connection.hpp

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#ifndef EAGINE_MESSAGE_BUS_CONNECTION_HPP
#define EAGINE_MESSAGE_BUS_CONNECTION_HPP
 
#include "../callable_ref.hpp"
#include "../interface.hpp"
#include "../message_id.hpp"
#include "../type_identity.hpp"
#include "../valid_if/positive.hpp"
#include "connection_kind.hpp"
#include "message.hpp"
#include <type_traits>
 
namespace eagine::msgbus {
//------------------------------------------------------------------------------
constexpr const span_size_t min_connection_data_size = 1024;
//------------------------------------------------------------------------------
enum class connection_addr_kind {
    none,
    filepath,
    ipv4
};
 
template <typename Selector>
constexpr auto
enumerator_mapping(type_identity<connection_addr_kind>, Selector) noexcept {
    return enumerator_map_type<connection_addr_kind, 3>{
      {{"none", connection_addr_kind::none},
       {"filepath", connection_addr_kind::filepath},
       {"ipv4", connection_addr_kind::ipv4}}};
}
 
template <connection_addr_kind Kind>
using connection_addr_kind_tag =
  std::integral_constant<connection_addr_kind, Kind>;
//------------------------------------------------------------------------------
enum class connection_protocol {
    stream,
    datagram,
    message
};
 
template <typename Selector>
constexpr auto
enumerator_mapping(type_identity<connection_protocol>, Selector) noexcept {
    return enumerator_map_type<connection_protocol, 3>{
      {{"stream", connection_protocol::stream},
       {"datagram", connection_protocol::datagram},
       {"message", connection_protocol::message}}};
}
 
template <connection_protocol Proto>
using connection_protocol_tag =
  std::integral_constant<connection_protocol, Proto>;
 
using stream_protocol_tag =
  connection_protocol_tag<connection_protocol::stream>;
 
using datagram_protocol_tag =
  connection_protocol_tag<connection_protocol::datagram>;
//------------------------------------------------------------------------------
struct connection_info : interface<connection_info> {
 
    virtual auto kind() -> connection_kind = 0;
 
    virtual auto addr_kind() -> connection_addr_kind = 0;
 
    virtual auto type_id() -> identifier = 0;
};
//------------------------------------------------------------------------------
struct connection : connection_info {
 
    using fetch_handler =
      callable_ref<bool(message_id, message_age, const message_view&)>;
 
    virtual auto update() -> bool {
        return false;
    }
 
    virtual void cleanup() {}
 
    virtual auto is_usable() -> bool {
        return true;
    }
 
    virtual auto max_data_size() -> valid_if_positive<span_size_t> {
        return {0};
    }
 
    virtual auto send(message_id msg_id, const message_view&) -> bool = 0;
 
    virtual auto fetch_messages(fetch_handler handler) -> bool = 0;
};
//------------------------------------------------------------------------------
struct connection_user : interface<connection_user> {
 
    virtual auto add_connection(std::unique_ptr<connection>) -> bool = 0;
};
//------------------------------------------------------------------------------
} // namespace eagine::msgbus
 
#endif // EAGINE_MESSAGE_BUS_CONNECTION_HPP