[ios] Use posix TimeExploded

With 32 bits build gone, iOS can use the posix implementation of
TimeExploded, which is faster.

Bug: 985061
Change-Id: Ic1d42ebddfa2d0bb0d37bb7b2086683914aa87a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1763679
Commit-Queue: David Jean <djean@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691094}

base/BUILD.gn

@@ -1969,6 +1969,7 @@ jumbo_component("base") {
       "task/thread_pool/thread_group_native_mac.mm",
       "threading/platform_thread_mac.mm",
       "time/time_conversion_posix.cc",
+      "time/time_exploded_posix.cc",
       "time/time_mac.cc",
     ]
 

base/time/time.h

@@ -492,10 +492,7 @@ class BASE_EXPORT Time : public time_internal::TimeBase<Time> {
 #if defined(OS_WIN)
   static constexpr int kExplodedMinYear = 1601;
   static constexpr int kExplodedMaxYear = 30827;
-#elif defined(OS_IOS)
-  static constexpr int kExplodedMinYear = std::numeric_limits<int>::min();
-  static constexpr int kExplodedMaxYear = std::numeric_limits<int>::max();
-#elif defined(OS_MACOSX)
+#elif defined(OS_IOS) || defined(OS_MACOSX)
   static constexpr int kExplodedMinYear = 1902;
   static constexpr int kExplodedMaxYear = std::numeric_limits<int>::max();
 #elif defined(OS_ANDROID)

base/time/time_exploded_posix.cc

@@ -32,7 +32,7 @@
 #include "base/numerics/clamped_math.h"
 #endif
 
-#if defined(OS_MACOSX)
+#if defined(OS_MACOSX) || defined(OS_IOS)
 static_assert(sizeof(time_t) >= 8, "Y2038 problem!");
 #endif
 

base/time/time_mac.cc

@@ -175,102 +175,6 @@ CFAbsoluteTime Time::ToCFAbsoluteTime() const {
          kCFAbsoluteTimeIntervalSince1970;
 }
 
-// Note: These implementations of Time::FromExploded() and Time::Explode() are
-// only used on iOS now. Since Mac is now always 64-bit, we can use the POSIX
-// versions of these functions as time_t is not capped at year 2038 on 64-bit
-// builds. The POSIX functions are preferred since they don't suffer from some
-// performance problems that are present in these implementations.
-// See crbug.com/781601 for more details.
-#if defined(OS_IOS)
-// static
-bool Time::FromExploded(bool is_local, const Exploded& exploded, Time* time) {
-  base::ScopedCFTypeRef<CFTimeZoneRef> time_zone(
-      is_local
-          ? CFTimeZoneCopySystem()
-          : CFTimeZoneCreateWithTimeIntervalFromGMT(kCFAllocatorDefault, 0));
-  base::ScopedCFTypeRef<CFCalendarRef> gregorian(CFCalendarCreateWithIdentifier(
-      kCFAllocatorDefault, kCFGregorianCalendar));
-  CFCalendarSetTimeZone(gregorian, time_zone);
-  CFAbsoluteTime absolute_time;
-  // 'S' is not defined in componentDesc in Apple documentation, but can be
-  // found at http://www.opensource.apple.com/source/CF/CF-855.17/CFCalendar.c
-  CFCalendarComposeAbsoluteTime(
-      gregorian, &absolute_time, "yMdHmsS", exploded.year, exploded.month,
-      exploded.day_of_month, exploded.hour, exploded.minute, exploded.second,
-      exploded.millisecond);
-  CFAbsoluteTime seconds = absolute_time + kCFAbsoluteTimeIntervalSince1970;
-
-  // CFAbsolutTime is typedef of double. Convert seconds to
-  // microseconds and then cast to int64. If
-  // it cannot be suited to int64, then fail to avoid overflows.
-  double microseconds =
-      (seconds * kMicrosecondsPerSecond) + kTimeTToMicrosecondsOffset;
-  if (microseconds > std::numeric_limits<int64_t>::max() ||
-      microseconds < std::numeric_limits<int64_t>::min()) {
-    *time = Time(0);
-    return false;
-  }
-
-  base::Time converted_time = Time(static_cast<int64_t>(microseconds));
-
-  // If |exploded.day_of_month| is set to 31
-  // on a 28-30 day month, it will return the first day of the next month.
-  // Thus round-trip the time and compare the initial |exploded| with
-  // |utc_to_exploded| time.
-  base::Time::Exploded to_exploded;
-  if (!is_local)
-    converted_time.UTCExplode(&to_exploded);
-  else
-    converted_time.LocalExplode(&to_exploded);
-
-  if (ExplodedMostlyEquals(to_exploded, exploded)) {
-    *time = converted_time;
-    return true;
-  }
-
-  *time = Time(0);
-  return false;
-}
-
-void Time::Explode(bool is_local, Exploded* exploded) const {
-  // Avoid rounding issues, by only putting the integral number of seconds
-  // (rounded towards -infinity) into a |CFAbsoluteTime| (which is a |double|).
-  int64_t microsecond = us_ % kMicrosecondsPerSecond;
-  if (microsecond < 0)
-    microsecond += kMicrosecondsPerSecond;
-  CFAbsoluteTime seconds = ((us_ - microsecond - kTimeTToMicrosecondsOffset) /
-                            kMicrosecondsPerSecond) -
-                           kCFAbsoluteTimeIntervalSince1970;
-
-  base::ScopedCFTypeRef<CFTimeZoneRef> time_zone(
-      is_local
-          ? CFTimeZoneCopySystem()
-          : CFTimeZoneCreateWithTimeIntervalFromGMT(kCFAllocatorDefault, 0));
-  base::ScopedCFTypeRef<CFCalendarRef> gregorian(CFCalendarCreateWithIdentifier(
-      kCFAllocatorDefault, kCFGregorianCalendar));
-  CFCalendarSetTimeZone(gregorian, time_zone);
-  int second, day_of_week;
-  // 'E' sets the day of week, but is not defined in componentDesc in Apple
-  // documentation. It can be found in open source code here:
-  // http://www.opensource.apple.com/source/CF/CF-855.17/CFCalendar.c
-  CFCalendarDecomposeAbsoluteTime(gregorian, seconds, "yMdHmsE",
-                                  &exploded->year, &exploded->month,
-                                  &exploded->day_of_month, &exploded->hour,
-                                  &exploded->minute, &second, &day_of_week);
-  // Make sure seconds are rounded down towards -infinity.
-  exploded->second = floor(second);
-  // |Exploded|'s convention for day of week is 0 = Sunday, i.e. different
-  // from CF's 1 = Sunday.
-  exploded->day_of_week = (day_of_week - 1) % 7;
-  // Calculate milliseconds ourselves, since we rounded the |seconds|, making
-  // sure to round towards -infinity.
-  exploded->millisecond =
-      (microsecond >= 0) ? microsecond / kMicrosecondsPerMillisecond :
-                           (microsecond - kMicrosecondsPerMillisecond + 1) /
-                               kMicrosecondsPerMillisecond;
-}
-#endif  // OS_IOS
-
 // TimeTicks ------------------------------------------------------------------
 
 namespace subtle {