ton/tdutils/td/utils/MovableValue.h

/*
    This file is part of TON Blockchain Library.

    TON Blockchain Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    TON Blockchain Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2017-2020 Telegram Systems LLP
*/
#pragma once

namespace td {

template <class T, T empty_val = T()>
class MovableValue {
 public:
  MovableValue() = default;
  MovableValue(T val) : val_(val) {
  }
  MovableValue(MovableValue &&other) : val_(other.val_) {
    other.clear();
  }
  MovableValue &operator=(MovableValue &&other) {
    if (this != &other) {
      val_ = other.val_;
      other.clear();
    }
    return *this;
  }
  MovableValue(const MovableValue &) = delete;
  MovableValue &operator=(const MovableValue &) = delete;
  ~MovableValue() = default;

  void clear() {
    val_ = empty_val;
  }
  const T &get() const {
    return val_;
  }

 private:
  T val_ = empty_val;
};

}  // namespace td