Generate the proto JSON converter for DOM distiller

third_party/dom_distiller_js/protoc_plugins/json_values_converter.py

+#!/usr/bin/env python
+# 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.
+
+"""protoc plugin to create C++ reader/writer for JSON-encoded protobufs
+
+The reader/writer use Chrome's base::Values.
+"""
+
+import optparse
+import os
+
+from util import plugin, plugin_protos, writer
+from util.plugin import Indented
+
+class CppConverterWriter(writer.CodeWriter):
+  def WriteProtoFile(self, proto_file, output_dir):
+    err = proto_file.CheckSupported()
+    if err:
+      self.AddError(err)
+      return
+
+    self.WriteCStyleHeader()
+
+    self.Output('#include "{output_dir}{generated_pb_h}"',
+                output_dir=output_dir + '/' if output_dir else '',
+                generated_pb_h=proto_file.CppBaseHeader())
+    self.Output('')
+
+    # import is not supported
+    assert [] == proto_file.GetDependencies()
+
+    self.Output('// base dependencies')
+    self.Output('#include "base/values.h"')
+    self.Output('')
+    self.Output('#include <memory>')
+    self.Output('#include <string>')
+    self.Output('#include <utility>')
+    self.Output('')
+
+    namespaces = proto_file.ProtoNamespaces() + ['json']
+    for name in namespaces:
+      self.Output('namespace {name} {{', name=name)
+      self.IncreaseIndent()
+
+    for message in proto_file.GetMessages():
+      self.WriteMessage(message)
+
+    # Nothing to do for enums
+
+    for name in namespaces:
+      self.DecreaseIndent()
+      self.Output('}}')
+
+  def WriteMessage(self, message):
+    self.Output('class {class_name} {{',
+                class_name=message.CppConverterClassName())
+    self.Output(' public:')
+    with self.AddIndent():
+      for nested_class in message.GetMessages():
+        self.WriteMessage(nested_class)
+
+      generated_class_name = message.QualifiedTypes().cpp_base
+      # Nothing to write for enums.
+
+      self.Output(
+          'static bool ReadFromValue(const base::Value* json, {generated_class_name}* message) {{\n'
+          #'  {generated_class_name} message;\n'
+          '  const base::DictionaryValue* dict;\n'
+          '  if (!json->GetAsDictionary(&dict)) goto error;\n'
+          '',
+          generated_class_name=generated_class_name)
+
+      with self.AddIndent():
+        for field_proto in message.GetFields():
+          self.WriteFieldRead(field_proto)
+
+      self.Output(
+          '  return true;\n'
+          '\n'
+          'error:\n'
+          '  return false;\n'
+          '}}\n'
+          '\n'
+          'static std::unique_ptr<base::DictionaryValue> WriteToValue(const {generated_class_name}& message) {{\n'
+          '  std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());\n'
+          '',
+          generated_class_name=generated_class_name)
+
+      with self.AddIndent():
+        for field_proto in message.GetFields():
+          self.FieldWriteToValue(field_proto)
+
+      self.Output(
+          '  return dict;\n'
+          '',
+          generated_class_name=generated_class_name)
+      self.Output('}}')
+
+    self.Output('}};')
+    self.Output('')
+
+  def FieldWriteToValue(self, field):
+    if field.IsRepeated():
+      self.Output('{{')
+    else:
+      self.Output('if (message.has_{field_name}()) {{\n', field_name=field.name)
+
+    with self.AddIndent():
+      if field.IsRepeated():
+        self.RepeatedMemberFieldWriteToValue(field)
+      else:
+        self.OptionalMemberFieldWriteToValue(field)
+
+    self.Output('}}')
+
+  def RepeatedMemberFieldWriteToValue(self, field):
+    prologue = (
+        'base::ListValue* field_list = new base::ListValue();\n'
+        'dict->Set("{field_number}", field_list);\n'
+        'for (int i = 0; i < message.{field_name}_size(); ++i) {{\n'
+        )
+
+    if field.IsClassType():
+      middle = (
+          'std::unique_ptr<base::Value> inner_message_value = \n'
+          '    {inner_class_converter}::WriteToValue(message.{field_name}(i));\n'
+          'field_list->Append(std::move(inner_message_value));\n'
+          )
+    else:
+      middle = (
+          'field_list->Append{value_type}(message.{field_name}(i));\n'
+          )
+    self.Output(
+        prologue + Indented(middle) + '\n}}',
+        field_number=field.JavascriptIndex(),
+        field_name=field.name,
+        value_type=field.CppValueType() if not field.IsClassType() else None,
+        inner_class_converter=field.CppConverterType()
+        )
+
+  def OptionalMemberFieldWriteToValue(self, field):
+    if field.IsClassType():
+      body = (
+          'std::unique_ptr<base::Value> inner_message_value = \n'
+          '    {inner_class_converter}::WriteToValue(message.{field_name}());\n'
+          'dict->Set("{field_number}", std::move(inner_message_value));\n'
+          )
+    else:
+      body = (
+          'dict->Set{value_type}("{field_number}", message.{field_name}());\n'
+          )
+
+    self.Output(
+        body,
+        field_number=field.JavascriptIndex(),
+        field_name=field.name,
+        value_type=field.CppValueType() if not field.IsClassType() else None,
+        inner_class_converter=field.CppConverterType(),
+        )
+
+  def WriteFieldRead(self, field):
+    self.Output('if (dict->HasKey("{field_number}")) {{',
+                field_number=field.JavascriptIndex())
+
+    with self.AddIndent():
+      if field.IsRepeated():
+        self.RepeatedMemberFieldRead(field)
+      else:
+        self.OptionalMemberFieldRead(field)
+
+    self.Output('}}')
+
+  def RepeatedMemberFieldRead(self, field):
+    prologue = (
+        'const base::ListValue* field_list;\n'
+        'if (!dict->GetList("{field_number}", &field_list)) {{\n'
+        '  goto error;\n'
+        '}}\n'
+        'for (size_t i = 0; i < field_list->GetSize(); ++i) {{\n'
+        )
+
+    if field.IsClassType():
+      middle = (
+          'const base::Value* inner_message_value;\n'
+          'if (!field_list->Get(i, &inner_message_value)) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          'if (!{inner_class_parser}::ReadFromValue(inner_message_value, message->add_{field_name}())) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          )
+    else:
+      middle = (
+          '{cpp_type} field_value;\n'
+          'if (!field_list->Get{value_type}(i, &field_value)) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          'message->add_{field_name}(field_value);\n'
+          )
+
+    self.Output(
+        prologue + Indented(middle) + '\n}}',
+        field_number=field.JavascriptIndex(),
+        field_name=field.name,
+        cpp_type=field.CppPrimitiveType() if not field.IsClassType() else None,
+        value_type=field.CppValueType() if not field.IsClassType() else None,
+        inner_class_parser=field.CppConverterType()
+        )
+
+  def OptionalMemberFieldRead(self, field):
+    if field.IsClassType():
+      self.Output(
+          'const base::Value* inner_message_value;\n'
+          'if (!dict->Get("{field_number}", &inner_message_value)) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          'if (!{inner_class_parser}::ReadFromValue(inner_message_value, message->mutable_{field_name}())) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          '',
+          field_number=field.JavascriptIndex(),
+          field_name=field.name,
+          inner_class_parser=field.CppConverterType()
+          )
+    else:
+      self.Output(
+          '{cpp_type} field_value;\n'
+          'if (!dict->Get{value_type}("{field_number}", &field_value)) {{\n'
+          '  goto error;\n'
+          '}}\n'
+          'message->set_{field_name}(field_value);\n'
+          '',
+          field_number=field.JavascriptIndex(),
+          field_name=field.name,
+          cpp_type=field.CppPrimitiveType(),
+          value_type=field.CppValueType()
+      )
+
+
+def main():
+  request = plugin.ReadRequestFromStdin()
+  response = plugin_protos.PluginResponse()
+
+  output_dir = request.GetArgs().get('output_dir', '')
+
+  for proto_file in request.GetAllFiles():
+    plugin.RegisterProtoFile(proto_file)
+
+    writer = CppConverterWriter()
+    writer.WriteProtoFile(proto_file, output_dir)
+
+    converter_filename = proto_file.CppConverterFilename()
+    if output_dir:
+      converter_filename = os.path.join(output_dir,
+                                        os.path.split(converter_filename)[1])
+
+    response.AddFileWithContent(converter_filename, writer.GetValue())
+    if writer.GetErrors():
+      response.AddError('\n'.join(writer.GetErrors()))
+
+  plugin.SetBinaryStdio()
+  response.WriteToStdout()
+
+
+if __name__ == '__main__':
+  main()