topic_sharename.hpp

// Copyright Takatoshi Kondo 2022
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
 
#if !defined(ASYNC_MQTT_PACKET_TOPIC_SHARENAME_HPP)
#define ASYNC_MQTT_PACKET_TOPIC_SHARENAME_HPP
 
#include <async_mqtt/util/buffer.hpp>
 
namespace async_mqtt {
 
class topic_sharename {
public:
 
    template <
        typename AllTopic,
        typename std::enable_if_t<
            std::is_convertible_v<std::decay_t<AllTopic>, std::string_view>,
            std::nullptr_t
        > = nullptr
    >
    topic_sharename(
        AllTopic&& all_topic
    ): all_topic_{std::forward<AllTopic>(all_topic)} {
        auto const shared_prefix = std::string_view("$share/");
        if (all_topic_.substr(0, shared_prefix.size()) == shared_prefix) {
            // must have sharename
            sharename_ = all_topic_.substr(shared_prefix.size());
 
            auto const idx = sharename_.find_first_of('/');
            if (idx == 0 || idx == std::string_view::npos) return;
 
            topic_ = sharename_.substr(idx + 1);
            sharename_ = sharename_.substr(0, sharename_.size() - topic_.size() - 1);
        }
        else {
            topic_ = all_topic_;
        }
    }
 
    std::string const& topic() const {
        return topic_;
    }
 
    std::string const& sharename() const {
        return sharename_;
    }
 
    std::string const& all_topic() const {
        return all_topic_;
    }
 
    operator bool() const {
        return !topic_.empty();
    }
 
    friend
    bool operator<(topic_sharename const& lhs, topic_sharename const& rhs) {
        return
            std::tie(lhs.topic_, lhs.sharename_) <
            std::tie(rhs.topic_, rhs.sharename_);
    }
 
    friend
    bool operator==(topic_sharename const& lhs, topic_sharename const& rhs) {
        return
            std::tie(lhs.topic_, lhs.sharename_) ==
            std::tie(rhs.topic_, rhs.sharename_);
    }
 
private:
    std::string all_topic_;
    std::string topic_;
    std::string sharename_;
};
 
} // namespace async_mqtt
 
#endif // ASYNC_MQTT_PACKET_TOPIC_SHARENAME_HPP