Merge pull request #11259 from Ghommie/Ghommie-cit590

Porting update_icon improvements.

code/datums/action.dm

@@ -31,6 +31,7 @@
 
 /datum/action/proc/link_to(Target)
 	target = Target
+	RegisterSignal(Target, COMSIG_ATOM_UPDATED_ICON, .proc/OnUpdatedIcon)
 
 /datum/action/Destroy()
 	if(owner)
@@ -153,6 +154,9 @@
 	var/mob/M = target
 	M.ghostize(1)
 
+/datum/action/proc/OnUpdatedIcon()
+	UpdateButtonIcon()
+
 //Presets for item actions
 /datum/action/item_action
 	check_flags = AB_CHECK_RESTRAINED|AB_CHECK_STUN|AB_CHECK_LYING|AB_CHECK_CONSCIOUS
@@ -824,4 +828,4 @@
 	for(var/datum/action/A in M.actions)
 		if(istype(A, action_type))
 			return A
-	return 
+	return

code/datums/components/armor_plate.dm

@@ -12,6 +12,8 @@
 	RegisterSignal(parent, COMSIG_PARENT_EXAMINE, .proc/examine)
 	RegisterSignal(parent, COMSIG_PARENT_ATTACKBY, .proc/applyplate)
 	RegisterSignal(parent, COMSIG_PARENT_PREQDELETED, .proc/dropplates)
+	if(istype(parent, /obj/mecha/working/ripley))
+		RegisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS, .proc/apply_mech_overlays)
 
 	if(_maxamount)
 		maxamount = _maxamount
@@ -75,4 +77,13 @@
 /datum/component/armor_plate/proc/dropplates(datum/source, force)
 	if(ismecha(parent)) //items didn't drop the plates before and it causes erroneous behavior for the time being with collapsible helmets
 		for(var/i in 1 to amount)
-			new upgrade_item(get_turf(parent))
+			new upgrade_item(get_turf(parent))
+
+/datum/component/armor_plate/proc/apply_mech_overlays(obj/mecha/mech, list/overlays)
+	if(amount)
+		var/overlay_string = "ripley-g"
+		if(amount >= 3)
+			overlay_string += "-full"
+		if(!mech.occupant)
+			overlay_string += "-open"
+		overlays += overlay_string

code/datums/elements/update_icon_blocker.dm

@@ -0,0 +1,10 @@
+//Prevents calling anything in update_icon() like update_icon_state() or update_overlays()
+
+/datum/element/update_icon_blocker/Attach(datum/target)
+	. = ..()
+	if(!istype(target, /atom))
+		return ELEMENT_INCOMPATIBLE
+	RegisterSignal(target, COMSIG_ATOM_UPDATE_ICON, .proc/block_update_icon)
+
+/datum/element/update_icon_blocker/proc/block_update_icon()
+	return COMSIG_ATOM_NO_UPDATE_ICON_STATE | COMSIG_ATOM_NO_UPDATE_OVERLAYS

code/datums/elements/update_icon_updates_onmob.dm

@@ -0,0 +1,16 @@
+//update_icon() may change the onmob icons
+//Very good name, I know
+
+/datum/element/update_icon_updates_onmob/Attach(datum/target)
+	. = ..()
+	if(!istype(target, /obj/item))
+		return ELEMENT_INCOMPATIBLE
+	RegisterSignal(target, COMSIG_ATOM_UPDATED_ICON, .proc/update_onmob)
+
+/datum/element/update_icon_updates_onmob/proc/update_onmob(obj/item/target)
+	if(ismob(target.loc))
+		var/mob/M = target.loc
+		if(M.is_holding(target))
+			M.update_inv_hands()
+		else
+			M.regenerate_icons() //yeah this is shit, but we don't know which update_foo() proc to call instead so we'll call them all