delegate.hpp

// Copyright (c) 2000-2023 TeamDev Ltd. All rights reserved.
// TeamDev PROPRIETARY and CONFIDENTIAL.
// Use is subject to license terms.
 
#ifndef MOLYBDEN_DELEGATE_HPP
#define MOLYBDEN_DELEGATE_HPP
 
#include <functional>
#include <memory>
#include <mutex>
 
namespace molybden {
 
template <typename Args, typename Action>
class Delegate {
 public:
  using Signature = void(const Args& args, Action action);
 
  Delegate& operator=(std::function<Signature> callback);
 
  void reset();
 
 private:
  std::mutex callback_mutex_;
  std::function<Signature> callback_;
 
  void operator()(const Args& args, Action action);
 
  friend class ObservableOwner;
};
 
template <typename Args, typename Action>
Delegate<Args, Action>& Delegate<Args, Action>::operator=(
    std::function<Signature> callback) {
  std::lock_guard<std::mutex> guard(callback_mutex_);
  callback_ = callback;
  return *this;
}
 
template <typename Args, typename Action>
void Delegate<Args, Action>::operator()(const Args& args, Action action) {
  std::lock_guard<std::mutex> guard(callback_mutex_);
  if (callback_) {
    callback_(args, std::move(action));
  }
}
 
template <typename Args, typename Action>
void Delegate<Args, Action>::reset() {
  std::lock_guard<std::mutex> guard(callback_mutex_);
  callback_ = nullptr;
}
 
}  // namespace molybden
 
#endif  // MOLYBDEN_DELEGATE_HPP