Actual performance improvements for GetAllContents (#32029)

* Actual performance improvements for GetAllContents

* Shaving off literal tens of clock cycles

code/__HELPERS/unsorted.dm

@@ -504,21 +504,19 @@ Turf and target are separate in case you want to teleport some distance from a t
 	return y
 
 /*
-Recursively gets all contents of contents and returns them all in a list.
-
-recursive_depth is useful if you only want a turf and everything on it (recursive_depth=1)
-Do not set recursive depth higher than MAX_PROC_DEPTH as byond breaks when that limit is reached.
+	Gets all contents of contents and returns them all in a list.
 */
-/atom/proc/GetAllContents(list/output=list(), recursive_depth=MAX_PROC_DEPTH, _current_depth=0)
-	. = output
-	output += src
-	if(_current_depth == recursive_depth)
-		if(_current_depth == MAX_PROC_DEPTH)
-			WARNING("Get all contents reached the max recursive depth of [MAX_PROC_DEPTH]. More and we would break shit. Offending atom: [src]")
-		return
-	for(var/i in 1 to contents.len)
-		var/atom/thing = contents[i]
-		thing.GetAllContents(output, recursive_depth, ++_current_depth)
+/atom/proc/GetAllContents()
+	var/list/processing_list = list(src)
+	var/list/assembled = list()
+	while(processing_list.len)
+		var/atom/A = processing_list[1]
+		processing_list.Cut(1, 2)
+		//Byond does not allow things to be in multiple contents, or double parent-child hierarchies, so only += is needed
+		//This is also why we don't need to check against assembled as we go along
+		processing_list += A.contents 
+		assembled += A
+	return assembled
 
 //Step-towards method of determining whether one atom can see another. Similar to viewers()
 /proc/can_see(atom/source, atom/target, length=5) // I couldnt be arsed to do actual raycasting :I This is horribly inaccurate.