diff options
Diffstat (limited to 'src/network/network_command.cpp')
| -rw-r--r-- | src/network/network_command.cpp | 156 |
1 files changed, 107 insertions, 49 deletions
diff --git a/src/network/network_command.cpp b/src/network/network_command.cpp index 58de73b19..28300310b 100644 --- a/src/network/network_command.cpp +++ b/src/network/network_command.cpp @@ -53,55 +53,95 @@ #include "../safeguards.h" -/** Table with all the callbacks we'll use for conversion*/ -static CommandCallback * const _callback_table[] = { - /* 0x00 */ nullptr, - /* 0x01 */ CcBuildPrimaryVehicle, - /* 0x02 */ CcBuildAirport, - /* 0x03 */ CcBuildBridge, - /* 0x04 */ CcPlaySound_CONSTRUCTION_WATER, - /* 0x05 */ CcBuildDocks, - /* 0x06 */ CcFoundTown, - /* 0x07 */ CcBuildRoadTunnel, - /* 0x08 */ CcBuildRailTunnel, - /* 0x09 */ CcBuildWagon, - /* 0x0A */ CcRoadDepot, - /* 0x0B */ CcRailDepot, - /* 0x0C */ CcPlaceSign, - /* 0x0D */ CcPlaySound_EXPLOSION, - /* 0x0E */ CcPlaySound_CONSTRUCTION_OTHER, - /* 0x0F */ CcPlaySound_CONSTRUCTION_RAIL, - /* 0x10 */ CcStation, - /* 0x11 */ CcTerraform, - /* 0x12 */ CcAI, - /* 0x13 */ CcCloneVehicle, - /* 0x14 */ nullptr, - /* 0x15 */ CcCreateGroup, - /* 0x16 */ CcFoundRandomTown, - /* 0x17 */ CcRoadStop, - /* 0x18 */ CcBuildIndustry, - /* 0x19 */ CcStartStopVehicle, - /* 0x1A */ CcGame, - /* 0x1B */ CcAddVehicleNewGroup, -}; +/** Typed list of all possible callbacks. */ +static constexpr auto _callback_tuple = std::make_tuple( + (CommandCallback *)nullptr, // Make sure this is actually a pointer-to-function. + &CcBuildPrimaryVehicle, + &CcBuildAirport, + &CcBuildBridge, + &CcPlaySound_CONSTRUCTION_WATER, + &CcBuildDocks, + &CcFoundTown, + &CcBuildRoadTunnel, + &CcBuildRailTunnel, + &CcBuildWagon, + &CcRoadDepot, + &CcRailDepot, + &CcPlaceSign, + &CcPlaySound_EXPLOSION, + &CcPlaySound_CONSTRUCTION_OTHER, + &CcPlaySound_CONSTRUCTION_RAIL, + &CcStation, + &CcTerraform, + &CcAI, + &CcCloneVehicle, + &CcCreateGroup, + &CcFoundRandomTown, + &CcRoadStop, + &CcBuildIndustry, + &CcStartStopVehicle, + &CcGame, + &CcAddVehicleNewGroup +); + +#ifdef SILENCE_GCC_FUNCTION_POINTER_CAST +/* + * We cast specialized function pointers to a generic one, but don't use the + * converted value to call the function, which is safe, except that GCC + * helpfully thinks it is not. + * + * "Any pointer to function can be converted to a pointer to a different function type. + * Calling the function through a pointer to a different function type is undefined, + * but converting such pointer back to pointer to the original function type yields + * the pointer to the original function." */ +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Wcast-function-type" +#endif + +/* Helpers to generate the callback table from the callback list. */ + +inline constexpr size_t _callback_tuple_size = std::tuple_size_v<decltype(_callback_tuple)>; + +template <size_t... i> +inline auto MakeCallbackTable(std::index_sequence<i...>) noexcept +{ + return std::array<CommandCallback *, sizeof...(i)>{{ reinterpret_cast<CommandCallback *>(reinterpret_cast<void(*)()>(std::get<i>(_callback_tuple)))... }}; // MingW64 fails linking when casting a pointer to its own type. To work around, cast it to some other type first. +} + +/** Type-erased table of callbacks. */ +static auto _callback_table = MakeCallbackTable(std::make_index_sequence<_callback_tuple_size>{}); + /* Helpers to generate the command dispatch table from the command traits. */ template <Commands Tcmd> static CommandDataBuffer SanitizeCmdStrings(const CommandDataBuffer &data); -template <Commands Tcmd> static void UnpackNetworkCommand(const CommandPacket *cp); +template <Commands Tcmd, size_t cb> static void UnpackNetworkCommand(const CommandPacket *cp); template <Commands Tcmd> static void NetworkReplaceCommandClientId(CommandPacket &cp, ClientID client_id); +using UnpackNetworkCommandProc = void (*)(const CommandPacket *); +using UnpackDispatchT = std::array<UnpackNetworkCommandProc, _callback_tuple_size>; struct CommandDispatch { CommandDataBuffer(*Sanitize)(const CommandDataBuffer &); void (*ReplaceClientId)(CommandPacket &, ClientID); - void (*Unpack)(const CommandPacket *); + UnpackDispatchT Unpack; }; -template<typename T, T... i> -inline constexpr auto MakeDispatchTable(std::integer_sequence<T, i...>) noexcept +template <Commands Tcmd, size_t... i> +constexpr UnpackDispatchT MakeUnpackNetworkCommand(std::index_sequence<i...>) noexcept { - return std::array<CommandDispatch, sizeof...(i)>{{ { &SanitizeCmdStrings<static_cast<Commands>(i)>, &NetworkReplaceCommandClientId<static_cast<Commands>(i)>, &UnpackNetworkCommand<static_cast<Commands>(i)> }... }}; + return UnpackDispatchT{{ {&UnpackNetworkCommand<Tcmd, i>}... }}; } -static constexpr auto _cmd_dispatch = MakeDispatchTable(std::make_integer_sequence<std::underlying_type_t<Commands>, CMD_END>{}); + +template <typename T, T... i, size_t... j> +inline constexpr auto MakeDispatchTable(std::integer_sequence<T, i...>, std::index_sequence<j...>) noexcept +{ + return std::array<CommandDispatch, sizeof...(i)>{{ { &SanitizeCmdStrings<static_cast<Commands>(i)>, &NetworkReplaceCommandClientId<static_cast<Commands>(i)>, MakeUnpackNetworkCommand<static_cast<Commands>(i)>(std::make_index_sequence<_callback_tuple_size>{}) }... }}; +} +/** Command dispatch table. */ +static constexpr auto _cmd_dispatch = MakeDispatchTable(std::make_integer_sequence<std::underlying_type_t<Commands>, CMD_END>{}, std::make_index_sequence<_callback_tuple_size>{}); + +#ifdef SILENCE_GCC_FUNCTION_POINTER_CAST +# pragma GCC diagnostic pop +#endif /** @@ -180,6 +220,20 @@ static CommandQueue _local_execution_queue; /** + * Find the callback index of a callback pointer. + * @param callback Address of callback to search for. + * @return Callback index or std::numeric_limits<size_t>::max() if the function wasn't found in the callback list. + */ +static size_t FindCallbackIndex(CommandCallback *callback) +{ + if (auto it = std::find(std::cbegin(_callback_table), std::cend(_callback_table), callback); it != std::cend(_callback_table)) { + return static_cast<size_t>(std::distance(std::cbegin(_callback_table), it)); + } + + return std::numeric_limits<size_t>::max(); +} + +/** * Prepare a DoCommand to be send over the network * @param cmd The command to execute (a CMD_* value) * @param err_message Message prefix to show on error @@ -259,7 +313,9 @@ void NetworkExecuteLocalCommandQueue() /* We can execute this command */ _current_company = cp->company; - _cmd_dispatch[cp->cmd].Unpack(cp); + size_t cb_index = FindCallbackIndex(cp->callback); + assert(cb_index < _callback_tuple_size); + _cmd_dispatch[cp->cmd].Unpack[cb_index](cp); queue.Pop(); delete cp; @@ -354,7 +410,7 @@ const char *NetworkGameSocketHandler::ReceiveCommand(Packet *p, CommandPacket *c cp->data = _cmd_dispatch[cp->cmd].Sanitize(p->Recv_buffer()); byte callback = p->Recv_uint8(); - if (callback >= lengthof(_callback_table)) return "invalid callback"; + if (callback >= _callback_table.size()) return "invalid callback"; cp->callback = _callback_table[callback]; return nullptr; @@ -373,16 +429,12 @@ void NetworkGameSocketHandler::SendCommand(Packet *p, const CommandPacket *cp) p->Send_uint32(cp->tile); p->Send_buffer(cp->data); - byte callback = 0; - while (callback < lengthof(_callback_table) && _callback_table[callback] != cp->callback) { - callback++; - } - - if (callback == lengthof(_callback_table)) { + size_t callback = FindCallbackIndex(cp->callback); + if (callback > UINT8_MAX) { Debug(net, 0, "Unknown callback for command; no callback sent (command: {})", cp->cmd); callback = 0; // _callback_table[0] == nullptr } - p->Send_uint8 (callback); + p->Send_uint8 ((uint8)callback); } /** Helper to process a single ClientID argument. */ @@ -455,9 +507,15 @@ CommandDataBuffer SanitizeCmdStrings(const CommandDataBuffer &data) return EndianBufferWriter<CommandDataBuffer>::FromValue(args); } -template <Commands Tcmd> -void UnpackNetworkCommand(const CommandPacket *cp) +/** + * Unpack a generic command packet into its actual typed components. + * @tparam Tcmd Command type to be unpacked. + * @tparam Tcb Index into the callback list. + * @param cp Command packet to unpack. + */ +template <Commands Tcmd, size_t Tcb> +void UnpackNetworkCommand(const CommandPacket* cp) { auto args = EndianBufferReader::ToValue<typename CommandTraits<Tcmd>::Args>(cp->data); - Command<Tcmd>::PostFromNet(cp->err_msg, cp->callback, cp->my_cmd, cp->tile, args); + Command<Tcmd>::PostFromNet(cp->err_msg, std::get<Tcb>(_callback_tuple), cp->my_cmd, cp->tile, args); } |