interprocess.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>
//   Ryan Govostes <rgovostes+git@gmail.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_INTERPROCESS_H
#define GOBY_MIDDLEWARE_TRANSPORT_INTERPROCESS_H
 
#include <atomic>
#include <functional>
#include <sys/types.h>
#include <thread>
#include <tuple>
#include <unistd.h>
 
#include "goby/middleware/group.h"
 
#include "goby/middleware/marshalling/interface.h"
#include "goby/middleware/transport/detail/static_group_names.h"
#include "goby/middleware/transport/identifier.h"
#include "goby/middleware/transport/null.h"
#include "goby/middleware/transport/poller.h"
#include "goby/middleware/transport/serialization_handlers.h"
 
namespace goby
{
namespace middleware
{

template <typename Derived, typename InnerTransporter, typename ImplementationTag>
class InterProcessTransporterBase
    : public StaticTransporterInterface<
          InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>,
          InnerTransporter>,
      public Poller<InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>>
{
    using InterfaceType = StaticTransporterInterface<
        InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>,
        InnerTransporter>;
 
    using PollerType =
        Poller<InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>>;
 
  public:
    using implementation_tag = ImplementationTag;
 
    InterProcessTransporterBase(InnerTransporter& inner)
        : InterfaceType(inner), PollerType(&this->inner())
    {
    }
    InterProcessTransporterBase() : PollerType(&this->inner()) {}
 
    virtual ~InterProcessTransporterBase() {}

    template <typename Data> static constexpr int scheme()
    {
        int scheme = goby::middleware::scheme<Data>();
        // if default returns DCCL, use PROTOBUF instead
        if (scheme == MarshallingScheme::DCCL)
            scheme = MarshallingScheme::PROTOBUF;
        return scheme;
    }

    template <typename Data, int scheme = InterProcessTransporterBase::scheme<Data>()>
    void publish_dynamic(const Data& data, const Group& group,
                         const Publisher<Data>& publisher = Publisher<Data>())
    {
        check_validity_runtime(group);
        static_cast<Derived*>(this)->template _publish<Data, scheme>(data, group, publisher);
        this->inner().template publish_dynamic<Data, scheme>(data, group, publisher);
    }

    template <typename Data, int scheme = InterProcessTransporterBase::scheme<Data>()>
    void publish_dynamic(std::shared_ptr<const Data> data, const Group& group,
                         const Publisher<Data>& publisher = Publisher<Data>())
    {
        if (data)
        {
            check_validity_runtime(group);
            static_cast<Derived*>(this)->template _publish<Data, scheme>(*data, group, publisher);
            this->inner().template publish_dynamic<Data, scheme>(data, group, publisher);
        }
    }

    template <typename Data, int scheme = InterProcessTransporterBase::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);
    }

    void publish_serialized(std::string type_name, int scheme, const std::vector<char>& bytes,
                            const goby::middleware::Group& group)
    {
        check_validity_runtime(group);
        static_cast<Derived*>(this)->_publish_serialized(type_name, scheme, bytes, group);
    }

    template <typename Data, int scheme = InterProcessTransporterBase::scheme<Data>()>
    void subscribe_dynamic(std::function<void(const Data&)> f, const Group& group,
                           const Subscriber<Data>& subscriber = Subscriber<Data>())
    {
        check_validity_runtime(group);
        static_cast<Derived*>(this)->template _subscribe<Data, scheme>(
            [=](std::shared_ptr<const Data> d) { f(*d); }, group, subscriber);
    }

    template <typename Data, int scheme = InterProcessTransporterBase::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);
        static_cast<Derived*>(this)->template _subscribe<Data, scheme>(f, group, subscriber);
    }

    template <typename Data, int scheme = InterProcessTransporterBase::scheme<Data>()>
    void unsubscribe_dynamic(const Group& group,
                             const Subscriber<Data>& subscriber = Subscriber<Data>())
    {
        check_validity_runtime(group);
        static_cast<Derived*>(this)->template _unsubscribe<Data, scheme>(group, subscriber);
    }

    void unsubscribe_all() { static_cast<Derived*>(this)->_unsubscribe_all(); }

    std::shared_ptr<SerializationSubscriptionRegex>
    subscribe_regex(std::function<void(const std::vector<unsigned char>&, int scheme,
                                       const std::string& type, const Group& group)>
                        f,
                    const std::set<int>& schemes, const std::string& type_regex = ".*",
                    const std::string& group_regex = ".*")
    {
        return static_cast<Derived*>(this)->_subscribe_regex(f, schemes, type_regex, group_regex);
    }

    template <typename Data, int scheme = InterProcessTransporterBase::scheme<Data>()>
    std::shared_ptr<SerializationSubscriptionRegex> subscribe_type_regex(
        std::function<void(std::shared_ptr<const Data>, const std::string& type)> f,
        const Group& group, const std::string& type_regex = ".*")
    {
        std::regex special_chars{R"([-[\‍]{}()*+?.,\^$|#\s])"};
        std::string sanitized_group =
            std::regex_replace(std::string(group), special_chars, R"(\$&)");
 
        auto regex_lambda = [f = std::move(f)](const std::vector<unsigned char>& data, int schm,
                                               const std::string& type, const Group& grp)
        {
            auto data_begin = data.begin(), data_end = data.end(), actual_end = data.end();
            auto msg =
                SerializerParserHelper<Data, scheme>::parse(data_begin, data_end, actual_end, type);
            f(msg, type);
        };
 
        return static_cast<Derived*>(this)->_subscribe_regex(regex_lambda, {scheme}, type_regex,
                                                             "^" + sanitized_group + "$");
    }

    template <const Group& group, typename Data,
              int scheme = InterProcessTransporterBase::scheme<Data>()>
    void subscribe_type_regex(
        std::function<void(std::shared_ptr<const Data>, const std::string& type)> f,
        const std::string& type_regex = ".*")
    {
        subscribe_type_regex(f, group, type_regex);
    }

    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 "
                      "InterProcess 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 InterProcess"));
    }
 
  protected:
    inline static constexpr auto to_portal_group_name_ =
        detail::concat(ImplementationTag::prefix, "::to_portal");
    inline static constexpr auto regex_group_name_ =
        detail::concat(ImplementationTag::prefix, "::regex");
    inline static constexpr auto from_portal_group_name_ =
        detail::concat(ImplementationTag::prefix, "::from_portal");
 
    inline static constexpr Group to_portal_group_{to_portal_group_name_.data()};
    inline static constexpr Group regex_group_{regex_group_name_.data()};
    inline static constexpr Group from_portal_group_{from_portal_group_name_.data()};
 
  private:
    friend PollerType;
    int _poll(std::unique_ptr<std::unique_lock<std::mutex>>& lock)
    {
        return static_cast<Derived*>(this)->_poll(lock);
    }
};

template <typename InnerTransporter, typename ImplementationTag = void> class InterProcessForwarder;

template <typename InnerTransporter, typename ImplementationTag>
class InterProcessForwarder
    : public InterProcessTransporterBase<InterProcessForwarder<InnerTransporter, ImplementationTag>,
                                         InnerTransporter, ImplementationTag>
{
  public:
    using Base =
        InterProcessTransporterBase<InterProcessForwarder<InnerTransporter, ImplementationTag>,
                                    InnerTransporter, ImplementationTag>;

    InterProcessForwarder(InnerTransporter& inner)
        : Base(inner), alive_(std::make_shared<std::atomic<bool>>(true))
    {
        this->inner()
            .template subscribe<Base::regex_group_,
                                goby::middleware::protobuf::SerializerTransporterMessage>(
                [this](
                    std::shared_ptr<const goby::middleware::protobuf::SerializerTransporterMessage>
                        msg) { _receive_regex_data_forwarded(msg); });
    }
    virtual ~InterProcessForwarder()
    {
        // Mark as no longer alive so that forwarding lambdas (captured by the
        // portal's subscription handlers) become no-ops. This avoids
        // use-after-free when the portal invokes a stale callback after the
        // forwarder has been destroyed.
        *alive_ = false;
 
        this->unsubscribe_all();
 
        // TODO - remove by adding in an explicit handshake with the unsubscribe_all publication so that we don't delete ourself (and thus our inner()) before the Portal has deleted all the subscriptions
        usleep(1e5);
    }
 
    friend Base;
 
  private:
    template <typename Data, int scheme>
    void _publish(const Data& d, const Group& group, const Publisher<Data>& publisher)
    {
        // create and forward publication to edge
        std::vector<char> bytes(SerializerParserHelper<Data, scheme>::serialize(d));
        std::string* sbytes = new std::string(bytes.begin(), bytes.end());
        auto msg = std::make_shared<goby::middleware::protobuf::SerializerTransporterMessage>();
        auto* key = msg->mutable_key();
 
        key->set_marshalling_scheme(scheme);
        key->set_type(SerializerParserHelper<Data, scheme>::type_name(d));
        key->set_group(std::string(group));
        msg->set_allocated_data(sbytes);
 
        *key->mutable_cfg() = publisher.cfg();
 
        this->inner().template publish<Base::to_portal_group_>(msg);
    }
 
    template <typename Data, int scheme>
    void _subscribe(std::function<void(std::shared_ptr<const Data> d)> f, const Group& group,
                    const Subscriber<Data>& subscriber)
    {
        this->inner().template subscribe_dynamic<Data, scheme>(f, group);
 
        // forward subscription to edge
        // Capture alive_ by value (shared_ptr copy) so the lambda can detect
        // when the forwarder has been destroyed and avoid use-after-free.
        auto alive = alive_;
        auto inner_publication_lambda = [=](std::shared_ptr<const Data> d)
        {
            if (*alive)
                this->inner().template publish_dynamic<Data, scheme>(d, group);
        };
 
        auto subscription = std::make_shared<SerializationSubscription<Data, scheme>>(
            inner_publication_lambda, group,
            middleware::Subscriber<Data>(goby::middleware::protobuf::TransporterConfig(),
                                         [=](const Data& d) { return group; }));
 
        this->inner().template publish<Base::to_portal_group_, SerializationHandlerBase<>>(
            subscription);
    }
 
    template <typename Data, int scheme>
    void _unsubscribe(const Group& group, const Subscriber<Data>& subscriber)
    {
        this->inner().template unsubscribe_dynamic<Data, scheme>(group, subscriber);
 
        auto unsubscription = std::shared_ptr<SerializationHandlerBase<>>(
            new SerializationUnSubscription<Data, scheme>(group));
 
        this->inner().template publish<Base::to_portal_group_, SerializationHandlerBase<>>(
            unsubscription);
    }
 
    void _publish_serialized(std::string type_name, int scheme, const std::vector<char>& bytes,
                             const goby::middleware::Group& group)
    {
        auto msg = std::make_shared<goby::middleware::protobuf::SerializerTransporterMessage>();
        auto* key = msg->mutable_key();
 
        key->set_marshalling_scheme(scheme);
        key->set_type(type_name);
        key->set_group(std::string(group));
        msg->set_data(std::string(bytes.begin(), bytes.end()));
 
        this->inner().template publish<Base::to_portal_group_>(msg);
    }
 
    void _unsubscribe_all()
    {
        regex_subscriptions_.clear();
        auto all = std::make_shared<SerializationUnSubscribeAll>();
        this->inner().template publish<Base::to_portal_group_, SerializationUnSubscribeAll>(all);
    }
 
    std::shared_ptr<SerializationSubscriptionRegex>
    _subscribe_regex(std::function<void(const std::vector<unsigned char>&, int scheme,
                                        const std::string& type, const Group& group)>
                         f,
                     const std::set<int>& schemes, const std::string& type_regex = ".*",
                     const std::string& group_regex = ".*")
    {
        auto alive = alive_;
        auto inner_publication_lambda = [=](const std::vector<unsigned char>& data, int scheme,
                                            const std::string& type, const Group& group)
        {
            if (!*alive)
                return;
            std::shared_ptr<goby::middleware::protobuf::SerializerTransporterMessage>
                forwarded_data(new goby::middleware::protobuf::SerializerTransporterMessage);
            forwarded_data->mutable_key()->set_marshalling_scheme(scheme);
            forwarded_data->mutable_key()->set_type(type);
            forwarded_data->mutable_key()->set_group(group);
            forwarded_data->set_data(std::string(data.begin(), data.end()));
            this->inner().template publish<Base::regex_group_>(forwarded_data);
        };
 
        auto portal_subscription = std::make_shared<SerializationSubscriptionRegex>(
            inner_publication_lambda, schemes, type_regex, group_regex);
        this->inner().template publish<Base::to_portal_group_, SerializationSubscriptionRegex>(
            portal_subscription);
 
        auto local_subscription = std::shared_ptr<SerializationSubscriptionRegex>(
            new SerializationSubscriptionRegex(f, schemes, type_regex, group_regex));
        regex_subscriptions_.insert(local_subscription);
        return local_subscription;
    }
 
    void _receive_regex_data_forwarded(
        std::shared_ptr<const goby::middleware::protobuf::SerializerTransporterMessage> msg)
    {
        const auto& bytes = msg->data();
        for (auto& sub : regex_subscriptions_)
            sub->post(bytes.begin(), bytes.end(), msg->key().marshalling_scheme(),
                      msg->key().type(), msg->key().group());
    }
 
    int _poll(std::unique_ptr<std::unique_lock<std::mutex>>& lock)
    {
        return 0;
    } // A forwarder is a shell, only the inner Transporter has data
 
  private:
    std::set<std::shared_ptr<const SerializationSubscriptionRegex>> regex_subscriptions_;
    // Shared flag checked by forwarding lambdas to avoid accessing `this`
    // after the forwarder has been destroyed (set to false in the destructor).
    std::shared_ptr<std::atomic<bool>> alive_;
};
 
template <typename Derived, typename InnerTransporter>
class InterProcessPortalCommon : public InterProcessIdentifierManager
{
  protected:
    template <typename Data, int scheme>
    void _publish(const Data& d, const goby::middleware::Group& group,
                  const middleware::Publisher<Data>& /*publisher*/)
    {
        std::vector<char> bytes(middleware::SerializerParserHelper<Data, scheme>::serialize(d));
        std::string type_name = middleware::SerializerParserHelper<Data, scheme>::type_name(d);
        _publish_serialized(type_name, scheme, bytes, group);
    }
 
    std::shared_ptr<middleware::SerializationSubscriptionRegex> _subscribe_regex(
        std::function<void(const std::vector<unsigned char>&, int scheme, const std::string& type,
                           const goby::middleware::Group& group)>
            f,
        const std::set<int>& schemes, const std::string& type_regex, const std::string& group_regex)
    {
        auto new_sub = std::make_shared<middleware::SerializationSubscriptionRegex>(
            f, schemes, type_regex, group_regex);
        static_cast<Derived*>(this)->_subscribe_regex_serialized(new_sub);
        return new_sub;
    }
 
    template <typename Data, int scheme>
    void _subscribe(std::function<void(std::shared_ptr<const Data> d)> f,
                    const goby::middleware::Group& group,
                    const middleware::Subscriber<Data>& /*subscriber*/)
    {
        std::string identifier = this->template _make_identifier<Data, scheme>(
            group, IdentifierWildcard::PROCESS_THREAD_WILDCARD);
 
        auto subscription = std::make_shared<middleware::SerializationSubscription<Data, scheme>>(
            f, group,
            middleware::Subscriber<Data>(goby::middleware::protobuf::TransporterConfig(),
                                         [=](const Data& /*d*/) { return group; }));
 
        if (forwarder_subscriptions_.count(identifier) == 0 &&
            portal_subscriptions_.count(identifier) == 0)
            static_cast<Derived*>(this)->_do_portal_subscribe(identifier);
 
        portal_subscriptions_.insert(std::make_pair(identifier, subscription));
    }
 
    template <typename Data, int scheme>
    void _unsubscribe(
        const goby::middleware::Group& group,
        const middleware::Subscriber<Data>& /*subscriber*/ = middleware::Subscriber<Data>())
    {
        std::string identifier = this->template _make_identifier<Data, scheme>(
            group, IdentifierWildcard::PROCESS_THREAD_WILDCARD);
 
        portal_subscriptions_.erase(identifier);
 
        // If no forwarded subscriptions, do the actual unsubscribe
        if (forwarder_subscriptions_.count(identifier) == 0)
            static_cast<Derived*>(this)->_do_portal_unsubscribe(identifier);
    }
    void _handle_received_data(std::unique_ptr<std::unique_lock<std::mutex>>& lock,
                               const std::string& data)
    {
        if (lock)
            lock.reset();
 
        std::string group, type;
        int scheme, process;
        std::size_t thread;
        std::tie(group, scheme, type, process, thread) = this->parse_identifier(data);
        std::string identifier = this->_make_identifier(
            type, scheme, group, IdentifierWildcard::PROCESS_THREAD_WILDCARD);
 
        // build a set so if any of the handlers unsubscribes, we still have a pointer to the middleware::SerializationHandlerBase<>
        std::vector<std::weak_ptr<const middleware::SerializationHandlerBase<>>> subs_to_post;
        auto portal_range = portal_subscriptions_.equal_range(identifier);
        for (auto it = portal_range.first; it != portal_range.second; ++it)
            subs_to_post.push_back(it->second);
        auto forwarder_it = forwarder_subscriptions_.find(identifier);
        if (forwarder_it != forwarder_subscriptions_.end())
            subs_to_post.push_back(forwarder_it->second);
 
        // actually post the data
        {
            auto null_delim_it = std::find(std::begin(data), std::end(data),
                                           InterProcessIdentifierManager::end_delimiter);
            for (auto& sub : subs_to_post)
            {
                if (auto sub_sp = sub.lock())
                    sub_sp->post(null_delim_it + 1, data.end());
            }
        }
 
        if (!regex_subscriptions_.empty())
        {
            auto null_delim_it = std::find(std::begin(data), std::end(data),
                                           InterProcessIdentifierManager::end_delimiter);
 
            bool forwarder_subscription_posted = false;
            for (auto& sub : regex_subscriptions_)
            {
                // only post at most once for forwarders as the threads will filter
                bool is_forwarded_sub =
                    sub.first != middleware::identifier_part_to_string(std::this_thread::get_id());
                if (is_forwarded_sub && forwarder_subscription_posted)
                    continue;
 
                if (sub.second->post(null_delim_it + 1, data.end(), scheme, type, group) &&
                    is_forwarded_sub)
                    forwarder_subscription_posted = true;
            }
        }
    }
 
    void _unsubscribe_all(const std::string& subscriber_id =
                              middleware::identifier_part_to_string(std::this_thread::get_id()))
    {
        // portal unsubscribe
        if (subscriber_id == middleware::identifier_part_to_string(std::this_thread::get_id()))
        {
            for (const auto& p : portal_subscriptions_)
            {
                const auto& identifier = p.first;
                if (forwarder_subscriptions_.count(identifier) == 0)
                    static_cast<Derived*>(this)->_do_portal_unsubscribe(identifier);
            }
            portal_subscriptions_.clear();
        }
        else // forwarder unsubscribe
        {
            while (forwarder_subscription_identifiers_[subscriber_id].size() > 0)
                _forwarder_unsubscribe(
                    subscriber_id,
                    forwarder_subscription_identifiers_[subscriber_id].begin()->first);
        }
 
        // regex
        if (regex_subscriptions_.size() > 0)
        {
            regex_subscriptions_.erase(subscriber_id);
            if (regex_subscriptions_.empty())
                static_cast<Derived*>(this)->_do_portal_wildcard_unsubscribe();
        }
    }
 
    void _receive_subscription_forwarded(
        const std::shared_ptr<const middleware::SerializationHandlerBase<>>& subscription)
    {
        std::string identifier = this->_make_identifier(
            subscription->type_name(), subscription->scheme(), subscription->subscribed_group(),
            IdentifierWildcard::PROCESS_THREAD_WILDCARD);
 
        goby::glog.is_debug2() &&
            goby::glog << "Received subscription forwarded for identifier [" << identifier
                       << "] from subscriber id: " << subscription->subscriber_id() << std::endl;
 
        switch (subscription->action())
        {
            case middleware::SerializationHandlerBase<>::SubscriptionAction::SUBSCRIBE:
            {
                // insert if this thread hasn't already subscribed
                if (forwarder_subscription_identifiers_[subscription->subscriber_id()].count(
                        identifier) == 0)
                {
                    // first to subscribe from a Forwarder
                    if (forwarder_subscriptions_.count(identifier) == 0)
                    {
                        // first to subscribe (locally or forwarded)
                        if (portal_subscriptions_.count(identifier) == 0)
                            static_cast<Derived*>(this)->_do_portal_subscribe(identifier);
 
                        // create Forwarder subscription
                        forwarder_subscriptions_.insert(std::make_pair(identifier, subscription));
                    }
                    forwarder_subscription_identifiers_[subscription->subscriber_id()].insert(
                        std::make_pair(identifier, forwarder_subscriptions_.find(identifier)));
                }
            }
            break;
 
            case middleware::SerializationHandlerBase<>::SubscriptionAction::UNSUBSCRIBE:
            {
                _forwarder_unsubscribe(subscription->subscriber_id(), identifier);
            }
            break;
 
            default: break;
        }
    }
 
    void _forwarder_unsubscribe(const std::string& subscriber_id, const std::string& identifier)
    {
        auto it = forwarder_subscription_identifiers_[subscriber_id].find(identifier);
        if (it != forwarder_subscription_identifiers_[subscriber_id].end())
        {
            bool no_forwarder_subscribers = true;
            for (const auto& p : forwarder_subscription_identifiers_)
            {
                if (p.second.count(identifier) != 0)
                {
                    no_forwarder_subscribers = false;
                    break;
                }
            }
 
            // if no Forwarder subscriptions left
            if (no_forwarder_subscribers)
            {
                // erase the Forwarder subscription
                forwarder_subscriptions_.erase(it->second);
 
                // do the actual unsubscribe if we aren't subscribe locally as well
                if (portal_subscriptions_.count(identifier) == 0)
                    static_cast<Derived*>(this)->_do_portal_unsubscribe(identifier);
            }
 
            forwarder_subscription_identifiers_[subscriber_id].erase(it);
        }
    }
 
    void _subscribe_regex_serialized(
        const std::shared_ptr<const middleware::SerializationSubscriptionRegex>& new_sub)
    {
        if (regex_subscriptions_.empty())
            static_cast<Derived*>(this)->_do_portal_wildcard_subscribe();
 
        regex_subscriptions_.insert(std::make_pair(new_sub->subscriber_id(), new_sub));
    }
 
    void _publish_serialized(std::string type_name, int scheme, const std::vector<char>& bytes,
                             const goby::middleware::Group& group)
    {
        std::string identifier =
            this->_make_identifier(type_name, scheme, group, IdentifierWildcard::NO_WILDCARDS) +
            InterProcessIdentifierManager::end_delimiter;
        static_cast<Derived*>(this)->_do_publish(identifier, bytes);
    }
 
  private:
    // portal_subscriptions_ and forwarder_subscriptions_: maps identifier to subscription
    std::unordered_multimap<std::string,
                            std::shared_ptr<const middleware::SerializationHandlerBase<>>>
        portal_subscriptions_;
    // only one subscription for each forwarded identifier
    std::unordered_map<std::string, std::shared_ptr<const middleware::SerializationHandlerBase<>>>
        forwarder_subscriptions_;
 
    // maps subscriber_id [thread id as string] to map of identifier to forwarder subscription
    std::unordered_map<
        std::string, std::unordered_map<
                         std::string, typename decltype(forwarder_subscriptions_)::const_iterator>>
        forwarder_subscription_identifiers_;
 
    // subscriber id to subscription
    std::unordered_multimap<std::string,
                            std::shared_ptr<const middleware::SerializationSubscriptionRegex>>
        regex_subscriptions_;
};
 
template <typename Derived, typename InnerTransporter, typename ImplementationTag>
class InterProcessPortalBase
    : public InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>,
      public InterProcessPortalCommon<Derived, InnerTransporter>
{
  public:
    using Base = InterProcessTransporterBase<Derived, InnerTransporter, ImplementationTag>;
    using Common = InterProcessPortalCommon<Derived, InnerTransporter>;
 
    InterProcessPortalBase(InnerTransporter& inner) : Base(inner) { _init(); }
    InterProcessPortalBase() { _init(); }
 
    virtual ~InterProcessPortalBase() {}
 
    friend Base;
 
  private:
    void _init()
    {
        using goby::middleware::protobuf::SerializerTransporterMessage;
        this->inner().template subscribe<Base::to_portal_group_, SerializerTransporterMessage>(
            [this](std::shared_ptr<const SerializerTransporterMessage> d)
            {
                std::vector<char> data(d->data().begin(), d->data().end());
                static_cast<Derived*>(this)->_publish_serialized(
                    d->key().type(), d->key().marshalling_scheme(), data,
                    goby::middleware::DynamicGroup(d->key().group()));
            });
 
        this->inner().template subscribe<Base::to_portal_group_, SerializationHandlerBase<>>(
            [this](std::shared_ptr<const middleware::SerializationHandlerBase<>> s)
            { static_cast<Derived*>(this)->_receive_subscription_forwarded(s); });
 
        this->inner().template subscribe<Base::to_portal_group_, SerializationSubscriptionRegex>(
            [this](std::shared_ptr<const middleware::SerializationSubscriptionRegex> s)
            { static_cast<Derived*>(this)->_subscribe_regex_serialized(s); });
 
        this->inner().template subscribe<Base::to_portal_group_, SerializationUnSubscribeAll>(
            [this](std::shared_ptr<const middleware::SerializationUnSubscribeAll> s)
            { static_cast<Derived*>(this)->_unsubscribe_all(s->subscriber_id()); });
    }
};
 
} // namespace middleware
} // namespace goby
 
#include "goby/zeromq/transport/detail/tags.h"
 
namespace goby
{
namespace middleware
{

template <typename InnerTransporter>
class InterProcessForwarder<InnerTransporter, void>
    : public InterProcessForwarder<InnerTransporter, zeromq::detail::InterProcessTag>
{
  public:
    using Base = InterProcessForwarder<InnerTransporter, zeromq::detail::InterProcessTag>;
 
    [[deprecated("Use zeromq::InterProcessForwarder<> or udpm::InterProcessForwarder<> instead of "
                 "middleware::InterProcessForwarder<>")]]
    explicit InterProcessForwarder(InnerTransporter& inner)
        : Base(inner)
    {
    }
};
 
} // namespace middleware
} // namespace goby
 
#endif