Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/libcxx/src/experimental/filesystem/directory_iterator.cpp

@@ -0,0 +1,342 @@
+//===------------------ directory_iterator.cpp ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "experimental/filesystem"
+#include "__config"
+#if defined(_LIBCPP_WIN32API)
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#else
+#include <dirent.h>
+#endif
+#include <errno.h>
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+namespace { namespace detail {
+
+#if !defined(_LIBCPP_WIN32API)
+inline error_code capture_errno() {
+    _LIBCPP_ASSERT(errno, "Expected errno to be non-zero");
+    return error_code{errno, std::generic_category()};
+}
+#endif
+
+template <class ...Args>
+inline bool set_or_throw(std::error_code& my_ec,
+                               std::error_code* user_ec,
+                               const char* msg, Args&&... args)
+{
+    if (user_ec) {
+        *user_ec = my_ec;
+        return true;
+    }
+    __throw_filesystem_error(msg, std::forward<Args>(args)..., my_ec);
+    return false;
+}
+
+#if !defined(_LIBCPP_WIN32API)
+inline path::string_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;
+    }
+}
+#endif
+
+}}                                                       // namespace detail
+
+using detail::set_or_throw;
+
+#if defined(_LIBCPP_WIN32API)
+class __dir_stream {
+public:
+  __dir_stream() = delete;
+  __dir_stream& operator=(const __dir_stream&) = delete;
+
+  __dir_stream(__dir_stream&& __ds) noexcept
+      : __stream_(__ds.__stream_), __root_(std::move(__ds.__root_)),
+        __entry_(std::move(__ds.__entry_)) {
+    __ds.__stream_ = INVALID_HANDLE_VALUE;
+  }
+
+  __dir_stream(const path& root, directory_options opts, error_code& ec)
+      : __stream_(INVALID_HANDLE_VALUE), __root_(root) {
+    __stream_ = ::FindFirstFile(root.c_str(), &__data_);
+    if (__stream_ == INVALID_HANDLE_VALUE) {
+      ec = error_code(::GetLastError(), std::generic_category());
+      const bool ignore_permission_denied =
+          bool(opts & directory_options::skip_permission_denied);
+      if (ignore_permission_denied && ec.value() == ERROR_ACCESS_DENIED)
+        ec.clear();
+      return;
+    }
+  }
+
+  ~__dir_stream() noexcept {
+    if (__stream_ == INVALID_HANDLE_VALUE)
+      return;
+    close();
+  }
+
+  bool good() const noexcept { return __stream_ != INVALID_HANDLE_VALUE; }
+
+  bool advance(error_code& ec) {
+    while (::FindNextFile(__stream_, &__data_)) {
+      if (!strcmp(__data_.cFileName, ".") || strcmp(__data_.cFileName, ".."))
+        continue;
+      __entry_.assign(__root_ / __data_.cFileName);
+      return true;
+    }
+    ec = error_code(::GetLastError(), std::generic_category());
+    close();
+    return false;
+  }
+
+private:
+  std::error_code close() noexcept {
+    std::error_code ec;
+    if (!::FindClose(__stream_))
+      ec = error_code(::GetLastError(), std::generic_category());
+    __stream_ = INVALID_HANDLE_VALUE;
+    return ec;
+  }
+
+  HANDLE __stream_{INVALID_HANDLE_VALUE};
+  WIN32_FIND_DATA __data_;
+
+public:
+  path __root_;
+  directory_entry __entry_;
+};
+#else
+class __dir_stream {
+public:
+    __dir_stream() = delete;
+    __dir_stream& operator=(const __dir_stream&) = delete;
+
+    __dir_stream(__dir_stream&& other) noexcept
+        : __stream_(other.__stream_), __root_(std::move(other.__root_)),
+          __entry_(std::move(other.__entry_))
+    {
+        other.__stream_ = nullptr;
+    }
+
+
+    __dir_stream(const path& root, directory_options opts, error_code& ec)
+        : __stream_(nullptr),
+          __root_(root)
+    {
+        if ((__stream_ = ::opendir(root.c_str())) == nullptr) {
+            ec = detail::capture_errno();
+            const bool allow_eacess =
+                bool(opts & directory_options::skip_permission_denied);
+            if (allow_eacess && ec.value() == EACCES)
+                ec.clear();
+            return;
+        }
+        advance(ec);
+    }
+
+    ~__dir_stream() noexcept
+      { if (__stream_) close(); }
+
+    bool good() const noexcept { return __stream_ != nullptr; }
+
+    bool advance(error_code &ec) {
+        while (true) {
+            auto str = detail::posix_readdir(__stream_,  ec);
+            if (str == "." || str == "..") {
+                continue;
+            } else if (ec || str.empty()) {
+                close();
+                return false;
+            } else {
+                __entry_.assign(__root_ / str);
+                return true;
+            }
+        }
+    }
+private:
+    std::error_code close() noexcept {
+        std::error_code m_ec;
+        if (::closedir(__stream_) == -1)
+           m_ec = detail::capture_errno();
+        __stream_ = nullptr;
+        return m_ec;
+    }
+
+    DIR * __stream_{nullptr};
+public:
+    path __root_;
+    directory_entry __entry_;
+};
+#endif
+
+// directory_iterator
+
+directory_iterator::directory_iterator(const path& p, error_code *ec,
+                                       directory_options opts)
+{
+    std::error_code m_ec;
+    __imp_ = make_shared<__dir_stream>(p, opts, m_ec);
+    if (ec) *ec = m_ec;
+    if (!__imp_->good()) {
+        __imp_.reset();
+        if (m_ec)
+            set_or_throw(m_ec, ec,
+                         "directory_iterator::directory_iterator(...)", p);
+    }
+}
+
+directory_iterator& directory_iterator::__increment(error_code *ec)
+{
+    _LIBCPP_ASSERT(__imp_, "Attempting to increment an invalid iterator");
+    std::error_code m_ec;
+    if (!__imp_->advance(m_ec)) {
+        __imp_.reset();
+        if (m_ec)
+            set_or_throw(m_ec, ec, "directory_iterator::operator++()");
+    } else {
+        if (ec) ec->clear();
+    }
+    return *this;
+
+}
+
+directory_entry const& directory_iterator::__dereference() const {
+    _LIBCPP_ASSERT(__imp_, "Attempting to dereference an invalid iterator");
+    return __imp_->__entry_;
+}
+
+// recursive_directory_iterator
+
+struct recursive_directory_iterator::__shared_imp {
+  stack<__dir_stream> __stack_;
+  directory_options   __options_;
+};
+
+recursive_directory_iterator::recursive_directory_iterator(const path& p,
+    directory_options opt, error_code *ec)
+    : __imp_(nullptr), __rec_(true)
+{
+    if (ec) ec->clear();
+    std::error_code m_ec;
+    __dir_stream new_s(p, opt, m_ec);
+    if (m_ec) set_or_throw(m_ec, ec, "recursive_directory_iterator", p);
+    if (m_ec || !new_s.good()) return;
+
+    __imp_ = _VSTD::make_shared<__shared_imp>();
+    __imp_->__options_ = opt;
+    __imp_->__stack_.push(_VSTD::move(new_s));
+}
+
+void recursive_directory_iterator::__pop(error_code* ec)
+{
+    _LIBCPP_ASSERT(__imp_, "Popping the end iterator");
+    if (ec) ec->clear();
+    __imp_->__stack_.pop();
+    if (__imp_->__stack_.size() == 0)
+        __imp_.reset();
+    else
+        __advance(ec);
+}
+
+directory_options recursive_directory_iterator::options() const {
+    return __imp_->__options_;
+}
+
+int recursive_directory_iterator::depth() const {
+    return __imp_->__stack_.size() - 1;
+}
+
+const directory_entry& recursive_directory_iterator::__dereference() const {
+    return __imp_->__stack_.top().__entry_;
+}
+
+recursive_directory_iterator&
+recursive_directory_iterator::__increment(error_code *ec)
+{
+    if (ec) ec->clear();
+    if (recursion_pending()) {
+        if (__try_recursion(ec) || (ec && *ec))
+            return *this;
+    }
+    __rec_ = true;
+    __advance(ec);
+    return *this;
+}
+
+void recursive_directory_iterator::__advance(error_code* ec) {
+    // REQUIRES: ec must be cleared before calling this function.
+    const directory_iterator end_it;
+    auto& stack = __imp_->__stack_;
+    std::error_code m_ec;
+    while (stack.size() > 0) {
+        if (stack.top().advance(m_ec))
+            return;
+        if (m_ec) break;
+        stack.pop();
+    }
+    __imp_.reset();
+    if (m_ec)
+        set_or_throw(m_ec, ec, "recursive_directory_iterator::operator++()");
+}
+
+bool recursive_directory_iterator::__try_recursion(error_code *ec) {
+    bool rec_sym =
+        bool(options() & directory_options::follow_directory_symlink);
+
+    auto& curr_it = __imp_->__stack_.top();
+
+    bool skip_rec = false;
+    std::error_code m_ec;
+    if (!rec_sym) {
+      file_status st = curr_it.__entry_.symlink_status(m_ec);
+      if (m_ec && status_known(st))
+        m_ec.clear();
+      if (m_ec || is_symlink(st) || !is_directory(st))
+        skip_rec = true;
+    } else {
+      file_status st = curr_it.__entry_.status(m_ec);
+      if (m_ec && status_known(st))
+        m_ec.clear();
+      if (m_ec || !is_directory(st))
+        skip_rec = true;
+    }
+
+    if (!skip_rec) {
+        __dir_stream new_it(curr_it.__entry_.path(), __imp_->__options_, m_ec);
+        if (new_it.good()) {
+            __imp_->__stack_.push(_VSTD::move(new_it));
+            return true;
+        }
+    }
+    if (m_ec) {
+        const bool allow_eacess = bool(__imp_->__options_
+            & directory_options::skip_permission_denied);
+        if (m_ec.value() == EACCES && allow_eacess) {
+          if (ec) ec->clear();
+        } else {
+          __imp_.reset();
+          set_or_throw(m_ec, ec,
+                       "recursive_directory_iterator::operator++()");
+        }
+    }
+    return false;
+}
+
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM

external/llvm-project/libcxx/src/experimental/filesystem/filesystem_time_helper.h

@@ -0,0 +1,173 @@
+//===----------------------------------------------------------------------===////
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef FILESYSTEM_TIME_HELPER_H
+#define FILESYSTEM_TIME_HELPER_H
+
+#include "experimental/__config"
+#include "chrono"
+#include "cstdlib"
+#include "climits"
+
+#include <unistd.h>
+#include <sys/stat.h>
+#if !defined(UTIME_OMIT)
+#include <sys/time.h> // for ::utimes as used in __last_write_time
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+namespace time_detail { namespace {
+
+using namespace chrono;
+
+template <class FileTimeT,
+          bool IsFloat = is_floating_point<typename FileTimeT::rep>::value>
+struct fs_time_util_base {
+  static constexpr auto max_seconds =
+      duration_cast<seconds>(FileTimeT::duration::max()).count();
+
+  static constexpr auto max_nsec =
+      duration_cast<nanoseconds>(FileTimeT::duration::max() -
+                                 seconds(max_seconds))
+          .count();
+
+  static constexpr auto min_seconds =
+      duration_cast<seconds>(FileTimeT::duration::min()).count();
+
+  static constexpr auto min_nsec_timespec =
+      duration_cast<nanoseconds>(
+          (FileTimeT::duration::min() - seconds(min_seconds)) + seconds(1))
+          .count();
+
+  // Static assert that these values properly round trip.
+  static_assert((seconds(min_seconds) +
+                 duration_cast<microseconds>(nanoseconds(min_nsec_timespec))) -
+                        duration_cast<microseconds>(seconds(1)) ==
+                    FileTimeT::duration::min(),
+                "");
+};
+
+template <class FileTimeT>
+struct fs_time_util_base<FileTimeT, true> {
+  static const long long max_seconds;
+  static const long long max_nsec;
+  static const long long min_seconds;
+  static const long long min_nsec_timespec;
+};
+
+template <class FileTimeT>
+const long long fs_time_util_base<FileTimeT, true>::max_seconds =
+    duration_cast<seconds>(FileTimeT::duration::max()).count();
+
+template <class FileTimeT>
+const long long fs_time_util_base<FileTimeT, true>::max_nsec =
+    duration_cast<nanoseconds>(FileTimeT::duration::max() -
+                               seconds(max_seconds))
+        .count();
+
+template <class FileTimeT>
+const long long fs_time_util_base<FileTimeT, true>::min_seconds =
+    duration_cast<seconds>(FileTimeT::duration::min()).count();
+
+template <class FileTimeT>
+const long long fs_time_util_base<FileTimeT, true>::min_nsec_timespec =
+    duration_cast<nanoseconds>((FileTimeT::duration::min() -
+                                seconds(min_seconds)) +
+                               seconds(1))
+        .count();
+
+template <class FileTimeT, class TimeT, class TimeSpecT>
+struct fs_time_util : fs_time_util_base<FileTimeT> {
+  using Base = fs_time_util_base<FileTimeT>;
+  using Base::max_nsec;
+  using Base::max_seconds;
+  using Base::min_nsec_timespec;
+  using Base::min_seconds;
+
+public:
+  template <class CType, class ChronoType>
+  static bool checked_set(CType* out, ChronoType time) {
+    using Lim = numeric_limits<CType>;
+    if (time > Lim::max() || time < Lim::min())
+      return false;
+    *out = static_cast<CType>(time);
+    return true;
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(TimeSpecT tm) {
+    if (tm.tv_sec >= 0) {
+      return (tm.tv_sec < max_seconds) ||
+             (tm.tv_sec == max_seconds && tm.tv_nsec <= max_nsec);
+    } else if (tm.tv_sec == (min_seconds - 1)) {
+      return tm.tv_nsec >= min_nsec_timespec;
+    } else {
+      return (tm.tv_sec >= min_seconds);
+    }
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(FileTimeT tm) {
+    auto secs = duration_cast<seconds>(tm.time_since_epoch());
+    auto nsecs = duration_cast<nanoseconds>(tm.time_since_epoch() - secs);
+    if (nsecs.count() < 0) {
+      secs = secs + seconds(1);
+      nsecs = nsecs + seconds(1);
+    }
+    using TLim = numeric_limits<TimeT>;
+    if (secs.count() >= 0)
+      return secs.count() <= TLim::max();
+    return secs.count() >= TLim::min();
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 FileTimeT
+  convert_timespec(TimeSpecT tm) {
+    auto adj_msec = duration_cast<microseconds>(nanoseconds(tm.tv_nsec));
+    if (tm.tv_sec >= 0) {
+      auto Dur = seconds(tm.tv_sec) + microseconds(adj_msec);
+      return FileTimeT(Dur);
+    } else if (duration_cast<microseconds>(nanoseconds(tm.tv_nsec)).count() ==
+               0) {
+      return FileTimeT(seconds(tm.tv_sec));
+    } else { // tm.tv_sec < 0
+      auto adj_subsec =
+          duration_cast<microseconds>(seconds(1) - nanoseconds(tm.tv_nsec));
+      auto Dur = seconds(tm.tv_sec + 1) - adj_subsec;
+      return FileTimeT(Dur);
+    }
+  }
+
+  template <class SubSecDurT, class SubSecT>
+  static bool set_times_checked(TimeT* sec_out, SubSecT* subsec_out,
+                                FileTimeT tp) {
+    using namespace chrono;
+    auto dur = tp.time_since_epoch();
+    auto sec_dur = duration_cast<seconds>(dur);
+    auto subsec_dur = duration_cast<SubSecDurT>(dur - sec_dur);
+    // The tv_nsec and tv_usec fields must not be negative so adjust accordingly
+    if (subsec_dur.count() < 0) {
+      if (sec_dur.count() > min_seconds) {
+        sec_dur -= seconds(1);
+        subsec_dur += seconds(1);
+      } else {
+        subsec_dur = SubSecDurT::zero();
+      }
+    }
+    return checked_set(sec_out, sec_dur.count()) &&
+           checked_set(subsec_out, subsec_dur.count());
+  }
+};
+
+} // end namespace
+} // end namespace time_detail
+
+using time_detail::fs_time_util;
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+#endif // FILESYSTEM_TIME_HELPER_H

external/llvm-project/libcxx/src/experimental/filesystem/path.cpp

@@ -0,0 +1,448 @@
+//===--------------------- filesystem/path.cpp ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#include "experimental/filesystem"
+#include "string_view"
+#include "utility"
+
+namespace { namespace parser
+{
+using namespace std;
+using namespace std::experimental::filesystem;
+
+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 = 1,
+    PS_InRootName,
+    PS_InRootDir,
+    PS_InFilenames,
+    PS_InTrailingSep,
+    PS_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 = consumeSeparator(Start, End);
+      // If we consumed exactly two separators we have a root name.
+      if (TkEnd && TkEnd == Start + 2) {
+        // FIXME Do we need to consume a name or is '//' a root name on its own?
+        // what about '//.', '//..', '//...'?
+        auto NameEnd = consumeName(TkEnd, End);
+        if (NameEnd)
+          TkEnd = NameEnd;
+        return makeState(PS_InRootName, Start, TkEnd);
+      }
+      else if (TkEnd)
+        return makeState(PS_InRootDir, Start, TkEnd);
+      else
+        return makeState(PS_InFilenames, Start, consumeName(Start, End));
+    }
+
+    case PS_InRootName:
+      return makeState(PS_InRootDir, Start, consumeSeparator(Start, End));
+    case PS_InRootDir:
+      return makeState(PS_InFilenames, Start, consumeName(Start, End));
+
+    case PS_InFilenames: {
+      PosPtr SepEnd = consumeSeparator(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;
+
+    switch (State) {
+    case PS_AtEnd: {
+      // Try to consume a trailing separator or root directory first.
+      if (PosPtr SepEnd = consumeSeparator(RStart, REnd)) {
+        if (SepEnd == REnd)
+          return makeState((RStart == REnd + 2) ? PS_InRootName : PS_InRootDir,
+                           Path.data(), RStart + 1);
+        // Check if we're seeing the root directory separator
+        auto PP = CreateBegin(Path);
+        bool InRootDir = PP.State == PS_InRootName &&
+            &PP.RawEntry.back() == SepEnd;
+        return makeState(InRootDir ? PS_InRootDir : PS_InTrailingSep,
+                         SepEnd + 1, RStart + 1);
+      } else {
+        PosPtr TkStart = consumeName(RStart, REnd);
+        if (TkStart == REnd + 2 && consumeSeparator(TkStart, REnd) == REnd)
+          return makeState(PS_InRootName, Path.data(), RStart + 1);
+        else
+          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 = consumeSeparator(RStart, REnd);
+      if (SepEnd == REnd)
+        return makeState((RStart == REnd + 2) ? PS_InRootName : PS_InRootDir,
+                         Path.data(), RStart + 1);
+      PosPtr TkEnd = consumeName(SepEnd, REnd);
+      if (TkEnd == REnd + 2 && consumeSeparator(TkEnd, REnd) == REnd)
+        return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
+      return makeState(PS_InFilenames, TkEnd + 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 "";
+    case PS_InRootDir:
+      return "/";
+    case PS_InTrailingSep:
+      return ".";
+    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;
+  }
+
+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();
+  }
+
+  PosPtr consumeSeparator(PosPtr P, PosPtr End) const noexcept {
+    if (P == End || *P != '/')
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && *P == '/')
+      P += Inc;
+    return P;
+  }
+
+  PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
+    if (P == End || *P == '/')
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && *P != '/')
+      P += Inc;
+    return P;
+  }
+};
+
+string_view_pair separate_filename(string_view_t const & s) {
+    if (s == "." || s == ".." || s.empty()) return string_view_pair{s, ""};
+    auto pos = s.find_last_of('.');
+    if (pos == string_view_t::npos)
+        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
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+using parser::string_view_t;
+using parser::string_view_pair;
+using parser::PathParser;
+using parser::createView;
+
+///////////////////////////////////////////////////////////////////////////////
+//                            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_ += ".";
+        }
+        __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 && *NextCh == '/') {
+        ++PP;
+        return createView(__pn_.data(), &PP.RawEntry.back());
+      }
+      return PP.RawEntry;
+    }
+    if (PP.State == PathParser::PS_InRootDir)
+      return *PP;
+    return {};
+}
+
+string_view_t path::__relative_path() const
+{
+    auto PP = PathParser::CreateBegin(__pn_);
+    while (PP.State <= PathParser::PS_InRootDir)
+      ++PP;
+    if (PP.State == PathParser::PS_AtEnd)
+      return {};
+    return createView(PP.RawEntry.data(), &__pn_.back());
+}
+
+string_view_t path::__parent_path() const
+{
+    if (empty())
+      return {};
+    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 {};
+    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.comparisons
+int path::__compare(string_view_t __s) const {
+    auto PP = PathParser::CreateBegin(__pn_);
+    auto PP2 = PathParser::CreateBegin(__s);
+    while (PP && PP2) {
+        int res = (*PP).compare(*PP2);
+        if (res != 0) return res;
+        ++PP; ++PP2;
+    }
+    if (PP.State == PP2.State && PP.State == PathParser::PS_AtEnd)
+        return 0;
+    if (PP.State == PathParser::PS_AtEnd)
+        return -1;
+    return 1;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.nonmembers
+size_t hash_value(const path& __p) noexcept {
+  auto PP = PathParser::CreateBegin(__p.native());
+  size_t hash_value = 0;
+  std::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_ = PP.State;
+    it.__entry_ = PP.RawEntry;
+    it.__stashed_elem_.__assign_view(*PP);
+    return it;
+}
+
+path::iterator path::end() const
+{
+    iterator it{};
+    it.__state_ = PathParser::PS_AtEnd;
+    it.__path_ptr_ = this;
+    return it;
+}
+
+path::iterator& path::iterator::__increment() {
+  static_assert(__at_end == PathParser::PS_AtEnd, "");
+  PathParser PP(__path_ptr_->native(), __entry_, __state_);
+  ++PP;
+  __state_ = 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_ = PP.State;
+  __entry_ = PP.RawEntry;
+  __stashed_elem_.__assign_view(*PP);
+  return *this;
+}
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM

external/llvm-project/libcxx/src/experimental/memory_resource.cpp

@@ -0,0 +1,143 @@
+//===------------------------ memory_resource.cpp -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "experimental/memory_resource"
+
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+#include "atomic"
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+#include "mutex"
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+// memory_resource
+
+//memory_resource::~memory_resource() {}
+
+// new_delete_resource()
+
+class _LIBCPP_TYPE_VIS __new_delete_memory_resource_imp
+    : public memory_resource
+{
+public:
+    ~__new_delete_memory_resource_imp() = default;
+
+protected:
+    virtual void* do_allocate(size_t __size, size_t __align)
+        { return __allocate(__size); }
+
+    virtual void do_deallocate(void * __p, size_t, size_t)
+        { _VSTD::__libcpp_deallocate(__p); }
+
+    virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT
+        { return &__other == this; }
+};
+
+// null_memory_resource()
+
+class _LIBCPP_TYPE_VIS __null_memory_resource_imp
+    : public memory_resource
+{
+public:
+    ~__null_memory_resource_imp() = default;
+
+protected:
+    virtual void* do_allocate(size_t, size_t) {
+        __throw_bad_alloc();
+    }
+    virtual void do_deallocate(void *, size_t, size_t) {}
+    virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT
+    { return &__other == this; }
+};
+
+namespace {
+
+union ResourceInitHelper {
+  struct {
+    __new_delete_memory_resource_imp new_delete_res;
+    __null_memory_resource_imp       null_res;
+  } resources;
+  char dummy;
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 ResourceInitHelper() : resources() {}
+  ~ResourceInitHelper() {}
+};
+// When compiled in C++14 this initialization should be a constant expression.
+// Only in C++11 is "init_priority" needed to ensure initialization order.
+#if _LIBCPP_STD_VER > 11
+_LIBCPP_SAFE_STATIC
+#endif
+ResourceInitHelper res_init  __attribute__((init_priority (101)));
+
+} // end namespace
+
+
+memory_resource * new_delete_resource() _NOEXCEPT {
+    return &res_init.resources.new_delete_res;
+}
+
+memory_resource * null_memory_resource() _NOEXCEPT {
+    return &res_init.resources.null_res;
+}
+
+// default_memory_resource()
+
+static memory_resource *
+__default_memory_resource(bool set = false, memory_resource * new_res = nullptr) _NOEXCEPT
+{
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+    _LIBCPP_SAFE_STATIC static atomic<memory_resource*> __res =
+        ATOMIC_VAR_INIT(&res_init.resources.new_delete_res);
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        // TODO: Can a weaker ordering be used?
+        return _VSTD::atomic_exchange_explicit(
+            &__res, new_res, memory_order::memory_order_acq_rel);
+    }
+    else {
+        return _VSTD::atomic_load_explicit(
+            &__res, memory_order::memory_order_acquire);
+    }
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+    _LIBCPP_SAFE_STATIC static memory_resource * res = &res_init.resources.new_delete_res;
+    static mutex res_lock;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        lock_guard<mutex> guard(res_lock);
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        lock_guard<mutex> guard(res_lock);
+        return res;
+    }
+#else
+    _LIBCPP_SAFE_STATIC static memory_resource* res = &res_init.resources.new_delete_res;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        return res;
+    }
+#endif
+}
+
+memory_resource * get_default_resource() _NOEXCEPT
+{
+    return __default_memory_resource();
+}
+
+memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT
+{
+    return __default_memory_resource(true, __new_res);
+}
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR