[tracing] Add support for TracedValue JSON serializer.

BUG=chromium:406277

Review-Url: https://codereview.chromium.org/2399463004
Cr-Commit-Position: refs/heads/master@{#40049}

BUILD.gn

@@ -1642,6 +1642,8 @@ v8_source_set("v8_base") {
     "src/strtod.h",
     "src/tracing/trace-event.cc",
     "src/tracing/trace-event.h",
+    "src/tracing/traced-value.cc",
+    "src/tracing/traced-value.h",
     "src/transitions-inl.h",
     "src/transitions.cc",
     "src/transitions.h",

src/tracing/traced-value.cc

+// 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/tracing/traced-value.h"
+
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace tracing {
+
+namespace {
+
+#define DCHECK_CURRENT_CONTAINER_IS(x) DCHECK_EQ(x, nesting_stack_.back())
+#define DCHECK_CONTAINER_STACK_DEPTH_EQ(x) DCHECK_EQ(x, nesting_stack_.size())
+#ifdef DEBUG
+const bool kStackTypeDict = false;
+const bool kStackTypeArray = true;
+#define DEBUG_PUSH_CONTAINER(x) nesting_stack_.push_back(x)
+#define DEBUG_POP_CONTAINER() nesting_stack_.pop_back()
+#else
+#define DEBUG_PUSH_CONTAINER(x) ((void)0)
+#define DEBUG_POP_CONTAINER() ((void)0)
+#endif
+
+std::string EscapeString(const std::string& value) {
+  std::string result;
+  result.reserve(value.length() + 2);
+  result += '"';
+  size_t length = value.length();
+  char number_buffer[10];
+  for (size_t src = 0; src < length; ++src) {
+    char c = value[src];
+    switch (c) {
+      case '\t':
+        result += "\\t";
+        break;
+      case '\n':
+        result += "\\n";
+        break;
+      case '\"':
+        result += "\\\"";
+        break;
+      case '\\':
+        result += "\\\\";
+        break;
+      default:
+        if (c < '\040') {
+          base::OS::SNPrintF(
+              number_buffer, arraysize(number_buffer), "\\u%04X",
+              static_cast<unsigned>(static_cast<unsigned char>(c)));
+          result += number_buffer;
+        } else {
+          result += c;
+        }
+    }
+  }
+  result += '"';
+  return result;
+}
+
+}  // namespace
+
+std::unique_ptr<TracedValue> TracedValue::Create() {
+  return std::unique_ptr<TracedValue>(new TracedValue());
+}
+
+TracedValue::TracedValue() : first_item_(true) {
+  DEBUG_PUSH_CONTAINER(kStackTypeDict);
+}
+
+TracedValue::~TracedValue() {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  DEBUG_POP_CONTAINER();
+  DCHECK_CONTAINER_STACK_DEPTH_EQ(0u);
+}
+
+void TracedValue::SetInteger(const char* name, int value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  WriteName(name);
+  data_ += std::to_string(value);
+}
+
+void TracedValue::SetDouble(const char* name, double value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  WriteName(name);
+  data_ += std::to_string(value);
+}
+
+void TracedValue::SetBoolean(const char* name, bool value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  WriteName(name);
+  data_ += value ? "true" : "false";
+}
+
+void TracedValue::SetString(const char* name, const std::string& value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  WriteName(name);
+  data_ += EscapeString(value);
+}
+
+void TracedValue::BeginDictionary(const char* name) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  DEBUG_PUSH_CONTAINER(kStackTypeDict);
+  WriteName(name);
+  data_ += '{';
+  first_item_ = true;
+}
+
+void TracedValue::BeginArray(const char* name) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  DEBUG_PUSH_CONTAINER(kStackTypeArray);
+  WriteName(name);
+  data_ += '[';
+  first_item_ = true;
+}
+
+void TracedValue::AppendInteger(int value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  WriteComma();
+  data_ += std::to_string(value);
+}
+
+void TracedValue::AppendDouble(double value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  WriteComma();
+  data_ += std::to_string(value);
+}
+
+void TracedValue::AppendBoolean(bool value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  WriteComma();
+  data_ += value ? "true" : "false";
+}
+
+void TracedValue::AppendString(const std::string& value) {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  WriteComma();
+  data_ += EscapeString(value);
+}
+
+void TracedValue::BeginDictionary() {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  DEBUG_PUSH_CONTAINER(kStackTypeDict);
+  WriteComma();
+  data_ += '{';
+  first_item_ = true;
+}
+
+void TracedValue::BeginArray() {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  DEBUG_PUSH_CONTAINER(kStackTypeArray);
+  WriteComma();
+  data_ += '[';
+  first_item_ = true;
+}
+
+void TracedValue::EndDictionary() {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeDict);
+  DEBUG_POP_CONTAINER();
+  data_ += '}';
+  first_item_ = false;
+}
+
+void TracedValue::EndArray() {
+  DCHECK_CURRENT_CONTAINER_IS(kStackTypeArray);
+  DEBUG_POP_CONTAINER();
+  data_ += ']';
+  first_item_ = false;
+}
+
+void TracedValue::WriteComma() {
+  if (first_item_) {
+    first_item_ = false;
+  } else {
+    data_ += ',';
+  }
+}
+
+void TracedValue::WriteName(const char* name) {
+  WriteComma();
+  data_ += '"';
+  data_ += name;
+  data_ += "\":";
+}
+
+void TracedValue::AppendAsTraceFormat(std::string* out) const {
+  *out += '{';
+  *out += data_;
+  *out += '}';
+}
+
+}  // namespace tracing
+}  // namespace v8

src/tracing/traced-value.h

+// 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.
+
+#ifndef V8_TRACING_TRACED_VALUE_H_
+#define V8_TRACING_TRACED_VALUE_H_
+
+#include <stddef.h>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "include/v8-platform.h"
+#include "src/base/macros.h"
+
+namespace v8 {
+namespace tracing {
+
+class TracedValue : public ConvertableToTraceFormat {
+ public:
+  ~TracedValue() override;
+
+  static std::unique_ptr<TracedValue> Create();
+
+  void EndDictionary();
+  void EndArray();
+
+  // These methods assume that |name| is a long lived "quoted" string.
+  void SetInteger(const char* name, int value);
+  void SetDouble(const char* name, double value);
+  void SetBoolean(const char* name, bool value);
+  void SetString(const char* name, const std::string& value);
+  void BeginDictionary(const char* name);
+  void BeginArray(const char* name);
+
+  void AppendInteger(int);
+  void AppendDouble(double);
+  void AppendBoolean(bool);
+  void AppendString(const std::string&);
+  void BeginArray();
+  void BeginDictionary();
+
+  // ConvertableToTraceFormat implementation.
+  void AppendAsTraceFormat(std::string* out) const override;
+
+ private:
+  TracedValue();
+
+  void WriteComma();
+  void WriteName(const char* name);
+
+#ifdef DEBUG
+  // In debug builds checks the pairings of {Begin,End}{Dictionary,Array}
+  std::vector<bool> nesting_stack_;
+#endif
+
+  std::string data_;
+  bool first_item_;
+
+  DISALLOW_COPY_AND_ASSIGN(TracedValue);
+};
+
+}  // namespace tracing
+}  // namespace v8
+
+#endif  // V8_TRACING_TRACED_VALUE_H_

src/v8.gyp

@@ -1212,6 +1212,8 @@
         'ic/stub-cache.h',
         'tracing/trace-event.cc',
         'tracing/trace-event.h',
+        'tracing/traced-value.cc',
+        'tracing/traced-value.h',
         'transitions-inl.h',
         'transitions.cc',
         'transitions.h',

test/cctest/BUILD.gn

@@ -166,6 +166,7 @@ v8_executable("cctest") {
     "test-thread-termination.cc",
     "test-threads.cc",
     "test-trace-event.cc",
+    "test-traced-value.cc",
     "test-transitions.cc",
     "test-typedarrays.cc",
     "test-types.cc",

test/cctest/cctest.gyp

@@ -186,6 +186,7 @@
       'test-thread-termination.cc',
       'test-threads.cc',
       'test-trace-event.cc',
+      'test-traced-value.cc',
       'test-transitions.cc',
       'test-typedarrays.cc',
       'test-ast-types.cc',

test/cctest/test-traced-value.cc

+// 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/tracing/traced-value.h"
+#include "test/cctest/cctest.h"
+
+using v8::tracing::TracedValue;
+
+TEST(FlatDictionary) {
+  auto value = TracedValue::Create();
+  value->SetInteger("int", 2014);
+  value->SetDouble("double", 0.0);
+  value->SetBoolean("bool", true);
+  value->SetString("string", "string");
+  std::string json = "PREFIX";
+  value->AppendAsTraceFormat(&json);
+  CHECK_EQ(
+      "PREFIX{\"int\":2014,\"double\":0.000000,\"bool\":true,\"string\":"
+      "\"string\"}",
+      json);
+}
+
+TEST(NoDotPathExpansion) {
+  auto value = TracedValue::Create();
+  value->SetInteger("in.t", 2014);
+  value->SetDouble("doub.le", 0.0);
+  value->SetBoolean("bo.ol", true);
+  value->SetString("str.ing", "str.ing");
+  std::string json;
+  value->AppendAsTraceFormat(&json);
+  CHECK_EQ(
+      "{\"in.t\":2014,\"doub.le\":0.000000,\"bo.ol\":true,\"str.ing\":\"str."
+      "ing\"}",
+      json);
+}
+
+TEST(Hierarchy) {
+  auto value = TracedValue::Create();
+  value->SetInteger("i0", 2014);
+  value->BeginDictionary("dict1");
+  value->SetInteger("i1", 2014);
+  value->BeginDictionary("dict2");
+  value->SetBoolean("b2", false);
+  value->EndDictionary();
+  value->SetString("s1", "foo");
+  value->EndDictionary();
+  value->SetDouble("d0", 0.0);
+  value->SetBoolean("b0", true);
+  value->BeginArray("a1");
+  value->AppendInteger(1);
+  value->AppendBoolean(true);
+  value->BeginDictionary();
+  value->SetInteger("i2", 3);
+  value->EndDictionary();
+  value->EndArray();
+  value->SetString("s0", "foo");
+
+  value->BeginArray("arr1");
+  value->BeginDictionary();
+  value->EndDictionary();
+  value->BeginArray();
+  value->EndArray();
+  value->BeginDictionary();
+  value->EndDictionary();
+  value->EndArray();
+
+  std::string json;
+  value->AppendAsTraceFormat(&json);
+  CHECK_EQ(
+      "{\"i0\":2014,\"dict1\":{\"i1\":2014,\"dict2\":{\"b2\":false},"
+      "\"s1\":\"foo\"},\"d0\":0.000000,\"b0\":true,\"a1\":[1,true,{\"i2\":3}],"
+      "\"s0\":\"foo\",\"arr1\":[{},[],{}]}",
+      json);
+}
+
+TEST(LongStrings) {
+  std::string long_string = "supercalifragilisticexpialidocious";
+  std::string long_string2 = "0123456789012345678901234567890123456789";
+  char long_string3[4096];
+  for (size_t i = 0; i < sizeof(long_string3); ++i)
+    long_string3[i] = static_cast<char>('a' + (i % 26));
+  long_string3[sizeof(long_string3) - 1] = '\0';
+
+  auto value = TracedValue::Create();
+  value->SetString("a", "short");
+  value->SetString("b", long_string);
+  value->BeginArray("c");
+  value->AppendString(long_string2);
+  value->AppendString("");
+  value->BeginDictionary();
+  value->SetString("a", long_string3);
+  value->EndDictionary();
+  value->EndArray();
+
+  std::string json;
+  value->AppendAsTraceFormat(&json);
+  CHECK_EQ("{\"a\":\"short\",\"b\":\"" + long_string + "\",\"c\":[\"" +
+               long_string2 + "\",\"\",{\"a\":\"" + long_string3 + "\"}]}",
+           json);
+}
+
+TEST(Escaping) {
+  const char* string1 = "abc\"\'\\\\x\"y\'z\n\x09\x17";
+  std::string chars127;
+  for (int i = 1; i <= 127; ++i) {
+    chars127 += static_cast<char>(i);
+  }
+  auto value = TracedValue::Create();
+  value->SetString("a", string1);
+  value->SetString("b", chars127);
+
+  std::string json;
+  value->AppendAsTraceFormat(&json);
+  // Cannot use the expected value literal directly in CHECK_EQ
+  // as it fails to process # character on Windows.
+  const char* expected =
+      "{\"a\":\"abc\\\"\'\\\\\\\\x\\\"y\'z\\n\\t\\u0017\",\"b\":"
+      "\"\\u0001\\u0002\\u0003\\u0004\\u0005\\u0006\\u0007\\u0008\\t\\n\\u000B"
+      "\\u000C\\u000D\\u000E\\u000F\\u0010\\u0011\\u0012\\u0013\\u0014\\u0015\\"
+      "u0016\\u0017\\u0018\\u0019\\u001A\\u001B\\u001C\\u001D\\u001E\\u001F "
+      "!\\\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_`"
+      "abcdefghijklmnopqrstuvwxyz{|}~\177\"}";
+  CHECK_EQ(expected, json);
+}