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-rw-r--r--src/experimental/filesystem/filesystem_time_helper.h173
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diff --git a/src/experimental/filesystem/filesystem_time_helper.h b/src/experimental/filesystem/filesystem_time_helper.h
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+//===----------------------------------------------------------------------===////
+//
+// 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