💿🐜 Antkeeper source code https://antkeeper.com
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/*
* Copyright (C) 2023 Christopher J. Howard
*
* This file is part of Antkeeper source code.
*
* Antkeeper source code is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Antkeeper source code 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ANTKEEPER_EVENT_CHANNEL_HPP
#define ANTKEEPER_EVENT_CHANNEL_HPP
#include <functional>
#include <list>
#include <memory>
#include <utility>
#include "event/subscriber.hpp"
#include "event/subscription.hpp"
#include "event/queue.hpp"
namespace event {
template <class T>
class publisher;
/**
* Channel through which messages are published.
*
* @tparam T Message type.
*/
template <class T>
class channel
{
public:
/// Message type.
typedef T message_type;
/// Subscriber function object type.
typedef subscriber<message_type> subscriber_type;
/**
* Subscribes a function object to messages published through this channel.
*
* @param subscriber Subscriber function object which will received published messages.
*
* @return Shared subscription object which will unsubscribe the subscriber on destruction.
*/
[[nodiscard]] std::shared_ptr<subscription> subscribe(subscriber_type&& subscriber)
{
// Construct shared pointer to subscriber function
std::shared_ptr<subscriber_type> shared_subscriber = std::make_shared<subscriber_type>(std::move(subscriber));
// Append subscriber to subscriber list and store iterator
auto iterator = subscribers.insert(subscribers.end(), shared_subscriber);
// Construct and return a shared subscription object which removes the subscriber from the subscriber list when unsubscribed or destructed
return std::make_shared<subscription>
(
std::static_pointer_cast<void>(shared_subscriber),
[this, iterator = std::move(iterator)]
{
this->subscribers.erase(iterator);
}
);
}
/**
* Subscribes a message queue to messages published through this channel.
*
* @param queue Message queue which will received published messages.
*
* @return Shared subscription object which will unsubscribe the queue on destruction.
*/
[[nodiscard]] std::shared_ptr<subscription> subscribe(event::queue& queue)
{
return subscribe
(
[&queue](const message_type& message)
{
queue.enqueue<message_type>(message);
}
);
}
private:
friend class publisher<T>;
/// List of subscribers.
std::list<std::shared_ptr<subscriber_type>> subscribers;
};
} // namespace event
#endif // ANTKEEPER_EVENT_CHANNEL_HPP