dom/performance/PerformanceService.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 dom_performance_PerformanceService_h
   8 #define dom_performance_PerformanceService_h
   9
  10 #include "mozilla/TimeStamp.h"
  11 #include "nsCOMPtr.h"
  12 #include "nsDOMNavigationTiming.h"
  13
  14 namespace mozilla::dom {
  15
  16 // This class is thread-safe.
  17
  18 // We use this singleton for having the correct value of performance.timeOrigin.
  19 // This value must be calculated on top of the pair:
  20 // - mCreationTimeStamp (monotonic clock)
  21 // - mCreationEpochTime (unix epoch time)
  22 // These 2 values must be taken "at the same time" in order to be used
  23 // correctly.
  24
  25 class PerformanceService {
  26  public:
  27   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PerformanceService)
  28
  29   static PerformanceService* GetOrCreate();
  30
  31   DOMHighResTimeStamp TimeOrigin(const TimeStamp& aCreationTimeStamp) const;
  32
  33  private:
  34   PerformanceService();
  35   ~PerformanceService() = default;
  36
  37   TimeStamp mCreationTimeStamp;
  38   PRTime mCreationEpochTime;
  39 };
  40
  41 }  // namespace mozilla::dom
  42
  43 #endif  // dom_performance_PerformanceService_h