react-native-macos/ReactCommon/fabric/core/primitives/Sealable.cpp

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#include "Sealable.h"

#include <stdexcept>

namespace facebook {
namespace react {

/*
 * Note:
 * We must explicitly implement all *the rule of five* methods because:
 *   1. Using `std::atomic` behind `sealed_` implicitly deletes default
 *      constructors;
 *   2. We have to establish behaviour where any new cloned or moved instances
 *      of the object lose `sealed` flag.
 *
 * See more about the rule of three/five/zero:
 * http://en.cppreference.com/w/cpp/language/rule_of_three
 */

#ifndef NDEBUG

Sealable::Sealable() : sealed_(false) {}

Sealable::Sealable(const Sealable &other) : sealed_(false){};

Sealable::Sealable(Sealable &&other) noexcept : sealed_(false) {
  other.ensureUnsealed();
};

Sealable::~Sealable() noexcept {};

Sealable &Sealable::operator=(const Sealable &other) {
  ensureUnsealed();
  return *this;
}

Sealable &Sealable::operator=(Sealable &&other) noexcept {
  ensureUnsealed();
  other.ensureUnsealed();
  return *this;
}

void Sealable::seal() const {
  sealed_ = true;
}

bool Sealable::getSealed() const {
  return sealed_;
}

void Sealable::ensureUnsealed() const {
  if (sealed_) {
    throw std::runtime_error("Attempt to mutate a sealed object.");
  }
}

#endif

} // namespace react
} // namespace facebook