xpcom/base/MemoryPressureLevelMac.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_MemoryPressureLevelMac_h
   8 #define mozilla_MemoryPressureLevelMac_h
   9
  10 namespace mozilla {
  11
  12 #if defined(XP_DARWIN)
  13 // An internal representation of the Mac memory-pressure level constants.
  14 class MacMemoryPressureLevel {
  15  public:
  16   // Order enum values so that higher integer values represent higher
  17   // memory pressure levels allowing comparison operators to be used.
  18   enum class Value {
  19     eUnset,
  20     eUnexpected,
  21     eNormal,
  22     eWarning,
  23     eCritical,
  24   };
  25
  26   MacMemoryPressureLevel() : mValue(Value::eUnset) {}
  27   MOZ_IMPLICIT MacMemoryPressureLevel(Value aValue) : mValue(aValue) {}
  28
  29   bool operator==(const Value& aRhsValue) const { return mValue == aRhsValue; }
  30   bool operator==(const MacMemoryPressureLevel& aRhs) const {
  31     return mValue == aRhs.mValue;
  32   }
  33
  34   // Implement '<' and derive the other comparators from it.
  35   bool operator<(const MacMemoryPressureLevel& aRhs) const {
  36     return mValue < aRhs.mValue;
  37   }
  38   bool operator>(const MacMemoryPressureLevel& aRhs) const {
  39     return aRhs < *this;
  40   }
  41   bool operator<=(const MacMemoryPressureLevel& aRhs) const {
  42     return !(aRhs < *this);
  43   }
  44   bool operator>=(const MacMemoryPressureLevel& aRhs) const {
  45     return !(*this < aRhs);
  46   }
  47
  48   Value GetValue() { return mValue; }
  49   bool IsNormal() { return mValue == Value::eNormal; }
  50   bool IsUnsetOrNormal() { return IsNormal() || (mValue == Value::eUnset); }
  51   bool IsWarningOrAbove() {
  52     return (mValue == Value::eWarning) || (mValue == Value::eCritical);
  53   }
  54
  55   const char* ToString() {
  56     switch (mValue) {
  57       case Value::eUnset:
  58         return "Unset";
  59       case Value::eUnexpected:
  60         return "Unexpected";
  61       case Value::eNormal:
  62         return "Normal";
  63       case Value::eWarning:
  64         return "Warning";
  65       case Value::eCritical:
  66         return "Critical";
  67     }
  68   }
  69
  70  private:
  71   Value mValue;
  72 };
  73 #endif
  74
  75 }  // namespace mozilla
  76
  77 #endif  // mozilla_MemoryPressureLevelMac_h