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// 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/mac/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 -----------------------------------------------------------------------
// 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 kWindowsEpochDeltaSeconds = GG_INT64_C(11644473600);
static const int64 kWindowsEpochDeltaMilliseconds =
kWindowsEpochDeltaSeconds * Time::kMillisecondsPerSecond;
// static
const int64 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 Time::kTimeTToMicrosecondsOffset = kWindowsEpochDeltaMicroseconds;
// static
Time Time::Now() {
CFAbsoluteTime now =
CFAbsoluteTimeGetCurrent() + kCFAbsoluteTimeIntervalSince1970;
return Time(static_cast<int64>(now * kMicrosecondsPerSecond) +
kWindowsEpochDeltaMicroseconds);
}
// 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::mac::ScopedCFTypeRef<CFTimeZoneRef>
time_zone(is_local ? CFTimeZoneCopySystem() : NULL);
CFAbsoluteTime seconds = CFGregorianDateGetAbsoluteTime(date, time_zone) +
kCFAbsoluteTimeIntervalSince1970;
return Time(static_cast<int64>(seconds * kMicrosecondsPerSecond) +
kWindowsEpochDeltaMicroseconds);
}
void Time::Explode(bool is_local, Exploded* exploded) const {
CFAbsoluteTime seconds =
((static_cast<double>(us_) - kWindowsEpochDeltaMicroseconds) /
kMicrosecondsPerSecond) - kCFAbsoluteTimeIntervalSince1970;
base::mac::ScopedCFTypeRef<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);
}
// static
TimeTicks TimeTicks::HighResNow() {
return Now();
}
} // namespace base
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