1 files changed, 43 insertions, 0 deletions
diff --git a/js/ipc/CPOWTimer.cpp b/js/ipc/CPOWTimer.cpp
new file mode 100644
index 000000000..4f2add7f5
--- /dev/null
+++ b/js/ipc/CPOWTimer.cpp
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=4 sw=4 et 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/. */
+
+#include "jsfriendapi.h"
+#include "nsContentUtils.h"
+#include "CPOWTimer.h"
+
+#include "jsapi.h"
+
+CPOWTimer::CPOWTimer(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL)
+    : cx_(nullptr)
+    , startInterval_(0)
+{
+    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+    if (!js::GetStopwatchIsMonitoringCPOW(cx))
+        return;
+    cx_ = cx;
+    startInterval_ = JS_Now();
+}
+CPOWTimer::~CPOWTimer()
+{
+    if (!cx_) {
+        // Monitoring was off when we started the timer.
+        return;
+    }
+
+    if (!js::GetStopwatchIsMonitoringCPOW(cx_)) {
+        // Monitoring has been deactivated while we were in the timer.
+        return;
+    }
+
+    const int64_t endInterval = JS_Now();
+    if (endInterval <= startInterval_) {
+        // Do not assume monotonicity.
+        return;
+    }
+
+    js::AddCPOWPerformanceDelta(cx_, endInterval - startInterval_);
+}