if (world != null) {
Extent extent;
// This extents are ALWAYS used
extent = fastModeExtent = new FastModeExtent(world, false);
extent = survivalExtent = new SurvivalModeExtent(extent, world);
extent = quirkExtent = new BlockQuirkExtent(extent, world);
extent = chunkLoadingExtent = new ChunkLoadingExtent(extent, world);
extent = cacheExtent = new LastAccessExtentCache(extent);
extent = wrapExtent(extent, eventBus, event, Stage.BEFORE_CHANGE);
extent = validator = new DataValidatorExtent(extent, world);
extent = blockBagExtent = new BlockBagExtent(extent, blockBag);
// This extent can be skipped by calling rawSetBlock()
extent = reorderExtent = new MultiStageReorder(extent, false);
extent = wrapExtent(extent, eventBus, event, Stage.BEFORE_REORDER);
// These extents can be skipped by calling smartSetBlock()
extent = changeSetExtent = new ChangeSetExtent(extent, changeSet);
extent = maskingExtent = new MaskingExtent(extent, Masks.alwaysTrue());
extent = changeLimiter = new BlockChangeLimiter(extent, maxBlocks);
extent = wrapExtent(extent, eventBus, event, Stage.BEFORE_HISTORY);
this.bypassReorderHistory = blockBagExtent;
this.bypassHistory = reorderExtent;
this.bypassNone = extent;
} else {
Extent extent = new NullExtent();
extent = survivalExtent = new SurvivalModeExtent(extent, NullWorld.getInstance());
extent = blockBagExtent = new BlockBagExtent(extent, blockBag);
extent = reorderExtent = new MultiStageReorder(extent, false);
extent = maskingExtent = new MaskingExtent(extent, Masks.alwaysTrue());
extent = changeLimiter = new BlockChangeLimiter(extent, maxBlocks);
this.bypassReorderHistory = extent;