::invalid_argument},
+      {ERROR_RETRY, errc::resource_unavailable_try_again},
+      {ERROR_SEEK, errc::io_error},
+      {ERROR_SHARING_VIOLATION, errc::permission_denied},
+      {ERROR_TOO_MANY_OPEN_FILES, errc::too_many_files_open},
+      {ERROR_WRITE_FAULT, errc::io_error},
+      {ERROR_WRITE_PROTECT, errc::permission_denied},
+  };
+
+  for (const auto &pair : win_error_mapping)
+    if (pair.win == static_cast<DWORD>(err))
+      return pair.errc;
+  return errc::invalid_argument;
+}
+
+#endif // _LIBCPP_WIN32API
+
+error_code capture_errno() {
+  _LIBCPP_ASSERT(errno != 0, "Expected errno to be non-zero");
+  return error_code(errno, generic_category());
+}
+
+#if defined(_LIBCPP_WIN32API)
+error_code make_windows_error(int err) {
+  return make_error_code(__win_err_to_errc(err));
+}
+#endif
+
+template <class T>
+T error_value();
+template <>
+_LIBCPP_CONSTEXPR_SINCE_CXX14 void error_value<void>() {}
+template <>
+bool error_value<bool>() {
+  return false;
+}
+#if __SIZEOF_SIZE_T__ != __SIZEOF_LONG_LONG__
+template <>
+size_t error_value<size_t>() {
+  return size_t(-1);
+}
+#endif
+template <>
+uintmax_t error_value<uintmax_t>() {
+  return uintmax_t(-1);
+}
+template <>
+_LIBCPP_CONSTEXPR_SINCE_CXX14 file_time_type error_value<file_time_type>() {
+  return file_time_type::min();
+}
+template <>
+path error_value<path>() {
+  return {};
+}
+
+template <class T>
+struct ErrorHandler {
+  const char* func_name_;
+  error_code* ec_ = nullptr;
+  const path* p1_ = nullptr;
+  const path* p2_ = nullptr;
+
+  ErrorHandler(const char* fname, error_code* ec, const path* p1 = nullptr,
+               const path* p2 = nullptr)
+      : func_name_(fname), ec_(ec), p1_(p1), p2_(p2) {
+    if (ec_)
+      ec_->clear();
+  }
+
+  T report(const error_code& ec) const {
+    if (ec_) {
+      *ec_ = ec;
+      return error_value<T>();
+    }
+    string what = string("in ") + func_name_;
+    switch (bool(p1_) + bool(p2_)) {
+    case 0:
+      __throw_filesystem_error(what, ec);
+    case 1:
+      __throw_filesystem_error(what, *p1_, ec);
+    case 2:
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
+    }
+    __libcpp_unreachable();
+  }
+
+  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 0)
+  void report_impl(const error_code& ec, const char* msg, va_list ap) const {
+    if (ec_) {
+      *ec_ = ec;
+      return;
+    }
+    string what =
+        string("in ") + func_name_ + ": " + detail::vformat_string(msg, ap);
+    switch (bool(p1_) + bool(p2_)) {
+    case 0:
+      __throw_filesystem_error(what, ec);
+    case 1:
+      __throw_filesystem_error(what, *p1_, ec);
+    case 2:
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
+    }
+    __libcpp_unreachable();
+  }
+
+  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 4)
+  T report(const error_code& ec, const char* msg, ...) const {
+    va_list ap;
+    va_start(ap, msg);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    try {
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+      report_impl(ec, msg, ap);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+      va_end(ap);
+      throw;
+    }
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+    va_end(ap);
+    return error_value<T>();
+  }
+
+  T report(errc const& err) const {
+    return report(make_error_code(err));
+  }
+
+  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 4)
+  T report(errc const& err, const char* msg, ...) const {
+    va_list ap;
+    va_start(ap, msg);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    try {
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+      report_impl(make_error_code(err), msg, ap);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+      va_end(ap);
+      throw;
+    }
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+    va_end(ap);
+    return error_value<T>();
+  }
+
+private:
+  ErrorHandler(ErrorHandler const&) = delete;
+  ErrorHandler& operator=(ErrorHandler const&) = delete;
+};
+
+} // end anonymous namespace
+} // end namespace detail
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+#endif // FILESYSTEM_ERROR_H

libcxx/src/filesystem/file_descriptor.h

+//===----------------------------------------------------------------------===////
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef FILESYSTEM_FILE_DESCRIPTOR_H
+#define FILESYSTEM_FILE_DESCRIPTOR_H
+
+#include <__config>
+#include <cstdint>
+#include <filesystem>
+#include <string_view>
+#include <system_error>
+#include <utility>
+
+#include "error.h"
+#include "posix_compat.h"
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h>
+#else
+# include <dirent.h>   // for DIR & friends
+# include <fcntl.h>    // values for fchmodat
+# include <sys/stat.h>
+# include <sys/statvfs.h>
+# include <unistd.h>
+#endif // defined(_LIBCPP_WIN32API)
+
+// TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+namespace {
+
+#if !defined(_LIBCPP_WIN32API)
+
+#if defined(DT_BLK)
+template <class DirEntT, class = decltype(DirEntT::d_type)>
+static file_type get_file_type(DirEntT* ent, int) {
+  switch (ent->d_type) {
+  case DT_BLK:
+    return file_type::block;
+  case DT_CHR:
+    return file_type::character;
+  case DT_DIR:
+    return file_type::directory;
+  case DT_FIFO:
+    return file_type::fifo;
+  case DT_LNK:
+    return file_type::symlink;
+  case DT_REG:
+    return file_type::regular;
+  case DT_SOCK:
+    return file_type::socket;
+  // Unlike in lstat, hitting "unknown" here simply means that the underlying
+  // filesystem doesn't support d_type. Report is as 'none' so we correctly
+  // set the cache to empty.
+  case DT_UNKNOWN:
+    break;
+  }
+  return file_type::none;
+}
+#endif // defined(DT_BLK)
+
+template <class DirEntT>
+static file_type get_file_type(DirEntT*, long) {
+  return file_type::none;
+}
+
+static pair<string_view, file_type> posix_readdir(DIR* dir_stream,
+                                                  error_code& ec) {
+  struct dirent* dir_entry_ptr = nullptr;
+  errno = 0; // zero errno in order to detect errors
+  ec.clear();
+  if ((dir_entry_ptr = ::readdir(dir_stream)) == nullptr) {
+    if (errno)
+      ec = capture_errno();
+    return {};
+  } else {
+    return {dir_entry_ptr->d_name, get_file_type(dir_entry_ptr, 0)};
+  }
+}
+
+#else // _LIBCPP_WIN32API
+
+static file_type get_file_type(const WIN32_FIND_DATAW& data) {
+  if (data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
+      data.dwReserved0 == IO_REPARSE_TAG_SYMLINK)
+    return file_type::symlink;
+  if (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+    return file_type::directory;
+  return file_type::regular;
+}
+static uintmax_t get_file_size(const WIN32_FIND_DATAW& data) {
+  return (static_cast<uint64_t>(data.nFileSizeHigh) << 32) + data.nFileSizeLow;
+}
+static file_time_type get_write_time(const WIN32_FIND_DATAW& data) {
+  ULARGE_INTEGER tmp;
+  const FILETIME& time = data.ftLastWriteTime;
+  tmp.u.LowPart = time.dwLowDateTime;
+  tmp.u.HighPart = time.dwHighDateTime;
+  return file_time_type(file_time_type::duration(tmp.QuadPart));
+}
+
+#endif // !_LIBCPP_WIN32API
+
+//                       POSIX HELPERS
+
+using value_type = path::value_type;
+using string_type = path::string_type;
+
+struct FileDescriptor {
+  const path& name;
+  int fd = -1;
+  StatT m_stat;
+  file_status m_status;
+
+  template <class... Args>
+  static FileDescriptor create(const path* p, error_code& ec, Args... args) {
+    ec.clear();
+    int fd;
+    if ((fd = detail::open(p->c_str(), args...)) == -1) {
+      ec = capture_errno();
+      return FileDescriptor{p};
+    }
+    return FileDescriptor(p, fd);
+  }
+
+  template <class... Args>
+  static FileDescriptor create_with_status(const path* p, error_code& ec,
+                                           Args... args) {
+    FileDescriptor fd = create(p, ec, args...);
+    if (!ec)
+      fd.refresh_status(ec);
+
+    return fd;
+  }
+
+  file_status get_status() const { return m_status; }
+  StatT const& get_stat() const { return m_stat; }
+
+  bool status_known() const { return _VSTD_FS::status_known(m_status); }
+
+  file_status refresh_status(error_code& ec);
+
+  void close() noexcept {
+    if (fd != -1)
+      detail::close(fd);
+    fd = -1;
+  }
+
+  FileDescriptor(FileDescriptor&& other)
+      : name(other.name), fd(other.fd), m_stat(other.m_stat),
+        m_status(other.m_status) {
+    other.fd = -1;
+    other.m_status = file_status{};
+  }
+
+  ~FileDescriptor() { close(); }
+
+  FileDescriptor(FileDescriptor const&) = delete;
+  FileDescriptor& operator=(FileDescriptor const&) = delete;
+
+private:
+  explicit FileDescriptor(const path* p, int descriptor = -1) : name(*p), fd(descriptor) {}
+};
+
+perms posix_get_perms(const StatT& st) noexcept {
+  return static_cast<perms>(st.st_mode) & perms::mask;
+}
+
+file_status create_file_status(error_code& m_ec, path const& p,
+                               const StatT& path_stat, error_code* ec) {
+  if (ec)
+    *ec = m_ec;
+  if (m_ec && (m_ec.value() == ENOENT || m_ec.value() == ENOTDIR)) {
+    return file_status(file_type::not_found);
+  } else if (m_ec) {
+    ErrorHandler<void> err("posix_stat", ec, &p);
+    err.report(m_ec, "failed to determine attributes for the specified path");
+    return file_status(file_type::none);
+  }
+  // else
+
+  file_status fs_tmp;
+  auto const mode = path_stat.st_mode;
+  if (S_ISLNK(mode))
+    fs_tmp.type(file_type::symlink);
+  else if (S_ISREG(mode))
+    fs_tmp.type(file_type::regular);
+  else if (S_ISDIR(mode))
+    fs_tmp.type(file_type::directory);
+  else if (S_ISBLK(mode))
+    fs_tmp.type(file_type::block);
+  else if (S_ISCHR(mode))
+    fs_tmp.type(file_type::character);
+  else if (S_ISFIFO(mode))
+    fs_tmp.type(file_type::fifo);
+  else if (S_ISSOCK(mode))
+    fs_tmp.type(file_type::socket);
+  else
+    fs_tmp.type(file_type::unknown);
+
+  fs_tmp.permissions(detail::posix_get_perms(path_stat));
+  return fs_tmp;
+}
+
+file_status posix_stat(path const& p, StatT& path_stat, error_code* ec) {
+  error_code m_ec;
+  if (detail::stat(p.c_str(), &path_stat) == -1)
+    m_ec = detail::capture_errno();
+  return create_file_status(m_ec, p, path_stat, ec);
+}
+
+file_status posix_stat(path const& p, error_code* ec) {
+  StatT path_stat;
+  return posix_stat(p, path_stat, ec);
+}
+
+file_status posix_lstat(path const& p, StatT& path_stat, error_code* ec) {
+  error_code m_ec;
+  if (detail::lstat(p.c_str(), &path_stat) == -1)
+    m_ec = detail::capture_errno();
+  return create_file_status(m_ec, p, path_stat, ec);
+}
+
+file_status posix_lstat(path const& p, error_code* ec) {
+  StatT path_stat;
+  return posix_lstat(p, path_stat, ec);
+}
+
+// http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
+bool posix_ftruncate(const FileDescriptor& fd, off_t to_size, error_code& ec) {
+  if (detail::ftruncate(fd.fd, to_size) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  ec.clear();
+  return false;
+}
+
+bool posix_fchmod(const FileDescriptor& fd, const StatT& st, error_code& ec) {
+  if (detail::fchmod(fd.fd, st.st_mode) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  ec.clear();
+  return false;
+}
+
+bool stat_equivalent(const StatT& st1, const StatT& st2) {
+  return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
+}
+
+file_status FileDescriptor::refresh_status(error_code& ec) {
+  // FD must be open and good.
+  m_status = file_status{};
+  m_stat = {};
+  error_code m_ec;
+  if (detail::fstat(fd, &m_stat) == -1)
+    m_ec = capture_errno();
+  m_status = create_file_status(m_ec, name, m_stat, &ec);
+  return m_status;
+}
+
+} // namespace
+} // end namespace detail
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+_LIBCPP_DIAGNOSTIC_POP
+
+#endif // FILESYSTEM_FILE_DESCRIPTOR_H

libcxx/src/filesystem/filesystem_clock.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+#include <chrono>
+#include <filesystem>
+#include <time.h>
+
+#include "posix_compat.h" // TimeSpec
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h>
+#endif
+
+#if !defined(CLOCK_REALTIME) && !defined(_LIBCPP_WIN32API)
+# include <sys/time.h> // for gettimeofday and timeval
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+const bool _FilesystemClock::is_steady;
+
+_FilesystemClock::time_point _FilesystemClock::now() noexcept {
+  typedef chrono::duration<rep> __secs;
+#if defined(_LIBCPP_WIN32API)
+  typedef chrono::duration<rep, nano> __nsecs;
+  FILETIME time;
+  GetSystemTimeAsFileTime(&time);
+  detail::TimeSpec tp = detail::filetime_to_timespec(time);
+  return time_point(__secs(tp.tv_sec) +
+                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
+#elif defined(CLOCK_REALTIME)
+  typedef chrono::duration<rep, nano> __nsecs;
+  struct timespec tp;
+  if (0 != clock_gettime(CLOCK_REALTIME, &tp))
+    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
+  return time_point(__secs(tp.tv_sec) +
+                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
+#else
+  typedef chrono::duration<rep, micro> __microsecs;
+  timeval tv;
+  gettimeofday(&tv, 0);
+  return time_point(__secs(tv.tv_sec) + __microsecs(tv.tv_usec));
+#endif // CLOCK_REALTIME
+}
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM

libcxx/src/filesystem/filesystem_error.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+#include <__utility/unreachable.h>
+#include <filesystem>
+#include <system_error>
+
+#include "format_string.h"
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+filesystem_error::~filesystem_error() {}
+
+void filesystem_error::__create_what(int __num_paths) {
+  const char* derived_what = system_error::what();
+  __storage_->__what_ = [&]() -> string {
+    switch (__num_paths) {
+    case 0:
+      return detail::format_string("filesystem error: %s", derived_what);
+    case 1:
+      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "]",
+                                   derived_what, path1().c_str());
+    case 2:
+      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "] [" PATH_CSTR_FMT "]",
+                                   derived_what, path1().c_str(), path2().c_str());
+    }
+    __libcpp_unreachable();
+  }();
+}
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM

libcxx/src/filesystem/format_string.h

+//===----------------------------------------------------------------------===////
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef FILESYSTEM_FORMAT_STRING_H
+#define FILESYSTEM_FORMAT_STRING_H
+
+#include <__assert>
+#include <__config>
+#include <array>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdio>
+#include <string>
+
+#if defined(_LIBCPP_WIN32API)
+#  define PATHSTR(x) (L##x)
+#  define PATH_CSTR_FMT "\"%ls\""
+#else
+#  define PATHSTR(x) (x)
+#  define PATH_CSTR_FMT "\"%s\""
+#endif
+
+// TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+namespace {
+
+_LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 0)
+string vformat_string(const char* msg, va_list ap) {
+  array<char, 256> buf;
+
+  va_list apcopy;
+  va_copy(apcopy, ap);
+  int ret = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
+  va_end(apcopy);
+
+  string result;
+  if (static_cast<size_t>(ret) < buf.size()) {
+    result.assign(buf.data(), static_cast<size_t>(ret));
+  } else {
+    // we did not provide a long enough buffer on our first attempt. The
+    // return value is the number of bytes (excluding the null byte) that are
+    // needed for formatting.
+    size_t size_with_null = static_cast<size_t>(ret) + 1;
+    result.__resize_default_init(size_with_null - 1);
+    ret = ::vsnprintf(&result[0], size_with_null, msg, ap);
+    _LIBCPP_ASSERT(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
+  }
+  return result;
+}
+
+_LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 2)
+string format_string(const char* msg, ...) {
+  string ret;
+  va_list ap;
+  va_start(ap, msg);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+  try {
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+    ret = detail::vformat_string(msg, ap);
+#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+  } catch (...) {
+    va_end(ap);
+    throw;
+  }
+#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+  va_end(ap);
+  return ret;
+}
+
+} // end anonymous namespace
+} // end namespace detail
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+_LIBCPP_DIAGNOSTIC_POP
+
+#endif // FILESYSTEM_FORMAT_STRING_H

libcxx/src/filesystem/operations.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include <__assert>
+#include <__config>
 #include <__utility/unreachable.h>
 #include <array>
 #include <climits>
 #include <cstdlib>
 #include <filesystem>
 #include <iterator>
 #include <string_view>
 #include <type_traits>
 #include <vector>
 
-#include "filesystem_common.h"
-
+#include "error.h"
+#include "file_descriptor.h"
+#include "path_parser.h"
 #include "posix_compat.h"
+#include "time_utils.h"
 
 #if defined(_LIBCPP_WIN32API)
 # define WIN32_LEAN_AND_MEAN
 # define NOMINMAX
 # include <windows.h>
 #else
 # include <dirent.h>
 # include <sys/stat.h>

 #elif defined(__APPLE__) || __has_include(<copyfile.h>)
 # include <copyfile.h>
 # define _LIBCPP_FILESYSTEM_USE_COPYFILE
 #else
 # include <fstream>
 # define _LIBCPP_FILESYSTEM_USE_FSTREAM
 #endif
 
-#if !defined(CLOCK_REALTIME) && !defined(_LIBCPP_WIN32API)
-# include <sys/time.h> // for gettimeofday and timeval
-#endif
-
 #if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
 # pragma comment(lib, "rt")
 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
-namespace {
-
-bool isSeparator(path::value_type C) {
-  if (C == '/')
-    return true;
-#if defined(_LIBCPP_WIN32API)
-  if (C == '\\')
-    return true;
-#endif
-  return false;
-}
-
-bool isDriveLetter(path::value_type C) {
-  return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z');
-}
-
-namespace parser {
-
-using string_view_t = path::__string_view;
-using string_view_pair = pair<string_view_t, string_view_t>;
-using PosPtr = path::value_type const*;
-
-struct PathParser {
-  enum ParserState : unsigned char {
-    // Zero is a special sentinel value used by default constructed iterators.
-    PS_BeforeBegin = path::iterator::_BeforeBegin,
-    PS_InRootName = path::iterator::_InRootName,
-    PS_InRootDir = path::iterator::_InRootDir,
-    PS_InFilenames = path::iterator::_InFilenames,
-    PS_InTrailingSep = path::iterator::_InTrailingSep,
-    PS_AtEnd = path::iterator::_AtEnd
-  };
-
-  const string_view_t Path;
-  string_view_t RawEntry;
-  ParserState State;
-
-private:
-  PathParser(string_view_t P, ParserState State) noexcept : Path(P),
-                                                            State(State) {}
-
-public:
-  PathParser(string_view_t P, string_view_t E, unsigned char S)
-      : Path(P), RawEntry(E), State(static_cast<ParserState>(S)) {
-    // S cannot be '0' or PS_BeforeBegin.
-  }
-
-  static PathParser CreateBegin(string_view_t P) noexcept {
-    PathParser PP(P, PS_BeforeBegin);
-    PP.increment();
-    return PP;
-  }
-
-  static PathParser CreateEnd(string_view_t P) noexcept {
-    PathParser PP(P, PS_AtEnd);
-    return PP;
-  }
-
-  PosPtr peek() const noexcept {
-    auto TkEnd = getNextTokenStartPos();
-    auto End = getAfterBack();
-    return TkEnd == End ? nullptr : TkEnd;
-  }
-
-  void increment() noexcept {
-    const PosPtr End = getAfterBack();
-    const PosPtr Start = getNextTokenStartPos();
-    if (Start == End)
-      return makeState(PS_AtEnd);
-
-    switch (State) {
-    case PS_BeforeBegin: {
-      PosPtr TkEnd = consumeRootName(Start, End);
-      if (TkEnd)
-        return makeState(PS_InRootName, Start, TkEnd);
-    }
-      _LIBCPP_FALLTHROUGH();
-    case PS_InRootName: {
-      PosPtr TkEnd = consumeAllSeparators(Start, End);
-      if (TkEnd)
-        return makeState(PS_InRootDir, Start, TkEnd);
-      else
-        return makeState(PS_InFilenames, Start, consumeName(Start, End));
-    }
-    case PS_InRootDir:
-      return makeState(PS_InFilenames, Start, consumeName(Start, End));
-
-    case PS_InFilenames: {
-      PosPtr SepEnd = consumeAllSeparators(Start, End);
-      if (SepEnd != End) {
-        PosPtr TkEnd = consumeName(SepEnd, End);
-        if (TkEnd)
-          return makeState(PS_InFilenames, SepEnd, TkEnd);
-      }
-      return makeState(PS_InTrailingSep, Start, SepEnd);
-    }
-
-    case PS_InTrailingSep:
-      return makeState(PS_AtEnd);
-
-    case PS_AtEnd:
-      __libcpp_unreachable();
-    }
-  }
-
-  void decrement() noexcept {
-    const PosPtr REnd = getBeforeFront();
-    const PosPtr RStart = getCurrentTokenStartPos() - 1;
-    if (RStart == REnd) // we're decrementing the begin
-      return makeState(PS_BeforeBegin);
-
-    switch (State) {
-    case PS_AtEnd: {
-      // Try to consume a trailing separator or root directory first.
-      if (PosPtr SepEnd = consumeAllSeparators(RStart, REnd)) {
-        if (SepEnd == REnd)
-          return makeState(PS_InRootDir, Path.data(), RStart + 1);
-        PosPtr TkStart = consumeRootName(SepEnd, REnd);
-        if (TkStart == REnd)
-          return makeState(PS_InRootDir, RStart, RStart + 1);
-        return makeState(PS_InTrailingSep, SepEnd + 1, RStart + 1);
-      } else {
-        PosPtr TkStart = consumeRootName(RStart, REnd);
-        if (TkStart == REnd)
-          return makeState(PS_InRootName, TkStart + 1, RStart + 1);
-        TkStart = consumeName(RStart, REnd);
-        return makeState(PS_InFilenames, TkStart + 1, RStart + 1);
-      }
-    }
-    case PS_InTrailingSep:
-      return makeState(PS_InFilenames, consumeName(RStart, REnd) + 1,
-                       RStart + 1);
-    case PS_InFilenames: {
-      PosPtr SepEnd = consumeAllSeparators(RStart, REnd);
-      if (SepEnd == REnd)
-        return makeState(PS_InRootDir, Path.data(), RStart + 1);
-      PosPtr TkStart = consumeRootName(SepEnd ? SepEnd : RStart, REnd);
-      if (TkStart == REnd) {
-        if (SepEnd)
-          return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
-        return makeState(PS_InRootName, TkStart + 1, RStart + 1);
-      }
-      TkStart = consumeName(SepEnd, REnd);
-      return makeState(PS_InFilenames, TkStart + 1, SepEnd + 1);
-    }
-    case PS_InRootDir:
-      return makeState(PS_InRootName, Path.data(), RStart + 1);
-    case PS_InRootName:
-    case PS_BeforeBegin:
-      __libcpp_unreachable();
-    }
-  }
-
-  /// \brief Return a view with the "preferred representation" of the current
-  ///   element. For example trailing separators are represented as a '.'
-  string_view_t operator*() const noexcept {
-    switch (State) {
-    case PS_BeforeBegin:
-    case PS_AtEnd:
-      return PATHSTR("");
-    case PS_InRootDir:
-      if (RawEntry[0] == '\\')
-        return PATHSTR("\\");
-      else
-        return PATHSTR("/");
-    case PS_InTrailingSep:
-      return PATHSTR("");
-    case PS_InRootName:
-    case PS_InFilenames:
-      return RawEntry;
-    }
-    __libcpp_unreachable();
-  }
-
-  explicit operator bool() const noexcept {
-    return State != PS_BeforeBegin && State != PS_AtEnd;
-  }
-
-  PathParser& operator++() noexcept {
-    increment();
-    return *this;
-  }
-
-  PathParser& operator--() noexcept {
-    decrement();
-    return *this;
-  }
-
-  bool atEnd() const noexcept {
-    return State == PS_AtEnd;
-  }
-
-  bool inRootDir() const noexcept {
-    return State == PS_InRootDir;
-  }
-
-  bool inRootName() const noexcept {
-    return State == PS_InRootName;
-  }
-
-  bool inRootPath() const noexcept {
-    return inRootName() || inRootDir();
-  }
-
-private:
-  void makeState(ParserState NewState, PosPtr Start, PosPtr End) noexcept {
-    State = NewState;
-    RawEntry = string_view_t(Start, End - Start);
-  }
-  void makeState(ParserState NewState) noexcept {
-    State = NewState;
-    RawEntry = {};
-  }
-
-  PosPtr getAfterBack() const noexcept { return Path.data() + Path.size(); }
-
-  PosPtr getBeforeFront() const noexcept { return Path.data() - 1; }
-
-  /// \brief Return a pointer to the first character after the currently
-  ///   lexed element.
-  PosPtr getNextTokenStartPos() const noexcept {
-    switch (State) {
-    case PS_BeforeBegin:
-      return Path.data();
-    case PS_InRootName:
-    case PS_InRootDir:
-    case PS_InFilenames:
-      return &RawEntry.back() + 1;
-    case PS_InTrailingSep:
-    case PS_AtEnd:
-      return getAfterBack();
-    }
-    __libcpp_unreachable();
-  }
-
-  /// \brief Return a pointer to the first character in the currently lexed
-  ///   element.
-  PosPtr getCurrentTokenStartPos() const noexcept {
-    switch (State) {
-    case PS_BeforeBegin:
-    case PS_InRootName:
-      return &Path.front();
-    case PS_InRootDir:
-    case PS_InFilenames:
-    case PS_InTrailingSep:
-      return &RawEntry.front();
-    case PS_AtEnd:
-      return &Path.back() + 1;
-    }
-    __libcpp_unreachable();
-  }
-
-  // Consume all consecutive separators.
-  PosPtr consumeAllSeparators(PosPtr P, PosPtr End) const noexcept {
-    if (P == nullptr || P == End || !isSeparator(*P))
-      return nullptr;
-    const int Inc = P < End ? 1 : -1;
-    P += Inc;
-    while (P != End && isSeparator(*P))
-      P += Inc;
-    return P;
-  }
-
-  // Consume exactly N separators, or return nullptr.
-  PosPtr consumeNSeparators(PosPtr P, PosPtr End, int N) const noexcept {
-    PosPtr Ret = consumeAllSeparators(P, End);
-    if (Ret == nullptr)
-      return nullptr;
-    if (P < End) {
-      if (Ret == P + N)
-        return Ret;
-    } else {
-      if (Ret == P - N)
-        return Ret;
-    }
-    return nullptr;
-  }
-
-  PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
-    PosPtr Start = P;
-    if (P == nullptr || P == End || isSeparator(*P))
-      return nullptr;
-    const int Inc = P < End ? 1 : -1;
-    P += Inc;
-    while (P != End && !isSeparator(*P))
-      P += Inc;
-    if (P == End && Inc < 0) {
-      // Iterating backwards and consumed all the rest of the input.
-      // Check if the start of the string would have been considered
-      // a root name.
-      PosPtr RootEnd = consumeRootName(End + 1, Start);
-      if (RootEnd)
-        return RootEnd - 1;
-    }
-    return P;
-  }
-
-  PosPtr consumeDriveLetter(PosPtr P, PosPtr End) const noexcept {
-    if (P == End)
-      return nullptr;
-    if (P < End) {
-      if (P + 1 == End || !isDriveLetter(P[0]) || P[1] != ':')
-        return nullptr;
-      return P + 2;
-    } else {
-      if (P - 1 == End || !isDriveLetter(P[-1]) || P[0] != ':')
-        return nullptr;
-      return P - 2;
-    }
-  }
-
-  PosPtr consumeNetworkRoot(PosPtr P, PosPtr End) const noexcept {
-    if (P == End)
-      return nullptr;
-    if (P < End)
-      return consumeName(consumeNSeparators(P, End, 2), End);
-    else
-      return consumeNSeparators(consumeName(P, End), End, 2);
-  }
-
-  PosPtr consumeRootName(PosPtr P, PosPtr End) const noexcept {
-#if defined(_LIBCPP_WIN32API)
-    if (PosPtr Ret = consumeDriveLetter(P, End))
-      return Ret;
-    if (PosPtr Ret = consumeNetworkRoot(P, End))
-      return Ret;
-#endif
-    return nullptr;
-  }
-};
-
-string_view_pair separate_filename(string_view_t const& s) {
-  if (s == PATHSTR(".") || s == PATHSTR("..") || s.empty())
-    return string_view_pair{s, PATHSTR("")};
-  auto pos = s.find_last_of('.');
-  if (pos == string_view_t::npos || pos == 0)
-    return string_view_pair{s, string_view_t{}};
-  return string_view_pair{s.substr(0, pos), s.substr(pos)};
-}
-
-string_view_t createView(PosPtr S, PosPtr E) noexcept {
-  return {S, static_cast<size_t>(E - S) + 1};
-}
-
-} // namespace parser
-} // namespace
-
-//                       POSIX HELPERS
-
-#if defined(_LIBCPP_WIN32API)
-namespace detail {
-
-errc __win_err_to_errc(int err) {
-  constexpr struct {
-    DWORD win;
-    errc errc;
-  } win_error_mapping[] = {
-      {ERROR_ACCESS_DENIED, errc::permission_denied},
-      {ERROR_ALREADY_EXISTS, errc::file_exists},
-      {ERROR_BAD_NETPATH, errc::no_such_file_or_directory},
-      {ERROR_BAD_PATHNAME, errc::no_such_file_or_directory},
-      {ERROR_BAD_UNIT, errc::no_such_device},
-      {ERROR_BROKEN_PIPE, errc::broken_pipe},
-      {ERROR_BUFFER_OVERFLOW, errc::filename_too_long},
-      {ERROR_BUSY, errc::device_or_resource_busy},
-      {ERROR_BUSY_DRIVE, errc::device_or_resource_busy},
-      {ERROR_CANNOT_MAKE, errc::permission_denied},
-      {ERROR_CANTOPEN, errc::io_error},
-      {ERROR_CANTREAD, errc::io_error},
-      {ERROR_CANTWRITE, errc::io_error},
-      {ERROR_CURRENT_DIRECTORY, errc::permission_denied},
-      {ERROR_DEV_NOT_EXIST, errc::no_such_device},
-      {ERROR_DEVICE_IN_USE, errc::device_or_resource_busy},
-      {ERROR_DIR_NOT_EMPTY, errc::directory_not_empty},
-      {ERROR_DIRECTORY, errc::invalid_argument},
-      {ERROR_DISK_FULL, errc::no_space_on_device},
-      {ERROR_FILE_EXISTS, errc::file_exists},
-      {ERROR_FILE_NOT_FOUND, errc::no_such_file_or_directory},
-      {ERROR_HANDLE_DISK_FULL, errc::no_space_on_device},
-      {ERROR_INVALID_ACCESS, errc::permission_denied},
-      {ERROR_INVALID_DRIVE, errc::no_such_device},
-      {ERROR_INVALID_FUNCTION, errc::function_not_supported},
-      {ERROR_INVALID_HANDLE, errc::invalid_argument},
-      {ERROR_INVALID_NAME, errc::no_such_file_or_directory},
-      {ERROR_INVALID_PARAMETER, errc::invalid_argument},
-      {ERROR_LOCK_VIOLATION, errc::no_lock_available},
-      {ERROR_LOCKED, errc::no_lock_available},
-      {ERROR_NEGATIVE_SEEK, errc::invalid_argument},
-      {ERROR_NOACCESS, errc::permission_denied},
-      {ERROR_NOT_ENOUGH_MEMORY, errc::not_enough_memory},
-      {ERROR_NOT_READY, errc::resource_unavailable_try_again},
-      {ERROR_NOT_SAME_DEVICE, errc::cross_device_link},
-      {ERROR_NOT_SUPPORTED, errc::not_supported},
-      {ERROR_OPEN_FAILED, errc::io_error},
-      {ERROR_OPEN_FILES, errc::device_or_resource_busy},
-      {ERROR_OPERATION_ABORTED, errc::operation_canceled},
-      {ERROR_OUTOFMEMORY, errc::not_enough_memory},
-      {ERROR_PATH_NOT_FOUND, errc::no_such_file_or_directory},
-      {ERROR_READ_FAULT, errc::io_error},
-      {ERROR_REPARSE_TAG_INVALID, errc::invalid_argument},
-      {ERROR_RETRY, errc::resource_unavailable_try_again},
-      {ERROR_SEEK, errc::io_error},
-      {ERROR_SHARING_VIOLATION, errc::permission_denied},
-      {ERROR_TOO_MANY_OPEN_FILES, errc::too_many_files_open},
-      {ERROR_WRITE_FAULT, errc::io_error},
-      {ERROR_WRITE_PROTECT, errc::permission_denied},
-  };
-
-  for (const auto &pair : win_error_mapping)
-    if (pair.win == static_cast<DWORD>(err))
-      return pair.errc;
-  return errc::invalid_argument;
-}
-
-} // namespace detail
-#endif
-
-namespace detail {
-namespace {
-
-using value_type = path::value_type;
-using string_type = path::string_type;
-
-struct FileDescriptor {
-  const path& name;
-  int fd = -1;
-  StatT m_stat;
-  file_status m_status;
-
-  template <class... Args>
-  static FileDescriptor create(const path* p, error_code& ec, Args... args) {
-    ec.clear();
-    int fd;
-    if ((fd = detail::open(p->c_str(), args...)) == -1) {
-      ec = capture_errno();
-      return FileDescriptor{p};
-    }
-    return FileDescriptor(p, fd);
-  }
-
-  template <class... Args>
-  static FileDescriptor create_with_status(const path* p, error_code& ec,
-                                           Args... args) {
-    FileDescriptor fd = create(p, ec, args...);
-    if (!ec)
-      fd.refresh_status(ec);
-
-    return fd;
-  }
-
-  file_status get_status() const { return m_status; }
-  StatT const& get_stat() const { return m_stat; }
-
-  bool status_known() const { return _VSTD_FS::status_known(m_status); }
-
-  file_status refresh_status(error_code& ec);
-
-  void close() noexcept {
-    if (fd != -1)
-      detail::close(fd);
-    fd = -1;
-  }
-
-  FileDescriptor(FileDescriptor&& other)
-      : name(other.name), fd(other.fd), m_stat(other.m_stat),
-        m_status(other.m_status) {
-    other.fd = -1;
-    other.m_status = file_status{};
-  }
-
-  ~FileDescriptor() { close(); }
-
-  FileDescriptor(FileDescriptor const&) = delete;
-  FileDescriptor& operator=(FileDescriptor const&) = delete;
-
-private:
-  explicit FileDescriptor(const path* p, int fd = -1) : name(*p), fd(fd) {}
-};
-
-perms posix_get_perms(const StatT& st) noexcept {
-  return static_cast<perms>(st.st_mode) & perms::mask;
-}
-
-file_status create_file_status(error_code& m_ec, path const& p,
-                               const StatT& path_stat, error_code* ec) {
-  if (ec)
-    *ec = m_ec;
-  if (m_ec && (m_ec.value() == ENOENT || m_ec.value() == ENOTDIR)) {
-    return file_status(file_type::not_found);
-  } else if (m_ec) {
-    ErrorHandler<void> err("posix_stat", ec, &p);
-    err.report(m_ec, "failed to determine attributes for the specified path");
-    return file_status(file_type::none);
-  }
-  // else
-
-  file_status fs_tmp;
-  auto const mode = path_stat.st_mode;
-  if (S_ISLNK(mode))
-    fs_tmp.type(file_type::symlink);
-  else if (S_ISREG(mode))
-    fs_tmp.type(file_type::regular);
-  else if (S_ISDIR(mode))
-    fs_tmp.type(file_type::directory);
-  else if (S_ISBLK(mode))
-    fs_tmp.type(file_type::block);
-  else if (S_ISCHR(mode))
-    fs_tmp.type(file_type::character);
-  else if (S_ISFIFO(mode))
-    fs_tmp.type(file_type::fifo);
-  else if (S_ISSOCK(mode))
-    fs_tmp.type(file_type::socket);
-  else
-    fs_tmp.type(file_type::unknown);
-
-  fs_tmp.permissions(detail::posix_get_perms(path_stat));
-  return fs_tmp;
-}
-
-file_status posix_stat(path const& p, StatT& path_stat, error_code* ec) {
-  error_code m_ec;
-  if (detail::stat(p.c_str(), &path_stat) == -1)
-    m_ec = detail::capture_errno();
-  return create_file_status(m_ec, p, path_stat, ec);
-}
-
-file_status posix_stat(path const& p, error_code* ec) {
-  StatT path_stat;
-  return posix_stat(p, path_stat, ec);
-}
-
-file_status posix_lstat(path const& p, StatT& path_stat, error_code* ec) {
-  error_code m_ec;
-  if (detail::lstat(p.c_str(), &path_stat) == -1)
-    m_ec = detail::capture_errno();
-  return create_file_status(m_ec, p, path_stat, ec);
-}
-
-file_status posix_lstat(path const& p, error_code* ec) {
-  StatT path_stat;
-  return posix_lstat(p, path_stat, ec);
-}
-
-// http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
-bool posix_ftruncate(const FileDescriptor& fd, off_t to_size, error_code& ec) {
-  if (detail::ftruncate(fd.fd, to_size) == -1) {
-    ec = capture_errno();
-    return true;
-  }
-  ec.clear();
-  return false;
-}
-
-bool posix_fchmod(const FileDescriptor& fd, const StatT& st, error_code& ec) {
-  if (detail::fchmod(fd.fd, st.st_mode) == -1) {
-    ec = capture_errno();
-    return true;
-  }
-  ec.clear();
-  return false;
-}
-
-bool stat_equivalent(const StatT& st1, const StatT& st2) {
-  return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
-}
-
-file_status FileDescriptor::refresh_status(error_code& ec) {
-  // FD must be open and good.
-  m_status = file_status{};
-  m_stat = {};
-  error_code m_ec;
-  if (detail::fstat(fd, &m_stat) == -1)
-    m_ec = capture_errno();
-  m_status = create_file_status(m_ec, name, m_stat, &ec);
-  return m_status;
-}
-} // namespace
-} // end namespace detail
-
 using detail::capture_errno;
 using detail::ErrorHandler;
 using detail::StatT;
 using detail::TimeSpec;
 using parser::createView;
 using parser::PathParser;
 using parser::string_view_t;
 
-const bool _FilesystemClock::is_steady;
-
-_FilesystemClock::time_point _FilesystemClock::now() noexcept {
-  typedef chrono::duration<rep> __secs;
-#if defined(_LIBCPP_WIN32API)
-  typedef chrono::duration<rep, nano> __nsecs;
-  FILETIME time;
-  GetSystemTimeAsFileTime(&time);
-  TimeSpec tp = detail::filetime_to_timespec(time);
-  return time_point(__secs(tp.tv_sec) +
-                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
-#elif defined(CLOCK_REALTIME)
-  typedef chrono::duration<rep, nano> __nsecs;
-  struct timespec tp;
-  if (0 != clock_gettime(CLOCK_REALTIME, &tp))
-    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
-  return time_point(__secs(tp.tv_sec) +
-                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
-#else
-  typedef chrono::duration<rep, micro> __microsecs;
-  timeval tv;
-  gettimeofday(&tv, 0);
-  return time_point(__secs(tv.tv_sec) + __microsecs(tv.tv_usec));
-#endif // CLOCK_REALTIME
-}
-
-filesystem_error::~filesystem_error() {}
-
-void filesystem_error::__create_what(int __num_paths) {
-  const char* derived_what = system_error::what();
-  __storage_->__what_ = [&]() -> string {
-    switch (__num_paths) {
-    case 0:
-      return detail::format_string("filesystem error: %s", derived_what);
-    case 1:
-      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "]",
-                                   derived_what, path1().c_str());
-    case 2:
-      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "] [" PATH_CSTR_FMT "]",
-                                   derived_what, path1().c_str(), path2().c_str());
-    }
-    __libcpp_unreachable();
-  }();
-}
-
 static path __do_absolute(const path& p, path* cwd, error_code* ec) {
   if (ec)
     ec->clear();
   if (p.is_absolute())
     return p;
   *cwd = __current_path(ec);
   if (ec && *ec)
     return {};
if (ec && *ec)
       return false;
     return it == directory_iterator{};
   } else if (is_regular_file(st))
     return static_cast<uintmax_t>(pst.st_size) == 0;
 
   __libcpp_unreachable();
 }
 
-static file_time_type __extract_last_write_time(const path& p, const StatT& st,
-                                                error_code* ec) {
-  using detail::fs_time;
-  ErrorHandler<file_time_type> err("last_write_time", ec, &p);
-
-  auto ts = detail::extract_mtime(st);
-  if (!fs_time::is_representable(ts))
-    return err.report(errc::value_too_large);
-
-  return fs_time::convert_from_timespec(ts);
-}
-
 file_time_type __last_write_time(const path& p, error_code* ec) {
   using namespace chrono;
   ErrorHandler<file_time_type> err("last_write_time", ec, &p);
 
   error_code m_ec;
   StatT st;
   detail::posix_stat(p, st, &m_ec);
   if (m_ec)
     return err.report(m_ec);
-  return __extract_last_write_time(p, st, ec);
+  return detail::__extract_last_write_time(p, st, ec);
 }
 
 void __last_write_time(const path& p, file_time_type new_time, error_code* ec) {
   using detail::fs_time;
   ErrorHandler<void> err("last_write_time", ec, &p);
 
 #if defined(_LIBCPP_WIN32API)
   TimeSpec ts;
if (ec)
     ec->clear();
   if (DNEParts.empty())
     return result;
   for (auto It = DNEParts.rbegin(); It != DNEParts.rend(); ++It)
     result /= *It;
   return result.lexically_normal();
 }
 
-///////////////////////////////////////////////////////////////////////////////
-//                            path definitions
-///////////////////////////////////////////////////////////////////////////////
-
-constexpr path::value_type path::preferred_separator;
-
-path& path::replace_extension(path const& replacement) {
-  path p = extension();
-  if (not p.empty()) {
-    __pn_.erase(__pn_.size() - p.native().size());
-  }
-  if (!replacement.empty()) {
-    if (replacement.native()[0] != '.') {
-      __pn_ += PATHSTR(".");
-    }
-    __pn_.append(replacement.__pn_);
-  }
-  return *this;
-}
-
-///////////////////////////////////////////////////////////////////////////////
-// path.decompose
-
-string_view_t path::__root_name() const {
-  auto PP = PathParser::CreateBegin(__pn_);
-  if (PP.State == PathParser::PS_InRootName)
-    return *PP;
-  return {};
-}
-
-string_view_t path::__root_directory() const {
-  auto PP = PathParser::CreateBegin(__pn_);
-  if (PP.State == PathParser::PS_InRootName)
-    ++PP;
-  if (PP.State == PathParser::PS_InRootDir)
-    return *PP;
-  return {};
-}
-
-string_view_t path::__root_path_raw() const {
-  auto PP = PathParser::CreateBegin(__pn_);
-  if (PP.State == PathParser::PS_InRootName) {
-    auto NextCh = PP.peek();
-    if (NextCh && isSeparator(*NextCh)) {
-      ++PP;
-      return createView(__pn_.data(), &PP.RawEntry.back());
-    }
-    return PP.RawEntry;
-  }
-  if (PP.State == PathParser::PS_InRootDir)
-    return *PP;
-  return {};
-}
-
-static bool ConsumeRootName(PathParser *PP) {
-  static_assert(PathParser::PS_BeforeBegin == 1 &&
-      PathParser::PS_InRootName == 2,
-      "Values for enums are incorrect");
-  while (PP->State <= PathParser::PS_InRootName)
-    ++(*PP);
-  return PP->State == PathParser::PS_AtEnd;
-}
-
-static bool ConsumeRootDir(PathParser* PP) {
-  static_assert(PathParser::PS_BeforeBegin == 1 &&
-                PathParser::PS_InRootName == 2 &&
-                PathParser::PS_InRootDir == 3, "Values for enums are incorrect");
-  while (PP->State <= PathParser::PS_InRootDir)
-    ++(*PP);
-  return PP->State == PathParser::PS_AtEnd;
-}
-
-string_view_t path::__relative_path() const {
-  auto PP = PathParser::CreateBegin(__pn_);
-  if (ConsumeRootDir(&PP))
-    return {};
-  return createView(PP.RawEntry.data(), &__pn_.back());
-}
-
-string_view_t path::__parent_path() const {
-  if (empty())
-    return {};
-  // Determine if we have a root path but not a relative path. In that case
-  // return *this.
-  {
-    auto PP = PathParser::CreateBegin(__pn_);
-    if (ConsumeRootDir(&PP))
-      return __pn_;
-  }
-  // Otherwise remove a single element from the end of the path, and return
-  // a string representing that path
-  {
-    auto PP = PathParser::CreateEnd(__pn_);
-    --PP;
-    if (PP.RawEntry.data() == __pn_.data())
-      return {};
-    --PP;
-    return createView(__pn_.data(), &PP.RawEntry.back());
-  }
-}
-
-string_view_t path::__filename() const {
-  if (empty())
-    return {};
-  {
-    PathParser PP = PathParser::CreateBegin(__pn_);
-    if (ConsumeRootDir(&PP))
-      return {};
-  }
-  return *(--PathParser::CreateEnd(__pn_));
-}
-
-string_view_t path::__stem() const {
-  return parser::separate_filename(__filename()).first;
-}
-
-string_view_t path::__extension() const {
-  return parser::separate_filename(__filename()).second;
-}
-
-////////////////////////////////////////////////////////////////////////////
-// path.gen
-
-enum PathPartKind : unsigned char {
-  PK_None,
-  PK_RootSep,
-  PK_Filename,
-  PK_Dot,
-  PK_DotDot,
-  PK_TrailingSep
-};
-
-static PathPartKind ClassifyPathPart(string_view_t Part) {
-  if (Part.empty())
-    return PK_TrailingSep;
-  if (Part == PATHSTR("."))
-    return PK_Dot;
-  if (Part == PATHSTR(".."))
-    return PK_DotDot;
-  if (Part == PATHSTR("/"))
-    return PK_RootSep;
-#if defined(_LIBCPP_WIN32API)
-  if (Part == PATHSTR("\\"))
-    return PK_RootSep;
-#endif
-  return PK_Filename;
-}
-
-path path::lexically_normal() const {
-  if (__pn_.empty())
-    return *this;
-
-  using PartKindPair = pair<string_view_t, PathPartKind>;
-  vector<PartKindPair> Parts;
-  // Guess as to how many elements the path has to avoid reallocating.
-  Parts.reserve(32);
-
-  // Track the total size of the parts as we collect them. This allows the
-  // resulting path to reserve the correct amount of memory.
-  size_t NewPathSize = 0;
-  auto AddPart = [&](PathPartKind K, string_view_t P) {
-    NewPathSize += P.size();
-    Parts.emplace_back(P, K);
-  };
-  auto LastPartKind = [&]() {
-    if (Parts.empty())
-      return PK_None;
-    return Parts.back().second;
-  };
-
-  bool MaybeNeedTrailingSep = false;
-  // Build a stack containing the remaining elements of the path, popping off
-  // elements which occur before a '..' entry.
-  for (auto PP = PathParser::CreateBegin(__pn_); PP; ++PP) {
-    auto Part = *PP;
-    PathPartKind Kind = ClassifyPathPart(Part);
-    switch (Kind) {
-    case PK_Filename:
-    case PK_RootSep: {
-      // Add all non-dot and non-dot-dot elements to the stack of elements.
-      AddPart(Kind, Part);
-      MaybeNeedTrailingSep = false;
-      break;
-    }
-    case PK_DotDot: {
-      // Only push a ".." element if there are no elements preceding the "..",
-      // or if the preceding element is itself "..".
-      auto LastKind = LastPartKind();
-      if (LastKind == PK_Filename) {
-        NewPathSize -= Parts.back().first.size();
-        Parts.pop_back();
-      } else if (LastKind != PK_RootSep)
-        AddPart(PK_DotDot, PATHSTR(".."));
-      MaybeNeedTrailingSep = LastKind == PK_Filename;
-      break;
-    }
-    case PK_Dot:
-    case PK_TrailingSep: {
-      MaybeNeedTrailingSep = true;
-      break;
-    }
-    case PK_None:
-      __libcpp_unreachable();
-    }
-  }
-  // [fs.path.generic]p6.8: If the path is empty, add a dot.
-  if (Parts.empty())
-    return PATHSTR(".");
-
-  // [fs.path.generic]p6.7: If the last filename is dot-dot, remove any
-  // trailing directory-separator.
-  bool NeedTrailingSep = MaybeNeedTrailingSep && LastPartKind() == PK_Filename;
-
-  path Result;
-  Result.__pn_.reserve(Parts.size() + NewPathSize + NeedTrailingSep);
-  for (auto& PK : Parts)
-    Result /= PK.first;
-
-  if (NeedTrailingSep)
-    Result /= PATHSTR("");
-
-  Result.make_preferred();
-  return Result;
-}
-
-static int DetermineLexicalElementCount(PathParser PP) {
-  int Count = 0;
-  for (; PP; ++PP) {
-    auto Elem = *PP;
-    if (Elem == PATHSTR(".."))
-      --Count;
-    else if (Elem != PATHSTR(".") && Elem != PATHSTR(""))
-      ++Count;
-  }
-  return Count;
-}
-
-path path::lexically_relative(const path& base) const {
-  { // perform root-name/root-directory mismatch checks
-    auto PP = PathParser::CreateBegin(__pn_);
-    auto PPBase = PathParser::CreateBegin(base.__pn_);
-    auto CheckIterMismatchAtBase = [&]() {
-      return PP.State != PPBase.State &&
-             (PP.inRootPath() || PPBase.inRootPath());
-    };
-    if (PP.inRootName() && PPBase.inRootName()) {
-      if (*PP != *PPBase)
-        return {};
-    } else if (CheckIterMismatchAtBase())
-      return {};
-
-    if (PP.inRootPath())
-      ++PP;
-    if (PPBase.inRootPath())
-      ++PPBase;
-    if (CheckIterMismatchAtBase())
-      return {};
-  }
-
-  // Find the first mismatching element
-  auto PP = PathParser::CreateBegin(__pn_);
-  auto PPBase = PathParser::CreateBegin(base.__pn_);
-  while (PP && PPBase && PP.State == PPBase.State && *PP == *PPBase) {
-    ++PP;
-    ++PPBase;
-  }
-
-  // If there is no mismatch, return ".".
-  if (!PP && !PPBase)
-    return ".";
-
-  // Otherwise, determine the number of elements, 'n', which are not dot or
-  // dot-dot minus the number of dot-dot elements.
-  int ElemCount = DetermineLexicalElementCount(PPBase);
-  if (ElemCount < 0)
-    return {};
-
-  // if n == 0 and (a == end() || a->empty()), returns path("."); otherwise
-  if (ElemCount == 0 && (PP.atEnd() || *PP == PATHSTR("")))
-    return PATHSTR(".");
-
-  // return a path constructed with 'n' dot-dot elements, followed by the
-  // elements of '*this' after the mismatch.
-  path Result;
-  // FIXME: Reserve enough room in Result that it won't have to re-allocate.
-  while (ElemCount--)
-    Result /= PATHSTR("..");
-  for (; PP; ++PP)
-    Result /= *PP;
-  return Result;
-}
-
-////////////////////////////////////////////////////////////////////////////
-// path.comparisons
-static int CompareRootName(PathParser *LHS, PathParser *RHS) {
-  if (!LHS->inRootName() && !RHS->inRootName())
-    return 0;
-
-  auto GetRootName = [](PathParser *Parser) -> string_view_t {
-    return Parser->inRootName() ? **Parser : PATHSTR("");
-  };
-  int res = GetRootName(LHS).compare(GetRootName(RHS));
-  ConsumeRootName(LHS);
-  ConsumeRootName(RHS);
-  return res;
-}
-
-static int CompareRootDir(PathParser *LHS, PathParser *RHS) {
-  if (!LHS->inRootDir() && RHS->inRootDir())
-    return -1;
-  else if (LHS->inRootDir() && !RHS->inRootDir())
-    return 1;
-  else {
-    ConsumeRootDir(LHS);
-    ConsumeRootDir(RHS);
-    return 0;
-  }
-}
-
-static int CompareRelative(PathParser *LHSPtr, PathParser *RHSPtr) {
-  auto &LHS = *LHSPtr;
-  auto &RHS = *RHSPtr;
-
-  int res;
-  while (LHS && RHS) {
-    if ((res = (*LHS).compare(*RHS)) != 0)
-      return res;
-    ++LHS;
-    ++RHS;
-  }
-  return 0;
-}
-
-static int CompareEndState(PathParser *LHS, PathParser *RHS) {
-  if (LHS->atEnd() && !RHS->atEnd())
-    return -1;
-  else if (!LHS->atEnd() && RHS->atEnd())
-    return 1;
-  return 0;
-}
-
-int path::__compare(string_view_t __s) const {
-  auto LHS = PathParser::CreateBegin(__pn_);
-  auto RHS = PathParser::CreateBegin(__s);
-  int res;
-
-  if ((res = CompareRootName(&LHS, &RHS)) != 0)
-    return res;
-
-  if ((res = CompareRootDir(&LHS, &RHS)) != 0)
-    return res;
-
-  if ((res = CompareRelative(&LHS, &RHS)) != 0)
-    return res;
-
-  return CompareEndState(&LHS, &RHS);
-}
-
-////////////////////////////////////////////////////////////////////////////
-// path.nonmembers
-size_t hash_value(const path& __p) noexcept {
-  auto PP = PathParser::CreateBegin(__p.native());
-  size_t hash_value = 0;
-  hash<string_view_t> hasher;
-  while (PP) {
-    hash_value = __hash_combine(hash_value, hasher(*PP));
-    ++PP;
-  }
-  return hash_value;
-}
-
-////////////////////////////////////////////////////////////////////////////
-// path.itr
-path::iterator path::begin() const {
-  auto PP = PathParser::CreateBegin(__pn_);
-  iterator it;
-  it.__path_ptr_ = this;
-  it.__state_ = static_cast<path::iterator::_ParserState>(PP.State);
-  it.__entry_ = PP.RawEntry;
-  it.__stashed_elem_.__assign_view(*PP);
-  return it;
-}
-
-path::iterator path::end() const {
-  iterator it{};
-  it.__state_ = path::iterator::_AtEnd;
-  it.__path_ptr_ = this;
-  return it;
-}
-
-path::iterator& path::iterator::__increment() {
-  PathParser PP(__path_ptr_->native(), __entry_, __state_);
-  ++PP;
-  __state_ = static_cast<_ParserState>(PP.State);
-  __entry_ = PP.RawEntry;
-  __stashed_elem_.__assign_view(*PP);
-  return *this;
-}
-
-path::iterator& path::iterator::__decrement() {
-  PathParser PP(__path_ptr_->native(), __entry_, __state_);
-  --PP;
-  __state_ = static_cast<_ParserState>(PP.State);
-  __entry_ = PP.RawEntry;
-  __stashed_elem_.__assign_view(*PP);
-  return *this;
-}
-
-#if defined(_LIBCPP_WIN32API)
-////////////////////////////////////////////////////////////////////////////
-// Windows path conversions
-size_t __wide_to_char(const wstring &str, char *out, size_t outlen) {
-  if (str.empty())
-    return 0;
-  ErrorHandler<size_t> err("__wide_to_char", nullptr);
-  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
-  BOOL used_default = FALSE;
-  int ret = WideCharToMultiByte(codepage, 0, str.data(), str.size(), out,
-                                outlen, nullptr, &used_default);
-  if (ret <= 0 || used_default)
-    return err.report(errc::illegal_byte_sequence);
-  return ret;
-}
-
-size_t __char_to_wide(const string &str, wchar_t *out, size_t outlen) {
-  if (str.empty())
-    return 0;
-  ErrorHandler<size_t> err("__char_to_wide", nullptr);
-  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
-  int ret = MultiByteToWideChar(codepage, MB_ERR_INVALID_CHARS, str.data(),
-                                str.size(), out, outlen);
-  if (ret <= 0)
-    return err.report(errc::illegal_byte_sequence);
-  return ret;
-}
-#endif
-
-
-///////////////////////////////////////////////////////////////////////////////
-//                           directory entry definitions
-///////////////////////////////////////////////////////////////////////////////
-
-error_code directory_entry::__do_refresh() noexcept {
-  __data_.__reset();
-  error_code failure_ec;
-
-  StatT full_st;
-  file_status st = detail::posix_lstat(__p_, full_st, &failure_ec);
-  if (!status_known(st)) {
-    __data_.__reset();
-    return failure_ec;
-  }
-
-  if (!_VSTD_FS::exists(st) || !_VSTD_FS::is_symlink(st)) {
-    __data_.__cache_type_ = directory_entry::_RefreshNonSymlink;
-    __data_.__type_ = st.type();
-    __data_.__non_sym_perms_ = st.permissions();
-  } else { // we have a symlink
-    __data_.__sym_perms_ = st.permissions();
-    // Get the information about the linked entity.
-    // Ignore errors from stat, since we don't want errors regarding symlink
-    // resolution to be reported to the user.
-    error_code ignored_ec;
-    st = detail::posix_stat(__p_, full_st, &ignored_ec);
-
-    __data_.__type_ = st.type();
-    __data_.__non_sym_perms_ = st.permissions();
-
-    // If we failed to resolve the link, then only partially populate the
-    // cache.
-    if (!status_known(st)) {
-      __data_.__cache_type_ = directory_entry::_RefreshSymlinkUnresolved;
-      return error_code{};
-    }
-    // Otherwise, we resolved the link, potentially as not existing.
-    // That's OK.
-    __data_.__cache_type_ = directory_entry::_RefreshSymlink;
-  }
-
-  if (_VSTD_FS::is_regular_file(st))
-    __data_.__size_ = static_cast<uintmax_t>(full_st.st_size);
-
-  if (_VSTD_FS::exists(st)) {
-    __data_.__nlink_ = static_cast<uintmax_t>(full_st.st_nlink);
-
-    // Attempt to extract the mtime, and fail if it's not representable using
-    // file_time_type. For now we ignore the error, as we'll report it when
-    // the value is actually used.
-    error_code ignored_ec;
-    __data_.__write_time_ =
-        __extract_last_write_time(__p_, full_st, &ignored_ec);
-  }
-
-  return failure_ec;
-}
-
 _LIBCPP_END_NAMESPACE_FILESYSTEM

libcxx/src/filesystem/path.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+#include <filesystem>
+#include <vector>
+
+#include "error.h"
+#include "path_parser.h"
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+using detail::ErrorHandler;
+using parser::createView;
+using parser::PathParser;
+using parser::string_view_t;
+
+///////////////////////////////////////////////////////////////////////////////
+//                            path definitions
+///////////////////////////////////////////////////////////////////////////////
+
+constexpr path::value_type path::preferred_separator;
+
+path& path::replace_extension(path const& replacement) {
+  path p = extension();
+  if (not p.empty()) {
+    __pn_.erase(__pn_.size() - p.native().size());
+  }
+  if (!replacement.empty()) {
+    if (replacement.native()[0] != '.') {
+      __pn_ += PATHSTR(".");
+    }
+    __pn_.append(replacement.__pn_);
+  }
+  return *this;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// path.decompose
+
+string_view_t path::__root_name() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName)
+    return *PP;
+  return {};
+}
+
+string_view_t path::__root_directory() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName)
+    ++PP;
+  if (PP.State == PathParser::PS_InRootDir)
+    return *PP;
+  return {};
+}
+
+string_view_t path::__root_path_raw() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName) {
+    auto NextCh = PP.peek();
+    if (NextCh && isSeparator(*NextCh)) {
+      ++PP;
+      return createView(__pn_.data(), &PP.RawEntry.back());
+    }
+    return PP.RawEntry;
+  }
+  if (PP.State == PathParser::PS_InRootDir)
+    return *PP;
+  return {};
+}
+
+static bool ConsumeRootName(PathParser *PP) {
+  static_assert(PathParser::PS_BeforeBegin == 1 &&
+      PathParser::PS_InRootName == 2,
+      "Values for enums are incorrect");
+  while (PP->State <= PathParser::PS_InRootName)
+    ++(*PP);
+  return PP->State == PathParser::PS_AtEnd;
+}
+
+static bool ConsumeRootDir(PathParser* PP) {
+  static_assert(PathParser::PS_BeforeBegin == 1 &&
+                PathParser::PS_InRootName == 2 &&
+                PathParser::PS_InRootDir == 3, "Values for enums are incorrect");
+  while (PP->State <= PathParser::PS_InRootDir)
+    ++(*PP);
+  return PP->State == PathParser::PS_AtEnd;
+}
+
+string_view_t path::__relative_path() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (ConsumeRootDir(&PP))
+    return {};
+  return createView(PP.RawEntry.data(), &__pn_.back());
+}
+
+string_view_t path::__parent_path() const {
+  if (empty())
+    return {};
+  // Determine if we have a root path but not a relative path. In that case
+  // return *this.
+  {
+    auto PP = PathParser::CreateBegin(__pn_);
+    if (ConsumeRootDir(&PP))
+      return __pn_;
+  }
+  // Otherwise remove a single element from the end of the path, and return
+  // a string representing that path
+  {
+    auto PP = PathParser::CreateEnd(__pn_);
+    --PP;
+    if (PP.RawEntry.data() == __pn_.data())
+      return {};
+    --PP;
+    return createView(__pn_.data(), &PP.RawEntry.back());
+  }
+}
+
+string_view_t path::__filename() const {
+  if (empty())
+    return {};
+  {
+    PathParser PP = PathParser::CreateBegin(__pn_);
+    if (ConsumeRootDir(&PP))
+      return {};
+  }
+  return *(--PathParser::CreateEnd(__pn_));
+}
+
+string_view_t path::__stem() const {
+  return parser::separate_filename(__filename()).first;
+}
+
+string_view_t path::__extension() const {
+  return parser::separate_filename(__filename()).second;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.gen
+
+enum PathPartKind : unsigned char {
+  PK_None,
+  PK_RootSep,
+  PK_Filename,
+  PK_Dot,
+  PK_DotDot,
+  PK_TrailingSep
+};
+
+static PathPartKind ClassifyPathPart(string_view_t Part) {
+  if (Part.empty())
+    return PK_TrailingSep;
+  if (Part == PATHSTR("."))
+    return PK_Dot;
+  if (Part == PATHSTR(".."))
+    return PK_DotDot;
+  if (Part == PATHSTR("/"))
+    return PK_RootSep;
+#if defined(_LIBCPP_WIN32API)
+  if (Part == PATHSTR("\\"))
+    return PK_RootSep;
+#endif
+  return PK_Filename;
+}
+
+path path::lexically_normal() const {
+  if (__pn_.empty())
+    return *this;
+
+  using PartKindPair = pair<string_view_t, PathPartKind>;
+  vector<PartKindPair> Parts;
+  // Guess as to how many elements the path has to avoid reallocating.
+  Parts.reserve(32);
+
+  // Track the total size of the parts as we collect them. This allows the
+  // resulting path to reserve the correct amount of memory.
+  size_t NewPathSize = 0;
+  auto AddPart = [&](PathPartKind K, string_view_t P) {
+    NewPathSize += P.size();
+    Parts.emplace_back(P, K);
+  };
+  auto LastPartKind = [&]() {
+    if (Parts.empty())
+      return PK_None;
+    return Parts.back().second;
+  };
+
+  bool MaybeNeedTrailingSep = false;
+  // Build a stack containing the remaining elements of the path, popping off
+  // elements which occur before a '..' entry.
+  for (auto PP = PathParser::CreateBegin(__pn_); PP; ++PP) {
+    auto Part = *PP;
+    PathPartKind Kind = ClassifyPathPart(Part);
+    switch (Kind) {
+    case PK_Filename:
+    case PK_RootSep: {
+      // Add all non-dot and non-dot-dot elements to the stack of elements.
+      AddPart(Kind, Part);
+      MaybeNeedTrailingSep = false;
+      break;
+    }
+    case PK_DotDot: {
+      // Only push a ".." element if there are no elements preceding the "..",
+      // or if the preceding element is itself "..".
+      auto LastKind = LastPartKind();
+      if (LastKind == PK_Filename) {
+        NewPathSize -= Parts.back().first.size();
+        Parts.pop_back();
+      } else if (LastKind != PK_RootSep)
+        AddPart(PK_DotDot, PATHSTR(".."));
+      MaybeNeedTrailingSep = LastKind == PK_Filename;
+      break;
+    }
+    case PK_Dot:
+    case PK_TrailingSep: {
+      MaybeNeedTrailingSep = true;
+      break;
+    }
+    case PK_None:
+      __libcpp_unreachable();
+    }
+  }
+  // [fs.path.generic]p6.8: If the path is empty, add a dot.
+  if (Parts.empty())
+    return PATHSTR(".");
+
+  // [fs.path.generic]p6.7: If the last filename is dot-dot, remove any
+  // trailing directory-separator.
+  bool NeedTrailingSep = MaybeNeedTrailingSep && LastPartKind() == PK_Filename;
+
+  path Result;
+  Result.__pn_.reserve(Parts.size() + NewPathSize + NeedTrailingSep);
+  for (auto& PK : Parts)
+    Result /= PK.first;
+
+  if (NeedTrailingSep)
+    Result /= PATHSTR("");
+
+  Result.make_preferred();
+  return Result;
+}
+
+static int DetermineLexicalElementCount(PathParser PP) {
+  int Count = 0;
+  for (; PP; ++PP) {
+    auto Elem = *PP;
+    if (Elem == PATHSTR(".."))
+      --Count;
+    else if (Elem != PATHSTR(".") && Elem != PATHSTR(""))
+      ++Count;
+  }
+  return Count;
+}
+
+path path::lexically_relative(const path& base) const {
+  { // perform root-name/root-directory mismatch checks
+    auto PP = PathParser::CreateBegin(__pn_);
+    auto PPBase = PathParser::CreateBegin(base.__pn_);
+    auto CheckIterMismatchAtBase = [&]() {
+      return PP.State != PPBase.State &&
+             (PP.inRootPath() || PPBase.inRootPath());
+    };
+    if (PP.inRootName() && PPBase.inRootName()) {
+      if (*PP != *PPBase)
+        return {};
+    } else if (CheckIterMismatchAtBase())
+      return {};
+
+    if (PP.inRootPath())
+      ++PP;
+    if (PPBase.inRootPath())
+      ++PPBase;
+    if (CheckIterMismatchAtBase())
+      return {};
+  }
+
+  // Find the first mismatching element
+  auto PP = PathParser::CreateBegin(__pn_);
+  auto PPBase = PathParser::CreateBegin(base.__pn_);
+  while (PP && PPBase && PP.State == PPBase.State && *PP == *PPBase) {
+    ++PP;
+    ++PPBase;
+  }
+
+  // If there is no mismatch, return ".".
+  if (!PP && !PPBase)
+    return ".";
+
+  // Otherwise, determine the number of elements, 'n', which are not dot or
+  // dot-dot minus the number of dot-dot elements.
+  int ElemCount = DetermineLexicalElementCount(PPBase);
+  if (ElemCount < 0)
+    return {};
+
+  // if n == 0 and (a == end() || a->empty()), returns path("."); otherwise
+  if (ElemCount == 0 && (PP.atEnd() || *PP == PATHSTR("")))
+    return PATHSTR(".");
+
+  // return a path constructed with 'n' dot-dot elements, followed by the
+  // elements of '*this' after the mismatch.
+  path Result;
+  // FIXME: Reserve enough room in Result that it won't have to re-allocate.
+  while (ElemCount--)
+    Result /= PATHSTR("..");
+  for (; PP; ++PP)
+    Result /= *PP;
+  return Result;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.comparisons
+static int CompareRootName(PathParser *LHS, PathParser *RHS) {
+  if (!LHS->inRootName() && !RHS->inRootName())
+    return 0;
+
+  auto GetRootName = [](PathParser *Parser) -> string_view_t {
+    return Parser->inRootName() ? **Parser : PATHSTR("");
+  };
+  int res = GetRootName(LHS).compare(GetRootName(RHS));
+  ConsumeRootName(LHS);
+  ConsumeRootName(RHS);
+  return res;
+}
+
+static int CompareRootDir(PathParser *LHS, PathParser *RHS) {
+  if (!LHS->inRootDir() && RHS->inRootDir())
+    return -1;
+  else if (LHS->inRootDir() && !RHS->inRootDir())
+    return 1;
+  else {
+    ConsumeRootDir(LHS);
+    ConsumeRootDir(RHS);
+    return 0;
+  }
+}
+
+static int CompareRelative(PathParser *LHSPtr, PathParser *RHSPtr) {
+  auto &LHS = *LHSPtr;
+  auto &RHS = *RHSPtr;
+
+  int res;
+  while (LHS && RHS) {
+    if ((res = (*LHS).compare(*RHS)) != 0)
+      return res;
+    ++LHS;
+    ++RHS;
+  }
+  return 0;
+}
+
+static int CompareEndState(PathParser *LHS, PathParser *RHS) {
+  if (LHS->atEnd() && !RHS->atEnd())
+    return -1;
+  else if (!LHS->atEnd() && RHS->atEnd())
+    return 1;
+  return 0;
+}
+
+int path::__compare(string_view_t __s) const {
+  auto LHS = PathParser::CreateBegin(__pn_);
+  auto RHS = PathParser::CreateBegin(__s);
+  int res;
+
+  if ((res = CompareRootName(&LHS, &RHS)) != 0)
+    return res;
+
+  if ((res = CompareRootDir(&LHS, &RHS)) != 0)
+    return res;
+
+  if ((res = CompareRelative(&LHS, &RHS)) != 0)
+    return res;
+
+  return CompareEndState(&LHS, &RHS);
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.nonmembers
+size_t hash_value(const path& __p) noexcept {
+  auto PP = PathParser::CreateBegin(__p.native());
+  size_t hash_value = 0;
+  hash<string_view_t> hasher;
+  while (PP) {
+    hash_value = __hash_combine(hash_value, hasher(*PP));
+    ++PP;
+  }
+  return hash_value;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.itr
+path::iterator path::begin() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  iterator it;
+  it.__path_ptr_ = this;
+  it.__state_ = static_cast<path::iterator::_ParserState>(PP.State);
+  it.__entry_ = PP.RawEntry;
+  it.__stashed_elem_.__assign_view(*PP);
+  return it;
+}
+
+path::iterator path::end() const {
+  iterator it{};
+  it.__state_ = path::iterator::_AtEnd;
+  it.__path_ptr_ = this;
+  return it;
+}
+
+path::iterator& path::iterator::__increment() {
+  PathParser PP(__path_ptr_->native(), __entry_, __state_);
+  ++PP;
+  __state_ = static_cast<_ParserState>(PP.State);
+  __entry_ = PP.RawEntry;
+  __stashed_elem_.__assign_view(*PP);
+  return *this;
+}
+
+path::iterator& path::iterator::__decrement() {
+  PathParser PP(__path_ptr_->native(), __entry_, __state_);
+  --PP;
+  __state_ = static_cast<_ParserState>(PP.State);
+  __entry_ = PP.RawEntry;
+  __stashed_elem_.__assign_view(*PP);
+  return *this;
+}
+
+#if defined(_LIBCPP_WIN32API)
+////////////////////////////////////////////////////////////////////////////
+// Windows path conversions
+size_t __wide_to_char(const wstring &str, char *out, size_t outlen) {
+  if (str.empty())
+    return 0;
+  ErrorHandler<size_t> err("__wide_to_char", nullptr);
+  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  BOOL used_default = FALSE;
+  int ret = WideCharToMultiByte(codepage, 0, str.data(), str.size(), out,
+                                outlen, nullptr, &used_default);
+  if (ret <= 0 || used_default)
+    return err.report(errc::illegal_byte_sequence);
+  return ret;
+}
+
+size_t __char_to_wide(const string &str, wchar_t *out, size_t outlen) {
+  if (str.empty())
+    return 0;
+  ErrorHandler<size_t> err("__char_to_wide", nullptr);
+  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  int ret = MultiByteToWideChar(codepage, MB_ERR_INVALID_CHARS, str.data(),
+                                str.size(), out, outlen);
+  if (ret <= 0)
+    return err.report(errc::illegal_byte_sequence);
+  return ret;
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM

libcxx/src/filesystem/path_parser.h

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef PATH_PARSER_H
+#define PATH_PARSER_H
+
+#include <__config>
+#include <__utility/unreachable.h>
+#include <cstddef>
+#include <filesystem>
+#include <utility>
+
+#include "format_string.h"
+
+// TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace {
+
+bool isSeparator(path::value_type C) {
+  if (C == '/')
+    return true;
+#if defined(_LIBCPP_WIN32API)
+  if (C == '\\')
+    return true;
+#endif
+  return false;
+}
+
+bool isDriveLetter(path::value_type C) {
+  return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z');
+}
+
+namespace parser {
+
+using string_view_t = path::__string_view;
+using string_view_pair = pair<string_view_t, string_view_t>;
+using PosPtr = path::value_type const*;
+
+struct PathParser {
+  enum ParserState : unsigned char {
+    // Zero is a special sentinel value used by default constructed iterators.
+    PS_BeforeBegin = path::iterator::_BeforeBegin,
+    PS_InRootName = path::iterator::_InRootName,
+    PS_InRootDir = path::iterator::_InRootDir,
+    PS_InFilenames = path::iterator::_InFilenames,
+    PS_InTrailingSep = path::iterator::_InTrailingSep,
+    PS_AtEnd = path::iterator::_AtEnd
+  };
+
+  const string_view_t Path;
+  string_view_t RawEntry;
+  ParserState State;
+
+private:
+  PathParser(string_view_t P, ParserState State) noexcept : Path(P),
+                                                            State(State) {}
+
+public:
+  PathParser(string_view_t P, string_view_t E, unsigned char S)
+      : Path(P), RawEntry(E), State(static_cast<ParserState>(S)) {
+    // S cannot be '0' or PS_BeforeBegin.
+  }
+
+  static PathParser CreateBegin(string_view_t P) noexcept {
+    PathParser PP(P, PS_BeforeBegin);
+    PP.increment();
+    return PP;
+  }
+
+  static PathParser CreateEnd(string_view_t P) noexcept {
+    PathParser PP(P, PS_AtEnd);
+    return PP;
+  }
+
+  PosPtr peek() const noexcept {
+    auto TkEnd = getNextTokenStartPos();
+    auto End = getAfterBack();
+    return TkEnd == End ? nullptr : TkEnd;
+  }
+
+  void increment() noexcept {
+    const PosPtr End = getAfterBack();
+    const PosPtr Start = getNextTokenStartPos();
+    if (Start == End)
+      return makeState(PS_AtEnd);
+
+    switch (State) {
+    case PS_BeforeBegin: {
+      PosPtr TkEnd = consumeRootName(Start, End);
+      if (TkEnd)
+        return makeState(PS_InRootName, Start, TkEnd);
+    }
+      _LIBCPP_FALLTHROUGH();
+    case PS_InRootName: {
+      PosPtr TkEnd = consumeAllSeparators(Start, End);
+      if (TkEnd)
+        return makeState(PS_InRootDir, Start, TkEnd);
+      else
+        return makeState(PS_InFilenames, Start, consumeName(Start, End));
+    }
+    case PS_InRootDir:
+      return makeState(PS_InFilenames, Start, consumeName(Start, End));
+
+    case PS_InFilenames: {
+      PosPtr SepEnd = consumeAllSeparators(Start, End);
+      if (SepEnd != End) {
+        PosPtr TkEnd = consumeName(SepEnd, End);
+        if (TkEnd)
+          return makeState(PS_InFilenames, SepEnd, TkEnd);
+      }
+      return makeState(PS_InTrailingSep, Start, SepEnd);
+    }
+
+    case PS_InTrailingSep:
+      return makeState(PS_AtEnd);
+
+    case PS_AtEnd:
+      __libcpp_unreachable();
+    }
+  }
+
+  void decrement() noexcept {
+    const PosPtr REnd = getBeforeFront();
+    const PosPtr RStart = getCurrentTokenStartPos() - 1;
+    if (RStart == REnd) // we're decrementing the begin
+      return makeState(PS_BeforeBegin);
+
+    switch (State) {
+    case PS_AtEnd: {
+      // Try to consume a trailing separator or root directory first.
+      if (PosPtr SepEnd = consumeAllSeparators(RStart, REnd)) {
+        if (SepEnd == REnd)
+          return makeState(PS_InRootDir, Path.data(), RStart + 1);
+        PosPtr TkStart = consumeRootName(SepEnd, REnd);
+        if (TkStart == REnd)
+          return makeState(PS_InRootDir, RStart, RStart + 1);
+        return makeState(PS_InTrailingSep, SepEnd + 1, RStart + 1);
+      } else {
+        PosPtr TkStart = consumeRootName(RStart, REnd);
+        if (TkStart == REnd)
+          return makeState(PS_InRootName, TkStart + 1, RStart + 1);
+        TkStart = consumeName(RStart, REnd);
+        return makeState(PS_InFilenames, TkStart + 1, RStart + 1);
+      }
+    }
+    case PS_InTrailingSep:
+      return makeState(PS_InFilenames, consumeName(RStart, REnd) + 1,
+                       RStart + 1);
+    case PS_InFilenames: {
+      PosPtr SepEnd = consumeAllSeparators(RStart, REnd);
+      if (SepEnd == REnd)
+        return makeState(PS_InRootDir, Path.data(), RStart + 1);
+      PosPtr TkStart = consumeRootName(SepEnd ? SepEnd : RStart, REnd);
+      if (TkStart == REnd) {
+        if (SepEnd)
+          return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
+        return makeState(PS_InRootName, TkStart + 1, RStart + 1);
+      }
+      TkStart = consumeName(SepEnd, REnd);
+      return makeState(PS_InFilenames, TkStart + 1, SepEnd + 1);
+    }
+    case PS_InRootDir:
+      return makeState(PS_InRootName, Path.data(), RStart + 1);
+    case PS_InRootName:
+    case PS_BeforeBegin:
+      __libcpp_unreachable();
+    }
+  }
+
+  /// \brief Return a view with the "preferred representation" of the current
+  ///   element. For example trailing separators are represented as a '.'
+  string_view_t operator*() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+    case PS_AtEnd:
+      return PATHSTR("");
+    case PS_InRootDir:
+      if (RawEntry[0] == '\\')
+        return PATHSTR("\\");
+      else
+        return PATHSTR("/");
+    case PS_InTrailingSep:
+      return PATHSTR("");
+    case PS_InRootName:
+    case PS_InFilenames:
+      return RawEntry;
+    }
+    __libcpp_unreachable();
+  }
+
+  explicit operator bool() const noexcept {
+    return State != PS_BeforeBegin && State != PS_AtEnd;
+  }
+
+  PathParser& operator++() noexcept {
+    increment();
+    return *this;
+  }
+
+  PathParser& operator--() noexcept {
+    decrement();
+    return *this;
+  }
+
+  bool atEnd() const noexcept {
+    return State == PS_AtEnd;
+  }
+
+  bool inRootDir() const noexcept {
+    return State == PS_InRootDir;
+  }
+
+  bool inRootName() const noexcept {
+    return State == PS_InRootName;
+  }
+
+  bool inRootPath() const noexcept {
+    return inRootName() || inRootDir();
+  }
+
+private:
+  void makeState(ParserState NewState, PosPtr Start, PosPtr End) noexcept {
+    State = NewState;
+    RawEntry = string_view_t(Start, End - Start);
+  }
+  void makeState(ParserState NewState) noexcept {
+    State = NewState;
+    RawEntry = {};
+  }
+
+  PosPtr getAfterBack() const noexcept { return Path.data() + Path.size(); }
+
+  PosPtr getBeforeFront() const noexcept { return Path.data() - 1; }
+
+  /// \brief Return a pointer to the first character after the currently
+  ///   lexed element.
+  PosPtr getNextTokenStartPos() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+      return Path.data();
+    case PS_InRootName:
+    case PS_InRootDir:
+    case PS_InFilenames:
+      return &RawEntry.back() + 1;
+    case PS_InTrailingSep:
+    case PS_AtEnd:
+      return getAfterBack();
+    }
+    __libcpp_unreachable();
+  }
+
+  /// \brief Return a pointer to the first character in the currently lexed
+  ///   element.
+  PosPtr getCurrentTokenStartPos() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+    case PS_InRootName:
+      return &Path.front();
+    case PS_InRootDir:
+    case PS_InFilenames:
+    case PS_InTrailingSep:
+      return &RawEntry.front();
+    case PS_AtEnd:
+      return &Path.back() + 1;
+    }
+    __libcpp_unreachable();
+  }
+
+  // Consume all consecutive separators.
+  PosPtr consumeAllSeparators(PosPtr P, PosPtr End) const noexcept {
+    if (P == nullptr || P == End || !isSeparator(*P))
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && isSeparator(*P))
+      P += Inc;
+    return P;
+  }
+
+  // Consume exactly N separators, or return nullptr.
+  PosPtr consumeNSeparators(PosPtr P, PosPtr End, int N) const noexcept {
+    PosPtr Ret = consumeAllSeparators(P, End);
+    if (Ret == nullptr)
+      return nullptr;
+    if (P < End) {
+      if (Ret == P + N)
+        return Ret;
+    } else {
+      if (Ret == P - N)
+        return Ret;
+    }
+    return nullptr;
+  }
+
+  PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
+    PosPtr Start = P;
+    if (P == nullptr || P == End || isSeparator(*P))
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && !isSeparator(*P))
+      P += Inc;
+    if (P == End && Inc < 0) {
+      // Iterating backwards and consumed all the rest of the input.
+      // Check if the start of the string would have been considered
+      // a root name.
+      PosPtr RootEnd = consumeRootName(End + 1, Start);
+      if (RootEnd)
+        return RootEnd - 1;
+    }
+    return P;
+  }
+
+  PosPtr consumeDriveLetter(PosPtr P, PosPtr End) const noexcept {
+    if (P == End)
+      return nullptr;
+    if (P < End) {
+      if (P + 1 == End || !isDriveLetter(P[0]) || P[1] != ':')
+        return nullptr;
+      return P + 2;
+    } else {
+      if (P - 1 == End || !isDriveLetter(P[-1]) || P[0] != ':')
+        return nullptr;
+      return P - 2;
+    }
+  }
+
+  PosPtr consumeNetworkRoot(PosPtr P, PosPtr End) const noexcept {
+    if (P == End)
+      return nullptr;
+    if (P < End)
+      return consumeName(consumeNSeparators(P, End, 2), End);
+    else
+      return consumeNSeparators(consumeName(P, End), End, 2);
+  }
+
+  PosPtr consumeRootName(PosPtr P, PosPtr End) const noexcept {
+#if defined(_LIBCPP_WIN32API)
+    if (PosPtr Ret = consumeDriveLetter(P, End))
+      return Ret;
+    if (PosPtr Ret = consumeNetworkRoot(P, End))
+      return Ret;
+#endif
+    return nullptr;
+  }
+};
+
+string_view_pair separate_filename(string_view_t const& s) {
+  if (s == PATHSTR(".") || s == PATHSTR("..") || s.empty())
+    return string_view_pair{s, PATHSTR("")};
+  auto pos = s.find_last_of('.');
+  if (pos == string_view_t::npos || pos == 0)
+    return string_view_pair{s, string_view_t{}};
+  return string_view_pair{s.substr(0, pos), s.substr(pos)};
+}
+
+string_view_t createView(PosPtr S, PosPtr E) noexcept {
+  return {S, static_cast<size_t>(E - S) + 1};
+}
+
+} // namespace parser
+} // namespace
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+_LIBCPP_DIAGNOSTIC_POP
+
+#endif // PATH_PARSER_H

libcxx/src/filesystem/posix_compat.h

 // namespace - callers need to include this header and call them as
 // detail::function(), regardless of platform.
 //
 
 #ifndef POSIX_COMPAT_H
 #define POSIX_COMPAT_H
 
 #include <__assert>
+#include <__config>
 #include <filesystem>
 
-#include "filesystem_common.h"
+#include "error.h"
 
 #if defined(_LIBCPP_WIN32API)
 # define WIN32_LEAN_AND_MEAN
 # define NOMINMAX
 # include <windows.h>
 # include <io.h>
 # include <winioctl.h>
 #else
+# include <fcntl.h>
 # include <unistd.h>
 # include <sys/stat.h>
 # include <sys/statvfs.h>
 #endif
+#include <stdlib.h>
 #include <time.h>
 
 #if defined(_LIBCPP_WIN32API)
 // This struct isn't defined in the normal Windows SDK, but only in the
 // Windows Driver Kit.
 struct LIBCPP_REPARSE_DATA_BUFFER {
   unsigned long  ReparseTag;
   unsigned short ReparseDataLength;
union {
     } MountPointReparseBuffer;
     struct {
       unsigned char DataBuffer[1];
     } GenericReparseBuffer;
   };
 };
 #endif
 
+// TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
+_LIBCPP_DIAGNOSTIC_PUSH
+_LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
+
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
 namespace detail {
 namespace {
 
 #if defined(_LIBCPP_WIN32API)
+// Various C runtime versions (UCRT, or the legacy msvcrt.dll used by
+// some mingw toolchains) provide different stat function implementations,
+// with a number of limitations with respect to what we want from the
+// stat function. Instead provide our own which does exactly what we want,
+// along with our own stat structure and flag macros.
+
+struct TimeSpec {
+  int64_t tv_sec;
+  int64_t tv_nsec;
+};
+struct StatT {
+  unsigned st_mode;
+  TimeSpec st_atim;
+  TimeSpec st_mtim;
+  uint64_t st_dev; // FILE_ID_INFO::VolumeSerialNumber
+  struct FileIdStruct {
+    unsigned char id[16]; // FILE_ID_INFO::FileId
+    bool operator==(const FileIdStruct &other) const {
+      for (int i = 0; i < 16; i++)
+        if (id[i] != other.id[i])
+          return false;
+      return true;
+    }
+  } st_ino;
+  uint32_t st_nlink;
+  uintmax_t st_size;
+};
+
+#else
+using TimeSpec = struct timespec;
+using TimeVal = struct timeval;
+using StatT = struct stat;
+#endif
+
+#if defined(_LIBCPP_WIN32API)
 
 // Various C runtime header sets provide more or less of these. As we
 // provide our own implementation, undef all potential defines from the
 // C runtime headers and provide a complete set of macros of our own.
 
 #undef _S_IFMT
 #undef _S_IFDIR
 #undef _S_IFCHR
int fchmod_handle(HANDLE h, int perms) {
   if ((perms & 0222) == 0)
     basic.FileAttributes |= FILE_ATTRIBUTE_READONLY;
   if (basic.FileAttributes != orig_attributes &&
       !SetFileInformationByHandle(h, FileBasicInfo, &basic, sizeof(basic)))
     return set_errno();
   return 0;
 }
 
-int fchmodat(int fd, const wchar_t *path, int perms, int flag) {
+int fchmodat(int /*fd*/, const wchar_t *path, int perms, int flag) {
   DWORD attributes = GetFileAttributesW(path);
   if (attributes == INVALID_FILE_ATTRIBUTES)
     return set_errno();
   if (attributes & FILE_ATTRIBUTE_REPARSE_POINT &&
       !(flag & AT_SYMLINK_NOFOLLOW)) {
     // If the file is a symlink, and we are supposed to operate on the target
     // of the symlink, we need to open a handle to it, without the
     // FILE_FLAG_OPEN_REPARSE_POINT flag, to open the destination of the

 
 #endif
 
 } // namespace
 } // end namespace detail
 
 _LIBCPP_END_NAMESPACE_FILESYSTEM
 
+_LIBCPP_DIAGNOSTIC_POP
+
 #endif // POSIX_COMPAT_H

libcxx/src/filesystem/time_utils.h

 //===----------------------------------------------------------------------===////
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===////
 
-#ifndef FILESYSTEM_COMMON_H
-#define FILESYSTEM_COMMON_H
+#ifndef FILESYSTEM_TIME_UTILS_H
+#define FILESYSTEM_TIME_UTILS_H
 
-#include <__assert>
 #include <__config>
 #include <array>
-#include <cerrno>
 #include <chrono>
-#include <climits>
-#include <cstdarg>
-#include <ctime>
 #include <filesystem>
+#include <limits>
 #include <ratio>
-#include <utility>
 #include <system_error>
+#include <type_traits>
+#include <utility>
+
+#include "error.h"
+#include "format_string.h"
+#include "posix_compat.h"
 
 #if defined(_LIBCPP_WIN32API)
 # define WIN32_LEAN_AND_MEAN
 # define NOMINMAX
 # include <windows.h>
 #else
-# include <dirent.h>   // for DIR & friends
-# include <fcntl.h>    /* values for fchmodat */
-# include <sys/stat.h>
-# include <sys/statvfs.h>
 # include <sys/time.h> // for ::utimes as used in __last_write_time
-# include <unistd.h>
-#endif // defined(_LIBCPP_WIN32API)
+#endif
 
 // We can use the presence of UTIME_OMIT to detect platforms that provide utimensat.
 #if defined(UTIME_OMIT)
 # define _LIBCPP_USE_UTIMENSAT
 #endif
 
 // TODO: Check whether these functions actually need internal linkage, or if they can be made normal header functions
 _LIBCPP_DIAGNOSTIC_PUSH
 _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wunused-function")
 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-function")
 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-template")
 
-#if defined(_LIBCPP_WIN32API)
-#  define PATHSTR(x) (L##x)
-#  define PATH_CSTR_FMT "\"%ls\""
-#else
-#  define PATHSTR(x) (x)
-#  define PATH_CSTR_FMT "\"%s\""
-#endif
-
 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
 
 namespace detail {
-
-#if defined(_LIBCPP_WIN32API)
-// Non anonymous, to allow access from two translation units.
-errc __win_err_to_errc(int err);
-#endif
-
 namespace {
 
-static _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 0) string
-format_string_impl(const char* msg, va_list ap) {
-  array<char, 256> buf;
-
-  va_list apcopy;
-  va_copy(apcopy, ap);
-  int ret = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
-  va_end(apcopy);
-
-  string result;
-  if (static_cast<size_t>(ret) < buf.size()) {
-    result.assign(buf.data(), static_cast<size_t>(ret));
-  } else {
-    // we did not provide a long enough buffer on our first attempt. The
-    // return value is the number of bytes (excluding the null byte) that are
-    // needed for formatting.
-    size_t size_with_null = static_cast<size_t>(ret) + 1;
-    result.__resize_default_init(size_with_null - 1);
-    ret = ::vsnprintf(&result[0], size_with_null, msg, ap);
-    _LIBCPP_ASSERT(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
-  }
-  return result;
-}
-
-static _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 2) string
-format_string(const char* msg, ...) {
-  string ret;
-  va_list ap;
-  va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-  try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    ret = format_string_impl(msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-  } catch (...) {
-    va_end(ap);
-    throw;
-  }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-  va_end(ap);
-  return ret;
-}
-
-error_code capture_errno() {
-  _LIBCPP_ASSERT(errno != 0, "Expected errno to be non-zero");
-  return error_code(errno, generic_category());
-}
-
-#if defined(_LIBCPP_WIN32API)
-error_code make_windows_error(int err) {
-  return make_error_code(__win_err_to_errc(err));
-}
-#endif
-
-template <class T>
-T error_value();
-template <>
-_LIBCPP_CONSTEXPR_SINCE_CXX14 void error_value<void>() {}
-template <>
-bool error_value<bool>() {
-  return false;
-}
-#if __SIZEOF_SIZE_T__ != __SIZEOF_LONG_LONG__
-template <>
-size_t error_value<size_t>() {
-  return size_t(-1);
-}
-#endif
-template <>
-uintmax_t error_value<uintmax_t>() {
-  return uintmax_t(-1);
-}
-template <>
-_LIBCPP_CONSTEXPR_SINCE_CXX14 file_time_type error_value<file_time_type>() {
-  return file_time_type::min();
-}
-template <>
-path error_value<path>() {
-  return {};
-}
-
-template <class T>
-struct ErrorHandler {
-  const char* func_name_;
-  error_code* ec_ = nullptr;
-  const path* p1_ = nullptr;
-  const path* p2_ = nullptr;
-
-  ErrorHandler(const char* fname, error_code* ec, const path* p1 = nullptr,
-               const path* p2 = nullptr)
-      : func_name_(fname), ec_(ec), p1_(p1), p2_(p2) {
-    if (ec_)
-      ec_->clear();
-  }
-
-  T report(const error_code& ec) const {
-    if (ec_) {
-      *ec_ = ec;
-      return error_value<T>();
-    }
-    string what = string("in ") + func_name_;
-    switch (bool(p1_) + bool(p2_)) {
-    case 0:
-      __throw_filesystem_error(what, ec);
-    case 1:
-      __throw_filesystem_error(what, *p1_, ec);
-    case 2:
-      __throw_filesystem_error(what, *p1_, *p2_, ec);
-    }
-    __libcpp_unreachable();
-  }
-
-  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 0)
-  void report_impl(const error_code& ec, const char* msg, va_list ap) const {
-    if (ec_) {
-      *ec_ = ec;
-      return;
-    }
-    string what =
-        string("in ") + func_name_ + ": " + format_string_impl(msg, ap);
-    switch (bool(p1_) + bool(p2_)) {
-    case 0:
-      __throw_filesystem_error(what, ec);
-    case 1:
-      __throw_filesystem_error(what, *p1_, ec);
-    case 2:
-      __throw_filesystem_error(what, *p1_, *p2_, ec);
-    }
-    __libcpp_unreachable();
-  }
-
-  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 4)
-  T report(const error_code& ec, const char* msg, ...) const {
-    va_list ap;
-    va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-      report_impl(ec, msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    } catch (...) {
-      va_end(ap);
-      throw;
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    va_end(ap);
-    return error_value<T>();
-  }
-
-  T report(errc const& err) const {
-    return report(make_error_code(err));
-  }
-
-  _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 3, 4)
-  T report(errc const& err, const char* msg, ...) const {
-    va_list ap;
-    va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-      report_impl(make_error_code(err), msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    } catch (...) {
-      va_end(ap);
-      throw;
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    va_end(ap);
-    return error_value<T>();
-  }
-
-private:
-  ErrorHandler(ErrorHandler const&) = delete;
-  ErrorHandler& operator=(ErrorHandler const&) = delete;
-};
-
 using chrono::duration;
 using chrono::duration_cast;
 
-#if defined(_LIBCPP_WIN32API)
-// Various C runtime versions (UCRT, or the legacy msvcrt.dll used by
-// some mingw toolchains) provide different stat function implementations,
-// with a number of limitations with respect to what we want from the
-// stat function. Instead provide our own (in the anonymous detail namespace
-// in posix_compat.h) which does exactly what we want, along with our own
-// stat structure and flag macros.
-
-struct TimeSpec {
-  int64_t tv_sec;
-  int64_t tv_nsec;
-};
-struct StatT {
-  unsigned st_mode;
-  TimeSpec st_atim;
-  TimeSpec st_mtim;
-  uint64_t st_dev; // FILE_ID_INFO::VolumeSerialNumber
-  struct FileIdStruct {
-    unsigned char id[16]; // FILE_ID_INFO::FileId
-    bool operator==(const FileIdStruct &other) const {
-      for (int i = 0; i < 16; i++)
-        if (id[i] != other.id[i])
-          return false;
-      return true;
-    }
-  } st_ino;
-  uint32_t st_nlink;
-  uintmax_t st_size;
-};
-
-#else
-using TimeSpec = struct timespec;
-using TimeVal = struct timeval;
-using StatT = struct stat;
-#endif
-
 template <class FileTimeT, class TimeT,
           bool IsFloat = is_floating_point<typename FileTimeT::rep>::value>
 struct time_util_base {
   using rep = typename FileTimeT::rep;
   using fs_duration = typename FileTimeT::duration;
   using fs_seconds = duration<rep>;
   using fs_nanoseconds = duration<rep, nano>;
   using fs_microseconds = duration<rep, micro>;
struct time_util_base {
 
   static constexpr rep min_nsec_timespec =
       duration_cast<fs_nanoseconds>(
           (FileTimeT::duration::min() - fs_seconds(min_seconds)) +
           fs_seconds(1))
           .count();
 
 private:
-  static _LIBCPP_CONSTEXPR_SINCE_CXX14 fs_duration get_min_nsecs() {
+  static _LIBCPP_CONSTEXPR fs_duration get_min_nsecs() {
     return duration_cast<fs_duration>(
         fs_nanoseconds(min_nsec_timespec) -
         duration_cast<fs_nanoseconds>(fs_seconds(1)));
   }
   // Static assert that these values properly round trip.
   static_assert(fs_seconds(min_seconds) + get_min_nsecs() ==
                     FileTimeT::duration::min(),
                 "value doesn't roundtrip");
 
   static _LIBCPP_CONSTEXPR_SINCE_CXX14 bool check_range() {
     // This kinda sucks, but it's what happens when we don't have __int128_t.
     if (sizeof(TimeT) == sizeof(rep)) {
       typedef duration<long long, ratio<3600 * 24 * 365> > Years;
       return duration_cast<Years>(fs_seconds(max_seconds)) > Years(250) &&
              duration_cast<Years>(fs_seconds(min_seconds)) < Years(-250);
     }
     return max_seconds >= numeric_limits<TimeT>::max() &&
            min_seconds <= numeric_limits<TimeT>::min();
   }
+#if _LIBCPP_STD_VER >= 14
   static_assert(check_range(), "the representable range is unacceptable small");
+#endif
 };
 
 template <class FileTimeT, class TimeT>
 struct time_util_base<FileTimeT, TimeT, true> {
   using rep = typename FileTimeT::rep;
   using fs_duration = typename FileTimeT::duration;
   using fs_seconds = duration<rep>;
   using fs_nanoseconds = duration<rep, nano>;
bool set_file_times(const path& p, std::array<TimeSpec, 2> const& TS,
                     error_code& ec) {
 #if !defined(_LIBCPP_USE_UTIMENSAT)
   return posix_utimes(p, TS, ec);
 #else
   return posix_utimensat(p, TS, ec);
 #endif
 }
 
-#if defined(DT_BLK)
-template <class DirEntT, class = decltype(DirEntT::d_type)>
-static file_type get_file_type(DirEntT* ent, int) {
-  switch (ent->d_type) {
-  case DT_BLK:
-    return file_type::block;
-  case DT_CHR:
-    return file_type::character;
-  case DT_DIR:
-    return file_type::directory;
-  case DT_FIFO:
-    return file_type::fifo;
-  case DT_LNK:
-    return file_type::symlink;
-  case DT_REG:
-    return file_type::regular;
-  case DT_SOCK:
-    return file_type::socket;
-  // Unlike in lstat, hitting "unknown" here simply means that the underlying
-  // filesystem doesn't support d_type. Report is as 'none' so we correctly
-  // set the cache to empty.
-  case DT_UNKNOWN:
-    break;
-  }
-  return file_type::none;
-}
-#endif // defined(DT_BLK)
-
-template <class DirEntT>
-static file_type get_file_type(DirEntT*, long) {
-  return file_type::none;
-}
-
-static pair<string_view, file_type> posix_readdir(DIR* dir_stream,
-                                                  error_code& ec) {
-  struct dirent* dir_entry_ptr = nullptr;
-  errno = 0; // zero errno in order to detect errors
-  ec.clear();
-  if ((dir_entry_ptr = ::readdir(dir_stream)) == nullptr) {
-    if (errno)
-      ec = capture_errno();
-    return {};
-  } else {
-    return {dir_entry_ptr->d_name, get_file_type(dir_entry_ptr, 0)};
-  }
-}
+#endif // !_LIBCPP_WIN32API
 
-#else // _LIBCPP_WIN32API
+file_time_type __extract_last_write_time(const path& p, const StatT& st,
+                                         error_code* ec) {
+  using detail::fs_time;
+  ErrorHandler<file_time_type> err("last_write_time", ec, &p);
+
+  auto ts = detail::extract_mtime(st);
+  if (!fs_time::is_representable(ts))
+    return err.report(errc::value_too_large);
 
-static file_type get_file_type(const WIN32_FIND_DATAW& data) {
-  if (data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
-      data.dwReserved0 == IO_REPARSE_TAG_SYMLINK)
-    return file_type::symlink;
-  if (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-    return file_type::directory;
-  return file_type::regular;
-}
-static uintmax_t get_file_size(const WIN32_FIND_DATAW& data) {
-  return (static_cast<uint64_t>(data.nFileSizeHigh) << 32) + data.nFileSizeLow;
+  return fs_time::convert_from_timespec(ts);
 }
-static file_time_type get_write_time(const WIN32_FIND_DATAW& data) {
-  ULARGE_INTEGER tmp;
-  const FILETIME& time = data.ftLastWriteTime;
-  tmp.u.LowPart = time.dwLowDateTime;
-  tmp.u.HighPart = time.dwHighDateTime;
-  return file_time_type(file_time_type::duration(tmp.QuadPart));
-}
-
-#endif // !_LIBCPP_WIN32API
 
 } // namespace
 } // end namespace detail
 
 _LIBCPP_END_NAMESPACE_FILESYSTEM
 
 _LIBCPP_DIAGNOSTIC_POP
 
-#endif // FILESYSTEM_COMMON_H
+#endif // FILESYSTEM_TIME_UTILS_H

libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03
-// ADDITIONAL_COMPILE_FLAGS: -I %S/../../../../../../src/filesystem
+// ADDITIONAL_COMPILE_FLAGS: -I %S/../../../../../../src
 
-// This test relies on calling functions from the libcxx internal header
-// filesystem_common.h; the Windows implementation uses different
+// This test relies on calling functions from the libcxx internal headers
+// of <filesystem>; the Windows implementation uses different
 // internals and doesn't provide the same set_file_times function as for
 // other platforms.
 // UNSUPPORTED: windows
 
 // This test assumes that time is stored as a 64 bit value when on MVS it is stored as 32 bit
 // UNSUPPORTED: target={{.+}}-zos{{.*}}
 
 // <filesystem>
 
 // class directory_entry
 
 #include "filesystem_include.h"
 #include <type_traits>
 #include <cassert>
 
 #include "assert_macros.h"
 #include "test_macros.h"
 #include "filesystem_test_helper.h"
 
-#include "filesystem_common.h"
+#include "filesystem/time_utils.h"
 
 using namespace fs::detail;
 
 static void last_write_time_not_representable_error() {
   using namespace fs;
   using namespace std::chrono;
   scoped_test_env env;
   const path dir = env.create_dir("dir");

libcxx/test/libcxx/input.output/filesystems/convert_file_time.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11
 
 // <filesystem>
 
 // typedef TrivialClock file_time_type;
 
-// ADDITIONAL_COMPILE_FLAGS: -I %S/../../../../src/filesystem -Wno-macro-redefined
+// ADDITIONAL_COMPILE_FLAGS: -I %S/../../../../src -Wno-macro-redefined
 
 #include <cassert>
 #include <chrono>
 #include <cstddef>
 #include <filesystem>
 #include <limits>
 #include <string>
 #include <type_traits>
 
-#include "filesystem_common.h"
+#include "filesystem/time_utils.h"
 
 #ifndef __SIZEOF_INT128__
 #define TEST_HAS_NO_INT128_T
 #endif
 
 using namespace std::chrono;
 namespace fs = std::__fs::filesystem;
 using fs::file_time_type;

libcxx/utils/data/ignore_format.txt

 libcxx/src/bind.cpp
 libcxx/src/charconv.cpp
 libcxx/src/chrono.cpp
 libcxx/src/condition_variable.cpp
 libcxx/src/condition_variable_destructor.cpp
 libcxx/src/debug.cpp
 libcxx/src/exception.cpp
 libcxx/src/experimental/memory_resource.cpp
+libcxx/src/filesystem/directory_entry.cpp
 libcxx/src/filesystem/directory_iterator.cpp
-libcxx/src/filesystem/filesystem_common.h
+libcxx/src/filesystem/error.h
+libcxx/src/filesystem/file_descriptor.h
+libcxx/src/filesystem/filesystem_clock.cpp
+libcxx/src/filesystem/filesystem_error.cpp
 libcxx/src/filesystem/int128_builtins.cpp
 libcxx/src/filesystem/operations.cpp
+libcxx/src/filesystem/path.cpp
+libcxx/src/filesystem/path_parser.h
 libcxx/src/filesystem/posix_compat.h
+libcxx/src/filesystem/time_utils.h
 libcxx/src/functional.cpp
 libcxx/src/future.cpp
 libcxx/src/hash.cpp
 libcxx/src/include/apple_availability.h
 libcxx/src/include/atomic_support.h
 libcxx/src/include/config_elast.h
 libcxx/src/include/refstring.h
 libcxx/src/include/ryu/ryu.h