Add builders for tracing event's structural arguments

base/debug/trace_event_argument.cc

Index: base/debug/trace_event_argument.cc
diff --git a/base/debug/trace_event_argument.cc b/base/debug/trace_event_argument.cc
new file mode 100644
index 0000000000000000000000000000000000000000..90e924f119e84352f79945360407219518e3f470
--- /dev/null
+++ b/base/debug/trace_event_argument.cc
@@ -0,0 +1,117 @@
+// Copyright (c) 2014 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/debug/trace_event_argument.h"
+
+#include "base/json/json_writer.h"
+#include "base/values.h"
+
+namespace base {
+namespace debug {
+
+TracedValue::TracedValue() : root_(new DictionaryValue()) {
+  stack_.push_back(root_.get());
+}
+
+TracedValue::~TracedValue() {
+  DCHECK_EQ(1u, stack_.size());
+}
+
+void TracedValue::SetInteger(const char* name, int value) {
+  GetCurrentDictionary()->SetInteger(name, value);
+}
+
+void TracedValue::SetDouble(const char* name, double value) {
+  GetCurrentDictionary()->SetDouble(name, value);
+}
+
+void TracedValue::SetBoolean(const char* name, bool value) {
+  GetCurrentDictionary()->SetBoolean(name, value);
+}
+
+void TracedValue::SetString(const char* name, const std::string& value) {
+  GetCurrentDictionary()->SetString(name, value);
+}
+
+void TracedValue::SetValue(const char* name, Value* value) {
+  GetCurrentDictionary()->Set(name, value);
+}
+
+void TracedValue::BeginDictionary(const char* name) {
+  DictionaryValue* dictionary = new DictionaryValue();
+  GetCurrentDictionary()->Set(name, dictionary);
+  stack_.push_back(dictionary);
+}
+
+void TracedValue::BeginArray(const char* name) {
+  ListValue* array = new ListValue();
+  GetCurrentDictionary()->Set(name, array);
+  stack_.push_back(array);
+}
+
+void TracedValue::EndDictionary() {
+  DCHECK_GT(stack_.size(), 1u);
+  DCHECK(GetCurrentDictionary());
+  stack_.pop_back();
+}
+
+void TracedValue::AppendInteger(int value) {
+  GetCurrentArray()->AppendInteger(value);
+}
+
+void TracedValue::AppendDouble(double value) {
+  GetCurrentArray()->AppendDouble(value);
+}
+
+void TracedValue::AppendBoolean(bool value) {
+  GetCurrentArray()->AppendBoolean(value);
+}
+
+void TracedValue::AppendString(const std::string& value) {
+  GetCurrentArray()->AppendString(value);
+}
+
+void TracedValue::BeginArray() {
+  ListValue* array = new ListValue();
+  GetCurrentArray()->Append(array);
+  stack_.push_back(array);
+}
+
+void TracedValue::BeginDictionary() {
+  DictionaryValue* dictionary = new DictionaryValue();
+  GetCurrentArray()->Append(dictionary);
+  stack_.push_back(dictionary);
+}
+
+void TracedValue::EndArray() {
+  DCHECK_GT(stack_.size(), 1u);
+  DCHECK(GetCurrentArray());
+  stack_.pop_back();
+}
+
+DictionaryValue* TracedValue::GetCurrentDictionary() {
+  DCHECK(!stack_.empty());
+  DictionaryValue* dictionary = NULL;
+  stack_.back()->GetAsDictionary(&dictionary);
+  DCHECK(dictionary);
+  return dictionary;
+}
+
+ListValue* TracedValue::GetCurrentArray() {
+  DCHECK(!stack_.empty());
+  ListValue* list = NULL;
+  stack_.back()->GetAsList(&list);
+  DCHECK(list);
+  return list;
+}
+
+void TracedValue::AppendAsTraceFormat(std::string* out) const {
+  std::string tmp;
+  JSONWriter::Write(stack_.front(), &tmp);
+  *out += tmp;
+  DCHECK_EQ(1u, stack_.size()) << tmp;
+}
+
+}  // namespace debug
+}  // namespace base