blob: b7bac35bb637168a25cee9cad872165dc08913f1 [file] [log] [blame]
// 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) {
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;
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()
: 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;
}
// TimeTicks ------------------------------------------------------------------
// static
TimeTicks TimeTicks::Now() {
return TimeTicks(ComputeCurrentTicks());
}
// static
bool TimeTicks::IsHighResolution() {
return true;
}
// static
TimeTicks::Clock TimeTicks::GetClock() {
#if defined(OS_IOS)
return Clock::IOS_CF_ABSOLUTE_TIME_MINUS_KERN_BOOTTIME;
#else
return Clock::MAC_MACH_ABSOLUTE_TIME;
#endif // defined(OS_IOS)
}
// static
ThreadTicks ThreadTicks::Now() {
return ThreadTicks(ComputeThreadTicks());
}
} // namespace base