2 files changed, 190 insertions, 150 deletions

diff --git a/src/experimental/filesystem/filesystem_time_helper.h b/src/experimental/filesystem/filesystem_time_helper.h
new file mode 100644
index 000000000000..a60fdef5f0d9
--- /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
diff --git a/src/experimental/filesystem/operations.cpp b/src/experimental/filesystem/operations.cpp
index e9bc0eb6e30e..641a3c53636d 100644
--- a/src/experimental/filesystem/operations.cpp
+++ b/src/experimental/filesystem/operations.cpp
@@ -15,6 +15,8 @@
 #include "cstdlib"
 #include "climits"
 
+#include "filesystem_time_helper.h"
+
 #include <unistd.h>
 #include <sys/stat.h>
 #include <sys/statvfs.h>
@@ -426,17 +428,20 @@ void __current_path(const path& p, std::error_code *ec) {
 
 bool __equivalent(const path& p1, const path& p2, std::error_code *ec)
 {
+    auto make_unsupported_error = [&]() {
+      set_or_throw(make_error_code(errc::not_supported), ec,
+                     "equivalent", p1, p2);
+      return false;
+    };
     std::error_code ec1, ec2;
     struct ::stat st1 = {};
     struct ::stat st2 = {};
     auto s1 = detail::posix_stat(p1.native(), st1, &ec1);
+    if (!exists(s1))
+      return make_unsupported_error();
     auto s2 = detail::posix_stat(p2.native(), st2, &ec2);
-
-    if ((!exists(s1) && !exists(s2)) || (is_other(s1) && is_other(s2))) {
-        set_or_throw(make_error_code(errc::not_supported), ec,
-                     "equivalent", p1, p2);
-        return false;
-    }
+    if (!exists(s2))
+      return make_unsupported_error();
     if (ec) ec->clear();
     return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
 }
@@ -502,17 +507,6 @@ bool __fs_is_empty(const path& p, std::error_code *ec)
 
 namespace detail { namespace {
 
-using namespace std::chrono;
-
-template <class CType, class ChronoType>
-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;
-}
-
 using TimeSpec = struct timespec;
 using StatT =  struct stat;
 
@@ -525,137 +519,10 @@ __attribute__((unused)) // Suppress warning
 TimeSpec extract_atime(StatT const& st) { return st.st_atim; }
 #endif
 
-constexpr auto max_seconds = duration_cast<seconds>(
-    file_time_type::duration::max()).count();
-
-constexpr auto max_nsec = duration_cast<nanoseconds>(
-    file_time_type::duration::max() - seconds(max_seconds)).count();
-
-constexpr auto min_seconds = duration_cast<seconds>(
-    file_time_type::duration::min()).count();
-
-constexpr auto min_nsec_timespec = duration_cast<nanoseconds>(
-    (file_time_type::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))
-                  == file_time_type::duration::min(), "");
-
-constexpr auto max_time_t = numeric_limits<time_t>::max();
-constexpr auto min_time_t = numeric_limits<time_t>::min();
-
-#if !defined(__LP64__) && defined(__clang__)
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare"
-#endif
-
-_LIBCPP_CONSTEXPR_AFTER_CXX11
-bool is_representable(TimeSpec const& 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);
-  }
-}
-#ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
-static_assert(is_representable({max_seconds, max_nsec}), "");
-static_assert(!is_representable({max_seconds + 1, 0}), "");
-static_assert(!is_representable({max_seconds, max_nsec + 1}), "");
-static_assert(!is_representable({max_time_t, 0}), "");
-static_assert(is_representable({min_seconds, 0}), "");
-static_assert(is_representable({min_seconds - 1, min_nsec_timespec}), "");
-static_assert(is_representable({min_seconds - 1, min_nsec_timespec + 1}), "");
-static_assert(!is_representable({min_seconds - 1, min_nsec_timespec - 1}), "");
-static_assert(!is_representable({min_time_t, 999999999}), "");
-#else
-static_assert(is_representable({max_time_t, 999999999}), "");
-static_assert(is_representable({max_time_t, 1000000000}), "");
-static_assert(is_representable({min_time_t, 0}), "");
-#endif
-#endif
-
-_LIBCPP_CONSTEXPR_AFTER_CXX11
-bool is_representable(file_time_type const& 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<time_t>;
-  if (secs.count() >= 0)
-    return secs.count() <= TLim::max();
-  return secs.count() >= TLim::min();
-}
-#ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
-static_assert(is_representable(file_time_type::max()), "");
-static_assert(is_representable(file_time_type::min()), "");
-#else
-static_assert(!is_representable(file_time_type::max()), "");
-static_assert(!is_representable(file_time_type::min()), "");
-static_assert(is_representable(file_time_type(seconds(max_time_t))), "");
-static_assert(is_representable(file_time_type(seconds(min_time_t))), "");
-#endif
-#endif
-
-_LIBCPP_CONSTEXPR_AFTER_CXX11
-file_time_type convert_timespec(TimeSpec const& 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 file_time_type(Dur);
-  } else if (duration_cast<microseconds>(nanoseconds(tm.tv_nsec)).count() == 0) {
-    return file_time_type(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 file_time_type(Dur);
-  }
-}
-#ifndef _LIBCPP_HAS_NO_CXX14_CONSTEXPR
-#if defined(__LP64__)
-static_assert(convert_timespec({max_seconds, max_nsec}) == file_time_type::max(), "");
-static_assert(convert_timespec({max_seconds, max_nsec - 1}) < file_time_type::max(), "");
-static_assert(convert_timespec({max_seconds - 1, 999999999}) < file_time_type::max(), "");
-static_assert(convert_timespec({min_seconds - 1, min_nsec_timespec}) == file_time_type::min(), "");
-static_assert(convert_timespec({min_seconds - 1, min_nsec_timespec + 1}) > file_time_type::min(), "");
-static_assert(convert_timespec({min_seconds , 0}) > file_time_type::min(), "");
-#else
-// FIXME add tests for 32 bit builds
-#endif
-#endif
-
-#if !defined(__LP64__) && defined(__clang__)
-#pragma clang diagnostic pop
-#endif
-
-template <class SubSecDurT, class SubSecT>
-bool set_times_checked(time_t* sec_out, SubSecT* subsec_out, file_time_type 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 detail
 
+using FSTime = fs_time_util<file_time_type, time_t, struct timespec>;
+
 file_time_type __last_write_time(const path& p, std::error_code *ec)
 {
     using namespace ::std::chrono;
@@ -668,12 +535,12 @@ file_time_type __last_write_time(const path& p, std::error_code *ec)
     }
     if (ec) ec->clear();
     auto ts = detail::extract_mtime(st);
-    if (!detail::is_representable(ts)) {
+    if (!FSTime::is_representable(ts)) {
         set_or_throw(error_code(EOVERFLOW, generic_category()), ec,
                      "last_write_time", p);
         return file_time_type::min();
     }
-    return detail::convert_timespec(ts);
+    return FSTime::convert_timespec(ts);
 }
 
 void __last_write_time(const path& p, file_time_type new_time,
@@ -698,7 +565,7 @@ void __last_write_time(const path& p, file_time_type new_time,
     struct ::timeval tbuf[2];
     tbuf[0].tv_sec = atime.tv_sec;
     tbuf[0].tv_usec = duration_cast<microseconds>(nanoseconds(atime.tv_nsec)).count();
-    const bool overflowed = !detail::set_times_checked<microseconds>(
+    const bool overflowed = !FSTime::set_times_checked<microseconds>(
         &tbuf[1].tv_sec, &tbuf[1].tv_usec, new_time);
 
     if (overflowed) {
@@ -714,7 +581,7 @@ void __last_write_time(const path& p, file_time_type new_time,
     tbuf[0].tv_sec = 0;
     tbuf[0].tv_nsec = UTIME_OMIT;
 
-    const bool overflowed = !detail::set_times_checked<nanoseconds>(
+    const bool overflowed = !FSTime::set_times_checked<nanoseconds>(
         &tbuf[1].tv_sec, &tbuf[1].tv_nsec, new_time);
     if (overflowed) {
         set_or_throw(make_error_code(errc::invalid_argument),