1 files changed, 60 insertions, 0 deletions
diff --git a/dom/media/webrtc/libwebrtcglue/SystemTime.cpp b/dom/media/webrtc/libwebrtcglue/SystemTime.cpp
new file mode 100644
index 0000000000..bba7fd788e
--- /dev/null
+++ b/dom/media/webrtc/libwebrtcglue/SystemTime.cpp
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#include "SystemTime.h"
+
+#include "TimeUnits.h"
+
+namespace mozilla {
+
+// webrtc::Timestamp may not be negative. `now-base` for the first call to
+// WebrtcSystemTime() is always 0, which makes it impossible for libwebrtc
+// code to calculate a timestamp older than the first one returned. This
+// offset makes sure the clock starts at a value equivalent to roughly 4.5h.
+static constexpr webrtc::TimeDelta kWebrtcTimeOffset =
+    webrtc::TimeDelta::Micros(0x10000000);
+
+RTCStatsTimestampMakerRealtimeClock::RTCStatsTimestampMakerRealtimeClock(
+    const dom::RTCStatsTimestampMaker& aTimestampMaker)
+    : mTimestampMaker(aTimestampMaker) {}
+
+webrtc::Timestamp RTCStatsTimestampMakerRealtimeClock::CurrentTime() {
+  return mTimestampMaker.GetNow().ToRealtime();
+}
+
+webrtc::NtpTime RTCStatsTimestampMakerRealtimeClock::ConvertTimestampToNtpTime(
+    webrtc::Timestamp aRealtime) {
+  return CreateNtp(
+      dom::RTCStatsTimestamp::FromRealtime(mTimestampMaker, aRealtime).ToNtp());
+}
+
+TimeStamp WebrtcSystemTimeBase() {
+  static TimeStamp now = TimeStamp::Now();
+  return now;
+}
+
+webrtc::Timestamp WebrtcSystemTime() {
+  const TimeStamp base = WebrtcSystemTimeBase();
+  const TimeStamp now = TimeStamp::Now();
+  return webrtc::Timestamp::Micros((now - base).ToMicroseconds()) +
+         kWebrtcTimeOffset;
+}
+
+webrtc::NtpTime CreateNtp(webrtc::Timestamp aTime) {
+  const int64_t timeNtpUs = aTime.us();
+  const uint32_t seconds = static_cast<uint32_t>(timeNtpUs / USECS_PER_S);
+
+  constexpr int64_t fractionsPerSec = 1LL << 32;
+  const int64_t fractionsUs = timeNtpUs % USECS_PER_S;
+  const uint32_t fractions = (fractionsUs * fractionsPerSec) / USECS_PER_S;
+
+  return webrtc::NtpTime(seconds, fractions);
+}
+}  // namespace mozilla
+
+namespace rtc {
+int64_t SystemTimeNanos() { return mozilla::WebrtcSystemTime().us() * 1000; }
+}  // namespace rtc