Bug 1313420 - Implement Performance.timeOrigin - part 1

https://hg.mozilla.org/mozilla-central/rev/cf0f72f0b0be

1 files changed, 48 insertions, 0 deletions

diff --git a/dom/performance/PerformanceService.h b/dom/performance/PerformanceService.h
new file mode 100644
index 000000000..9abbd674d
--- /dev/null
+++ b/dom/performance/PerformanceService.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef dom_performance_PerformanceService_h
+#define dom_performance_PerformanceService_h
+
+#include "mozilla/TimeStamp.h"
+#include "nsCOMPtr.h"
+#include "nsDOMNavigationTiming.h"
+
+namespace mozilla {
+namespace dom {
+
+// This class is thread-safe.
+
+// We use this singleton for having the correct value of performance.timeOrigin.
+// This value must be calculated on top of the pair:
+// - mCreationTimeStamp (monotonic clock)
+// - mCreationEpochTime (unix epoch time)
+// These 2 values must be taken "at the same time" in order to be used
+// correctly.
+
+class PerformanceService
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PerformanceService)
+
+  static PerformanceService*
+  GetOrCreate();
+
+  DOMHighResTimeStamp
+  TimeOrigin(const TimeStamp& aCreationTimeStamp) const;
+
+private:
+  PerformanceService();
+  ~PerformanceService() = default;
+
+  TimeStamp mCreationTimeStamp;
+  PRTime mCreationEpochTime;
+};
+
+} // dom namespace
+} // mozilla namespace
+
+#endif // dom_performance_PerformanceService_h