path: root/contrib/libs/cxxsupp/libcxx/src/filesystem/filesystem_common.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 
 
#include "__config" 
#include "array" 
#include "chrono" 
#include "climits" 
#include "cstdarg" 
#include "cstdlib" 
#include "ctime" 
#include "filesystem" 
 
#if !defined(_LIBCPP_WIN32API) 
# include <unistd.h>
# include <sys/stat.h>
# include <sys/statvfs.h>
# include <sys/time.h> // for ::utimes as used in __last_write_time
# include <fcntl.h>    /* values for fchmodat */
#endif 
 
#include "../include/apple_availability.h" 
 
#if !defined(__APPLE__) 
// We can use the presence of UTIME_OMIT to detect platforms that provide 
// utimensat. 
#if defined(UTIME_OMIT) 
#define _LIBCPP_USE_UTIMENSAT 
#endif 
#endif 
 
#if defined(__GNUC__) || defined(__clang__) 
#pragma GCC diagnostic push 
#pragma GCC diagnostic ignored "-Wunused-function" 
#endif 
 
#if defined(_LIBCPP_WIN32API) 
#define PS(x) (L##x) 
#define PATH_CSTR_FMT "\"%ls\"" 
#else 
#define PS(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_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_FORMAT_PRINTF(1, 2) string 
format_string(const char* msg, ...) { 
  string ret; 
  va_list ap; 
  va_start(ap, msg); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
  try { 
#endif // _LIBCPP_NO_EXCEPTIONS 
    ret = format_string_impl(msg, ap); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
  } catch (...) { 
    va_end(ap); 
    throw; 
  } 
#endif // _LIBCPP_NO_EXCEPTIONS 
  va_end(ap); 
  return ret; 
} 
 
error_code capture_errno() { 
  _LIBCPP_ASSERT(errno, "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_AFTER_CXX11 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_AFTER_CXX11 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_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_FORMAT_PRINTF(3, 4) 
  T report(const error_code& ec, const char* msg, ...) const { 
    va_list ap; 
    va_start(ap, msg); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
    try { 
#endif // _LIBCPP_NO_EXCEPTIONS 
      report_impl(ec, msg, ap); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
    } catch (...) { 
      va_end(ap); 
      throw; 
    } 
#endif // _LIBCPP_NO_EXCEPTIONS 
    va_end(ap); 
    return error_value<T>(); 
  } 
 
  T report(errc const& err) const { 
    return report(make_error_code(err)); 
  } 
 
  _LIBCPP_FORMAT_PRINTF(3, 4) 
  T report(errc const& err, const char* msg, ...) const { 
    va_list ap; 
    va_start(ap, msg); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
    try { 
#endif // _LIBCPP_NO_EXCEPTIONS 
      report_impl(make_error_code(err), msg, ap); 
#ifndef _LIBCPP_NO_EXCEPTIONS 
    } catch (...) { 
      va_end(ap); 
      throw; 
    } 
#endif // _LIBCPP_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>; 
 
  static constexpr rep max_seconds = 
      duration_cast<fs_seconds>(FileTimeT::duration::max()).count(); 
 
  static constexpr rep max_nsec = 
      duration_cast<fs_nanoseconds>(FileTimeT::duration::max() - 
                                    fs_seconds(max_seconds)) 
          .count(); 
 
  static constexpr rep min_seconds = 
      duration_cast<fs_seconds>(FileTimeT::duration::min()).count(); 
 
  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_AFTER_CXX11 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_AFTER_CXX11 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(); 
  } 
  static_assert(check_range(), "the representable range is unacceptable small"); 
}; 
 
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>; 
  using fs_microseconds = duration<rep, micro>; 
 
  static const rep max_seconds; 
  static const rep max_nsec; 
  static const rep min_seconds; 
  static const rep min_nsec_timespec; 
}; 
 
template <class FileTimeT, class TimeT> 
const typename FileTimeT::rep 
    time_util_base<FileTimeT, TimeT, true>::max_seconds = 
        duration_cast<fs_seconds>(FileTimeT::duration::max()).count(); 
 
template <class FileTimeT, class TimeT> 
const typename FileTimeT::rep time_util_base<FileTimeT, TimeT, true>::max_nsec = 
    duration_cast<fs_nanoseconds>(FileTimeT::duration::max() - 
                                  fs_seconds(max_seconds)) 
        .count(); 
 
template <class FileTimeT, class TimeT> 
const typename FileTimeT::rep 
    time_util_base<FileTimeT, TimeT, true>::min_seconds = 
        duration_cast<fs_seconds>(FileTimeT::duration::min()).count(); 
 
template <class FileTimeT, class TimeT> 
const typename FileTimeT::rep 
    time_util_base<FileTimeT, TimeT, true>::min_nsec_timespec = 
        duration_cast<fs_nanoseconds>((FileTimeT::duration::min() - 
                                       fs_seconds(min_seconds)) + 
                                      fs_seconds(1)) 
            .count(); 
 
template <class FileTimeT, class TimeT, class TimeSpecT> 
struct time_util : time_util_base<FileTimeT, TimeT> { 
  using Base = time_util_base<FileTimeT, TimeT>; 
  using Base::max_nsec; 
  using Base::max_seconds; 
  using Base::min_nsec_timespec; 
  using Base::min_seconds; 
 
  using typename Base::fs_duration; 
  using typename Base::fs_microseconds; 
  using typename Base::fs_nanoseconds; 
  using typename Base::fs_seconds; 
 
public: 
  template <class CType, class ChronoType> 
  static _LIBCPP_CONSTEXPR_AFTER_CXX11 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<fs_seconds>(tm.time_since_epoch()); 
    auto nsecs = duration_cast<fs_nanoseconds>(tm.time_since_epoch() - secs); 
    if (nsecs.count() < 0) { 
      secs = secs + fs_seconds(1); 
      nsecs = nsecs + fs_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_from_timespec(TimeSpecT tm) { 
    if (tm.tv_sec >= 0 || tm.tv_nsec == 0) { 
      return FileTimeT(fs_seconds(tm.tv_sec) + 
                       duration_cast<fs_duration>(fs_nanoseconds(tm.tv_nsec))); 
    } else { // tm.tv_sec < 0 
      auto adj_subsec = duration_cast<fs_duration>(fs_seconds(1) - 
                                                   fs_nanoseconds(tm.tv_nsec)); 
      auto Dur = fs_seconds(tm.tv_sec + 1) - adj_subsec; 
      return FileTimeT(Dur); 
    } 
  } 
 
  template <class SubSecT> 
  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool 
  set_times_checked(TimeT* sec_out, SubSecT* subsec_out, FileTimeT tp) { 
    auto dur = tp.time_since_epoch(); 
    auto sec_dur = duration_cast<fs_seconds>(dur); 
    auto subsec_dur = duration_cast<fs_nanoseconds>(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 = sec_dur - fs_seconds(1); 
        subsec_dur = subsec_dur + fs_seconds(1); 
      } else { 
        subsec_dur = fs_nanoseconds::zero(); 
      } 
    } 
    return checked_set(sec_out, sec_dur.count()) && 
           checked_set(subsec_out, subsec_dur.count()); 
  } 
  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool convert_to_timespec(TimeSpecT& dest, 
                                                                FileTimeT tp) { 
    if (!is_representable(tp)) 
      return false; 
    return set_times_checked(&dest.tv_sec, &dest.tv_nsec, tp); 
  } 
}; 
 
#if defined(_LIBCPP_WIN32API) 
using fs_time = time_util<file_time_type, int64_t, TimeSpec>; 
#else 
using fs_time = time_util<file_time_type, time_t, TimeSpec>; 
#endif 
 
#if defined(__APPLE__) 
inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; } 
inline TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; } 
#elif defined(__MVS__) 
inline TimeSpec extract_mtime(StatT const& st) { 
  TimeSpec TS = {st.st_mtime, 0}; 
  return TS; 
} 
inline TimeSpec extract_atime(StatT const& st) { 
  TimeSpec TS = {st.st_atime, 0}; 
  return TS; 
} 
#elif defined(_AIX) 
inline TimeSpec extract_mtime(StatT const& st) { 
  TimeSpec TS = {st.st_mtime, st.st_mtime_n}; 
  return TS; 
} 
inline TimeSpec extract_atime(StatT const& st) { 
  TimeSpec TS = {st.st_atime, st.st_atime_n}; 
  return TS; 
} 
#else 
inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; } 
inline TimeSpec extract_atime(StatT const& st) { return st.st_atim; } 
#endif 
 
#if !defined(_LIBCPP_WIN32API) 
inline TimeVal make_timeval(TimeSpec const& ts) { 
  using namespace chrono; 
  auto Convert = [](long nsec) { 
    using int_type = decltype(std::declval<TimeVal>().tv_usec); 
    auto dur = duration_cast<microseconds>(nanoseconds(nsec)).count(); 
    return static_cast<int_type>(dur); 
  }; 
  TimeVal TV = {}; 
  TV.tv_sec = ts.tv_sec; 
  TV.tv_usec = Convert(ts.tv_nsec); 
  return TV; 
} 
 
inline bool posix_utimes(const path& p, std::array<TimeSpec, 2> const& TS, 
                  error_code& ec) { 
  TimeVal ConvertedTS[2] = {make_timeval(TS[0]), make_timeval(TS[1])}; 
  if (::utimes(p.c_str(), ConvertedTS) == -1) { 
    ec = capture_errno(); 
    return true; 
  } 
  return false; 
} 
 
#if defined(_LIBCPP_USE_UTIMENSAT) 
bool posix_utimensat(const path& p, std::array<TimeSpec, 2> const& TS, 
                     error_code& ec) { 
  if (::utimensat(AT_FDCWD, p.c_str(), TS.data(), 0) == -1) { 
    ec = capture_errno(); 
    return true; 
  } 
  return false; 
} 
#endif 
 
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 
} 
#endif /* !_LIBCPP_WIN32API */ 
 
} // namespace 
} // end namespace detail 
 
_LIBCPP_END_NAMESPACE_FILESYSTEM 
 
#endif // FILESYSTEM_COMMON_H