Too remove potential excessive garbage collection per tick. We will be reusing lists for overlays instead of deleting and creating them.

the .Cut() proc on a list will empty a list by default. This also will set the len to 0.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@5465 316c924e-a436-60f5-8080-3fe189b3f50e

code/modules/power/antimatter/shielding.dm

@@ -123,7 +123,7 @@ proc/cardinalrange(var/center)
 
 
 /obj/machinery/am_shielding/update_icon()
-	overlays = null
+	overlays.Cut()
 	for(var/direction in alldirs)
 		var/machine = locate(/obj/machinery, get_step(loc, direction))
 		if((istype(machine, /obj/machinery/am_shielding) && machine:control_unit == control_unit)||(istype(machine, /obj/machinery/power/am_control_unit) && machine == control_unit))

code/modules/power/apc.dm

@@ -178,7 +178,7 @@
 // also add overlays for indicator lights
 /obj/machinery/power/apc/update_icon()
 
-	overlays = null
+	overlays.Cut()
 	if(opened)
 		var/basestate = "apc[ cell ? "2" : "1" ]"	// if opened, show cell if it's inserted
 		if (opened==1)

code/modules/power/cell.dm

@@ -10,7 +10,7 @@
 		updateicon()
 
 /obj/item/weapon/cell/proc/updateicon()
-	overlays = null
+	overlays.Cut()
 
 	if(charge < 0.01)
 		return

code/modules/power/generator.dm

@@ -43,9 +43,9 @@
 /obj/machinery/power/generator/proc/updateicon()
 
 	if(stat & (NOPOWER|BROKEN))
-		overlays = null
+		overlays.Cut()
 	else
-		overlays = null
+		overlays.Cut()
 
 		if(lastgenlev != 0)
 			overlays += image('icons/obj/power.dmi', "teg-op[lastgenlev]")

code/modules/power/generator_type2.dm

@@ -26,9 +26,9 @@
 /obj/machinery/power/generator_type2/proc/updateicon()
 
 	if(stat & (NOPOWER|BROKEN))
-		overlays = null
+		overlays.Cut()
 	else
-		overlays = null
+		overlays.Cut()
 
 		if(lastgenlev != 0)
 			overlays += image('icons/obj/power.dmi', "teg-op[lastgenlev]")

code/modules/power/singularity/collector.dm

@@ -129,7 +129,7 @@ var/global/list/rad_collectors = list()
 
 
 /obj/machinery/power/rad_collector/proc/update_icons()
-	overlays = null
+	overlays.Cut()
 	if(P)
 		overlays += image('icons/obj/singularity.dmi', "ptank")
 	if(stat & (NOPOWER|BROKEN))

code/modules/power/singularity/field_generator.dm

@@ -34,7 +34,7 @@ field_generator power level display
 
 
 /obj/machinery/field_generator/update_icon()
-	overlays = null
+	overlays.Cut()
 	if(!active)
 		if(warming_up)
 			overlays += "+a[warming_up]"

code/modules/power/smes.dm

@@ -44,7 +44,7 @@
 
 
 /obj/machinery/power/smes/proc/updateicon()
-	overlays = null
+	overlays.Cut()
 	if(stat & BROKEN)	return
 
 	overlays += image('icons/obj/power.dmi', "smes-op[online]")

code/modules/power/solar.dm

@@ -101,7 +101,7 @@ var/list/solars_list = list()
 
 /obj/machinery/power/solar/update_icon()
 	..()
-	overlays = null
+	overlays.Cut()
 	if(stat & BROKEN)
 		overlays += image('icons/obj/power.dmi', icon_state = "solar_panel-b", layer = FLY_LAYER)
 	else
@@ -306,14 +306,14 @@ var/list/solars_list = list()
 /obj/machinery/power/solar_control/update_icon()
 	if(stat & BROKEN)
 		icon_state = "broken"
-		overlays = null
+		overlays.Cut()
 		return
 	if(stat & NOPOWER)
 		icon_state = "c_unpowered"
-		overlays = null
+		overlays.Cut()
 		return
 	icon_state = "solar"
-	overlays = null
+	overlays.Cut()
 	if(cdir > 0)
 		overlays += image('icons/obj/computer.dmi', "solcon-o", FLY_LAYER, angle2dir(cdir))
 	return

code/modules/power/turbine.dm

@@ -58,7 +58,7 @@
 /obj/machinery/compressor/process()
 	if(!starter)
 		return
-	overlays = null
+	overlays.Cut()
 	if(stat & BROKEN)
 		return
 	if(!turbine)
@@ -113,7 +113,7 @@
 /obj/machinery/power/turbine/process()
 	if(!compressor.starter)
 		return
-	overlays = null
+	overlays.Cut()
 	if(stat & BROKEN)
 		return
 	if(!compressor)