stitches together some tg code to make swarmers able to eat stuff I think (#10287)

* Update atoms.dm

* add return composition bit

* yeah this'll probably work

* ok

* Update swarmer_act.dm

code/datums/materials/_material.dm

@@ -65,3 +65,14 @@ Simple datum which is instanced once per type and is used for every object of sa
 	o.max_integrity = new_max_integrity
 	o.force = initial(o.force)
 	o.throwforce = initial(o.throwforce)
+
+/** Returns the composition of this material.
+  *
+  * Mostly used for alloys when breaking down materials.
+  *
+  * Arguments:
+  * - amount: The amount of the material to break down.
+  * - breakdown_flags: Some flags dictating how exactly this material is being broken down.
+  */
+/datum/material/proc/return_composition(amount=1, breakdown_flags=NONE)
+	return list((src) = amount) // Yes we need the parenthesis, without them BYOND stringifies src into "src" and things break.

code/game/atoms.dm

@@ -1116,6 +1116,25 @@
 /atom/proc/intercept_zImpact(atom/movable/AM, levels = 1)
 	return FALSE
 
+/**Returns the material composition of the atom.
+  *
+  * Used when recycling items, specifically to turn alloys back into their component mats.
+  *
+  * Exists because I'd need to add a way to un-alloy alloys or otherwise deal
+  * with people converting the entire stations material supply into alloys.
+  *
+  * Arguments:
+  * - flags: A set of flags determining how exactly the materials are broken down.
+  */
+/atom/proc/get_material_composition(breakdown_flags=NONE)
+	. = list()
+	var/list/cached_materials = custom_materials
+	for(var/mat in cached_materials)
+		var/datum/material/material = getmaterialref(mat)
+		var/list/material_comp = material.return_composition(cached_materials[material], breakdown_flags)
+		for(var/comp_mat in material_comp)
+			.[comp_mat] += material_comp[comp_mat]
+
 /**
   * Causes effects when the atom gets hit by a rust effect from heretics
   *

code/modules/swarmers/swarmer_act.dm

@@ -28,7 +28,8 @@
 	return 0
 
 /obj/item/integrate_amount() //returns the amount of resources gained when eating this item
-	if(materials[/datum/material/iron] || materials[/datum/material/glass])
+	var/list/mats = get_material_composition(ALL) // Ensures that items made from plasteel, and plas/titanium/plastitaniumglass get integrated correctly.
+	if(length(mats) && (mats[getmaterialref(/datum/material/iron)] || mats[getmaterialref(/datum/material/glass)]))
 		return 1
 	return ..()