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| 1 // Copyright (c) 2008 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "base/time.h" |
| 6 |
| 7 #include <CoreFoundation/CFDate.h> |
| 8 #include <CoreFoundation/CFTimeZone.h> |
| 9 #include <mach/mach_time.h> |
| 10 #include <sys/time.h> |
| 11 #include <time.h> |
| 12 |
| 13 #include "base/basictypes.h" |
| 14 #include "base/logging.h" |
| 15 #include "base/scoped_cftyperef.h" |
| 16 |
| 17 namespace base { |
| 18 |
| 19 // The Time routines in this file use Mach and CoreFoundation APIs, since the |
| 20 // POSIX definition of time_t in Mac OS X wraps around after 2038--and |
| 21 // there are already cookie expiration dates, etc., past that time out in |
| 22 // the field. Using CFDate prevents that problem, and using mach_absolute_time |
| 23 // for TimeTicks gives us nice high-resolution interval timing. |
| 24 |
| 25 // Time ----------------------------------------------------------------------- |
| 26 |
| 27 // The internal representation of Time uses a 64-bit microsecond count |
| 28 // from 1970-01-01 00:00:00 UTC. Core Foundation uses a double second count |
| 29 // since 2001-01-01 00:00:00 UTC. |
| 30 |
| 31 // Some functions in time.c use time_t directly, so we provide a zero offset |
| 32 // for them. The epoch is 1970-01-01 00:00:00 UTC. |
| 33 // static |
| 34 const int64 Time::kTimeTToMicrosecondsOffset = GG_INT64_C(0); |
| 35 |
| 36 // static |
| 37 Time Time::Now() { |
| 38 CFAbsoluteTime now = |
| 39 CFAbsoluteTimeGetCurrent() + kCFAbsoluteTimeIntervalSince1970; |
| 40 return Time(static_cast<int64>(now * kMicrosecondsPerSecond)); |
| 41 } |
| 42 |
| 43 // static |
| 44 Time Time::FromExploded(bool is_local, const Exploded& exploded) { |
| 45 CFGregorianDate date; |
| 46 date.second = exploded.second + |
| 47 exploded.millisecond / static_cast<double>(kMillisecondsPerSecond); |
| 48 date.minute = exploded.minute; |
| 49 date.hour = exploded.hour; |
| 50 date.day = exploded.day_of_month; |
| 51 date.month = exploded.month; |
| 52 date.year = exploded.year; |
| 53 |
| 54 scoped_cftyperef<CFTimeZoneRef> time_zone; |
| 55 if (is_local) |
| 56 time_zone.reset(CFTimeZoneCopySystem()); |
| 57 CFAbsoluteTime seconds = CFGregorianDateGetAbsoluteTime(date, time_zone) + |
| 58 kCFAbsoluteTimeIntervalSince1970; |
| 59 return Time(static_cast<int64>(seconds * kMicrosecondsPerSecond)); |
| 60 } |
| 61 |
| 62 void Time::Explode(bool is_local, Exploded* exploded) const { |
| 63 CFAbsoluteTime seconds = |
| 64 (static_cast<double>(us_) / kMicrosecondsPerSecond) - |
| 65 kCFAbsoluteTimeIntervalSince1970; |
| 66 |
| 67 scoped_cftyperef<CFTimeZoneRef> time_zone; |
| 68 if (is_local) |
| 69 time_zone.reset(CFTimeZoneCopySystem()); |
| 70 CFGregorianDate date = CFAbsoluteTimeGetGregorianDate(seconds, time_zone); |
| 71 |
| 72 exploded->year = date.year; |
| 73 exploded->month = date.month; |
| 74 exploded->day_of_month = date.day; |
| 75 exploded->hour = date.hour; |
| 76 exploded->minute = date.minute; |
| 77 exploded->second = date.second; |
| 78 exploded->millisecond = |
| 79 static_cast<int>(date.second * kMillisecondsPerSecond) % |
| 80 kMillisecondsPerSecond; |
| 81 } |
| 82 |
| 83 // TimeTicks ------------------------------------------------------------------ |
| 84 |
| 85 // static |
| 86 TimeTicks TimeTicks::Now() { |
| 87 uint64_t absolute_micro; |
| 88 |
| 89 static mach_timebase_info_data_t timebase_info; |
| 90 if (timebase_info.denom == 0) { |
| 91 // Zero-initialization of statics guarantees that denom will be 0 before |
| 92 // calling mach_timebase_info. mach_timebase_info will never set denom to |
| 93 // 0 as that would be invalid, so the zero-check can be used to determine |
| 94 // whether mach_timebase_info has already been called. This is |
| 95 // recommended by Apple's QA1398. |
| 96 kern_return_t kr = mach_timebase_info(&timebase_info); |
| 97 DCHECK(kr == KERN_SUCCESS); |
| 98 } |
| 99 |
| 100 // mach_absolute_time is it when it comes to ticks on the Mac. Other calls |
| 101 // with less precision (such as TickCount) just call through to |
| 102 // mach_absolute_time. |
| 103 |
| 104 // timebase_info converts absolute time tick units into nanoseconds. Convert |
| 105 // to microseconds up front to stave off overflows. |
| 106 absolute_micro = mach_absolute_time() / Time::kNanosecondsPerMicrosecond * |
| 107 timebase_info.numer / timebase_info.denom; |
| 108 |
| 109 // Don't bother with the rollover handling that the Windows version does. |
| 110 // With numer and denom = 1 (the expected case), the 64-bit absolute time |
| 111 // reported in nanoseconds is enough to last nearly 585 years. |
| 112 |
| 113 return TimeTicks(absolute_micro); |
| 114 } |
| 115 |
| 116 // static |
| 117 TimeTicks TimeTicks::HighResNow() { |
| 118 return Now(); |
| 119 } |
| 120 |
| 121 } // namespace base |
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