Atomic.h

/*
 * Copyright (C) 2019-2021 HERE Europe B.V.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 * License-Filename: LICENSE
 */
 
#pragma once
 
#include <functional>
#include <mutex>
#include <utility>
 
namespace olp {
namespace thread {
template <class Type, typename MutexType = std::mutex,
          typename ReadLockType = std::lock_guard<MutexType> >
class Atomic {
 public:
  using value_type = Type;
 
  using WriteLockType = std::lock_guard<MutexType>;
 
  template <class SomeType>
  explicit Atomic(SomeType&& am) : m(std::forward<SomeType>(am)) {}
 
  Atomic() : m() {}
 
  template <class Functor>
  auto locked(Functor&& lambda) -> decltype(lambda(std::declval<Type&>())) {
    WriteLockType lock(m_mutex);
    return lambda(m);
  }
 
  template <class Functor>
  auto locked(Functor&& lambda) const
      -> decltype(lambda(std::declval<const Type&>())) const {
    ReadLockType lock(m_mutex);
    return lambda(m);
  }
 
  Type lockedCopy() const {
    ReadLockType lock(m_mutex);
    return m;
  }
 
  Type lockedMove() {
    WriteLockType lock(m_mutex);
    return std::move(m);
  }
 
  template <class SomeType>
  void lockedAssign(SomeType&& am) {
    WriteLockType lock(m_mutex);
    m = std::forward<SomeType>(am);
  }
 
  void lockedSwap(Type& other) {
    WriteLockType lock(m_mutex);
    std::swap(m, other);
  }
 
  Type lockedSwapWithDefault() {
    WriteLockType lock(m_mutex);
    Type other{};
    std::swap(m, other);
    return other;
  }
 
  explicit operator bool() const {
    ReadLockType lock(m_mutex);
    return static_cast<bool>(m);
  }
 
 protected:
  mutable MutexType m_mutex;
 
  Type m;
};
 
}  // namespace thread
}  // namespace olp