It's re-entrant now

code/controllers/master_controller.dm

@@ -41,11 +41,13 @@ var/global/pipe_processing_killed = 0
 /datum/controller/game_controller/proc/setup()
 	world.tick_lag = config.Ticklag
 
+	zlevels.initialize()
+
 	preloadTemplates()
 	if(!config.disable_away_missions)
 		createRandomZlevel()
 	if(!config.disable_space_ruins)
-		seedRuins(7, rand(10, 13), /area/space, space_ruins_templates)
+		seedRuins(7, rand(0, 3), /area/space, space_ruins_templates)
 
 	setup_objects()
 	setupgenetics()

code/datums/helper_datums/map_template.dm

@@ -23,7 +23,7 @@
 		height = bounds[MAP_MAXY]
 	return bounds
 
-/datum/map_template/proc/load(turf/T, centered = 0)
+/datum/map_template/proc/load(turf/T, centered = 0, delay_init = 0)
 	var/turf/placement = T
 	var/min_x = placement.x
 	var/min_y = placement.y
@@ -43,7 +43,7 @@
 	// 1 bigger, to update the turf smoothing
 	var/turf/ST_bot_left = locate(max(1, min_x-1), max(1, min_y-1), placement.z)
 	var/turf/ST_top_right = locate(min(world.maxx, max_x+1), min(world.maxy, max_y+1), placement.z)
-	var/list/bounds = maploader.load_map(get_file(), min_x, min_y, placement.z, cropMap = 1)
+	var/list/bounds = maploader.load_map(get_file(), min_x, min_y, placement.z, cropMap = 1, delay_init = delay_init)
 	if(!bounds)
 		return 0
 	if(bot_left == null || top_right == null)

code/game/atoms_movable.dm

@@ -31,7 +31,7 @@ var/list/dirty_z_levels = list()
 
 	// If you're wondering what goofery this is, this is for things that need the environment
 	// around them set up - like `air_update_turf` and the like
-	if(!(T && T.z in dirty_z_levels) && auto_init && ticker && ticker.current_state == GAME_STATE_PLAYING)
+	if(!(T && zlevels.is_zlevel_dirty(T.z)) && auto_init && ticker && ticker.current_state == GAME_STATE_PLAYING)
 		initialize()
 
 /atom/movable/Destroy()

code/game/turfs/turf.dm

@@ -192,15 +192,16 @@
 
 	return W
 
-/turf/proc/AfterChange() //called after a turf has been replaced in ChangeTurf()
+// I'm including `ignore_air` because BYOND lacks positional-only arguments
+/turf/proc/AfterChange(ignore_air, but_its_not_the_saaaaaame = FALSE) //called after a turf has been replaced in ChangeTurf()
 	levelupdate()
 	CalculateAdjacentTurfs()
 
-	if(!can_have_cabling())
+	if(!but_its_not_the_saaaaaame && !can_have_cabling())
 		for(var/obj/structure/cable/C in contents)
 			qdel(C)
 
-/turf/simulated/AfterChange(ignore_air)
+/turf/simulated/AfterChange(ignore_air, but_its_not_the_saaaaaame = FALSE)
 	..()
 	RemoveLattice()
 	if(!ignore_air)

code/modules/admin/verbs/map_template_loadverb.dm

@@ -19,6 +19,10 @@
 		to_chat(usr, "Map is too large to fit in bounds. Map's dimensions: ([template.width], [template.height])")
 		return
 
+	var/delay_init = 0
+	if(alert(usr,"Delay initialization? (Needed for large atmos-containing maps)","Delay","Yes","No") == "Yes")
+		delay_init = 1
+
 	var/list/preview = list()
 	for(var/S in template.get_affected_turfs(T,centered = TRUE))
 		preview += image('icons/turf/overlays.dmi',S,"greenOverlay")
@@ -26,7 +30,7 @@
 	if(alert(usr,"Confirm location.","Template Confirm","Yes","No") == "Yes")
 		var/timer = start_watch()
 		message_admins("<span class='adminnotice'>[key_name_admin(usr)] has started to place the map template ([template.name]) at <A HREF='?_src_=holder;adminplayerobservecoodjump=1;X=[T.x];Y=[T.y];Z=[T.z]'>(JMP)</a></span>")
-		if(template.load(T, centered = TRUE))
+		if(template.load(T, centered = TRUE, delay_init = delay_init))
 			message_admins("<span class='adminnotice'>[key_name_admin(usr)] has placed a map template ([template.name]) at <A HREF='?_src_=holder;adminplayerobservecoodjump=1;X=[T.x];Y=[T.y];Z=[T.z]'>(JMP)</a>. Took [stop_watch(timer)]s.</span>")
 		else
 			to_chat(usr, "Failed to place map")

code/modules/awaymissions/maploader/reader.dm

@@ -27,8 +27,13 @@ var/global/dmm_suite/preloader/_preloader = new
  *
  * If `measureOnly` is set, then no atoms will be created, and all this will do
  * is return the bounds after parsing the file
+ *
+ * If delay_init is set, then all initializations while the map is loading will
+ * be deferred until later
+ * You'll need it for large initializations like loading the cyberiad, where
+ * glass and similar can cause atmos to initialize before it's ready
  */
-/dmm_suite/load_map(dmm_file as file, x_offset as num, y_offset as num, z_offset as num, cropMap as num, measureOnly as num)
+/dmm_suite/load_map(dmm_file as file, x_offset as num, y_offset as num, z_offset as num, cropMap as num, measureOnly as num, delay_init as num)
 	var/tfile = dmm_file//the map file we're creating
 	if(isfile(tfile))
 		tfile = file2text(tfile)
@@ -43,14 +48,12 @@ var/global/dmm_suite/preloader/_preloader = new
 	var/list/bounds = list(1.#INF, 1.#INF, 1.#INF, -1.#INF, -1.#INF, -1.#INF)
 	var/list/grid_models = list()
 	var/key_len = 0
-	// This ain't re-entrant
-	// Meaning - don't load more than one map at once, using `spawn` or whatever
-	var/list/old_dirty_z_levels = deepCopyList(dirty_z_levels)
+	var/list/touched_z_levels = list()
 
 	var/dmm_suite/loaded_map/LM = new
 
-	// This try-catch is used as a budget "Finally" clause, as the "touched_z_levels"
-	// var needs to be reset
+	// This try-catch is used as a budget "Finally" clause, as the dirt count
+	// needs to be reset
 	try
 		dmmRegex.next = 1
 		while(dmmRegex.Find(tfile, dmmRegex.next))
@@ -78,14 +81,15 @@ var/global/dmm_suite/preloader/_preloader = new
 				var/xcrd
 				var/ycrd = text2num(dmmRegex.group[4]) + y_offset - 1
 				var/zcrd = text2num(dmmRegex.group[5]) + z_offset - 1
-				if(!measureOnly)
-					dirty_z_levels |= zcrd
+				if(!measureOnly && delay_init)
+					zlevels.add_dirt(zcrd)
+					touched_z_levels |= zcrd
 
 				if(zcrd > world.maxz)
 					if(cropMap)
 						continue
 					else
-						world.maxz = zcrd //create a new z_level if needed
+						zlevels.increase_max_zlevel_to(zcrd) //create a new z_level if needed
 
 				bounds[MAP_MINX] = min(bounds[MAP_MINX], xcrdStart)
 				bounds[MAP_MINZ] = min(bounds[MAP_MINZ], zcrd)
@@ -144,27 +148,28 @@ var/global/dmm_suite/preloader/_preloader = new
 
 			CHECK_TICK
 	catch(var/exception/e)
-		if(!measureOnly)
-			dirty_z_levels = old_dirty_z_levels
+		if(!measureOnly && delay_init)
+			for(var/i in touched_z_levels)
+				zlevels.remove_dirt(i)
 		throw e
 
-	// This *might* leak memory? Whatever it's a trivial quantity
-	if(!measureOnly)
-		dirty_z_levels = old_dirty_z_levels
+	if(!measureOnly && delay_init)
+		for(var/i in touched_z_levels)
+			zlevels.remove_dirt(i)
 	qdel(LM)
 	if(bounds[MAP_MINX] == 1.#INF) // Shouldn't need to check every item
-		log_startup_progress("Min x: bounds[MAP_MINX]")
-		log_startup_progress("Min y: bounds[MAP_MINY]")
-		log_startup_progress("Min z: bounds[MAP_MINZ]")
-		log_startup_progress("Max x: bounds[MAP_MAXX]")
-		log_startup_progress("Max y: bounds[MAP_MAXY]")
-		log_startup_progress("Max z: bounds[MAP_MAXZ]")
+		log_debug("Min x: bounds[MAP_MINX]")
+		log_debug("Min y: bounds[MAP_MINY]")
+		log_debug("Min z: bounds[MAP_MINZ]")
+		log_debug("Max x: bounds[MAP_MAXX]")
+		log_debug("Max y: bounds[MAP_MAXY]")
+		log_debug("Max z: bounds[MAP_MAXZ]")
 		return null
 	else
 		for(var/t in block(locate(bounds[MAP_MINX], bounds[MAP_MINY], bounds[MAP_MINZ]), locate(bounds[MAP_MAXX], bounds[MAP_MAXY], bounds[MAP_MAXZ])))
 			var/turf/T = t
 			//we do this after we load everything in. if we don't; we'll have weird atmos bugs regarding atmos adjacent turfs
-			T.AfterChange(1)
+			T.AfterChange(1,but_its_not_the_saaaaaame = TRUE) // are you happy now
 		return bounds
 
 /**

code/modules/awaymissions/maploader/swapmaps.dm

@@ -326,7 +326,7 @@ swapmap
 		x2+=x1-1
 		y2+=y1-1
 		z2+=z1-1
-		world.maxz=max(z2,world.maxz)	// stretch z if necessary
+		zlevels.increase_max_zlevel_to(z2)	// stretch z if necessary
 		if(!ischunk)
 			swapmaps_loaded[src]=null
 			swapmaps_byname[id]=src
@@ -373,7 +373,7 @@ swapmap
 			mz=max(mz,M.z2)
 		world.maxx=mx
 		world.maxy=my
-		world.maxz=mz
+		zlevels.cut_levels_downto(mz)
 
 	// save and delete
 	proc/Unload()

code/modules/spacial_allocator/zlevel.dm

@@ -0,0 +1,7 @@
+/datum/zlevel
+  var/flags = 0
+  var/dirt_count = 0
+  var/zpos
+
+/datum/zlevel/New(z)
+  zpos = z

code/modules/spacial_allocator/zlevel_manager.dm

@@ -0,0 +1,69 @@
+var/global/datum/zlev_manager/zlevels = new
+
+/datum/zlev_manager
+  // A list of z-levels
+  var/list/z_list = list()
+
+
+// Populate our z level list
+/datum/zlev_manager/proc/initialize()
+  for(var/i = 1, i < world.maxz, i++)
+    z_list.Add(new /datum/zlevel(i))
+
+
+// For when you need the z-level to be at a certain point
+/datum/zlev_manager/proc/increase_max_zlevel_to(new_maxz)
+  if(world.maxz>=new_maxz)
+    return
+  while(world.maxz<new_maxz)
+    add_new_zlevel()
+
+// Increments the max z-level by one
+// For convenience's sake returns the z-level added
+/datum/zlev_manager/proc/add_new_zlevel()
+  world.maxz++
+  var/our_z = world.maxz
+  z_list.Add(new /datum/zlevel(our_z))
+  return our_z
+
+/datum/zlev_manager/proc/cut_levels_downto(new_maxz)
+  if(world.maxz <= new_maxz)
+    return
+  while(world.maxz>new_maxz)
+    kill_topmost_zlevel()
+
+// Decrements the max z-level by one
+// not normally used, but hey the swapmap loader wanted it
+/datum/zlev_manager/proc/kill_topmost_zlevel()
+  var/our_z = world.maxz
+  qdel(z_list[our_z])
+  z_list.Remove(our_z)
+  world.maxz--
+
+/*
+* "Dirt" management
+* "Dirt" is used to keep track of whether a z level should automatically have
+* stuff on it initialize or not - the map loaders, when set to defer init, place
+* a freeze on the z levels they touch so as to prevent atmos from exploding,
+* among other things
+*/
+
+
+// Returns whether the given z level has a freeze on initialization
+/datum/zlev_manager/proc/is_zlevel_dirty(z)
+  if(z > z_list.len)
+    return 0 // It's not dirty if it's not being tracked
+  var/datum/zlevel/our_z = z_list[z]
+  return (our_z.dirt_count > 0)
+
+
+// Increases the dirt count on a z level
+/datum/zlev_manager/proc/add_dirt(z)
+  var/datum/zlevel/our_z = z_list[z]
+  our_z.dirt_count++
+
+
+// Decreases the dirt count on a z level
+/datum/zlev_manager/proc/remove_dirt(z)
+  var/datum/zlevel/our_z = z_list[z]
+  our_z.dirt_count--

paradise.dme

@@ -1990,6 +1990,8 @@
 #include "code\modules\spacepods\parts.dm"
 #include "code\modules\spacepods\pod_fabricator.dm"
 #include "code\modules\spacepods\spacepod.dm"
+#include "code\modules\spacial_allocator\zlevel.dm"
+#include "code\modules\spacial_allocator\zlevel_manager.dm"
 #include "code\modules\store\items.dm"
 #include "code\modules\store\store.dm"
 #include "code\modules\surgery\bones.dm"