1 files changed, 162 insertions, 0 deletions
diff --git a/dom/media/webrtc/jsapi/RTCStatsReport.cpp b/dom/media/webrtc/jsapi/RTCStatsReport.cpp
new file mode 100644
index 0000000000..252dd63482
--- /dev/null
+++ b/dom/media/webrtc/jsapi/RTCStatsReport.cpp
@@ -0,0 +1,162 @@
+/* -*- 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 https://mozilla.org/MPL/2.0/. */
+
+#include "RTCStatsReport.h"
+#include "libwebrtcglue/SystemTime.h"
+#include "mozilla/dom/Performance.h"
+#include "nsRFPService.h"
+#include "WebrtcGlobal.h"
+
+namespace mozilla::dom {
+
+RTCStatsTimestampMaker::RTCStatsTimestampMaker()
+    : mRandomTimelineSeed(0),
+      mStartRealtime(WebrtcSystemTimeBase()),
+      mRTPCallerType(RTPCallerType::Normal),
+      mStartWallClockRaw(
+          PerformanceService::GetOrCreate()->TimeOrigin(mStartRealtime)) {}
+
+RTCStatsTimestampMaker::RTCStatsTimestampMaker(nsPIDOMWindowInner* aWindow)
+    : mRandomTimelineSeed(
+          aWindow && aWindow->GetPerformance()
+              ? aWindow->GetPerformance()->GetRandomTimelineSeed()
+              : 0),
+      mStartRealtime(aWindow && aWindow->GetPerformance()
+                         ? aWindow->GetPerformance()->CreationTimeStamp()
+                         : WebrtcSystemTimeBase()),
+      mRTPCallerType(aWindow && aWindow->GetPerformance()
+                         ? aWindow->GetPerformance()->GetRTPCallerType()
+                         : RTPCallerType::Normal),
+      mStartWallClockRaw(
+          PerformanceService::GetOrCreate()->TimeOrigin(mStartRealtime)) {}
+
+DOMHighResTimeStamp RTCStatsTimestampMaker::ReduceRealtimePrecision(
+    webrtc::Timestamp aRealtime) const {
+  // webrtc-pc says to use performance.timeOrigin + performance.now(), but
+  // keeping a Performance object around is difficult because it is
+  // main-thread-only. So, we perform the same calculation here. Note that this
+  // can be very different from the current wall-clock time because of changes
+  // to the wall clock, or monotonic clock drift over long periods of time.
+  // We are very careful to do exactly what Performance does, to avoid timestamp
+  // discrepancies.
+
+  DOMHighResTimeStamp realtime = aRealtime.ms<double>();
+  // mRandomTimelineSeed is not set in the unit-tests.
+  if (mRandomTimelineSeed) {
+    realtime = nsRFPService::ReduceTimePrecisionAsMSecs(
+        realtime, mRandomTimelineSeed, mRTPCallerType);
+  }
+
+  // Ugh. Performance::TimeOrigin is not constant, which means we need to
+  // emulate this weird behavior so our time stamps are consistent with JS
+  // timeOrigin. This is based on the code here:
+  // https://searchfox.org/mozilla-central/rev/
+  // 053826b10f838f77c27507e5efecc96e34718541/dom/performance/Performance.cpp#111-117
+  DOMHighResTimeStamp start = nsRFPService::ReduceTimePrecisionAsMSecs(
+      mStartWallClockRaw, 0, mRTPCallerType);
+
+  return start + realtime;
+}
+
+webrtc::Timestamp RTCStatsTimestampMaker::ConvertRealtimeTo1Jan1970(
+    webrtc::Timestamp aRealtime) const {
+  return aRealtime + webrtc::TimeDelta::Millis(mStartWallClockRaw);
+}
+
+DOMHighResTimeStamp RTCStatsTimestampMaker::ConvertNtpToDomTime(
+    webrtc::Timestamp aNtpTime) const {
+  const auto realtime = aNtpTime -
+                        webrtc::TimeDelta::Seconds(webrtc::kNtpJan1970) -
+                        webrtc::TimeDelta::Millis(mStartWallClockRaw);
+  // Ntp times exposed by libwebrtc to stats are always **rounded** to
+  // milliseconds. That means they can jump up to half a millisecond into the
+  // future. We compensate for that here so that things seem consistent to js.
+  return ReduceRealtimePrecision(realtime - webrtc::TimeDelta::Micros(500));
+}
+
+webrtc::Timestamp RTCStatsTimestampMaker::ConvertMozTimeToRealtime(
+    TimeStamp aMozTime) const {
+  return webrtc::Timestamp::Micros(
+      (aMozTime - mStartRealtime).ToMicroseconds());
+}
+
+DOMHighResTimeStamp RTCStatsTimestampMaker::GetNow() const {
+  return ReduceRealtimePrecision(GetNowRealtime());
+}
+
+webrtc::Timestamp RTCStatsTimestampMaker::GetNowRealtime() const {
+  return ConvertMozTimeToRealtime(TimeStamp::Now());
+}
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(RTCStatsReport, mParent)
+
+RTCStatsReport::RTCStatsReport(nsPIDOMWindowInner* aParent)
+    : mParent(aParent) {}
+
+/*static*/
+already_AddRefed<RTCStatsReport> RTCStatsReport::Constructor(
+    const GlobalObject& aGlobal) {
+  nsCOMPtr<nsPIDOMWindowInner> window(
+      do_QueryInterface(aGlobal.GetAsSupports()));
+  RefPtr<RTCStatsReport> report(new RTCStatsReport(window));
+  return report.forget();
+}
+
+JSObject* RTCStatsReport::WrapObject(JSContext* aCx,
+                                     JS::Handle<JSObject*> aGivenProto) {
+  return RTCStatsReport_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void RTCStatsReport::Incorporate(RTCStatsCollection& aStats) {
+  ForAllPublicRTCStatsCollectionMembers(
+      aStats, [&](auto... aMember) { (SetRTCStats(aMember), ...); });
+}
+
+void RTCStatsReport::Set(const nsAString& aKey, JS::Handle<JSObject*> aValue,
+                         ErrorResult& aRv) {
+  RTCStatsReport_Binding::MaplikeHelpers::Set(this, aKey, aValue, aRv);
+}
+
+namespace {
+template <size_t I, typename... Ts>
+bool MoveInto(std::tuple<Ts...>& aFrom, std::tuple<Ts*...>& aInto) {
+  return std::get<I>(aInto)->AppendElements(std::move(std::get<I>(aFrom)),
+                                            fallible);
+}
+
+template <size_t... Is, typename... Ts>
+bool MoveInto(std::tuple<Ts...>&& aFrom, std::tuple<Ts*...>& aInto,
+              std::index_sequence<Is...>) {
+  return (... && MoveInto<Is>(aFrom, aInto));
+}
+
+template <typename... Ts>
+bool MoveInto(std::tuple<Ts...>&& aFrom, std::tuple<Ts*...>& aInto) {
+  return MoveInto(std::move(aFrom), aInto, std::index_sequence_for<Ts...>());
+}
+}  // namespace
+
+void MergeStats(UniquePtr<RTCStatsCollection> aFromStats,
+                RTCStatsCollection* aIntoStats) {
+  auto fromTuple = ForAllRTCStatsCollectionMembers(
+      *aFromStats,
+      [&](auto&... aMember) { return std::make_tuple(std::move(aMember)...); });
+  auto intoTuple = ForAllRTCStatsCollectionMembers(
+      *aIntoStats,
+      [&](auto&... aMember) { return std::make_tuple(&aMember...); });
+  if (!MoveInto(std::move(fromTuple), intoTuple)) {
+    mozalloc_handle_oom(0);
+  }
+}
+
+void FlattenStats(nsTArray<UniquePtr<RTCStatsCollection>> aFromStats,
+                  RTCStatsCollection* aIntoStats) {
+  for (auto& stats : aFromStats) {
+    MergeStats(std::move(stats), aIntoStats);
+  }
+}
+
+}  // namespace mozilla::dom