common.hpp

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/*!
 * \file
 * \brief Common parts for Asio's env_infrastructures.
 */

#pragma once

#include <so_5/rt/impl/h/st_env_infrastructure_reuse.hpp>

#include <so_5/h/stdcpp.hpp>

#include <asio.hpp>

namespace so_5 {

namespace extra {

namespace env_infrastructures {

namespace asio {

namespace common {

namespace helpers {

//
// ensure_we_can_handle_this_timer_error_code
//
/*!
 * \brief Helper function which checke error_code value.
 *
 * It returns normally if there is no an error or if the error 
 * is ::asio::error::operation_aborted.
 */
void
ensure_we_can_handle_this_timer_error_code(
    const ::asio::error_code & ec )
    {
        if( ec && ::asio::error::operation_aborted != ec )
            SO_5_THROW_EXCEPTION( rc_unexpected_error,
                    "Only asio::operation_aborted error code can be handled "
                    "by timer handler" );
    }

} /* namespace helpers */

//
// singleshot_timer_holder_t
//
/*!
 * \brief A main part of implementation of single-shot timer.
 */
class singleshot_timer_holder_t : public atomic_refcounted_t
    {
        friend intrusive_ptr_t< singleshot_timer_holder_t >;

        //! Actual Asio's timer.
        ::asio::steady_timer m_timer;
        //! Type of message/signal to be delivered.
        const std::type_index m_type_index;
        //! Instance of message to be delivered.
        const message_ref_t m_msg;
        //! A destination mbox.
        const mbox_t m_mbox;

    public :
        //! Initializing constructor.
        singleshot_timer_holder_t(
            //! Asio's io_context to be used for timer.
            ::asio::io_context & io_svc,
            //! Type of message/signal to be delivered.
            const std::type_index & type_index,
            //! Message instance to be delivered.
            const message_ref_t & msg,
            //! A destination mbox.
            const mbox_t & mbox )
            :   m_timer( io_svc )
            ,   m_type_index( type_index )
            ,   m_msg( msg )
            ,   m_mbox( mbox )
            {}

        //! Cancelation of the timer.
        void
        cancel()
            {
                m_timer.cancel();
            }

        //! Scheduling of timer.
        void
        schedule_from_now(
            //! A pause in message delivery.
            std::chrono::steady_clock::duration pause )
            {
                intrusive_ptr_t< singleshot_timer_holder_t > self{ this };
                m_timer.expires_after( pause );
                m_timer.async_wait(
                    // Timer action shouldn't throw because we don't know
                    // how to repair it.
                    [self]( const ::asio::error_code & ec ) noexcept {
                        helpers::ensure_we_can_handle_this_timer_error_code( ec );
                        if( ::asio::error::operation_aborted == ec )
                            return;

                        ::so_5::rt::impl::mbox_iface_for_timers_t{ self->m_mbox }
                                .deliver_message_from_timer(
                                        self->m_type_index,
                                        self->m_msg );
                    } );
            }
    };

//
// periodic_timer_holder_t
//
/*!
 * \brief A main part of implementation of periodic timer.
 *
 * \note This class is very similar to singleshot_timer_holder_t, but
 * these classes are not related to simplify implemenation of them.
 */
class periodic_timer_holder_t : public atomic_refcounted_t
    {
        friend intrusive_ptr_t< periodic_timer_holder_t >;

        //! Actual Asio's timer.
        ::asio::steady_timer m_timer;
        //! Type of message/signal to be delivered.
        const std::type_index m_type_index;
        //! Instance of message to be delivered.
        const message_ref_t m_msg;
        //! A destination mbox.
        const mbox_t m_mbox;
        //! A repetition period for periodic message delivery.
        const std::chrono::steady_clock::duration m_period;

    public :
        periodic_timer_holder_t(
            //! Asio's io_context to be used for timer.
            ::asio::io_context & io_svc,
            //! Type of message/signal to be delivered.
            const std::type_index & type_index,
            //! Message instance to be delivered.
            const message_ref_t & msg,
            //! A destination mbox.
            const mbox_t & mbox,
            //! A repetition period for periodic message delivery.
            std::chrono::steady_clock::duration period )
            :   m_timer( io_svc )
            ,   m_type_index( type_index )
            ,   m_msg( msg )
            ,   m_mbox( mbox )
            ,   m_period( period )
            {}

        //! Cancelation of the timer.
        void
        cancel()
            {
                m_timer.cancel();
            }

        //! Scheduling of timer.
        void
        schedule_from_now(
            //! A pause in message delivery.
            std::chrono::steady_clock::duration pause )
            {
                intrusive_ptr_t< periodic_timer_holder_t > self{ this };
                m_timer.expires_after( pause );
                m_timer.async_wait(
                    // Timer action shouldn't throw because we don't know
                    // how to repair it.
                    [self]( const ::asio::error_code & ec ) noexcept {
                        helpers::ensure_we_can_handle_this_timer_error_code( ec );
                        if( ::asio::error::operation_aborted == ec )
                            return;

                        ::so_5::rt::impl::mbox_iface_for_timers_t{ self->m_mbox }
                                .deliver_message_from_timer(
                                        self->m_type_index,
                                        self->m_msg );
                        self->schedule_from_now( self->m_period );
                    } );
            }
    };

//
// actual_timer_t
//
/*!
 * \brief A template for implementation of actual timer.
 *
 * \tparam Holder Type of actual timer data. Expected to be
 * periodic_timer_holder_t or singleshot_timer_holder_t.
 */
template< typename Holder >
class actual_timer_t : public timer_t
    {
    public :
        using holder_t = Holder;
        using holder_smart_ptr_t = intrusive_ptr_t< holder_t >;

        actual_timer_t(
            holder_smart_ptr_t holder )
            :   m_holder( std::move(holder) )
            {}
        virtual ~actual_timer_t()
            {
                release();
            }

        virtual bool
        is_active() const noexcept override
            {
                return m_holder;
            }

        virtual void
        release() noexcept override
            {
                if( m_holder )
                    {
                        m_holder->cancel();
                        m_holder.reset();
                    }
            }

    private :
        holder_smart_ptr_t m_holder;
    };

} /* namespace common */

} /* namespace asio */

} /* namespace env_infrastructures */

} /* namespace extra */

} /* namespace so_5 */