Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards


// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// Official repository:


#include <boost/smart_ptr.hpp>
#include <memory>
#include <mutex>
#include <string>
#include <unordered_set>

// Forward declaration
class websocket_session;

// Represents the shared server state
class shared_state
    std::string const doc_root_;

    // This mutex synchronizes all access to sessions_
    std::mutex mutex_;

    // Keep a list of all the connected clients
    std::unordered_set<websocket_session*> sessions_;

    shared_state(std::string doc_root);

    std::string const&
    doc_root() const noexcept
        return doc_root_;

    void join  (websocket_session* session);
    void leave (websocket_session* session);
    void send  (std::string message);