shmPublisher.hpp

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#ifndef RTCTK_TELSUB_SHMPUBLISHER_HPP
#define RTCTK_TELSUB_SHMPUBLISHER_HPP
#include <network/optional.hpp>
#include <system_error>
 
#include <ipcq/writer.hpp>
 
#include <rtctk/telSub/shmPublisherIf.hpp>
 
namespace rtctk::telSub {

template <class UserTopicType, class DataBlender, class ShmWriter = ipcq::Writer<UserTopicType>>
class ShmPublisher final : public ShmPublisherIf {
public:
    ShmPublisher(ShmWriter&& shm_writer, DataBlender& blender);

    PublisherError Publish(const DataSamplesView& samples) noexcept override;
 
    void CloseQueue() noexcept override;
 
private:
    UserTopicType m_topic;
    DataBlender& m_blender;
    ShmWriter m_shm;
};

template <class UserTopicType, class DataBlender, class ShmWriter>
auto MakeShmPublisher(ShmWriter&& shm_writer, DataBlender& blender)
    -> std::unique_ptr<ShmPublisher<UserTopicType, DataBlender, ShmWriter>> {
    return std::make_unique<ShmPublisher<UserTopicType, DataBlender, ShmWriter>>(
        std::forward<ShmWriter>(shm_writer), blender);
}
 
template <class UserTopicType, class DataBlender, class ShmWriter>
ShmPublisher<UserTopicType, DataBlender, ShmWriter>::ShmPublisher(ShmWriter&& shm_writer,
                                                                  DataBlender& blender)
    : m_topic(), m_blender(blender), m_shm(std::move(shm_writer)) {
    static_assert(std::is_invocable_r_v<std::error_code,
                                        DataBlender,
                                        const rtctk::telSub::DataSamplesView&,
                                        UserTopicType&>,
                  "DataBlender must have the signature "
                  "`std::error_code(const rtctk::telSub::DataSamplesView&, "
                  "UserTopicType&)`");
}
 
template <class UserTopicType, class DataBlender, class ShmWriter>
ShmPublisherIf::PublisherError ShmPublisher<UserTopicType, DataBlender, ShmWriter>::Publish(
    const DataSamplesView& samples) noexcept {
    // Invoke blender and write to SHM queue.
    if (auto err = m_blender(samples, m_topic); !err) /*[[likely]]*/ {
        auto shm_err = m_shm.Write(m_topic, ipcq::Notify::All);
        if (shm_err) {
            return ShmError{shm_err};
        }
        return {};
    } else /*[[unlikely]]*/ {
        return BlenderError{err};
    }
}
 
template <class UserTopicType, class DataBlender, class ShmWriter>
void ShmPublisher<UserTopicType, DataBlender, ShmWriter>::CloseQueue() noexcept {
    m_shm.Close();
}
 
}  // namespace rtctk::telSub
 
#endif  // RTCTK_TELSUB_SHMPUBLISHER_HPP