Client.h

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/*+-------------------------------------------------------------------------+
  |                       MultiVehicle simulator (libmvsim)                 |
  |                                                                         |
  | Copyright (C) 2014-2020  Jose Luis Blanco Claraco                       |
  | Copyright (C) 2017  Borys Tymchenko (Odessa Polytechnic University)     |
  | Distributed under 3-clause BSD License                                  |
  |   See COPYING                                                           |
  +-------------------------------------------------------------------------+ */

#pragma once

#include <mrpt/system/COutputLogger.h>
#include <mvsim/Comms/common.h>
#include <mvsim/Comms/zmq_fwrds.h>

#include <atomic>
#include <memory>
#include <thread>

namespace mvsim::internal
{
struct InfoPerService;
struct InfoPerSubscribedTopic;
}  // namespace mvsim::internal

namespace mvsim
{
class Client : public mrpt::system::COutputLogger
{
   public:
        Client();
        Client(const std::string& nodeName);

        ~Client();

        void setName(const std::string& nodeName);

        void connect();

        bool connected() const;

        void shutdown() noexcept;

        template <typename T>
        void advertiseTopic(const std::string& topicName);

        void publishTopic(
                const std::string& topicName, const google::protobuf::Message& msg);

        template <typename MSG_T>
        void subscribeTopic(
                const std::string& topicName,
                const std::function<void(const MSG_T&)>& callback);

        template <typename INPUT_MSG_T, typename OUTPUT_MSG_T>
        void advertiseService(
                const std::string& serviceName,
                const std::function<OUTPUT_MSG_T(const INPUT_MSG_T&)>& callback);

        template <typename INPUT_MSG_T, typename OUTPUT_MSG_T>
        void callService(
                const std::string& serviceName, const INPUT_MSG_T& input,
                OUTPUT_MSG_T& output);

        // Overload for python wrapper
        std::string callService(
                const std::string& serviceName, const std::string& inputSerializedMsg);

        struct InfoPerNode
        {
                std::string name;
        };
        std::vector<InfoPerNode> requestListOfNodes();

        struct InfoPerTopic
        {
                std::string name;
                std::string type;
                std::vector<std::string> endpoints, publishers;
        };
        std::vector<InfoPerTopic> requestListOfTopics();

   private:
        struct ZMQImpl;
        std::unique_ptr<ZMQImpl> zmq_;

        std::string serverHostAddress_ = "localhost";
        std::string nodeName_ = "anonymous";

        std::thread serviceInvokerThread_;
        std::thread topicUpdatesThread_;

        void doRegisterClient();
        void doUnregisterClient();

        void internalServiceServingThread();
        void internalTopicUpdatesThread();
        void internalTopicSubscribeThread(internal::InfoPerSubscribedTopic& ipt);

        using service_callback_t =
                std::function<std::shared_ptr<google::protobuf::Message>(
                        const std::string& /*inAsString*/)>;

        void doAdvertiseTopic(
                const std::string& topicName,
                const google::protobuf::Descriptor* descriptor);
        void doAdvertiseService(
                const std::string& serviceName,
                const google::protobuf::Descriptor* descIn,
                const google::protobuf::Descriptor* descOut,
                service_callback_t callback);

        using topic_callback_t = std::function<void(const zmq::message_t& /*m*/)>;

        void doSubscribeTopic(
                const std::string& topicName,
                const google::protobuf::Descriptor* descriptor,
                const topic_callback_t& callback);
        void doCallService(
                const std::string& serviceName, const std::string& inputSerializedMsg,
                mrpt::optional_ref<google::protobuf::Message> outputMsg,
                mrpt::optional_ref<std::string> outputSerializedMsg = std::nullopt,
                mrpt::optional_ref<std::string> outputMsgTypeName = std::nullopt);

        friend struct internal::InfoPerService;
        friend struct internal::InfoPerSubscribedTopic;
};

template <typename T>
void Client::advertiseTopic(const std::string& topicName)
{
        doAdvertiseTopic(topicName, T::descriptor());
}

template <typename INPUT_MSG_T, typename OUTPUT_MSG_T>
void Client::advertiseService(
        const std::string& serviceName,
        const std::function<OUTPUT_MSG_T(const INPUT_MSG_T&)>& callback)
{
        doAdvertiseService(
                serviceName, INPUT_MSG_T::descriptor(), OUTPUT_MSG_T::descriptor(),
                service_callback_t([callback](const std::string& inData) {
                        INPUT_MSG_T in;
                        in.ParseFromString(inData);
                        return std::make_shared<OUTPUT_MSG_T>(callback(in));
                }));
}

template <typename MSG_T>
void Client::subscribeTopic(
        const std::string& topicName,
        const std::function<void(const MSG_T&)>& callback)
{
        doSubscribeTopic(
                topicName, MSG_T::descriptor(),
                topic_callback_t([callback](const zmq::message_t& m) {
                        MSG_T in;
                        mvsim::parseMessage(m, in);
                        callback(in);
                }));
}

template <typename INPUT_MSG_T, typename OUTPUT_MSG_T>
void Client::callService(
        const std::string& serviceName, const INPUT_MSG_T& input,
        OUTPUT_MSG_T& output)
{
        doCallService(serviceName, input.SerializeAsString(), output);
}

}  // namespace mvsim