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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_COMMON_H
#define FILESYSTEM_COMMON_H
#include "__config"
#include "filesystem"
#include "array"
#include "chrono"
#include "cstdlib"
#include "climits"
#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 */
#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__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif
_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
namespace detail {
namespace {
static string format_string_imp(const char* msg, ...) {
// we might need a second shot at this, so pre-emptivly make a copy
struct GuardVAList {
va_list& target;
bool active = true;
GuardVAList(va_list& target) : target(target), active(true) {}
void clear() {
if (active)
va_end(target);
active = false;
}
~GuardVAList() {
if (active)
va_end(target);
}
};
va_list args;
va_start(args, msg);
GuardVAList args_guard(args);
va_list args_cp;
va_copy(args_cp, args);
GuardVAList args_copy_guard(args_cp);
std::string result;
array<char, 256> local_buff;
size_t size_with_null = local_buff.size();
auto ret = ::vsnprintf(local_buff.data(), size_with_null, msg, args_cp);
args_copy_guard.clear();
// handle empty expansion
if (ret == 0)
return result;
if (static_cast<size_t>(ret) < size_with_null) {
result.assign(local_buff.data(), static_cast<size_t>(ret));
return result;
}
// 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_with_null = static_cast<size_t>(ret) + 1;
result.__resize_default_init(size_with_null - 1);
ret = ::vsnprintf(&result[0], size_with_null, msg, args);
_LIBCPP_ASSERT(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
return result;
}
const char* unwrap(string const& s) { return s.c_str(); }
const char* unwrap(path const& p) { return p.native().c_str(); }
template <class Arg>
Arg const& unwrap(Arg const& a) {
static_assert(!is_class<Arg>::value, "cannot pass class here");
return a;
}
template <class... Args>
string format_string(const char* fmt, Args const&... args) {
return format_string_imp(fmt, unwrap(args)...);
}
error_code capture_errno() {
_LIBCPP_ASSERT(errno, "Expected errno to be non-zero");
return error_code(errno, generic_category());
}
template <class T>
T error_value();
template <>
_LIBCPP_CONSTEXPR_AFTER_CXX11 void error_value<void>() {}
template <>
bool error_value<bool>() {
return false;
}
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& m_ec) const {
if (ec) {
*ec = m_ec;
return error_value<T>();
}
string what = string("in ") + func_name;
switch (bool(p1) + bool(p2)) {
case 0:
__throw_filesystem_error(what, m_ec);
case 1:
__throw_filesystem_error(what, *p1, m_ec);
case 2:
__throw_filesystem_error(what, *p1, *p2, m_ec);
}
_LIBCPP_UNREACHABLE();
}
template <class... Args>
T report(const error_code& m_ec, const char* msg, Args const&... args) const {
if (ec) {
*ec = m_ec;
return error_value<T>();
}
string what =
string("in ") + func_name + ": " + format_string(msg, args...);
switch (bool(p1) + bool(p2)) {
case 0:
__throw_filesystem_error(what, m_ec);
case 1:
__throw_filesystem_error(what, *p1, m_ec);
case 2:
__throw_filesystem_error(what, *p1, *p2, m_ec);
}
_LIBCPP_UNREACHABLE();
}
T report(errc const& err) const { return report(make_error_code(err)); }
template <class... Args>
T report(errc const& err, const char* msg, Args const&... args) const {
return report(make_error_code(err), msg, args...);
}
private:
ErrorHandler(ErrorHandler const&) = delete;
ErrorHandler& operator=(ErrorHandler const&) = delete;
};
using chrono::duration;
using chrono::duration_cast;
using TimeSpec = struct ::timespec;
using StatT = struct ::stat;
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:
#if _LIBCPP_STD_VER > 11 && !defined(_LIBCPP_HAS_NO_CXX14_CONSTEXPR)
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();
}
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 _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);
}
};
using fs_time = time_util<file_time_type, time_t, TimeSpec>;
#if defined(__APPLE__)
TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }
TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; }
#else
TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; }
TimeSpec extract_atime(StatT const& st) { return st.st_atim; }
#endif
// allow the utimes implementation to compile even it we're not going
// to use it.
bool posix_utimes(const path& p, std::array<TimeSpec, 2> const& TS,
error_code& ec) {
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);
};
struct ::timeval ConvertedTS[2] = {{TS[0].tv_sec, Convert(TS[0].tv_nsec)},
{TS[1].tv_sec, Convert(TS[1].tv_nsec)}};
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
}
} // namespace
} // end namespace detail
_LIBCPP_END_NAMESPACE_FILESYSTEM
#endif // FILESYSTEM_COMMON_H