src/emerge.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4 Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU Lesser General Public License as published by
   8 the Free Software Foundation; either version 2.1 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU Lesser General Public License for more details.
  15
  16 You should have received a copy of the GNU Lesser General Public License along
  17 with this program; if not, write to the Free Software Foundation, Inc.,
  18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21
  22 #include "emerge.h"
  23
  24 #include <iostream>
  25 #include <queue>
  26
  27 #include "util/container.h"
  28 #include "util/thread.h"
  29 #include "threading/event.h"
  30
  31 #include "config.h"
  32 #include "constants.h"
  33 #include "environment.h"
  34 #include "log.h"
  35 #include "map.h"
  36 #include "mapblock.h"
  37 #include "mapgen/mg_biome.h"
  38 #include "mapgen/mg_ore.h"
  39 #include "mapgen/mg_decoration.h"
  40 #include "mapgen/mg_schematic.h"
  41 #include "nodedef.h"
  42 #include "profiler.h"
  43 #include "scripting_server.h"
  44 #include "server.h"
  45 #include "settings.h"
  46 #include "voxel.h"
  47
  48 class EmergeThread : public Thread {
  49 public:
  50         bool enable_mapgen_debug_info;
  51         int id;
  52
  53         EmergeThread(Server *server, int ethreadid);
  54         ~EmergeThread() = default;
  55
  56         void *run();
  57         void signal();
  58
  59         // Requires queue mutex held
  60         bool pushBlock(const v3s16 &pos);
  61
  62         void cancelPendingItems();
  63
  64 protected:
  65
  66         void runCompletionCallbacks(
  67                 const v3s16 &pos, EmergeAction action,
  68                 const EmergeCallbackList &callbacks);
  69
  70 private:
  71         Server *m_server;
  72         ServerMap *m_map;
  73         EmergeManager *m_emerge;
  74         Mapgen *m_mapgen;
  75
  76         Event m_queue_event;
  77         std::queue<v3s16> m_block_queue;
  78
  79         bool popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata);
  80
  81         EmergeAction getBlockOrStartGen(
  82                 const v3s16 &pos, bool allow_gen, MapBlock **block, BlockMakeData *data);
  83         MapBlock *finishGen(v3s16 pos, BlockMakeData *bmdata,
  84                 std::map<v3s16, MapBlock *> *modified_blocks);
  85
  86         friend class EmergeManager;
  87 };
  88
  89 class MapEditEventAreaIgnorer
  90 {
  91 public:
  92         MapEditEventAreaIgnorer(VoxelArea *ignorevariable, const VoxelArea &a):
  93                 m_ignorevariable(ignorevariable)
  94         {
  95                 if(m_ignorevariable->getVolume() == 0)
  96                         *m_ignorevariable = a;
  97                 else
  98                         m_ignorevariable = NULL;
  99         }
 100
 101         ~MapEditEventAreaIgnorer()
 102         {
 103                 if(m_ignorevariable)
 104                 {
 105                         assert(m_ignorevariable->getVolume() != 0);
 106                         *m_ignorevariable = VoxelArea();
 107                 }
 108         }
 109
 110 private:
 111         VoxelArea *m_ignorevariable;
 112 };
 113
 114 EmergeParams::~EmergeParams()
 115 {
 116         infostream << "EmergeParams: destroying " << this << std::endl;
 117         // Delete everything that was cloned on creation of EmergeParams
 118         delete biomegen;
 119         delete biomemgr;
 120         delete oremgr;
 121         delete decomgr;
 122         delete schemmgr;
 123 }
 124
 125 EmergeParams::EmergeParams(EmergeManager *parent, const BiomeGen *biomegen,
 126         const BiomeManager *biomemgr,
 127         const OreManager *oremgr, const DecorationManager *decomgr,
 128         const SchematicManager *schemmgr) :
 129         ndef(parent->ndef),
 130         enable_mapgen_debug_info(parent->enable_mapgen_debug_info),
 131         gen_notify_on(parent->gen_notify_on),
 132         gen_notify_on_deco_ids(&parent->gen_notify_on_deco_ids),
 133         biomemgr(biomemgr->clone()), oremgr(oremgr->clone()),
 134         decomgr(decomgr->clone()), schemmgr(schemmgr->clone())
 135 {
 136         this->biomegen = biomegen->clone(this->biomemgr);
 137 }
 138
 139 ////
 140 //// EmergeManager
 141 ////
 142
 143 EmergeManager::EmergeManager(Server *server, MetricsBackend *mb)
 144 {
 145         this->ndef      = server->getNodeDefManager();
 146         this->biomemgr  = new BiomeManager(server);
 147         this->oremgr    = new OreManager(server);
 148         this->decomgr   = new DecorationManager(server);
 149         this->schemmgr  = new SchematicManager(server);
 150
 151         // initialized later
 152         this->mgparams = nullptr;
 153         this->biomegen = nullptr;
 154
 155         // Note that accesses to this variable are not synchronized.
 156         // This is because the *only* thread ever starting or stopping
 157         // EmergeThreads should be the ServerThread.
 158
 159         enable_mapgen_debug_info = g_settings->getBool("enable_mapgen_debug_info");
 160
 161         STATIC_ASSERT(ARRLEN(emergeActionStrs) == ARRLEN(m_completed_emerge_counter),
 162                 enum_size_mismatches);
 163         for (u32 i = 0; i < ARRLEN(m_completed_emerge_counter); i++) {
 164                 std::string help_str("Number of completed emerges with status ");
 165                 help_str.append(emergeActionStrs[i]);
 166                 m_completed_emerge_counter[i] = mb->addCounter(
 167                         "minetest_emerge_completed", help_str,
 168                         {{"status", emergeActionStrs[i]}}
 169                 );
 170         }
 171
 172         s16 nthreads = 1;
 173         g_settings->getS16NoEx("num_emerge_threads", nthreads);
 174         // If automatic, leave a proc for the main thread and one for
 175         // some other misc thread
 176         if (nthreads <= 0)
 177                 nthreads = Thread::getNumberOfProcessors() - 2;
 178         if (nthreads < 1)
 179                 nthreads = 1;
 180
 181         m_qlimit_total = g_settings->getU32("emergequeue_limit_total");
 182         // FIXME: these fallback values are probably not good
 183         if (!g_settings->getU32NoEx("emergequeue_limit_diskonly", m_qlimit_diskonly))
 184                 m_qlimit_diskonly = nthreads * 5 + 1;
 185         if (!g_settings->getU32NoEx("emergequeue_limit_generate", m_qlimit_generate))
 186                 m_qlimit_generate = nthreads + 1;
 187
 188         // don't trust user input for something very important like this
 189         m_qlimit_total = rangelim(m_qlimit_total, 1, 1000000);
 190         m_qlimit_diskonly = rangelim(m_qlimit_diskonly, 1, 1000000);
 191         m_qlimit_generate = rangelim(m_qlimit_generate, 1, 1000000);
 192
 193         for (s16 i = 0; i < nthreads; i++)
 194                 m_threads.push_back(new EmergeThread(server, i));
 195
 196         infostream << "EmergeManager: using " << nthreads << " threads" << std::endl;
 197 }
 198
 199
 200 EmergeManager::~EmergeManager()
 201 {
 202         for (u32 i = 0; i != m_threads.size(); i++) {
 203                 EmergeThread *thread = m_threads[i];
 204
 205                 if (m_threads_active) {
 206                         thread->stop();
 207                         thread->signal();
 208                         thread->wait();
 209                 }
 210
 211                 delete thread;
 212
 213                 // Mapgen init might not be finished if there is an error during startup.
 214                 if (m_mapgens.size() > i)
 215                         delete m_mapgens[i];
 216         }
 217
 218         delete biomegen;
 219         delete biomemgr;
 220         delete oremgr;
 221         delete decomgr;
 222         delete schemmgr;
 223 }
 224
 225
 226 BiomeManager *EmergeManager::getWritableBiomeManager()
 227 {
 228         FATAL_ERROR_IF(!m_mapgens.empty(),
 229                 "Writable managers can only be returned before mapgen init");
 230         return biomemgr;
 231 }
 232
 233 OreManager *EmergeManager::getWritableOreManager()
 234 {
 235         FATAL_ERROR_IF(!m_mapgens.empty(),
 236                 "Writable managers can only be returned before mapgen init");
 237         return oremgr;
 238 }
 239
 240 DecorationManager *EmergeManager::getWritableDecorationManager()
 241 {
 242         FATAL_ERROR_IF(!m_mapgens.empty(),
 243                 "Writable managers can only be returned before mapgen init");
 244         return decomgr;
 245 }
 246
 247 SchematicManager *EmergeManager::getWritableSchematicManager()
 248 {
 249         FATAL_ERROR_IF(!m_mapgens.empty(),
 250                 "Writable managers can only be returned before mapgen init");
 251         return schemmgr;
 252 }
 253
 254
 255 void EmergeManager::initMapgens(MapgenParams *params)
 256 {
 257         FATAL_ERROR_IF(!m_mapgens.empty(), "Mapgen already initialised.");
 258
 259         mgparams = params;
 260
 261         v3s16 csize = v3s16(1, 1, 1) * (params->chunksize * MAP_BLOCKSIZE);
 262         biomegen = biomemgr->createBiomeGen(BIOMEGEN_ORIGINAL, params->bparams, csize);
 263
 264         for (u32 i = 0; i != m_threads.size(); i++) {
 265                 EmergeParams *p = new EmergeParams(this, biomegen,
 266                         biomemgr, oremgr, decomgr, schemmgr);
 267                 infostream << "EmergeManager: Created params " << p
 268                         << " for thread " << i << std::endl;
 269                 m_mapgens.push_back(Mapgen::createMapgen(params->mgtype, params, p));
 270         }
 271 }
 272
 273
 274 Mapgen *EmergeManager::getCurrentMapgen()
 275 {
 276         if (!m_threads_active)
 277                 return nullptr;
 278
 279         for (u32 i = 0; i != m_threads.size(); i++) {
 280                 EmergeThread *t = m_threads[i];
 281                 if (t->isRunning() && t->isCurrentThread())
 282                         return t->m_mapgen;
 283         }
 284
 285         return nullptr;
 286 }
 287
 288
 289 void EmergeManager::startThreads()
 290 {
 291         if (m_threads_active)
 292                 return;
 293
 294         for (u32 i = 0; i != m_threads.size(); i++)
 295                 m_threads[i]->start();
 296
 297         m_threads_active = true;
 298 }
 299
 300
 301 void EmergeManager::stopThreads()
 302 {
 303         if (!m_threads_active)
 304                 return;
 305
 306         // Request thread stop in parallel
 307         for (u32 i = 0; i != m_threads.size(); i++) {
 308                 m_threads[i]->stop();
 309                 m_threads[i]->signal();
 310         }
 311
 312         // Then do the waiting for each
 313         for (u32 i = 0; i != m_threads.size(); i++)
 314                 m_threads[i]->wait();
 315
 316         m_threads_active = false;
 317 }
 318
 319
 320 bool EmergeManager::isRunning()
 321 {
 322         return m_threads_active;
 323 }
 324
 325
 326 bool EmergeManager::enqueueBlockEmerge(
 327         session_t peer_id,
 328         v3s16 blockpos,
 329         bool allow_generate,
 330         bool ignore_queue_limits)
 331 {
 332         u16 flags = 0;
 333         if (allow_generate)
 334                 flags |= BLOCK_EMERGE_ALLOW_GEN;
 335         if (ignore_queue_limits)
 336                 flags |= BLOCK_EMERGE_FORCE_QUEUE;
 337
 338         return enqueueBlockEmergeEx(blockpos, peer_id, flags, NULL, NULL);
 339 }
 340
 341
 342 bool EmergeManager::enqueueBlockEmergeEx(
 343         v3s16 blockpos,
 344         session_t peer_id,
 345         u16 flags,
 346         EmergeCompletionCallback callback,
 347         void *callback_param)
 348 {
 349         EmergeThread *thread = NULL;
 350         bool entry_already_exists = false;
 351
 352         {
 353                 MutexAutoLock queuelock(m_queue_mutex);
 354
 355                 if (!pushBlockEmergeData(blockpos, peer_id, flags,
 356                                 callback, callback_param, &entry_already_exists))
 357                         return false;
 358
 359                 if (entry_already_exists)
 360                         return true;
 361
 362                 thread = getOptimalThread();
 363                 thread->pushBlock(blockpos);
 364         }
 365
 366         thread->signal();
 367
 368         return true;
 369 }
 370
 371
 372 bool EmergeManager::isBlockInQueue(v3s16 pos)
 373 {
 374         MutexAutoLock queuelock(m_queue_mutex);
 375         return m_blocks_enqueued.find(pos) != m_blocks_enqueued.end();
 376 }
 377
 378
 379 //
 380 // Mapgen-related helper functions
 381 //
 382
 383
 384 // TODO(hmmmm): Move this to ServerMap
 385 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos, s16 chunksize)
 386 {
 387         s16 coff = -chunksize / 2;
 388         v3s16 chunk_offset(coff, coff, coff);
 389
 390         return getContainerPos(blockpos - chunk_offset, chunksize)
 391                 * chunksize + chunk_offset;
 392 }
 393
 394
 395 int EmergeManager::getSpawnLevelAtPoint(v2s16 p)
 396 {
 397         if (m_mapgens.empty() || !m_mapgens[0]) {
 398                 errorstream << "EmergeManager: getSpawnLevelAtPoint() called"
 399                         " before mapgen init" << std::endl;
 400                 return 0;
 401         }
 402
 403         return m_mapgens[0]->getSpawnLevelAtPoint(p);
 404 }
 405
 406
 407 // TODO(hmmmm): Move this to ServerMap
 408 bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 409 {
 410         // Use a simple heuristic
 411         return blockpos.Y * (MAP_BLOCKSIZE + 1) <= mgparams->water_level;
 412 }
 413
 414 bool EmergeManager::pushBlockEmergeData(
 415         v3s16 pos,
 416         u16 peer_requested,
 417         u16 flags,
 418         EmergeCompletionCallback callback,
 419         void *callback_param,
 420         bool *entry_already_exists)
 421 {
 422         u32 &count_peer = m_peer_queue_count[peer_requested];
 423
 424         if ((flags & BLOCK_EMERGE_FORCE_QUEUE) == 0) {
 425                 if (m_blocks_enqueued.size() >= m_qlimit_total)
 426                         return false;
 427
 428                 if (peer_requested != PEER_ID_INEXISTENT) {
 429                         u32 qlimit_peer = (flags & BLOCK_EMERGE_ALLOW_GEN) ?
 430                                 m_qlimit_generate : m_qlimit_diskonly;
 431                         if (count_peer >= qlimit_peer)
 432                                 return false;
 433                 } else {
 434                         // limit block enqueue requests for active blocks to 1/2 of total
 435                         if (count_peer * 2 >= m_qlimit_total)
 436                                 return false;
 437                 }
 438         }
 439
 440         std::pair<std::map<v3s16, BlockEmergeData>::iterator, bool> findres;
 441         findres = m_blocks_enqueued.insert(std::make_pair(pos, BlockEmergeData()));
 442
 443         BlockEmergeData &bedata = findres.first->second;
 444         *entry_already_exists   = !findres.second;
 445
 446         if (callback)
 447                 bedata.callbacks.emplace_back(callback, callback_param);
 448
 449         if (*entry_already_exists) {
 450                 bedata.flags |= flags;
 451         } else {
 452                 bedata.flags = flags;
 453                 bedata.peer_requested = peer_requested;
 454
 455                 count_peer++;
 456         }
 457
 458         return true;
 459 }
 460
 461
 462 bool EmergeManager::popBlockEmergeData(v3s16 pos, BlockEmergeData *bedata)
 463 {
 464         auto it = m_blocks_enqueued.find(pos);
 465         if (it == m_blocks_enqueued.end())
 466                 return false;
 467
 468         *bedata = it->second;
 469
 470         auto it2 = m_peer_queue_count.find(bedata->peer_requested);
 471         if (it2 == m_peer_queue_count.end())
 472                 return false;
 473
 474         u32 &count_peer = it2->second;
 475
 476         assert(count_peer != 0);
 477         count_peer--;
 478
 479         m_blocks_enqueued.erase(it);
 480
 481         return true;
 482 }
 483
 484
 485 EmergeThread *EmergeManager::getOptimalThread()
 486 {
 487         size_t nthreads = m_threads.size();
 488
 489         FATAL_ERROR_IF(nthreads == 0, "No emerge threads!");
 490
 491         size_t index = 0;
 492         size_t nitems_lowest = m_threads[0]->m_block_queue.size();
 493
 494         for (size_t i = 1; i < nthreads; i++) {
 495                 size_t nitems = m_threads[i]->m_block_queue.size();
 496                 if (nitems < nitems_lowest) {
 497                         index = i;
 498                         nitems_lowest = nitems;
 499                 }
 500         }
 501
 502         return m_threads[index];
 503 }
 504
 505 void EmergeManager::reportCompletedEmerge(EmergeAction action)
 506 {
 507         assert((size_t)action < ARRLEN(m_completed_emerge_counter));
 508         m_completed_emerge_counter[(int)action]->increment();
 509 }
 510
 511
 512 ////
 513 //// EmergeThread
 514 ////
 515
 516 EmergeThread::EmergeThread(Server *server, int ethreadid) :
 517         enable_mapgen_debug_info(false),
 518         id(ethreadid),
 519         m_server(server),
 520         m_map(NULL),
 521         m_emerge(NULL),
 522         m_mapgen(NULL)
 523 {
 524         m_name = "Emerge-" + itos(ethreadid);
 525 }
 526
 527
 528 void EmergeThread::signal()
 529 {
 530         m_queue_event.signal();
 531 }
 532
 533
 534 bool EmergeThread::pushBlock(const v3s16 &pos)
 535 {
 536         m_block_queue.push(pos);
 537         return true;
 538 }
 539
 540
 541 void EmergeThread::cancelPendingItems()
 542 {
 543         MutexAutoLock queuelock(m_emerge->m_queue_mutex);
 544
 545         while (!m_block_queue.empty()) {
 546                 BlockEmergeData bedata;
 547                 v3s16 pos;
 548
 549                 pos = m_block_queue.front();
 550                 m_block_queue.pop();
 551
 552                 m_emerge->popBlockEmergeData(pos, &bedata);
 553
 554                 runCompletionCallbacks(pos, EMERGE_CANCELLED, bedata.callbacks);
 555         }
 556 }
 557
 558
 559 void EmergeThread::runCompletionCallbacks(const v3s16 &pos, EmergeAction action,
 560         const EmergeCallbackList &callbacks)
 561 {
 562         m_emerge->reportCompletedEmerge(action);
 563
 564         for (size_t i = 0; i != callbacks.size(); i++) {
 565                 EmergeCompletionCallback callback;
 566                 void *param;
 567
 568                 callback = callbacks[i].first;
 569                 param    = callbacks[i].second;
 570
 571                 callback(pos, action, param);
 572         }
 573 }
 574
 575
 576 bool EmergeThread::popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata)
 577 {
 578         MutexAutoLock queuelock(m_emerge->m_queue_mutex);
 579
 580         if (m_block_queue.empty())
 581                 return false;
 582
 583         *pos = m_block_queue.front();
 584         m_block_queue.pop();
 585
 586         m_emerge->popBlockEmergeData(*pos, bedata);
 587
 588         return true;
 589 }
 590
 591
 592 EmergeAction EmergeThread::getBlockOrStartGen(
 593         const v3s16 &pos, bool allow_gen, MapBlock **block, BlockMakeData *bmdata)
 594 {
 595         MutexAutoLock envlock(m_server->m_env_mutex);
 596
 597         // 1). Attempt to fetch block from memory
 598         *block = m_map->getBlockNoCreateNoEx(pos);
 599         if (*block) {
 600                 if ((*block)->isGenerated())
 601                         return EMERGE_FROM_MEMORY;
 602         } else {
 603                 // 2). Attempt to load block from disk if it was not in the memory
 604                 *block = m_map->loadBlock(pos);
 605                 if (*block && (*block)->isGenerated())
 606                         return EMERGE_FROM_DISK;
 607         }
 608
 609         // 3). Attempt to start generation
 610         if (allow_gen && m_map->initBlockMake(pos, bmdata))
 611                 return EMERGE_GENERATED;
 612
 613         // All attempts failed; cancel this block emerge
 614         return EMERGE_CANCELLED;
 615 }
 616
 617
 618 MapBlock *EmergeThread::finishGen(v3s16 pos, BlockMakeData *bmdata,
 619         std::map<v3s16, MapBlock *> *modified_blocks)
 620 {
 621         MutexAutoLock envlock(m_server->m_env_mutex);
 622         ScopeProfiler sp(g_profiler,
 623                 "EmergeThread: after Mapgen::makeChunk", SPT_AVG);
 624
 625         /*
 626                 Perform post-processing on blocks (invalidate lighting, queue liquid
 627                 transforms, etc.) to finish block make
 628         */
 629         m_map->finishBlockMake(bmdata, modified_blocks);
 630
 631         MapBlock *block = m_map->getBlockNoCreateNoEx(pos);
 632         if (!block) {
 633                 errorstream << "EmergeThread::finishGen: Couldn't grab block we "
 634                         "just generated: " << PP(pos) << std::endl;
 635                 return NULL;
 636         }
 637
 638         v3s16 minp = bmdata->blockpos_min * MAP_BLOCKSIZE;
 639         v3s16 maxp = bmdata->blockpos_max * MAP_BLOCKSIZE +
 640                                  v3s16(1,1,1) * (MAP_BLOCKSIZE - 1);
 641
 642         // Ignore map edit events, they will not need to be sent
 643         // to anybody because the block hasn't been sent to anybody
 644         MapEditEventAreaIgnorer ign(
 645                 &m_server->m_ignore_map_edit_events_area,
 646                 VoxelArea(minp, maxp));
 647
 648         /*
 649                 Run Lua on_generated callbacks
 650         */
 651         try {
 652                 m_server->getScriptIface()->environment_OnGenerated(
 653                         minp, maxp, m_mapgen->blockseed);
 654         } catch (LuaError &e) {
 655                 m_server->setAsyncFatalError(e);
 656         }
 657
 658         EMERGE_DBG_OUT("ended up with: " << analyze_block(block));
 659
 660         /*
 661                 Clear mapgen state
 662         */
 663         assert(!m_mapgen->generating);
 664         m_mapgen->gennotify.clearEvents();
 665         m_mapgen->vm = nullptr;
 666
 667         /*
 668                 Activate the block
 669         */
 670         m_server->m_env->activateBlock(block, 0);
 671
 672         return block;
 673 }
 674
 675
 676 void *EmergeThread::run()
 677 {
 678         BEGIN_DEBUG_EXCEPTION_HANDLER
 679
 680         v3s16 pos;
 681         std::map<v3s16, MapBlock *> modified_blocks;
 682
 683         m_map    = &m_server->m_env->getServerMap();
 684         m_emerge = m_server->m_emerge;
 685         m_mapgen = m_emerge->m_mapgens[id];
 686         enable_mapgen_debug_info = m_emerge->enable_mapgen_debug_info;
 687
 688         try {
 689         while (!stopRequested()) {
 690                 BlockEmergeData bedata;
 691                 BlockMakeData bmdata;
 692                 EmergeAction action;
 693                 MapBlock *block = nullptr;
 694
 695                 if (!popBlockEmerge(&pos, &bedata)) {
 696                         m_queue_event.wait();
 697                         continue;
 698                 }
 699
 700                 if (blockpos_over_max_limit(pos))
 701                         continue;
 702
 703                 bool allow_gen = bedata.flags & BLOCK_EMERGE_ALLOW_GEN;
 704                 EMERGE_DBG_OUT("pos=" PP(pos) " allow_gen=" << allow_gen);
 705
 706                 action = getBlockOrStartGen(pos, allow_gen, &block, &bmdata);
 707                 if (action == EMERGE_GENERATED) {
 708                         {
 709                                 ScopeProfiler sp(g_profiler,
 710                                         "EmergeThread: Mapgen::makeChunk", SPT_AVG);
 711
 712                                 m_mapgen->makeChunk(&bmdata);
 713                         }
 714
 715                         block = finishGen(pos, &bmdata, &modified_blocks);
 716                         if (!block)
 717                                 action = EMERGE_ERRORED;
 718                 }
 719
 720                 runCompletionCallbacks(pos, action, bedata.callbacks);
 721
 722                 if (block)
 723                         modified_blocks[pos] = block;
 724
 725                 if (!modified_blocks.empty())
 726                         m_server->SetBlocksNotSent(modified_blocks);
 727                 modified_blocks.clear();
 728         }
 729         } catch (VersionMismatchException &e) {
 730                 std::ostringstream err;
 731                 err << "World data version mismatch in MapBlock " << PP(pos) << std::endl
 732                         << "----" << std::endl
 733                         << "\"" << e.what() << "\"" << std::endl
 734                         << "See debug.txt." << std::endl
 735                         << "World probably saved by a newer version of " PROJECT_NAME_C "."
 736                         << std::endl;
 737                 m_server->setAsyncFatalError(err.str());
 738         } catch (SerializationError &e) {
 739                 std::ostringstream err;
 740                 err << "Invalid data in MapBlock " << PP(pos) << std::endl
 741                         << "----" << std::endl
 742                         << "\"" << e.what() << "\"" << std::endl
 743                         << "See debug.txt." << std::endl
 744                         << "You can ignore this using [ignore_world_load_errors = true]."
 745                         << std::endl;
 746                 m_server->setAsyncFatalError(err.str());
 747         }
 748
 749         cancelPendingItems();
 750
 751         END_DEBUG_EXCEPTION_HANDLER
 752         return NULL;
 753 }