element memes

code/datums/elements/persistence.dm

@@ -0,0 +1,60 @@
+/**
+  * Simple object persistence elements
+  * For now, it just attachs and detaches and all objects with it are recorded to disk based on map and stuff at round end
+  * Can expand later for more functionality
+  *
+  * WARNING: All atoms recorded are stored to turf! This does not yet support things like loading into inventories. This is mostly for on-floor objects.
+  */
+/datum/element/persistence
+	flags = ELEMENT_DETACH
+
+	/// List of persistent atoms. Associated list to their GUID
+	var/list/atom/objects = list()
+
+/**
+  * Serializes all objects into a list for json encode or anything else needed.
+  * Includes data the datum includes in serialize_list(), the GUID of the datum's entry, and its turf location.
+  */
+/datum/element/persistence/proc/SerializeAll()
+	. = list()
+	var/atom/A
+	var/guid
+	for(var/i in objects)
+		A = i
+		guid = objects[A]
+		var/turf/location = get_turf(A)
+		if(!A || !guid || !location)
+			continue
+		. += list(A.serialize_list(), guid, list(location.x, location.y, location.z), "[A.type]")
+
+/**
+  * Instantiates all objects from a data list and attaches to them.
+  */
+/datum/element/persistence/proc/DeserializeAndInstantiateAll(list/data)
+	for(var/i in data)
+		var/list/L = i
+		if(!istype(L) || (length(L) < 3))
+			continue
+		var/list/datumdata = L[1]
+		var/guid = L[2]
+		var/coords = L[3]
+		var/datumtype = text2path(L[4])
+		if(!ispath(datumtype))
+			continue
+		var/turf/T = locate(coords[1], coords[2], coords[3])
+		if(!T)
+			continue
+		var/atom/A = new datumtype(T)
+		A.deserialize_list(datumdata)
+		Attach(A, guid)
+
+/datum/element/persistence/Attach(datum/D, guid = GUID())
+	if(!isatom(D))
+		return ELEMENT_INCOMPATIBLE
+	. = ..()
+	if(. == ELEMENT_INCOMPATIBLE)
+		return
+	objects[D] = guid
+
+/datum/element/persistence/Detach(datum/D)
+	objects -= D