mozglue/misc/TimeStamp_windows.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_TimeStamp_windows_h
   8 #define mozilla_TimeStamp_windows_h
   9
  10 #include "mozilla/Types.h"
  11
  12 namespace mozilla {
  13
  14 /**
  15  * The [mt] unit:
  16  *
  17  * Many values are kept in ticks of the Performance Counter x 1000,
  18  * further just referred as [mt], meaning milli-ticks.
  19  *
  20  * This is needed to preserve maximum precision of the performance frequency
  21  * representation.  GetTickCount64 values in milliseconds are multiplied with
  22  * frequency per second.  Therefore we need to multiply QPC value by 1000 to
  23  * have the same units to allow simple arithmentic with both QPC and GTC.
  24  */
  25 #define ms2mt(x) ((x)*mozilla::GetQueryPerformanceFrequencyPerSec())
  26 #define mt2ms(x) ((x) / mozilla::GetQueryPerformanceFrequencyPerSec())
  27 #define mt2ms_f(x) (double(x) / mozilla::GetQueryPerformanceFrequencyPerSec())
  28
  29 MFBT_API uint64_t GetQueryPerformanceFrequencyPerSec();
  30
  31 class TimeStamp;
  32 class TimeStampValue;
  33
  34 TimeStampValue NowInternal(bool aHighResolution);
  35
  36 class TimeStampValue {
  37   friend TimeStampValue NowInternal(bool);
  38   friend bool IsCanonicalTimeStamp(TimeStampValue);
  39   friend struct IPC::ParamTraits<mozilla::TimeStampValue>;
  40   friend class TimeStamp;
  41
  42   // Both QPC and GTC are kept in [mt] units.
  43   uint64_t mGTC;
  44   uint64_t mQPC;
  45
  46   bool mIsNull;
  47   bool mHasQPC;
  48
  49   MFBT_API TimeStampValue(uint64_t aGTC, uint64_t aQPC, bool aHasQPC);
  50
  51   MFBT_API uint64_t CheckQPC(const TimeStampValue& aOther) const;
  52
  53   // This struct is used to allow doing TimeStampValue a = 0 and similar
  54   struct _SomethingVeryRandomHere;
  55   constexpr MOZ_IMPLICIT TimeStampValue(_SomethingVeryRandomHere* aNullValue)
  56       : mGTC(0), mQPC(0), mIsNull(true), mHasQPC(false) {}
  57
  58  public:
  59   MFBT_API uint64_t operator-(const TimeStampValue& aOther) const;
  60
  61   TimeStampValue operator+(const int64_t aOther) const {
  62     return TimeStampValue(mGTC + aOther, mQPC + aOther, mHasQPC);
  63   }
  64   TimeStampValue operator-(const int64_t aOther) const {
  65     return TimeStampValue(mGTC - aOther, mQPC - aOther, mHasQPC);
  66   }
  67   MFBT_API TimeStampValue& operator+=(const int64_t aOther);
  68   MFBT_API TimeStampValue& operator-=(const int64_t aOther);
  69
  70   bool operator<(const TimeStampValue& aOther) const {
  71     return int64_t(*this - aOther) < 0;
  72   }
  73   bool operator>(const TimeStampValue& aOther) const {
  74     return int64_t(*this - aOther) > 0;
  75   }
  76   bool operator<=(const TimeStampValue& aOther) const {
  77     return int64_t(*this - aOther) <= 0;
  78   }
  79   bool operator>=(const TimeStampValue& aOther) const {
  80     return int64_t(*this - aOther) >= 0;
  81   }
  82   bool operator==(const TimeStampValue& aOther) const {
  83     return int64_t(*this - aOther) == 0;
  84   }
  85   bool operator!=(const TimeStampValue& aOther) const {
  86     return int64_t(*this - aOther) != 0;
  87   }
  88   bool IsNull() const { return mIsNull; }
  89 };
  90
  91 }  // namespace mozilla
  92
  93 #endif /* mozilla_TimeStamp_h */