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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // Time represents an absolute point in coordinated universal time (UTC), | 5 // Time represents an absolute point in coordinated universal time (UTC), |
6 // internally represented as microseconds (s/1,000,000) since the Windows epoch | 6 // internally represented as microseconds (s/1,000,000) since the Windows epoch |
7 // (1601-01-01 00:00:00 UTC). System-dependent clock interface routines are | 7 // (1601-01-01 00:00:00 UTC). System-dependent clock interface routines are |
8 // defined in time_PLATFORM.cc. Note that values for Time may skew and jump | 8 // defined in time_PLATFORM.cc. Note that values for Time may skew and jump |
9 // around as the operating system makes adjustments to synchronize (e.g., with | 9 // around as the operating system makes adjustments to synchronize (e.g., with |
10 // NTP servers). Thus, client code that uses the Time class must account for | 10 // NTP servers). Thus, client code that uses the Time class must account for |
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635 } | 635 } |
636 | 636 |
637 // For logging use only. | 637 // For logging use only. |
638 BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time); | 638 BASE_EXPORT std::ostream& operator<<(std::ostream& os, Time time); |
639 | 639 |
640 // TimeTicks ------------------------------------------------------------------ | 640 // TimeTicks ------------------------------------------------------------------ |
641 | 641 |
642 // Represents monotonically non-decreasing clock time. | 642 // Represents monotonically non-decreasing clock time. |
643 class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> { | 643 class BASE_EXPORT TimeTicks : public time_internal::TimeBase<TimeTicks> { |
644 public: | 644 public: |
| 645 // The underlying clock used to generate new TimeTicks. |
| 646 enum class Clock { |
| 647 LINUX_CLOCK_MONOTONIC, |
| 648 IOS_CF_ABSOLUTE_TIME_MINUS_KERN_BOOTTIME, |
| 649 MAC_MACH_ABSOLUTE_TIME, |
| 650 WIN_QPC, |
| 651 WIN_ROLLOVER_PROTECTED_TIME_GET_TIME |
| 652 }; |
| 653 |
645 TimeTicks() : TimeBase(0) { | 654 TimeTicks() : TimeBase(0) { |
646 } | 655 } |
647 | 656 |
648 // Platform-dependent tick count representing "right now." When | 657 // Platform-dependent tick count representing "right now." When |
649 // IsHighResolution() returns false, the resolution of the clock could be | 658 // IsHighResolution() returns false, the resolution of the clock could be |
650 // as coarse as ~15.6ms. Otherwise, the resolution should be no worse than one | 659 // as coarse as ~15.6ms. Otherwise, the resolution should be no worse than one |
651 // microsecond. | 660 // microsecond. |
652 static TimeTicks Now(); | 661 static TimeTicks Now(); |
653 | 662 |
654 // Returns true if the high resolution clock is working on this system and | 663 // Returns true if the high resolution clock is working on this system and |
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673 // the same value for the duration of the application, but will be different | 682 // the same value for the duration of the application, but will be different |
674 // in future application runs. | 683 // in future application runs. |
675 static TimeTicks UnixEpoch(); | 684 static TimeTicks UnixEpoch(); |
676 | 685 |
677 // Returns |this| snapped to the next tick, given a |tick_phase| and | 686 // Returns |this| snapped to the next tick, given a |tick_phase| and |
678 // repeating |tick_interval| in both directions. |this| may be before, | 687 // repeating |tick_interval| in both directions. |this| may be before, |
679 // after, or equal to the |tick_phase|. | 688 // after, or equal to the |tick_phase|. |
680 TimeTicks SnappedToNextTick(TimeTicks tick_phase, | 689 TimeTicks SnappedToNextTick(TimeTicks tick_phase, |
681 TimeDelta tick_interval) const; | 690 TimeDelta tick_interval) const; |
682 | 691 |
| 692 // Returns an enum indicating the underlying clock being used to generate |
| 693 // TimeTicks timestamps. This function should only be used for debugging and |
| 694 // logging purposes. |
| 695 static Clock GetClock(); |
| 696 |
683 #if defined(OS_WIN) | 697 #if defined(OS_WIN) |
684 protected: | 698 protected: |
685 typedef DWORD (*TickFunctionType)(void); | 699 typedef DWORD (*TickFunctionType)(void); |
686 static TickFunctionType SetMockTickFunction(TickFunctionType ticker); | 700 static TickFunctionType SetMockTickFunction(TickFunctionType ticker); |
687 #endif | 701 #endif |
688 | 702 |
689 private: | 703 private: |
690 friend class time_internal::TimeBase<TimeTicks>; | 704 friend class time_internal::TimeBase<TimeTicks>; |
691 | 705 |
692 // Please use Now() to create a new object. This is for internal use | 706 // Please use Now() to create a new object. This is for internal use |
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755 static void WaitUntilInitializedWin(); | 769 static void WaitUntilInitializedWin(); |
756 #endif | 770 #endif |
757 }; | 771 }; |
758 | 772 |
759 // For logging use only. | 773 // For logging use only. |
760 BASE_EXPORT std::ostream& operator<<(std::ostream& os, ThreadTicks time_ticks); | 774 BASE_EXPORT std::ostream& operator<<(std::ostream& os, ThreadTicks time_ticks); |
761 | 775 |
762 } // namespace base | 776 } // namespace base |
763 | 777 |
764 #endif // BASE_TIME_TIME_H_ | 778 #endif // BASE_TIME_TIME_H_ |
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