# autoreplace_cmd.cpp

Go to the documentation of this file.

    00001 /* $Id: autoreplace_cmd.cpp 20585 2010-08-20 18:28:46Z rubidium $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
    00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
    00008  */
    00009
    00012 #include "stdafx.h"
    00013 #include "company_func.h"
    00014 #include "train.h"
    00015 #include "rail.h"
    00016 #include "command_func.h"
    00017 #include "engine_base.h"
    00018 #include "engine_func.h"
    00019 #include "vehicle_func.h"
    00020 #include "functions.h"
    00021 #include "autoreplace_func.h"
    00022 #include "articulated_vehicles.h"
    00023 #include "core/random_func.hpp"
    00024
    00025 #include "table/strings.h"
    00026
    00027 extern void ChangeVehicleViewports(VehicleID from_index, VehicleID to_index);
    00028 extern void ChangeVehicleNews(VehicleID from_index, VehicleID to_index);
    00029 extern void ChangeVehicleViewWindow(VehicleID from_index, VehicleID to_index);
    00030
    00037 static bool EnginesHaveCargoInCommon(EngineID engine_a, EngineID engine_b)
    00038 {
    00039   uint32 available_cargos_a = GetUnionOfArticulatedRefitMasks(engine_a, true);
    00040   uint32 available_cargos_b = GetUnionOfArticulatedRefitMasks(engine_b, true);
    00041   return (available_cargos_a == 0 || available_cargos_b == 0 || (available_cargos_a & available_cargos_b) != 0);
    00042 }
    00043
    00051 bool CheckAutoreplaceValidity(EngineID from, EngineID to, CompanyID company)
    00052 {
    00053   assert(Engine::IsValidID(from) && Engine::IsValidID(to));
    00054
    00055   /* we can't replace an engine into itself (that would be autorenew) */
    00056   if (from == to) return false;
    00057
    00058   const Engine *e_from = Engine::Get(from);
    00059   const Engine *e_to = Engine::Get(to);
    00060   VehicleType type = e_from->type;
    00061
    00062   /* check that the new vehicle type is available to the company and its type is the same as the original one */
    00063   if (!IsEngineBuildable(to, type, company)) return false;
    00064
    00065   switch (type) {
    00066     case VEH_TRAIN: {
    00067       /* make sure the railtypes are compatible */
    00068       if ((GetRailTypeInfo(e_from->u.rail.railtype)->compatible_railtypes & GetRailTypeInfo(e_to->u.rail.railtype)->compatible_railtypes) == 0) return false;
    00069
    00070       /* make sure we do not replace wagons with engines or vise versa */
    00071       if ((e_from->u.rail.railveh_type == RAILVEH_WAGON) != (e_to->u.rail.railveh_type == RAILVEH_WAGON)) return false;
    00072       break;
    00073     }
    00074
    00075     case VEH_ROAD:
    00076       /* make sure that we do not replace a tram with a normal road vehicles or vise versa */
    00077       if (HasBit(e_from->info.misc_flags, EF_ROAD_TRAM) != HasBit(e_to->info.misc_flags, EF_ROAD_TRAM)) return false;
    00078       break;
    00079
    00080     case VEH_AIRCRAFT:
    00081       /* make sure that we do not replace a plane with a helicopter or vise versa */
    00082       if ((e_from->u.air.subtype & AIR_CTOL) != (e_to->u.air.subtype & AIR_CTOL)) return false;
    00083       break;
    00084
    00085     default: break;
    00086   }
    00087
    00088   /* the engines needs to be able to carry the same cargo */
    00089   return EnginesHaveCargoInCommon(from, to);
    00090 }
    00091
    00097 static void TransferCargo(Vehicle *old_veh, Vehicle *new_head, bool part_of_chain)
    00098 {
    00099   assert(!part_of_chain || new_head->IsPrimaryVehicle());
    00100   /* Loop through source parts */
    00101   for (Vehicle *src = old_veh; src != NULL; src = src->Next()) {
    00102     if (!part_of_chain && src->type == VEH_TRAIN && src != old_veh && src != Train::From(old_veh)->other_multiheaded_part && !Train::From(src)->IsArticulatedPart()) {
    00103       /* Skip vehicles, which do not belong to old_veh */
    00104       src = Train::From(src)->GetLastEnginePart();
    00105       continue;
    00106     }
    00107     if (src->cargo_type >= NUM_CARGO || src->cargo.Count() == 0) continue;
    00108
    00109     /* Find free space in the new chain */
    00110     for (Vehicle *dest = new_head; dest != NULL && src->cargo.Count() > 0; dest = dest->Next()) {
    00111       if (!part_of_chain && dest->type == VEH_TRAIN && dest != new_head && dest != Train::From(new_head)->other_multiheaded_part && !Train::From(dest)->IsArticulatedPart()) {
    00112         /* Skip vehicles, which do not belong to new_head */
    00113         dest = Train::From(dest)->GetLastEnginePart();
    00114         continue;
    00115       }
    00116       if (dest->cargo_type != src->cargo_type) continue;
    00117
    00118       uint amount = min(src->cargo.Count(), dest->cargo_cap - dest->cargo.Count());
    00119       if (amount <= 0) continue;
    00120
    00121       src->cargo.MoveTo(&dest->cargo, amount, VehicleCargoList::MTA_UNLOAD, NULL);
    00122     }
    00123   }
    00124
    00125   /* Update train weight etc., the old vehicle will be sold anyway */
    00126   if (part_of_chain && new_head->type == VEH_TRAIN) Train::From(new_head)->ConsistChanged(true);
    00127 }
    00128
    00135 static bool VerifyAutoreplaceRefitForOrders(const Vehicle *v, EngineID engine_type)
    00136 {
    00137   const Order *o;
    00138   const Vehicle *u;
    00139
    00140   uint32 union_refit_mask_a = GetUnionOfArticulatedRefitMasks(v->engine_type, false);
    00141   uint32 union_refit_mask_b = GetUnionOfArticulatedRefitMasks(engine_type, false);
    00142
    00143   if (v->type == VEH_TRAIN) {
    00144     u = v->First();
    00145   } else {
    00146     u = v;
    00147   }
    00148
    00149   FOR_VEHICLE_ORDERS(u, o) {
    00150     if (!o->IsRefit()) continue;
    00151     CargoID cargo_type = o->GetRefitCargo();
    00152
    00153     if (!HasBit(union_refit_mask_a, cargo_type)) continue;
    00154     if (!HasBit(union_refit_mask_b, cargo_type)) return false;
    00155   }
    00156
    00157   return true;
    00158 }
    00159
    00169 static CargoID GetNewCargoTypeForReplace(Vehicle *v, EngineID engine_type, bool part_of_chain)
    00170 {
    00171   CargoID cargo_type;
    00172   uint32 available_cargo_types, union_mask;
    00173   GetArticulatedRefitMasks(engine_type, true, &union_mask, &available_cargo_types);
    00174
    00175   if (union_mask == 0) return CT_NO_REFIT; // Don't try to refit an engine with no cargo capacity
    00176
    00177   if (IsArticulatedVehicleCarryingDifferentCargos(v, &cargo_type)) return CT_INVALID; // We cannot refit to mixed cargos in an automated way
    00178
    00179   if (cargo_type == CT_INVALID) {
    00180     if (v->type != VEH_TRAIN) return CT_NO_REFIT; // If the vehicle does not carry anything at all, every replacement is fine.
    00181
    00182     if (!part_of_chain) return CT_NO_REFIT;
    00183
    00184     /* the old engine didn't have cargo capacity, but the new one does
    00185      * now we will figure out what cargo the train is carrying and refit to fit this */
    00186
    00187     for (v = v->First(); v != NULL; v = v->Next()) {
    00188       if (v->cargo_cap == 0) continue;
    00189       /* Now we found a cargo type being carried on the train and we will see if it is possible to carry to this one */
    00190       if (HasBit(available_cargo_types, v->cargo_type)) {
    00191         /* Do we have to refit the vehicle, or is it already carrying the right cargo? */
    00192         CargoArray default_capacity = GetCapacityOfArticulatedParts(engine_type);
    00193         for (CargoID cid = 0; cid < NUM_CARGO; cid++) {
    00194           if (cid != v->cargo_type && default_capacity[cid] > 0) return v->cargo_type;
    00195         }
    00196
    00197         return CT_NO_REFIT;
    00198       }
    00199     }
    00200
    00201     return CT_NO_REFIT; // We failed to find a cargo type on the old vehicle and we will not refit the new one
    00202   } else {
    00203     if (!HasBit(available_cargo_types, cargo_type)) return CT_INVALID; // We can't refit the vehicle to carry the cargo we want
    00204
    00205     if (part_of_chain && !VerifyAutoreplaceRefitForOrders(v, engine_type)) return CT_INVALID; // Some refit orders lose their effect
    00206
    00207     /* Do we have to refit the vehicle, or is it already carrying the right cargo? */
    00208     CargoArray default_capacity = GetCapacityOfArticulatedParts(engine_type);
    00209     for (CargoID cid = 0; cid < NUM_CARGO; cid++) {
    00210       if (cid != cargo_type && default_capacity[cid] > 0) return cargo_type;
    00211     }
    00212
    00213     return CT_NO_REFIT;
    00214   }
    00215 }
    00216
    00222 static EngineID GetNewEngineType(const Vehicle *v, const Company *c)
    00223 {
    00224   assert(v->type != VEH_TRAIN || !Train::From(v)->IsArticulatedPart());
    00225
    00226   if (v->type == VEH_TRAIN && Train::From(v)->IsRearDualheaded()) {
    00227     /* we build the rear ends of multiheaded trains with the front ones */
    00228     return INVALID_ENGINE;
    00229   }
    00230
    00231   EngineID e = EngineReplacementForCompany(c, v->engine_type, v->group_id);
    00232
    00233   if (e != INVALID_ENGINE && IsEngineBuildable(e, v->type, _current_company)) {
    00234     return e;
    00235   }
    00236
    00237   if (v->NeedsAutorenewing(c) && // replace if engine is too old
    00238       IsEngineBuildable(v->engine_type, v->type, _current_company)) { // engine can still be build
    00239     return v->engine_type;
    00240   }
    00241
    00242   return INVALID_ENGINE;
    00243 }
    00244
    00252 static CommandCost BuildReplacementVehicle(Vehicle *old_veh, Vehicle **new_vehicle, bool part_of_chain)
    00253 {
    00254   *new_vehicle = NULL;
    00255
    00256   /* Shall the vehicle be replaced? */
    00257   const Company *c = Company::Get(_current_company);
    00258   EngineID e = GetNewEngineType(old_veh, c);
    00259   if (e == INVALID_ENGINE) return CommandCost(); // neither autoreplace is set, nor autorenew is triggered
    00260
    00261   /* Does it need to be refitted */
    00262   CargoID refit_cargo = GetNewCargoTypeForReplace(old_veh, e, part_of_chain);
    00263   if (refit_cargo == CT_INVALID) return CommandCost(); // incompatible cargos
    00264
    00265   /* Build the new vehicle */
    00266   CommandCost cost = DoCommand(old_veh->tile, e, 0, DC_EXEC | DC_AUTOREPLACE, GetCmdBuildVeh(old_veh));
    00267   if (cost.Failed()) return cost;
    00268
    00269   Vehicle *new_veh = Vehicle::Get(_new_vehicle_id);
    00270   *new_vehicle = new_veh;
    00271
    00272   /* Refit the vehicle if needed */
    00273   byte subtype = GetBestFittingSubType(old_veh, new_veh);
    00274   /* If the subtype isn't zero and the refit cargo is not set,
    00275    * we're better off setting the refit cargo too. */
    00276   if (subtype != 0 && refit_cargo == CT_NO_REFIT) refit_cargo = old_veh->cargo_type;
    00277
    00278   if (refit_cargo != CT_NO_REFIT) {
    00279     cost.AddCost(DoCommand(0, new_veh->index, refit_cargo | (subtype << 8), DC_EXEC, GetCmdRefitVeh(new_veh)));
    00280     assert(cost.Succeeded()); // This should be ensured by GetNewCargoTypeForReplace()
    00281   }
    00282
    00283   /* Try to reverse the vehicle, but do not care if it fails as the new type might not be reversible */
    00284   if (new_veh->type == VEH_TRAIN && HasBit(Train::From(old_veh)->flags, VRF_REVERSE_DIRECTION)) {
    00285     DoCommand(0, new_veh->index, true, DC_EXEC, CMD_REVERSE_TRAIN_DIRECTION);
    00286   }
    00287
    00288   return cost;
    00289 }
    00290
    00296 static inline CommandCost StartStopVehicle(const Vehicle *v, bool evaluate_callback)
    00297 {
    00298   return DoCommand(0, v->index, evaluate_callback ? 1 : 0, DC_EXEC | DC_AUTOREPLACE, CMD_START_STOP_VEHICLE);
    00299 }
    00300
    00308 static inline CommandCost MoveVehicle(const Vehicle *v, const Vehicle *after, DoCommandFlag flags, bool whole_chain)
    00309 {
    00310   return DoCommand(0, v->index | (after != NULL ? after->index : INVALID_VEHICLE) << 16, whole_chain ? 1 : 0, flags, CMD_MOVE_RAIL_VEHICLE);
    00311 }
    00312
    00318 static CommandCost CopyHeadSpecificThings(Vehicle *old_head, Vehicle *new_head, DoCommandFlag flags)
    00319 {
    00320   CommandCost cost = CommandCost();
    00321
    00322   /* Share orders */
    00323   if (cost.Succeeded() && old_head != new_head) cost.AddCost(DoCommand(0, (old_head->index << 16) | new_head->index, CO_SHARE, DC_EXEC, CMD_CLONE_ORDER));
    00324
    00325   /* Copy group membership */
    00326   if (cost.Succeeded() && old_head != new_head) cost.AddCost(DoCommand(0, old_head->group_id, new_head->index, DC_EXEC, CMD_ADD_VEHICLE_GROUP));
    00327
    00328   /* Perform start/stop check whether the new vehicle suits newgrf restrictions etc. */
    00329   if (cost.Succeeded()) {
    00330     /* Start the vehicle, might be denied by certain things */
    00331     assert((new_head->vehstatus & VS_STOPPED) != 0);
    00332     cost.AddCost(StartStopVehicle(new_head, true));
    00333
    00334     /* Stop the vehicle again, but do not care about evil newgrfs allowing starting but not stopping :p */
    00335     if (cost.Succeeded()) cost.AddCost(StartStopVehicle(new_head, false));
    00336   }
    00337
    00338   /* Last do those things which do never fail (resp. we do not care about), but which are not undo-able */
    00339   if (cost.Succeeded() && old_head != new_head && (flags & DC_EXEC) != 0) {
    00340     /* Copy vehicle name */
    00341     if (old_head->name != NULL) {
    00342       DoCommand(0, new_head->index, 0, DC_EXEC | DC_AUTOREPLACE, CMD_RENAME_VEHICLE, old_head->name);
    00343     }
    00344
    00345     /* Copy other things which cannot be copied by a command and which shall not stay resetted from the build vehicle command */
    00346     new_head->CopyVehicleConfigAndStatistics(old_head);
    00347
    00348     /* Switch vehicle windows/news to the new vehicle, so they are not closed/deleted when the old vehicle is sold */
    00349     ChangeVehicleViewports(old_head->index, new_head->index);
    00350     ChangeVehicleViewWindow(old_head->index, new_head->index);
    00351     ChangeVehicleNews(old_head->index, new_head->index);
    00352   }
    00353
    00354   return cost;
    00355 }
    00356
    00363 static CommandCost ReplaceFreeUnit(Vehicle **single_unit, DoCommandFlag flags, bool *nothing_to_do)
    00364 {
    00365   Train *old_v = Train::From(*single_unit);
    00366   assert(!old_v->IsArticulatedPart() && !old_v->IsRearDualheaded());
    00367
    00368   CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES, 0);
    00369
    00370   /* Build and refit replacement vehicle */
    00371   Vehicle *new_v = NULL;
    00372   cost.AddCost(BuildReplacementVehicle(old_v, &new_v, false));
    00373
    00374   /* Was a new vehicle constructed? */
    00375   if (cost.Succeeded() && new_v != NULL) {
    00376     *nothing_to_do = false;
    00377
    00378     if ((flags & DC_EXEC) != 0) {
    00379       /* Move the new vehicle behind the old */
    00380       MoveVehicle(new_v, old_v, DC_EXEC, false);
    00381
    00382       /* Take over cargo
    00383        * Note: We do only transfer cargo from the old to the new vehicle.
    00384        *       I.e. we do not transfer remaining cargo to other vehicles.
    00385        *       Else you would also need to consider moving cargo to other free chains,
    00386        *       or doing the same in ReplaceChain(), which would be quite troublesome.
    00387        */
    00388       TransferCargo(old_v, new_v, false);
    00389
    00390       *single_unit = new_v;
    00391     }
    00392
    00393     /* Sell the old vehicle */
    00394     cost.AddCost(DoCommand(0, old_v->index, 0, flags, GetCmdSellVeh(old_v)));
    00395
    00396     /* If we are not in DC_EXEC undo everything */
    00397     if ((flags & DC_EXEC) == 0) {
    00398       DoCommand(0, new_v->index, 0, DC_EXEC, GetCmdSellVeh(new_v));
    00399     }
    00400   }
    00401
    00402   return cost;
    00403 }
    00404
    00412 static CommandCost ReplaceChain(Vehicle **chain, DoCommandFlag flags, bool wagon_removal, bool *nothing_to_do)
    00413 {
    00414   Vehicle *old_head = *chain;
    00415   assert(old_head->IsPrimaryVehicle());
    00416
    00417   CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES, 0);
    00418
    00419   if (old_head->type == VEH_TRAIN) {
    00420     /* Store the length of the old vehicle chain, rounded up to whole tiles */
    00421     uint16 old_total_length = (Train::From(old_head)->tcache.cached_total_length + TILE_SIZE - 1) / TILE_SIZE * TILE_SIZE;
    00422
    00423     int num_units = 0;
    00424     for (Train *w = Train::From(old_head); w != NULL; w = w->GetNextUnit()) num_units++;
    00425
    00426     Train **old_vehs = CallocT<Train *>(num_units);
    00427     Train **new_vehs = CallocT<Train *>(num_units);
    00428     Money *new_costs = MallocT<Money>(num_units);
    00429
    00430     /* Collect vehicles and build replacements
    00431      * Note: The replacement vehicles can only successfully build as long as the old vehicles are still in their chain */
    00432     int i;
    00433     Train *w;
    00434     for (w = Train::From(old_head), i = 0; w != NULL; w = w->GetNextUnit(), i++) {
    00435       assert(i < num_units);
    00436       old_vehs[i] = w;
    00437
    00438       CommandCost ret = BuildReplacementVehicle(old_vehs[i], (Vehicle**)&new_vehs[i], true);
    00439       cost.AddCost(ret);
    00440       if (cost.Failed()) break;
    00441
    00442       new_costs[i] = ret.GetCost();
    00443       if (new_vehs[i] != NULL) *nothing_to_do = false;
    00444     }
    00445     Train *new_head = (new_vehs[0] != NULL ? new_vehs[0] : old_vehs[0]);
    00446
    00447     /* Note: When autoreplace has already failed here, old_vehs[] is not completely initialized. But it is also not needed. */
    00448     if (cost.Succeeded()) {
    00449       /* Separate the head, so we can start constructing the new chain */
    00450       Train *second = Train::From(old_head)->GetNextUnit();
    00451       if (second != NULL) cost.AddCost(MoveVehicle(second, NULL, DC_EXEC | DC_AUTOREPLACE, true));
    00452
    00453       assert(Train::From(new_head)->GetNextUnit() == NULL);
    00454
    00455       /* Append engines to the new chain
    00456        * We do this from back to front, so that the head of the temporary vehicle chain does not change all the time.
    00457        * That way we also have less trouble when exceeding the unitnumber limit.
    00458        * OTOH the vehicle attach callback is more expensive this way :s */
    00459       Train *last_engine = NULL;
    00460       if (cost.Succeeded()) {
    00461         for (int i = num_units - 1; i > 0; i--) {
    00462           Train *append = (new_vehs[i] != NULL ? new_vehs[i] : old_vehs[i]);
    00463
    00464           if (RailVehInfo(append->engine_type)->railveh_type == RAILVEH_WAGON) continue;
    00465
    00466           if (new_vehs[i] != NULL) {
    00467             /* Move the old engine to a separate row with DC_AUTOREPLACE. Else
    00468              * moving the wagon in front may fail later due to unitnumber limit.
    00469              * (We have to attach wagons without DC_AUTOREPLACE.) */
    00470             MoveVehicle(old_vehs[i], NULL, DC_EXEC | DC_AUTOREPLACE, false);
    00471           }
    00472
    00473           if (last_engine == NULL) last_engine = append;
    00474           cost.AddCost(MoveVehicle(append, new_head, DC_EXEC, false));
    00475           if (cost.Failed()) break;
    00476         }
    00477         if (last_engine == NULL) last_engine = new_head;
    00478       }
    00479
    00480       /* When wagon removal is enabled and the new engines without any wagons are already longer than the old, we have to fail */
    00481       if (cost.Succeeded() && wagon_removal && new_head->tcache.cached_total_length > old_total_length) cost = CommandCost(STR_ERROR_TRAIN_TOO_LONG_AFTER_REPLACEMENT);
    00482
    00483       /* Append/insert wagons into the new vehicle chain
    00484        * We do this from back to front, so we can stop when wagon removal or maximum train length (i.e. from mammoth-train setting) is triggered.
    00485        */
    00486       if (cost.Succeeded()) {
    00487         for (int i = num_units - 1; i > 0; i--) {
    00488           assert(last_engine != NULL);
    00489           Vehicle *append = (new_vehs[i] != NULL ? new_vehs[i] : old_vehs[i]);
    00490
    00491           if (RailVehInfo(append->engine_type)->railveh_type == RAILVEH_WAGON) {
    00492             /* Insert wagon after 'last_engine' */
    00493             CommandCost res = MoveVehicle(append, last_engine, DC_EXEC, false);
    00494
    00495             if (res.Succeeded() && wagon_removal && new_head->tcache.cached_total_length > old_total_length) {
    00496               MoveVehicle(append, NULL, DC_EXEC | DC_AUTOREPLACE, false);
    00497               break;
    00498             }
    00499
    00500             cost.AddCost(res);
    00501             if (cost.Failed()) break;
    00502           } else {
    00503             /* We have reached 'last_engine', continue with the next engine towards the front */
    00504             assert(append == last_engine);
    00505             last_engine = last_engine->GetPrevUnit();
    00506           }
    00507         }
    00508       }
    00509
    00510       /* Sell superfluous new vehicles that could not be inserted. */
    00511       if (cost.Succeeded() && wagon_removal) {
    00512         for (int i = 1; i < num_units; i++) {
    00513           Vehicle *wagon = new_vehs[i];
    00514           if (wagon == NULL) continue;
    00515           if (wagon->First() == new_head) break;
    00516
    00517           assert(RailVehInfo(wagon->engine_type)->railveh_type == RAILVEH_WAGON);
    00518
    00519           /* Sell wagon */
    00520           CommandCost ret = DoCommand(0, wagon->index, 0, DC_EXEC, GetCmdSellVeh(wagon));
    00521           assert(ret.Succeeded());
    00522           new_vehs[i] = NULL;
    00523
    00524           /* Revert the money subtraction when the vehicle was built.
    00525            * This value is different from the sell value, esp. because of refitting */
    00526           cost.AddCost(-new_costs[i]);
    00527         }
    00528       }
    00529
    00530       /* The new vehicle chain is constructed, now take over orders and everything... */
    00531       if (cost.Succeeded()) cost.AddCost(CopyHeadSpecificThings(old_head, new_head, flags));
    00532
    00533       if (cost.Succeeded()) {
    00534         /* Success ! */
    00535         if ((flags & DC_EXEC) != 0 && new_head != old_head) {
    00536           *chain = new_head;
    00537         }
    00538
    00539         /* Transfer cargo of old vehicles and sell them */
    00540         for (int i = 0; i < num_units; i++) {
    00541           Vehicle *w = old_vehs[i];
    00542           /* Is the vehicle again part of the new chain?
    00543            * Note: We cannot test 'new_vehs[i] != NULL' as wagon removal might cause to remove both */
    00544           if (w->First() == new_head) continue;
    00545
    00546           if ((flags & DC_EXEC) != 0) TransferCargo(w, new_head, true);
    00547
    00548           /* Sell the vehicle.
    00549            * Note: This might temporarly construct new trains, so use DC_AUTOREPLACE to prevent
    00550            *       it from failing due to engine limits. */
    00551           cost.AddCost(DoCommand(0, w->index, 0, flags | DC_AUTOREPLACE, GetCmdSellVeh(w)));
    00552           if ((flags & DC_EXEC) != 0) {
    00553             old_vehs[i] = NULL;
    00554             if (i == 0) old_head = NULL;
    00555           }
    00556         }
    00557       }
    00558
    00559       /* If we are not in DC_EXEC undo everything, i.e. rearrange old vehicles.
    00560        * We do this from back to front, so that the head of the temporary vehicle chain does not change all the time.
    00561        * Note: The vehicle attach callback is disabled here :) */
    00562       if ((flags & DC_EXEC) == 0) {
    00563         /* Separate the head, so we can reattach the old vehicles */
    00564         Train *second = Train::From(old_head)->GetNextUnit();
    00565         if (second != NULL) MoveVehicle(second, NULL, DC_EXEC | DC_AUTOREPLACE, true);
    00566
    00567         assert(Train::From(old_head)->GetNextUnit() == NULL);
    00568
    00569         for (int i = num_units - 1; i > 0; i--) {
    00570           CommandCost ret = MoveVehicle(old_vehs[i], old_head, DC_EXEC | DC_AUTOREPLACE, false);
    00571           assert(ret.Succeeded());
    00572         }
    00573       }
    00574     }
    00575
    00576     /* Finally undo buying of new vehicles */
    00577     if ((flags & DC_EXEC) == 0) {
    00578       for (int i = num_units - 1; i >= 0; i--) {
    00579         if (new_vehs[i] != NULL) {
    00580           DoCommand(0, new_vehs[i]->index, 0, DC_EXEC, GetCmdSellVeh(new_vehs[i]));
    00581           new_vehs[i] = NULL;
    00582         }
    00583       }
    00584     }
    00585
    00586     free(old_vehs);
    00587     free(new_vehs);
    00588     free(new_costs);
    00589   } else {
    00590     /* Build and refit replacement vehicle */
    00591     Vehicle *new_head = NULL;
    00592     cost.AddCost(BuildReplacementVehicle(old_head, &new_head, true));
    00593
    00594     /* Was a new vehicle constructed? */
    00595     if (cost.Succeeded() && new_head != NULL) {
    00596       *nothing_to_do = false;
    00597
    00598       /* The new vehicle is constructed, now take over orders and everything... */
    00599       cost.AddCost(CopyHeadSpecificThings(old_head, new_head, flags));
    00600
    00601       if (cost.Succeeded()) {
    00602         /* The new vehicle is constructed, now take over cargo */
    00603         if ((flags & DC_EXEC) != 0) {
    00604           TransferCargo(old_head, new_head, true);
    00605           *chain = new_head;
    00606         }
    00607
    00608         /* Sell the old vehicle */
    00609         cost.AddCost(DoCommand(0, old_head->index, 0, flags, GetCmdSellVeh(old_head)));
    00610       }
    00611
    00612       /* If we are not in DC_EXEC undo everything */
    00613       if ((flags & DC_EXEC) == 0) {
    00614         DoCommand(0, new_head->index, 0, DC_EXEC, GetCmdSellVeh(new_head));
    00615       }
    00616     }
    00617   }
    00618
    00619   return cost;
    00620 }
    00621
    00631 CommandCost CmdAutoreplaceVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
    00632 {
    00633   CommandCost cost = CommandCost(EXPENSES_NEW_VEHICLES, 0);
    00634   bool nothing_to_do = true;
    00635
    00636   Vehicle *v = Vehicle::GetIfValid(p1);
    00637   if (v == NULL) return CMD_ERROR;
    00638
    00639   if (!CheckOwnership(v->owner)) return CMD_ERROR;
    00640   if (!v->IsInDepot()) return CMD_ERROR;
    00641   if (v->vehstatus & VS_CRASHED) return CMD_ERROR;
    00642
    00643   bool free_wagon = false;
    00644   if (v->type == VEH_TRAIN) {
    00645     Train *t = Train::From(v);
    00646     if (t->IsArticulatedPart() || t->IsRearDualheaded()) return CMD_ERROR;
    00647     free_wagon = !t->IsFrontEngine();
    00648     if (free_wagon && t->First()->IsFrontEngine()) return CMD_ERROR;
    00649   } else {
    00650     if (!v->IsPrimaryVehicle()) return CMD_ERROR;
    00651   }
    00652
    00653   const Company *c = Company::Get(_current_company);
    00654   bool wagon_removal = c->settings.renew_keep_length;
    00655
    00656   /* Test whether any replacement is set, before issuing a whole lot of commands that would end in nothing changed */
    00657   Vehicle *w = v;
    00658   bool any_replacements = false;
    00659   while (w != NULL && !any_replacements) {
    00660     any_replacements = (GetNewEngineType(w, c) != INVALID_ENGINE);
    00661     w = (!free_wagon && w->type == VEH_TRAIN ? Train::From(w)->GetNextUnit() : NULL);
    00662   }
    00663
    00664   if (any_replacements) {
    00665     bool was_stopped = free_wagon || ((v->vehstatus & VS_STOPPED) != 0);
    00666
    00667     /* Stop the vehicle */
    00668     if (!was_stopped) cost.AddCost(StartStopVehicle(v, true));
    00669     if (cost.Failed()) return cost;
    00670
    00671     assert(v->IsStoppedInDepot());
    00672
    00673     /* We have to construct the new vehicle chain to test whether it is valid.
    00674      * Vehicle construction needs random bits, so we have to save the random seeds
    00675      * to prevent desyncs and to replay newgrf callbacks during DC_EXEC */
    00676     SavedRandomSeeds saved_seeds;
    00677     SaveRandomSeeds(&saved_seeds);
    00678     if (free_wagon) {
    00679       cost.AddCost(ReplaceFreeUnit(&v, flags & ~DC_EXEC, &nothing_to_do));
    00680     } else {
    00681       cost.AddCost(ReplaceChain(&v, flags & ~DC_EXEC, wagon_removal, &nothing_to_do));
    00682     }
    00683     RestoreRandomSeeds(saved_seeds);
    00684
    00685     if (cost.Succeeded() && (flags & DC_EXEC) != 0) {
    00686       CommandCost ret;
    00687       if (free_wagon) {
    00688         ret = ReplaceFreeUnit(&v, flags, &nothing_to_do);
    00689       } else {
    00690         ret = ReplaceChain(&v, flags, wagon_removal, &nothing_to_do);
    00691       }
    00692       assert(ret.Succeeded() && ret.GetCost() == cost.GetCost());
    00693     }
    00694
    00695     /* Restart the vehicle */
    00696     if (!was_stopped) cost.AddCost(StartStopVehicle(v, false));
    00697   }
    00698
    00699   if (cost.Succeeded() && nothing_to_do) cost = CommandCost(STR_ERROR_AUTOREPLACE_NOTHING_TO_DO);
    00700   return cost;
    00701 }