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Diffstat (limited to 'src/experimental/filesystem/filesystem_time_helper.h')
| -rw-r--r-- | src/experimental/filesystem/filesystem_time_helper.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/src/experimental/filesystem/filesystem_time_helper.h b/src/experimental/filesystem/filesystem_time_helper.h new file mode 100644 index 000000000..a60fdef5f --- /dev/null +++ b/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 |