/** * @param \google\protobuf\FieldDescriptorProto $fieldDescriptor * * @return boolean */ protected function isProtobufExtension(FieldDescriptorProto $fieldDescriptor) { if (!$fieldDescriptor->hasExtendee()) { return false; } $extendee = trim($fieldDescriptor->getExtendee(), '.'); $package = 'google.protobuf'; $length = strlen($package); return substr($extendee, 0, $length) === $package; }