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- // 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"
- #import <Foundation/Foundation.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/notreached.h"
- #include "base/numerics/safe_conversions.h"
- #include "base/time/time_override.h"
- #include "build/build_config.h"
- #if BUILDFLAG(IS_IOS)
- #include <time.h>
- #include "base/ios/ios_util.h"
- #endif
- namespace {
- #if BUILDFLAG(IS_MAC)
- // Returns a pointer to the initialized Mach timebase info struct.
- mach_timebase_info_data_t* MachTimebaseInfo() {
- static mach_timebase_info_data_t timebase_info = []() {
- mach_timebase_info_data_t info;
- kern_return_t kr = mach_timebase_info(&info);
- MACH_DCHECK(kr == KERN_SUCCESS, kr) << "mach_timebase_info";
- DCHECK(info.numer);
- DCHECK(info.denom);
- return info;
- }();
- return &timebase_info;
- }
- int64_t MachTimeToMicroseconds(uint64_t mach_time) {
- // timebase_info gives us the conversion factor between absolute time tick
- // units and nanoseconds.
- mach_timebase_info_data_t* timebase_info = MachTimebaseInfo();
- // Take the fast path when the conversion is 1:1. The result will for sure fit
- // into an int_64 because we're going from nanoseconds to microseconds.
- if (timebase_info->numer == timebase_info->denom) {
- return static_cast<int64_t>(mach_time /
- base::Time::kNanosecondsPerMicrosecond);
- }
- uint64_t microseconds = 0;
- const uint64_t divisor =
- timebase_info->denom * base::Time::kNanosecondsPerMicrosecond;
- // Microseconds is mach_time * timebase.numer /
- // (timebase.denom * kNanosecondsPerMicrosecond). Divide first to reduce
- // the chance of overflow. Also stash the remainder right now, a likely
- // byproduct of the division.
- microseconds = mach_time / divisor;
- const uint64_t mach_time_remainder = mach_time % divisor;
- // Now multiply, keeping an eye out for overflow.
- CHECK(!__builtin_umulll_overflow(microseconds, timebase_info->numer,
- µseconds));
- // By dividing first we lose precision. Regain it by adding back the
- // microseconds from the remainder, with an eye out for overflow.
- uint64_t least_significant_microseconds =
- (mach_time_remainder * timebase_info->numer) / divisor;
- CHECK(!__builtin_uaddll_overflow(microseconds, least_significant_microseconds,
- µseconds));
- // Don't bother with the rollover handling that the Windows version does.
- // The returned time in microseconds is enough for 292,277 years (starting
- // from 2^63 because the returned int64_t is signed,
- // 9223372036854775807 / (1e6 * 60 * 60 * 24 * 365.2425) = 292,277).
- return base::checked_cast<int64_t>(microseconds);
- }
- #endif // BUILDFLAG(IS_MAC)
- // Returns monotonically growing number of ticks in microseconds since some
- // unspecified starting point.
- int64_t ComputeCurrentTicks() {
- #if BUILDFLAG(IS_IOS)
- // iOS 10 supports clock_gettime(CLOCK_MONOTONIC, ...), which is
- // around 15 times faster than sysctl() call. Use it if possible;
- // otherwise, fall back to sysctl().
- if (__builtin_available(iOS 10, *)) {
- struct timespec tp;
- if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) {
- return (int64_t)tp.tv_sec * 1000000 + tp.tv_nsec / 1000;
- }
- }
- // 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, std::size(mib), &boottime, &size, nullptr, 0);
- DCHECK_EQ(KERN_SUCCESS, kr);
- base::TimeDelta time_difference = base::subtle::TimeNowIgnoringOverride() -
- (base::Time::FromTimeT(boottime.tv_sec) +
- base::Microseconds(boottime.tv_usec));
- return time_difference.InMicroseconds();
- #else
- // 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.
- return MachTimeToMicroseconds(mach_absolute_time());
- #endif // BUILDFLAG(IS_IOS)
- }
- int64_t ComputeThreadTicks() {
- #if BUILDFLAG(IS_IOS)
- NOTREACHED();
- return 0;
- #else
- // The pthreads library keeps a cached reference to the thread port, which
- // does not have to be released like mach_thread_self() does.
- mach_port_t thread_port = pthread_mach_thread_np(pthread_self());
- if (thread_port == MACH_PORT_NULL) {
- DLOG(ERROR) << "Failed to get pthread_mach_thread_np()";
- return 0;
- }
- mach_msg_type_number_t thread_info_count = THREAD_BASIC_INFO_COUNT;
- thread_basic_info_data_t thread_info_data;
- kern_return_t kr = thread_info(
- thread_port, 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 +
- thread_info_data.system_time.seconds);
- absolute_micros *= base::Time::kMicrosecondsPerSecond;
- absolute_micros += (thread_info_data.user_time.microseconds +
- thread_info_data.system_time.microseconds);
- return absolute_micros.ValueOrDie();
- #endif // BUILDFLAG(IS_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 -----------------------------------------------------------------------
- namespace subtle {
- Time TimeNowIgnoringOverride() {
- return Time::FromCFAbsoluteTime(CFAbsoluteTimeGetCurrent());
- }
- Time TimeNowFromSystemTimeIgnoringOverride() {
- // Just use TimeNowIgnoringOverride() because it returns the system time.
- return TimeNowIgnoringOverride();
- }
- } // namespace subtle
- // 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.
- return (t == std::numeric_limits<CFAbsoluteTime>::infinity())
- ? Max()
- : (UnixEpoch() +
- Seconds(double{t + kCFAbsoluteTimeIntervalSince1970}));
- }
- 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.
- return is_max() ? std::numeric_limits<CFAbsoluteTime>::infinity()
- : (CFAbsoluteTime{(*this - UnixEpoch()).InSecondsF()} -
- kCFAbsoluteTimeIntervalSince1970);
- }
- // static
- Time Time::FromNSDate(NSDate* date) {
- DCHECK(date);
- return FromCFAbsoluteTime(date.timeIntervalSinceReferenceDate);
- }
- NSDate* Time::ToNSDate() const {
- return [NSDate dateWithTimeIntervalSinceReferenceDate:ToCFAbsoluteTime()];
- }
- // TimeDelta ------------------------------------------------------------------
- #if BUILDFLAG(IS_MAC)
- // static
- TimeDelta TimeDelta::FromMachTime(uint64_t mach_time) {
- return Microseconds(MachTimeToMicroseconds(mach_time));
- }
- #endif // BUILDFLAG(IS_MAC)
- // TimeTicks ------------------------------------------------------------------
- namespace subtle {
- TimeTicks TimeTicksNowIgnoringOverride() {
- return TimeTicks() + Microseconds(ComputeCurrentTicks());
- }
- } // namespace subtle
- // static
- bool TimeTicks::IsHighResolution() {
- return true;
- }
- // static
- bool TimeTicks::IsConsistentAcrossProcesses() {
- return true;
- }
- #if BUILDFLAG(IS_MAC)
- // static
- TimeTicks TimeTicks::FromMachAbsoluteTime(uint64_t mach_absolute_time) {
- return TimeTicks(MachTimeToMicroseconds(mach_absolute_time));
- }
- // static
- mach_timebase_info_data_t TimeTicks::SetMachTimebaseInfoForTesting(
- mach_timebase_info_data_t timebase) {
- mach_timebase_info_data_t orig_timebase = *MachTimebaseInfo();
- *MachTimebaseInfo() = timebase;
- return orig_timebase;
- }
- #endif // BUILDFLAG(IS_MAC)
- // static
- TimeTicks::Clock TimeTicks::GetClock() {
- #if BUILDFLAG(IS_IOS)
- return Clock::IOS_CF_ABSOLUTE_TIME_MINUS_KERN_BOOTTIME;
- #else
- return Clock::MAC_MACH_ABSOLUTE_TIME;
- #endif // BUILDFLAG(IS_IOS)
- }
- // ThreadTicks ----------------------------------------------------------------
- namespace subtle {
- ThreadTicks ThreadTicksNowIgnoringOverride() {
- return ThreadTicks() + Microseconds(ComputeThreadTicks());
- }
- } // namespace subtle
- } // namespace base
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