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 class TimeStampValueTests;
  34 class TimeStampTests;
  35
  36 TimeStampValue NowInternal(bool aHighResolution);
  37
  38 class TimeStampValue {
  39   friend TimeStampValue NowInternal(bool);
  40   friend bool IsCanonicalTimeStamp(TimeStampValue);
  41   friend struct IPC::ParamTraits<mozilla::TimeStampValue>;
  42   friend class TimeStamp;
  43   friend class TimeStampValueTests;
  44   friend class TimeStampTests;
  45
  46   // Both QPC and GTC are kept in [mt] units.
  47   uint64_t mGTC;
  48   uint64_t mQPC;
  49
  50   bool mIsNull;
  51   bool mHasQPC;
  52
  53   constexpr MFBT_API TimeStampValue(uint64_t aGTC, uint64_t aQPC, bool aHasQPC)
  54       : mGTC(aGTC),
  55         mQPC(aQPC),
  56         mIsNull(aGTC == 0 && aQPC == 0),
  57         mHasQPC(aHasQPC) {}
  58
  59   // This constructor should be explicit but it is replacing a constructor that
  60   // was MOZ_IMPLICIT and there are many locations that are using the automatic
  61   // conversion.
  62   constexpr MOZ_IMPLICIT MFBT_API TimeStampValue(uint64_t aGTCAndQPC)
  63       : TimeStampValue(aGTCAndQPC, aGTCAndQPC, true) {}
  64
  65   MFBT_API uint64_t CheckQPC(const TimeStampValue& aOther) const;
  66
  67  public:
  68   MFBT_API uint64_t operator-(const TimeStampValue& aOther) const;
  69
  70   TimeStampValue operator+(const int64_t aOther) const {
  71     return TimeStampValue(mGTC + aOther, mQPC + aOther, mHasQPC);
  72   }
  73   TimeStampValue operator-(const int64_t aOther) const {
  74     return TimeStampValue(mGTC - aOther, mQPC - aOther, mHasQPC);
  75   }
  76   MFBT_API TimeStampValue& operator+=(const int64_t aOther);
  77   MFBT_API TimeStampValue& operator-=(const int64_t aOther);
  78
  79   constexpr bool operator<(const TimeStampValue& aOther) const {
  80     return mHasQPC && aOther.mHasQPC ? mQPC < aOther.mQPC : mGTC < aOther.mGTC;
  81   }
  82   constexpr bool operator>(const TimeStampValue& aOther) const {
  83     return mHasQPC && aOther.mHasQPC ? mQPC > aOther.mQPC : mGTC > aOther.mGTC;
  84   }
  85   constexpr bool operator<=(const TimeStampValue& aOther) const {
  86     return mHasQPC && aOther.mHasQPC ? mQPC <= aOther.mQPC
  87                                      : mGTC <= aOther.mGTC;
  88   }
  89   constexpr bool operator>=(const TimeStampValue& aOther) const {
  90     return mHasQPC && aOther.mHasQPC ? mQPC >= aOther.mQPC
  91                                      : mGTC >= aOther.mGTC;
  92   }
  93   constexpr bool operator==(const TimeStampValue& aOther) const {
  94     return mHasQPC && aOther.mHasQPC ? mQPC == aOther.mQPC
  95                                      : mGTC == aOther.mGTC;
  96   }
  97   constexpr bool operator!=(const TimeStampValue& aOther) const {
  98     return mHasQPC && aOther.mHasQPC ? mQPC != aOther.mQPC
  99                                      : mGTC != aOther.mGTC;
 100   }
 101   constexpr bool IsNull() const { return mIsNull; }
 102
 103 #if defined(DEBUG)
 104   uint64_t GTC() const { return mGTC; }
 105   uint64_t QPC() const { return mQPC; }
 106
 107   bool HasQPC() const { return mHasQPC; }
 108 #endif
 109 };
 110
 111 }  // namespace mozilla
 112
 113 #endif /* mozilla_TimeStamp_h */