Method AppendValue

cpp/src/arrow/json/from_string.cc:721–760

Append a JSON value that is either an array of N elements in order or an object mapping struct names to values (omitted struct members are mapped to null).

  // or an object mapping struct names to values (omitted struct members
  // are mapped to null).
  Status AppendValue(const rj::Value& json_obj) override {
    if (json_obj.IsNull()) {
      return this->AppendNull();
    }
    if (json_obj.IsArray()) {
      auto size = json_obj.Size();
      auto expected_size = static_cast<uint32_t>(type_->num_fields());
      if (size != expected_size) {
        return Status::Invalid("Expected array of size ", expected_size,
                               ", got array of size ", size);
      }
      for (uint32_t i = 0; i < size; ++i) {
        RETURN_NOT_OK(child_converters_[i]->AppendValue(json_obj[i]));
      }
      return builder_->Append();
    }
    if (json_obj.IsObject()) {
      auto remaining = json_obj.MemberCount();
      auto num_children = type_->num_fields();
      for (int32_t i = 0; i < num_children; ++i) {
        const auto& field = type_->field(i);
        auto it = json_obj.FindMember(field->name());
        if (it != json_obj.MemberEnd()) {
          --remaining;
          RETURN_NOT_OK(child_converters_[i]->AppendValue(it->value));
        } else {
          RETURN_NOT_OK(child_converters_[i]->AppendNull());
        }
      }
      if (remaining > 0) {
        rj::StringBuffer sb;
        rj::Writer<rj::StringBuffer> writer(sb);
        json_obj.Accept(writer);
        return Status::Invalid("Unexpected members in JSON object for type ",
                               type_->ToString(), " Object: ", sb.GetString());
      }
      return builder_->Append();
    }
    return JSONTypeError("array or object", json_obj.GetType());
  }

  std::shared_ptr<ArrayBuilder> builder() override { return builder_; }