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 {
  15 namespace dom {
  16
  17 // This class is thread-safe.
  18
  19 // We use this singleton for having the correct value of performance.timeOrigin.
  20 // This value must be calculated on top of the pair:
  21 // - mCreationTimeStamp (monotonic clock)
  22 // - mCreationEpochTime (unix epoch time)
  23 // These 2 values must be taken "at the same time" in order to be used
  24 // correctly.
  25
  26 class PerformanceService {
  27  public:
  28   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PerformanceService)
  29
  30   static PerformanceService* GetOrCreate();
  31
  32   DOMHighResTimeStamp TimeOrigin(const TimeStamp& aCreationTimeStamp) const;
  33
  34  private:
  35   PerformanceService();
  36   ~PerformanceService() = default;
  37
  38   TimeStamp mCreationTimeStamp;
  39   PRTime mCreationEpochTime;
  40 };
  41
  42 }  // namespace dom
  43 }  // namespace mozilla
  44
  45 #endif  // dom_performance_PerformanceService_h