mozglue/misc/AwakeTimeStamp.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_AwakeTimeStamp_h
   8 #define mozilla_AwakeTimeStamp_h
   9
  10 #include <stdint.h>
  11 #include <mozilla/Types.h>
  12 #include "mozilla/Assertions.h"
  13
  14 namespace mozilla {
  15
  16 class AwakeTimeDuration;
  17
  18 // Conceptually like mozilla::TimeStamp, but only increments when the device is
  19 // awake, on all platforms, and with a restricted API.
  20 //
  21 // It is always valid, there is no way to acquire an AwakeTimeStamp that is not
  22 // valid, unlike TimeStamp that can be null.
  23 //
  24 // Some arithmetic and ordering operations are supported, when they make sense.
  25 //
  26 // This timestamp shouldn't be considered to be high-resolution, and is suitable
  27 // to measure time from a hundred of milliseconds (because of Windows
  28 // limitations).
  29 class AwakeTimeStamp {
  30  public:
  31   MFBT_API static AwakeTimeStamp NowLoRes();
  32   MFBT_API void operator+=(const AwakeTimeDuration& aOther);
  33   MFBT_API void operator-=(const AwakeTimeDuration& aOther);
  34   MFBT_API bool operator<(const AwakeTimeStamp& aOther) const {
  35     return mValueUs < aOther.mValueUs;
  36   }
  37   MFBT_API bool operator<=(const AwakeTimeStamp& aOther) const {
  38     return mValueUs <= aOther.mValueUs;
  39   }
  40   MFBT_API bool operator>=(const AwakeTimeStamp& aOther) const {
  41     return mValueUs >= aOther.mValueUs;
  42   }
  43   MFBT_API bool operator>(const AwakeTimeStamp& aOther) const {
  44     return mValueUs > aOther.mValueUs;
  45   }
  46   MFBT_API bool operator==(const AwakeTimeStamp& aOther) const {
  47     return mValueUs == aOther.mValueUs;
  48   }
  49   MFBT_API bool operator!=(const AwakeTimeStamp& aOther) const {
  50     return !(*this == aOther);
  51   }
  52   MFBT_API AwakeTimeDuration operator-(AwakeTimeStamp const& aOther) const;
  53   MFBT_API AwakeTimeStamp operator+(const AwakeTimeDuration& aDuration) const;
  54
  55  private:
  56   explicit AwakeTimeStamp(uint64_t aValueUs) : mValueUs(aValueUs) {}
  57
  58   uint64_t mValueUs;
  59 };
  60
  61 // A duration, only counting the time the computer was awake.
  62 //
  63 // Can be obtained via subtracting two AwakeTimeStamp, or default-contructed to
  64 // mean a empty duration.
  65 //
  66 // Arithmetic and ordering operations are defined when they make sense.
  67 class AwakeTimeDuration {
  68  public:
  69   MFBT_API AwakeTimeDuration() : mValueUs(0) {}
  70
  71   MFBT_API double ToSeconds() const;
  72   MFBT_API double ToMilliseconds() const;
  73   MFBT_API double ToMicroseconds() const;
  74   MFBT_API void operator+=(const AwakeTimeDuration& aDuration) {
  75     mValueUs += aDuration.mValueUs;
  76   }
  77   MFBT_API AwakeTimeDuration operator+(const AwakeTimeDuration& aOther) const {
  78     return AwakeTimeDuration(mValueUs + aOther.mValueUs);
  79   }
  80   MFBT_API AwakeTimeDuration operator-(const AwakeTimeDuration& aOther) const {
  81     MOZ_ASSERT(mValueUs >= aOther.mValueUs);
  82     return AwakeTimeDuration(mValueUs - aOther.mValueUs);
  83   }
  84   MFBT_API void operator-=(const AwakeTimeDuration& aOther) {
  85     MOZ_ASSERT(mValueUs >= aOther.mValueUs);
  86     mValueUs -= aOther.mValueUs;
  87   }
  88   MFBT_API bool operator<(const AwakeTimeDuration& aOther) const {
  89     return mValueUs < aOther.mValueUs;
  90   }
  91   MFBT_API bool operator<=(const AwakeTimeDuration& aOther) const {
  92     return mValueUs <= aOther.mValueUs;
  93   }
  94   MFBT_API bool operator>=(const AwakeTimeDuration& aOther) const {
  95     return mValueUs >= aOther.mValueUs;
  96   }
  97   MFBT_API bool operator>(const AwakeTimeDuration& aOther) const {
  98     return mValueUs > aOther.mValueUs;
  99   }
 100   MFBT_API bool operator==(const AwakeTimeDuration& aOther) const {
 101     return mValueUs == aOther.mValueUs;
 102   }
 103   MFBT_API bool operator!=(const AwakeTimeDuration& aOther) const {
 104     return !(*this == aOther);
 105   }
 106
 107  private:
 108   friend AwakeTimeStamp;
 109   // Not using a default value because we want this private, but allow creating
 110   // duration that are empty.
 111   explicit AwakeTimeDuration(uint64_t aValueUs) : mValueUs(aValueUs) {}
 112
 113   uint64_t mValueUs;
 114 };
 115
 116 };  // namespace mozilla
 117
 118 #endif  // mozilla_AwakeTimeStamp_h