mods that hopefully work for a TechAge-based pack

mods/techage_modpack/techage/basis/nodedata_meta.lua

@@ -0,0 +1,103 @@
+--[[
+
+	TechAge
+	=======
+
+	Copyright (C) 2020 Joachim Stolberg
+
+	AGPL v3
+	See LICENSE.txt for more information
+
+	Storage backend for node related data as node metadata
+
+]]--
+
+-- for lazy programmers
+local M = minetest.get_meta
+
+local storage = techage.storage
+
+-------------------------------------------------------------------
+-- Marshaling
+-------------------------------------------------------------------
+local use_marshal = minetest.settings:get_bool('techage_use_marshal', false)
+local MAR_MAGIC = 0x8e
+
+-- default functions
+local serialize = minetest.serialize
+local deserialize = minetest.deserialize
+
+if use_marshal then
+	if not techage.IE then
+		error("Please add 'secure.trusted_mods = techage' to minetest.conf!")
+	end
+	local marshal = techage.IE.require("marshal")
+	if not marshal then
+		error("Please install marshal via 'luarocks install lua-marshal'")
+	end
+
+	serialize = marshal.encode
+
+	deserialize = function(s)
+		if s ~= "" then
+			if s:byte(1) == MAR_MAGIC then
+				return marshal.decode(s)
+			else
+				return minetest.deserialize(s)
+			end
+		end
+	end
+end
+
+-------------------------------------------------------------------
+-- API functions
+-------------------------------------------------------------------
+local api = {}
+
+function api.get_mapblock_data(key)
+	return {}
+end
+
+function api.store_mapblock_data(key, mapblock_data)
+	for key, item in pairs(mapblock_data) do
+		if key ~= "in_use" then
+			local pos = item and item._POS_
+			if pos then
+				item._POS_ = nil
+				local data = serialize(item)
+				item._POS_ = pos
+				local meta = M(pos)
+				meta:set_string("ta_data", data)
+				meta:mark_as_private("ta_data")
+			end
+		end
+	end
+end
+
+function api.get_node_data(pos)
+	local tbl = {}
+	local s = M(pos):get_string("ta_data")
+
+	if s ~= "" then
+		tbl = deserialize(s) or {}
+	end
+	tbl._POS_ = table.copy(pos)
+
+	return tbl
+end
+
+-- Meta data can't be written reliable at shutdown,
+-- so we have to store/restore the data differently
+function api.freeze_at_shutdown(data)
+	storage:set_string("shutdown_nodedata", serialize(data))
+end
+
+function api.restore_at_startup()
+	local s = storage:get_string("shutdown_nodedata")
+	if s ~= "" then
+		return deserialize(s) or {}
+	end
+	return {}
+end
+
+return api