//===----------------------------------------------------------------------===////
//
// 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_TIME_UTILS_H
#define FILESYSTEM_TIME_UTILS_H
#include <__config>
#include <array>
#include <chrono>
#include <filesystem>
#include <limits>
#include <ratio>
#include <system_error>
#include <type_traits>
#include <utility>
#include "error.h"
#include "format_string.h"
#if defined(_LIBCPP_WIN32API)
# define WIN32_LEAN_AND_MEAN
# define NOMINMAX
# include <windows.h>
#else
# include <fcntl.h>
# include <sys/stat.h>
# include <sys/time.h> // for ::utimes as used in __last_write_time
#endif
// We can use the presence of UTIME_OMIT to detect platforms that provide utimensat.
#if defined(UTIME_OMIT)
# define _LIBCPP_USE_UTIMENSAT
#endif
_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
namespace detail {
#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;
};
// There were 369 years and 89 leap days from the Windows epoch
// (1601) to the Unix epoch (1970).
# define FILE_TIME_OFFSET_SECS (uint64_t(369 * 365 + 89) * (24 * 60 * 60))
inline TimeSpec filetime_to_timespec(LARGE_INTEGER li) {
TimeSpec ret;
ret.tv_sec = li.QuadPart / 10000000 - FILE_TIME_OFFSET_SECS;
ret.tv_nsec = (li.QuadPart % 10000000) * 100;
return ret;
}
inline TimeSpec filetime_to_timespec(FILETIME ft) {
LARGE_INTEGER li;
li.LowPart = ft.dwLowDateTime;
li.HighPart = ft.dwHighDateTime;
return filetime_to_timespec(li);
}
inline FILETIME timespec_to_filetime(TimeSpec ts) {
LARGE_INTEGER li;
li.QuadPart = ts.tv_nsec / 100 + (ts.tv_sec + FILE_TIME_OFFSET_SECS) * 10000000;
FILETIME ft;
ft.dwLowDateTime = li.LowPart;
ft.dwHighDateTime = li.HighPart;
return ft;
}
#else
using TimeSpec = struct timespec;
using TimeVal = struct timeval;
using StatT = struct stat;
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;
}
#endif
using chrono::duration;
using chrono::duration_cast;
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 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 constexpr 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>;
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 constexpr 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 constexpr 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 constexpr 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 constexpr 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 constexpr 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 constexpr 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
#ifndef _LIBCPP_HAS_NO_FILESYSTEM
# if !defined(_LIBCPP_WIN32API)
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)
inline 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
inline 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
inline 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);
}
#endif // !_LIBCPP_HAS_NO_FILESYSTEM
} // namespace detail
_LIBCPP_END_NAMESPACE_FILESYSTEM
#endif // FILESYSTEM_TIME_UTILS_H
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