Optimize item.lua

Replace slow ItemStack get_definitions with registered_nodes one's and cached playername as it's used multiple times.  Also removed local item = itemstack:peek_item() as it is never used.

builtin/game/item.lua

@@ -156,7 +156,8 @@ function core.yaw_to_dir(yaw)
end

function core.get_node_drops(nodename, toolname)
	local drop = ItemStack({name=nodename}):get_definition().drop
	local def = core.registered_nodes[nodename]
	local drop = def and def.drop
	if drop == nil then
		-- default drop
		return {nodename}
@@ -205,7 +206,6 @@ function core.get_node_drops(nodename, toolname)
end

function core.item_place_node(itemstack, placer, pointed_thing, param2)
	local item = itemstack:peek_item()
	local def = itemstack:get_definition()
	if def.type ~= "node" or pointed_thing.type ~= "node" then
		return itemstack, false
@@ -215,20 +215,21 @@ function core.item_place_node(itemstack, placer, pointed_thing, param2)
	local oldnode_under = core.get_node_or_nil(under)
	local above = pointed_thing.above
	local oldnode_above = core.get_node_or_nil(above)
	local playername = placer:get_player_name()

	if not oldnode_under or not oldnode_above then
		core.log("info", placer:get_player_name() .. " tried to place"
		core.log("info", playername .. " tried to place"
			.. " node in unloaded position " .. core.pos_to_string(above))
		return itemstack, false
	end

	local olddef_under = ItemStack({name=oldnode_under.name}):get_definition()
	local olddef_under = core.registered_nodes[oldnode_under.name]
	olddef_under = olddef_under or core.nodedef_default
	local olddef_above = ItemStack({name=oldnode_above.name}):get_definition()
	local olddef_above = core.registered_nodes[oldnode_above.name]
	olddef_above = olddef_above or core.nodedef_default

	if not olddef_above.buildable_to and not olddef_under.buildable_to then
		core.log("info", placer:get_player_name() .. " tried to place"
		core.log("info", playername .. " tried to place"
			.. " node in invalid position " .. core.pos_to_string(above)
			.. ", replacing " .. oldnode_above.name)
		return itemstack, false
@@ -243,17 +244,17 @@ function core.item_place_node(itemstack, placer, pointed_thing, param2)
		place_to = {x = under.x, y = under.y, z = under.z}
	end

	if core.is_protected(place_to, placer:get_player_name()) and
	if core.is_protected(place_to, playername) and
			not minetest.check_player_privs(placer, "protection_bypass") then
		core.log("action", placer:get_player_name()
		core.log("action", playername
				.. " tried to place " .. def.name
				.. " at protected position "
				.. core.pos_to_string(place_to))
		core.record_protection_violation(place_to, placer:get_player_name())
		core.record_protection_violation(place_to, playername)
		return itemstack
	end

	core.log("action", placer:get_player_name() .. " places node "
	core.log("action", playername .. " places node "
		.. def.name .. " at " .. core.pos_to_string(place_to))

	local oldnode = core.get_node(place_to)
@@ -262,17 +263,17 @@ function core.item_place_node(itemstack, placer, pointed_thing, param2)
	-- Calculate direction for wall mounted stuff like torches and signs
	if def.place_param2 ~= nil then
		newnode.param2 = def.place_param2
	elseif (def.paramtype2 == 'wallmounted' or
			def.paramtype2 == 'colorwallmounted') and not param2 then
	elseif (def.paramtype2 == "wallmounted" or
			def.paramtype2 == "colorwallmounted") and not param2 then
		local dir = {
			x = under.x - above.x,
			y = under.y - above.y,
			z = under.z - above.z
		}
		newnode.param2 = core.dir_to_wallmounted(dir)
	-- Calculate the direction for furnaces and chests and stuff
	elseif (def.paramtype2 == 'facedir' or
			def.paramtype2 == 'colorfacedir') and not param2 then
	elseif (def.paramtype2 == "facedir" or
			def.paramtype2 == "colorfacedir") and not param2 then
		local placer_pos = placer:getpos()
		if placer_pos then
			local dir = {
@@ -310,7 +311,6 @@ function core.item_place_node(itemstack, placer, pointed_thing, param2)
	end

	-- Run script hook
	local _, callback
	for _, callback in ipairs(core.registered_on_placenodes) do
		-- Deepcopy pos, node and pointed_thing because callback can modify them
		local place_to_copy = {x=place_to.x, y=place_to.y, z=place_to.z}
@@ -451,8 +451,9 @@ function core.handle_node_drops(pos, drops, digger)
end

function core.node_dig(pos, node, digger)
	local def = ItemStack({name=node.name}):get_definition()
	if not def.diggable or (def.can_dig and not def.can_dig(pos,digger)) then
	local def = core.registered_nodes[node.name]
	if def and (not def.diggable or
			(def.can_dig and not def.can_dig(pos, digger))) then
		core.log("info", digger:get_player_name() .. " tried to dig "
			.. node.name .. " which is not diggable "
			.. core.pos_to_string(pos))
@@ -477,7 +478,7 @@ function core.node_dig(pos, node, digger)

	local wdef = wielded:get_definition()
	local tp = wielded:get_tool_capabilities()
	local dp = core.get_dig_params(def.groups, tp)
	local dp = core.get_dig_params(def and def.groups, tp)
	if wdef and wdef.after_use then
		wielded = wdef.after_use(wielded, digger, node, dp) or wielded
	else