runtime optimization - table.copy is bad

block_devices.lua

@@ -77,8 +77,8 @@ function bdev:get_removable_disk(removable_type)
 			if not self.stack then
 				return false
 			end
-			local drop_pos = table.copy(self.bdev.os.pos)
-			drop_pos = { x=drop_pos.x+math.random()*2-1, y=drop_pos.y,z=drop_pos.z+math.random()*2-1 }
+			local p = self.bdev.os.pos
+			local drop_pos = { x=p.x+math.random()*2-1, y=p.y,z=p.z+math.random()*2-1 }
 			minetest.item_drop(self.stack, nil, drop_pos)
 			self.stack = nil
 			return true
@@ -192,7 +192,10 @@ end
 
 -- Get handler
 function laptop.get_bdev_handler(mtos)
-	local bdevobj = table.copy(bdev)
+	local bdevobj = {}
+	for k,v in pairs(bdev) do
+		bdevobj[k] = v
+	end
 	bdevobj.os = mtos
 	return bdevobj
 end

mtos.lua

@@ -208,10 +208,12 @@ function os_class:set_theme(theme)
 end
 
 function os_class:get_os_attr()
-	local os_attr = table.copy(laptop.os_version_attr.default)
-	if self.hwdef.os_version then
-		os_attr = table.copy(laptop.os_version_attr[self.hwdef.os_version])
+	local os_attr = {}
+	local os_version = self.hwdef.os_version or 'default'
+	for k, v in pairs(laptop.os_version_attr[os_version]) do
+		os_attr[k] = v
 	end
+
 	os_attr.tty_style = self.hwdef.tty_style or os_attr.tty_style
 	if self.hwdef.tty_monochrome ~= nil then
 		os_attr.tty_monochrome = self.hwdef.tty_monochrome
@@ -278,7 +280,10 @@ function os_class:get_app(name)
 	if not template then
 		return
 	end
-	local app = setmetatable(table.copy(template), laptop.class_lib.app)
+	local app = setmetatable({}, laptop.class_lib.app)
+	for k,v in pairs(template) do
+		app[k] = v
+	end
 	app.name = name
 	app.os = self
 	return app

themes.lua

@@ -111,8 +111,11 @@ end
 
 
 function laptop.get_theme(theme_name)
-	local self = setmetatable(table.copy(laptop.themes.default), theme_class)
 	theme_name = theme_name or "Freedom"
+	local self = setmetatable({}, theme_class)
+	for k, v in pairs(laptop.themes.default) do
+		self[k] = v
+	end
 	if theme_name and laptop.themes[theme_name] then
 		for k,v in pairs(laptop.themes[theme_name]) do
 			self[k] = v