Tracing V2 prototype [NOT FOR REVIEW]

base/trace_event/v2/trace_event.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/v2/trace_event.h"
+
+#include "base/logging.h"
+
+namespace base {
+namespace trace_event {
+namespace v2 {
+
+TraceEvent::TraceEvent() : handle_(nullptr) {}
+
+TraceEvent::~TraceEvent() {
+  // TODO this (and all the = nullptr) should be only on DCHECK_IS_ON or debug.
+  if (handle_)
+    handle_->event_ = nullptr;
+}
+
+TraceEventHandle::TraceEventHandle() : event_(nullptr) {}
+
+TraceEventHandle::TraceEventHandle(TraceEvent* event) : event_(event) {
+  event_->set_event_handle(this);
+}
+
+TraceEventHandle::~TraceEventHandle() {
+  if (event_) {
+    event_->Finalize();
+    event_->set_event_handle(nullptr);
+  }
+}
+
+TraceEventHandle::TraceEventHandle(TraceEventHandle&& other) {
+  Swap(&other);
+}
+
+TraceEventHandle& TraceEventHandle::operator=(TraceEventHandle&& other) {
+  Swap(&other);
+  return *this;
+}
+
+void TraceEventHandle::Swap(TraceEventHandle* other) {
+  if (event_) {
+    event_->Finalize();
+    event_->set_event_handle(nullptr);
+  }
+  event_ = other->event_;
+  other->event_ = nullptr;
+  event_->set_event_handle(this);
+}
+
+}  // namespace v2
+}  // namespace trace_event
+}  // namespace base