Method Evaluate

eval/eval/select_step.cc:139–248

};

absl::Status SelectStep::Evaluate(ExecutionFrame* frame) const {
  if (!frame->value_stack().HasEnough(1)) {
    return absl::Status(absl::StatusCode::kInternal,
                        "No arguments supplied for Select-type expression");
  }

  const Value& arg = frame->value_stack().Peek();
  const AttributeTrail& trail = frame->value_stack().PeekAttribute();

  if (arg.IsUnknown() || arg.IsError()) {
    // Bubble up unknowns and errors.
    return absl::OkStatus();
  }

  AttributeTrail result_trail;

  // Handle unknown resolution.
  if (frame->enable_unknowns() || frame->enable_missing_attribute_errors()) {
    result_trail = trail.Step(&field_);
  }

  absl::optional<OptionalValue> optional_arg;

  if (enable_optional_types_ && arg.IsOptional()) {
    optional_arg = arg.GetOptional();
  }

  if (!(optional_arg || arg->Is<MapValue>() || arg->Is<StructValue>())) {
    frame->value_stack().PopAndPush(cel::ErrorValue(InvalidSelectTargetError()),
                                    std::move(result_trail));
    return absl::OkStatus();
  }

  absl::optional<Value> marked_attribute_check =
      CheckForMarkedAttributes(result_trail, *frame);
  if (marked_attribute_check.has_value()) {
    frame->value_stack().PopAndPush(std::move(marked_attribute_check).value(),
                                    std::move(result_trail));
    return absl::OkStatus();
  }

  // Handle test only Select.
  if (test_field_presence_) {
    if (optional_arg) {
      if (!optional_arg->HasValue()) {
        frame->value_stack().PopAndPush(cel::BoolValue{false});
        return absl::OkStatus();
      }
      Value value;
      optional_arg->Value(&value);
      return PerformTestOnlySelect(frame, value);
    }
    return PerformTestOnlySelect(frame, arg);
  }

  // Normal select path.
  // Select steps can be applied to either maps or messages
  if (optional_arg) {