interthread.h

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// Copyright 2016-2026:
//   GobySoft, LLC (2013-)
//   Community contributors (see AUTHORS file)
// File authors:
//   Toby Schneider <toby@gobysoft.org>
//   Copilot <198982749+Copilot@users.noreply.github.com>
//
//
// This file is part of the Goby Underwater Autonomy Project Libraries
// ("The Goby Libraries").
//
// The Goby Libraries are free software: you can redistribute them and/or modify
// them 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.
//
// The Goby Libraries are distributed in the hope that they 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 Goby.  If not, see <http://www.gnu.org/licenses/>.
 
#ifndef GOBY_MIDDLEWARE_TRANSPORT_INTERTHREAD_H
#define GOBY_MIDDLEWARE_TRANSPORT_INTERTHREAD_H
 
#include <functional> // for fun...
#include <memory>     // for sha...
#include <mutex>      // for mutex
#include <thread>     // for get_id
 
#include "goby/exception.h"                                      // for Exc...
#include "goby/middleware/group.h"                               // for Group
#include "goby/middleware/marshalling/interface.h"               // for Mar...
#include "goby/middleware/transport/detail/subscription_store.h" // for Sub...
#include "goby/middleware/transport/interface.h"                 // for Sta...
#include "goby/middleware/transport/null.h"                      // for Nul...
#include "goby/middleware/transport/poller.h"                    // for Poller
#include "goby/middleware/transport/publisher.h"                 // for Pub...
#include "goby/middleware/transport/subscriber.h"                // for Sub...
 
namespace goby
{
namespace middleware
{
class InterThreadTransporter
    : public StaticTransporterInterface<InterThreadTransporter, NullTransporter>,
      public Poller<InterThreadTransporter>
{
  private:
    struct EmptyMessage
    {
    };
 
  public:
    using implementation_tag = void;
 
    InterThreadTransporter() : data_mutex_(std::make_shared<std::mutex>()) {}
 
    virtual ~InterThreadTransporter()
    {
        detail::SubscriptionStoreBase::unsubscribe_all(std::this_thread::get_id());
        detail::SubscriptionStoreBase::remove(std::this_thread::get_id());
    }

    template <typename Data> static constexpr int scheme() { return MarshallingScheme::CXX_OBJECT; }

    template <const Group& group> void check_validity()
    {
        static_assert((group.c_str() != nullptr) && (group.c_str()[0] != '\0'),
                      "goby::middleware::Group must have non-zero length string to publish on the "
                      "InterThread layer");
    }

    void check_validity_runtime(const Group& group)
    {
        if ((group.c_str() == nullptr) || (group.c_str()[0] == '\0'))
            throw(goby::Exception("Group must have a non-empty string for use on InterThread"));
    }

    template <typename Data, int scheme = scheme<Data>()>
    void publish_dynamic(const Data& data, const Group& group,
                         const Publisher<Data>& publisher = Publisher<Data>())
    {
        check_validity_runtime(group);
        std::shared_ptr<Data> data_ptr(new Data(data));
        publish_dynamic<Data>(data_ptr, group, publisher);
    }

    template <typename Data, int scheme = scheme<Data>()>
    void publish_dynamic(std::shared_ptr<const Data> data, const Group& group,
                         const Publisher<Data>& publisher = Publisher<Data>())
    {
        check_validity_runtime(group);
        detail::SubscriptionStore<Data>::publish(data, group, publisher);
    }

    template <typename Data, int scheme = scheme<Data>()>
    void publish_dynamic(std::shared_ptr<Data> data, const Group& group,
                         const Publisher<Data>& publisher = Publisher<Data>())
    {
        publish_dynamic<Data, scheme>(std::shared_ptr<const Data>(data), group, publisher);
    }

    template <const Group& group> void publish_empty()
    {
        publish_dynamic<EmptyMessage>(
            std::shared_ptr<EmptyMessage>(std::make_shared<EmptyMessage>()), group);
    }

    template <typename Data, int scheme = scheme<Data>()>
    void subscribe_dynamic(std::function<void(const Data&)> f, const Group& group,
                           const Subscriber<Data>& /*subscriber*/ = Subscriber<Data>())
    {
        check_validity_runtime(group);
        detail::SubscriptionStore<Data>::subscribe([=](std::shared_ptr<const Data> pd) { f(*pd); },
                                                   group, std::this_thread::get_id(), data_mutex_,
                                                   Poller<InterThreadTransporter>::cv(),
                                                   Poller<InterThreadTransporter>::poll_mutex());
    }

    template <typename Data, int scheme = scheme<Data>()>
    void subscribe_dynamic(std::function<void(std::shared_ptr<const Data>)> f, const Group& group,
                           const Subscriber<Data>& /*subscriber*/ = Subscriber<Data>())
    {
        check_validity_runtime(group);
        detail::SubscriptionStore<Data>::subscribe(
            f, group, std::this_thread::get_id(), data_mutex_, Poller<InterThreadTransporter>::cv(),
            Poller<InterThreadTransporter>::poll_mutex());
    }

    template <const Group& group> void subscribe_empty(const std::function<void()>& f)
    {
        subscribe_dynamic<EmptyMessage>([=](const std::shared_ptr<const EmptyMessage>&) { f(); },
                                        group);
    }

    template <typename Data, int scheme = scheme<Data>()>
    void unsubscribe_dynamic(const Group& group,
                             const Subscriber<Data>& /*subscriber*/ = Subscriber<Data>())
    {
        check_validity_runtime(group);
        detail::SubscriptionStore<Data>::unsubscribe(group, std::this_thread::get_id());
    }

    void unsubscribe_all()
    {
        detail::SubscriptionStoreBase::unsubscribe_all(std::this_thread::get_id());
    }
 
  private:
    friend Poller<InterThreadTransporter>;
    int _poll(std::unique_ptr<std::unique_lock<std::mutex>>& lock)
    {
        return detail::SubscriptionStoreBase::poll_all(std::this_thread::get_id(), lock);
    }
 
  private:
    // protects this thread's DataQueue
    std::shared_ptr<std::mutex> data_mutex_;
};
 
} // namespace middleware
} // namespace goby
 
#endif