refcount.h

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

#pragma once

#include <atomic>

/*
 *  Reference counting for Frames and Replayers.
 *
 *  Enables frames and replayers to be referenced by Lua variables and other
 *  C++ objects at the same time.
 *
 *  We cannot use a C++ shared_pointer because that doesn't help us with the
 *  interaction with Lua.
 */
class RefCounted {
 private:
  std::atomic_int refs;

 public:
  RefCounted() {
    refs = 1;
  }
  // Destructor needs to be virtual for delete this to work correctly.
  virtual ~RefCounted() {}

  void incref() {
    refs++;
  }
  void decref() {
    if (--refs == 0)
      delete this;
  }
};