libdatachannel/include/rtc/message.hpp

/**
 * Copyright (c) 2019 Paul-Louis Ageneau
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RTC_MESSAGE_H
#define RTC_MESSAGE_H

#include "include.hpp"
#include "reliability.hpp"

#include <functional>
#include <memory>
#include <optional>
#include <variant>

namespace rtc {

struct Message : binary {
	enum Type { Binary, String, Control, Reset };

	Message(const Message &message) = default;
	Message(size_t size, Type type_ = Binary) : binary(size), type(type_) {}

	template <typename Iterator>
	Message(Iterator begin_, Iterator end_, Type type_ = Binary)
	    : binary(begin_, end_), type(type_) {}

	Message(binary &&data, Type type_ = Binary) : binary(std::move(data)), type(type_) {}

	Type type;
	unsigned int stream = 0;
	std::shared_ptr<Reliability> reliability;
};

using message_ptr = std::shared_ptr<Message>;
using message_callback = std::function<void(message_ptr message)>;
using message_variant = std::variant<binary, string>;

constexpr auto message_size_func = [](const message_ptr &m) -> size_t {
	return m->type == Message::Binary || m->type == Message::String ? m->size() : 0;
};

template <typename Iterator>
message_ptr make_message(Iterator begin, Iterator end, Message::Type type = Message::Binary,
                         unsigned int stream = 0,
                         std::shared_ptr<Reliability> reliability = nullptr) {
	auto message = std::make_shared<Message>(begin, end, type);
	message->stream = stream;
	message->reliability = reliability;
	return message;
}

inline message_ptr make_message(size_t size, Message::Type type = Message::Binary,
                                unsigned int stream = 0,
                                std::shared_ptr<Reliability> reliability = nullptr) {
	auto message = std::make_shared<Message>(size, type);
	message->stream = stream;
	message->reliability = reliability;
	return message;
}

inline message_ptr make_message(binary &&data, Message::Type type = Message::Binary,
                                unsigned int stream = 0,
                                std::shared_ptr<Reliability> reliability = nullptr) {
	auto message = std::make_shared<Message>(std::move(data), type);
	message->stream = stream;
	message->reliability = reliability;
	return message;
}

inline message_ptr make_message(message_variant data) {
	return std::visit( //
	    overloaded{
	        [&](binary data) { return make_message(std::move(data), Message::Binary); },
	        [&](string data) {
		        auto b = reinterpret_cast<const byte *>(data.data());
		        return make_message(b, b + data.size(), Message::String);
	        },
	    },
	    std::move(data));
}

inline std::optional<message_variant> to_variant(Message &&message) {
	switch (message.type) {
	case Message::String:
		return std::make_optional(
		    string(reinterpret_cast<const char *>(message.data()), message.size()));
	case Message::Binary:
		return std::make_optional(std::move(message));
	default:
		return nullopt;
	}
}

} // namespace rtc

#endif