Source code
Revision control
Copy as Markdown
Other Tools
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2008 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.h"
#include <CoreFoundation/CFDate.h>
#include <CoreFoundation/CFTimeZone.h>
#include <mach/mach_time.h>
#include <sys/time.h>
#include <time.h>
#include "base/basictypes.h"
#include "base/logging.h"
#include "base/scoped_cftyperef.h"
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 -----------------------------------------------------------------------
// The internal representation of Time uses a 64-bit microsecond count
// from 1970-01-01 00:00:00 UTC. Core Foundation uses a double second count
// since 2001-01-01 00:00:00 UTC.
// Some functions in time.cc use time_t directly, so we provide a zero offset
// for them. The epoch is 1970-01-01 00:00:00 UTC.
// static
const int64_t Time::kTimeTToMicrosecondsOffset = GG_INT64_C(0);
// static
Time Time::Now() {
CFAbsoluteTime now =
CFAbsoluteTimeGetCurrent() + kCFAbsoluteTimeIntervalSince1970;
return Time(static_cast<int64_t>(now * kMicrosecondsPerSecond));
}
// 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;
scoped_cftyperef<CFTimeZoneRef> time_zone(is_local ? CFTimeZoneCopySystem()
: NULL);
CFAbsoluteTime seconds = CFGregorianDateGetAbsoluteTime(date, time_zone) +
kCFAbsoluteTimeIntervalSince1970;
return Time(static_cast<int64_t>(seconds * kMicrosecondsPerSecond));
}
void Time::Explode(bool is_local, Exploded* exploded) const {
CFAbsoluteTime seconds = (static_cast<double>(us_) / kMicrosecondsPerSecond) -
kCFAbsoluteTimeIntervalSince1970;
scoped_cftyperef<CFTimeZoneRef> time_zone(is_local ? CFTimeZoneCopySystem()
: NULL);
CFGregorianDate date = CFAbsoluteTimeGetGregorianDate(seconds, time_zone);
exploded->year = date.year;
exploded->month = date.month;
exploded->day_of_month = date.day;
exploded->hour = date.hour;
exploded->minute = date.minute;
exploded->second = date.second;
exploded->millisecond =
static_cast<int>(date.second * kMillisecondsPerSecond) %
kMillisecondsPerSecond;
}
// TimeTicks ------------------------------------------------------------------
// static
TimeTicks TimeTicks::Now() {
uint64_t absolute_micro;
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);
DCHECK(kr == KERN_SUCCESS);
}
// 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.
absolute_micro = mach_absolute_time() / Time::kNanosecondsPerMicrosecond *
timebase_info.numer / 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 TimeTicks(absolute_micro);
}
} // namespace base