/******************************************************************************
 *                       ____    _    _____                                   *
 *                      / ___|  / \  |  ___|    C++                           *
 *                     | |     / _ \ | |_       Actor                         *
 *                     | |___ / ___ \|  _|      Framework                     *
 *                      \____/_/   \_|_|                                      *
 *                                                                            *
 * Copyright 2011-2018 Dominik Charousset                                     *
 *                                                                            *
 * Distributed under the terms and conditions of the BSD 3-Clause License or  *
 * (at your option) under the terms and conditions of the Boost Software      *
 * License 1.0. See accompanying files LICENSE and LICENSE_ALTERNATIVE.       *
 *                                                                            *
 * If you did not receive a copy of the license files, see                    *
 * http://opensource.org/licenses/BSD-3-Clause and                            *
 * http://www.boost.org/LICENSE_1_0.txt.                                      *
 ******************************************************************************/

#pragma once

#include <mutex>

namespace caf {

template <class Lockable>
using unique_lock = std::unique_lock<Lockable>;

template <class SharedLockable>
class shared_lock {
public:
  using lockable = SharedLockable;

  explicit shared_lock(lockable& arg) : lockable_(&arg) {
    lockable_->lock_shared();
  }

  ~shared_lock() {
    unlock();
  }

  bool owns_lock() const {
    return lockable_ != nullptr;
  }

  void unlock() {
    if (lockable_) {
      lockable_->unlock_shared();
      lockable_ = nullptr;
    }
  }

  lockable* release() {
    auto result = lockable_;
    lockable_ = nullptr;
    return result;
  }

private:
  lockable* lockable_;
};

template <class SharedLockable>
using upgrade_lock = shared_lock<SharedLockable>;

template <class UpgradeLockable>
class upgrade_to_unique_lock {
public:
  using lockable = UpgradeLockable;

  template <class LockType>
  explicit upgrade_to_unique_lock(LockType& other) {
    lockable_ = other.release();
    if (lockable_) lockable_->unlock_upgrade_and_lock();
  }

  ~upgrade_to_unique_lock() {
    unlock();
  }

  bool owns_lock() const {
    return lockable_ != nullptr;
  }

  void unlock() {
    if (lockable_) {
      lockable_->unlock();
      lockable_ = nullptr;
    }
  }

private:
  lockable* lockable_;
};

} // namespace caf

