[Tracing] V8 Tracing Controller

src/libplatform/tracing/trace-writer.cc

Index: src/libplatform/tracing/trace-writer.cc
diff --git a/src/libplatform/tracing/trace-writer.cc b/src/libplatform/tracing/trace-writer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..464b5713fc2b69b6076f43b7cd40ef0ad7e8dd50
--- /dev/null
+++ b/src/libplatform/tracing/trace-writer.cc
@@ -0,0 +1,57 @@
+// Copyright 2016 the V8 project 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 "src/libplatform/tracing/trace-writer.h"
+
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace platform {
+namespace tracing {
+
+JSONTraceWriter::JSONTraceWriter(std::ostream& stream) : stream_(stream) {
+  stream_ << "{\"traceEvents\":[";
+}
+
+JSONTraceWriter::~JSONTraceWriter() { stream_ << "]}"; }
+
+void JSONTraceWriter::AppendTraceEvent(TraceObject* trace_event) {
+  if (append_comma_) stream_ << ",";
+  append_comma_ = true;
+  if (trace_event->scope() == NULL) {
+    stream_ << "{\"pid\":" << trace_event->pid()
+            << ",\"tid\":" << trace_event->tid()
+            << ",\"ts\":" << trace_event->ts()
+            << ",\"tts\":" << trace_event->tts() << ",\"ph\":\""
+            << trace_event->phase() << "\",\"cat\":\""
+            << TracingController::GetCategoryGroupName(
+                   trace_event->category_enabled_flag())
+            << "\",\"name\":\"" << trace_event->name()
+            << "\",\"args\":{},\"dur\":" << trace_event->duration()
+            << ",\"tdur\":" << trace_event->cpu_duration() << "}";
+  } else {
+    stream_ << "{\"pid\":" << trace_event->pid()
+            << ",\"tid\":" << trace_event->tid()
+            << ",\"ts\":" << trace_event->ts()
+            << ",\"tts\":" << trace_event->tts() << ",\"ph\":\""
+            << trace_event->phase() << "\",\"cat\":\""
+            << TracingController::GetCategoryGroupName(
+                   trace_event->category_enabled_flag())
+            << "\",\"name\":\"" << trace_event->name() << "\",\"scope\":\""
+            << trace_event->scope()
+            << "\",\"args\":{},\"dur\":" << trace_event->duration()
+            << ",\"tdur\":" << trace_event->cpu_duration() << "}";
+  }
+  // TODO(fmeawad): Add support for Flow Events.
+}
+
+void JSONTraceWriter::Flush() {}
+
+TraceWriter* TraceWriter::CreateJSONTraceWriter(std::ostream& stream) {
+  return new JSONTraceWriter(stream);
+}
+
+}  // namespace tracing
+}  // namespace platform
+}  // namespace v8