Use base/time/time_posix.cc on OS X and iOS.

base/time/time_mac.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/time/time.h"
-
-#include <CoreFoundation/CFDate.h>
-#include <CoreFoundation/CFTimeZone.h>
-#include <mach/mach.h>
-#include <mach/mach_time.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <sys/sysctl.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <time.h>
-
-#include "base/logging.h"
-#include "base/mac/mach_logging.h"
-#include "base/mac/scoped_cftyperef.h"
-#include "base/mac/scoped_mach_port.h"
-#include "base/macros.h"
-#include "base/numerics/safe_conversions.h"
-#include "build/build_config.h"
-
-namespace {
-
-int64_t ComputeCurrentTicks() {
-#if defined(OS_IOS)
-  // On iOS mach_absolute_time stops while the device is sleeping. Instead use
-  // now - KERN_BOOTTIME to get a time difference that is not impacted by clock
-  // changes. KERN_BOOTTIME will be updated by the system whenever the system
-  // clock change.
-  struct timeval boottime;
-  int mib[2] = {CTL_KERN, KERN_BOOTTIME};
-  size_t size = sizeof(boottime);
-  int kr = sysctl(mib, arraysize(mib), &boottime, &size, NULL, 0);
-  DCHECK_EQ(KERN_SUCCESS, kr);
-  base::TimeDelta time_difference = base::Time::Now() -
-      (base::Time::FromTimeT(boottime.tv_sec) +
-       base::TimeDelta::FromMicroseconds(boottime.tv_usec));
-  return time_difference.InMicroseconds();
-#else
-  static mach_timebase_info_data_t timebase_info;
-  if (timebase_info.denom == 0) {
-    // Zero-initialization of statics guarantees that denom will be 0 before
-    // calling mach_timebase_info.  mach_timebase_info will never set denom to
-    // 0 as that would be invalid, so the zero-check can be used to determine
-    // whether mach_timebase_info has already been called.  This is
-    // recommended by Apple's QA1398.
-    kern_return_t kr = mach_timebase_info(&timebase_info);
-    MACH_DCHECK(kr == KERN_SUCCESS, kr) << "mach_timebase_info";
-  }
-
-  // mach_absolute_time is it when it comes to ticks on the Mac.  Other calls
-  // with less precision (such as TickCount) just call through to
-  // mach_absolute_time.
-
-  // timebase_info converts absolute time tick units into nanoseconds.  Convert
-  // to microseconds up front to stave off overflows.
-  base::CheckedNumeric<uint64_t> result(
-      mach_absolute_time() / base::Time::kNanosecondsPerMicrosecond);
-  result *= timebase_info.numer;
-  result /= timebase_info.denom;
-
-  // Don't bother with the rollover handling that the Windows version does.
-  // With numer and denom = 1 (the expected case), the 64-bit absolute time
-  // reported in nanoseconds is enough to last nearly 585 years.
-  return base::checked_cast<int64_t>(result.ValueOrDie());
-#endif  // defined(OS_IOS)
-}
-
-int64_t ComputeThreadTicks() {
-#if defined(OS_IOS)
-  NOTREACHED();
-  return 0;
-#else
-  base::mac::ScopedMachSendRight thread(mach_thread_self());
-  mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
-  thread_basic_info_data_t thread_info_data;
-
-  if (thread.get() == MACH_PORT_NULL) {
-    DLOG(ERROR) << "Failed to get mach_thread_self()";
-    return 0;
-  }
-
-  kern_return_t kr = thread_info(
-      thread.get(),
-      THREAD_BASIC_INFO,
-      reinterpret_cast<thread_info_t>(&thread_info_data),
-      &thread_info_count);
-  MACH_DCHECK(kr == KERN_SUCCESS, kr) << "thread_info";
-
-  base::CheckedNumeric<int64_t> absolute_micros(
-      thread_info_data.user_time.seconds);
-  absolute_micros *= base::Time::kMicrosecondsPerSecond;
-  absolute_micros += thread_info_data.user_time.microseconds;
-  return absolute_micros.ValueOrDie();
-#endif  // defined(OS_IOS)
-}
-
-}  // namespace
-
-namespace base {
-
-// The Time routines in this file use Mach and CoreFoundation APIs, since the
-// POSIX definition of time_t in Mac OS X wraps around after 2038--and
-// there are already cookie expiration dates, etc., past that time out in
-// the field.  Using CFDate prevents that problem, and using mach_absolute_time
-// for TimeTicks gives us nice high-resolution interval timing.
-
-// Time -----------------------------------------------------------------------
-
-// Core Foundation uses a double second count since 2001-01-01 00:00:00 UTC.
-// The UNIX epoch is 1970-01-01 00:00:00 UTC.
-// Windows uses a Gregorian epoch of 1601.  We need to match this internally
-// so that our time representations match across all platforms.  See bug 14734.
-//   irb(main):010:0> Time.at(0).getutc()
-//   => Thu Jan 01 00:00:00 UTC 1970
-//   irb(main):011:0> Time.at(-11644473600).getutc()
-//   => Mon Jan 01 00:00:00 UTC 1601
-static const int64_t kWindowsEpochDeltaSeconds = INT64_C(11644473600);
-
-// static
-const int64_t Time::kWindowsEpochDeltaMicroseconds =
-    kWindowsEpochDeltaSeconds * Time::kMicrosecondsPerSecond;
-
-// Some functions in time.cc use time_t directly, so we provide an offset
-// to convert from time_t (Unix epoch) and internal (Windows epoch).
-// static
-const int64_t Time::kTimeTToMicrosecondsOffset = kWindowsEpochDeltaMicroseconds;
-
-// static
-Time Time::Now() {
-  return FromCFAbsoluteTime(CFAbsoluteTimeGetCurrent());
-}
-
-// static
-Time Time::FromCFAbsoluteTime(CFAbsoluteTime t) {
-  static_assert(std::numeric_limits<CFAbsoluteTime>::has_infinity,
-                "CFAbsoluteTime must have an infinity value");
-  if (t == 0)
-    return Time();  // Consider 0 as a null Time.
-  if (t == std::numeric_limits<CFAbsoluteTime>::infinity())
-    return Max();
-  return Time(static_cast<int64_t>((t + kCFAbsoluteTimeIntervalSince1970) *
-                                   kMicrosecondsPerSecond) +
-              kWindowsEpochDeltaMicroseconds);
-}
-
-CFAbsoluteTime Time::ToCFAbsoluteTime() const {
-  static_assert(std::numeric_limits<CFAbsoluteTime>::has_infinity,
-                "CFAbsoluteTime must have an infinity value");
-  if (is_null())
-    return 0;  // Consider 0 as a null Time.
-  if (is_max())
-    return std::numeric_limits<CFAbsoluteTime>::infinity();
-  return (static_cast<CFAbsoluteTime>(us_ - kWindowsEpochDeltaMicroseconds) /
-      kMicrosecondsPerSecond) - kCFAbsoluteTimeIntervalSince1970;
-}
-
-// static
-Time Time::NowFromSystemTime() {
-  // Just use Now() because Now() returns the system time.
-  return Now();
-}
-
-// static
-Time Time::FromExploded(bool is_local, const Exploded& exploded) {
-  CFGregorianDate date;
-  date.second = exploded.second +
-      exploded.millisecond / static_cast<double>(kMillisecondsPerSecond);
-  date.minute = exploded.minute;
-  date.hour = exploded.hour;
-  date.day = exploded.day_of_month;
-  date.month = exploded.month;
-  date.year = exploded.year;
-
-  base::ScopedCFTypeRef<CFTimeZoneRef> time_zone(
-      is_local ? CFTimeZoneCopySystem() : NULL);
-  CFAbsoluteTime seconds = CFGregorianDateGetAbsoluteTime(date, time_zone) +
-      kCFAbsoluteTimeIntervalSince1970;
-  return Time(static_cast<int64_t>(seconds * kMicrosecondsPerSecond) +
-              kWindowsEpochDeltaMicroseconds);
-}
-
-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) / kMicrosecondsPerSecond) -
-                           kWindowsEpochDeltaSeconds -
-                           kCFAbsoluteTimeIntervalSince1970;
-
-  base::ScopedCFTypeRef<CFTimeZoneRef> time_zone(
-      is_local ? CFTimeZoneCopySystem() : NULL);
-  CFGregorianDate date = CFAbsoluteTimeGetGregorianDate(seconds, time_zone);
-  // 1 = Monday, ..., 7 = Sunday.
-  int cf_day_of_week = CFAbsoluteTimeGetDayOfWeek(seconds, time_zone);
-
-  exploded->year = date.year;
-  exploded->month = date.month;
-  exploded->day_of_week = cf_day_of_week % 7;
-  exploded->day_of_month = date.day;
-  exploded->hour = date.hour;
-  exploded->minute = date.minute;
-  // Make sure seconds are rounded down towards -infinity.
-  exploded->second = floor(date.second);
-  // Calculate milliseconds ourselves, since we rounded the |seconds|, making
-  // sure to round towards -infinity.
-  exploded->millisecond =
-      (microsecond >= 0) ? microsecond / kMicrosecondsPerMillisecond :
-                           (microsecond - kMicrosecondsPerMillisecond + 1) /
-                               kMicrosecondsPerMillisecond;
-}
-
-// TimeTicks ------------------------------------------------------------------
-
-// static
-TimeTicks TimeTicks::Now() {
-  return TimeTicks(ComputeCurrentTicks());
-}
-
-// static
-bool TimeTicks::IsHighResolution() {
-  return true;
-}
-
-// static
-ThreadTicks ThreadTicks::Now() {
-  return ThreadTicks(ComputeThreadTicks());
-}
-
-}  // namespace base