mods that hopefully work for a TechAge-based pack

mods/techage_modpack/techage/basis/numbers_sqlite.lua

@@ -0,0 +1,142 @@
+--[[
+
+	TechAge
+	=======
+
+	Copyright (C) 2020 Joachim Stolberg
+
+	AGPL v3
+	See LICENSE.txt for more information
+
+	Storage backend for node number mapping via sqlite database
+
+]]--
+
+-- for lazy programmers
+local M = minetest.get_meta
+
+local storage = techage.storage
+
+-------------------------------------------------------------------
+-- Database
+-------------------------------------------------------------------
+local MN = minetest.get_current_modname()
+local WP = minetest.get_worldpath()
+local MAR_MAGIC = 0x8e
+
+if not techage.IE then
+	error("Please add 'secure.trusted_mods = techage' to minetest.conf!")
+end
+
+local sqlite3 = techage.IE.require("lsqlite3")
+local marshal = techage.IE.require("marshal")
+
+if not sqlite3 then
+	error("Please install sqlite3 via 'luarocks install lsqlite3'")
+end
+if not marshal then
+	error("Please install marshal via 'luarocks install lua-marshal'")
+end
+
+local db = sqlite3.open(WP.."/techage_numbers.sqlite")
+local ROW = sqlite3.ROW
+
+-- Prevent use of this db instance.
+if sqlite3 then sqlite3 = nil end
+
+db:exec[[
+  CREATE TABLE numbers(id INTEGER PRIMARY KEY, number INTEGER, x INTEGER, y INTEGER, z INTEGER);
+  CREATE UNIQUE INDEX idx ON numbers(number);
+]]
+
+local set = db:prepare("INSERT or REPLACE INTO numbers VALUES(NULL, ?, ?, ?, ?);")
+local get = db:prepare("SELECT * FROM numbers WHERE number=?;")
+
+local function set_block(number, pos)
+	set:reset()
+	set:bind(1, number)
+	set:bind(2, pos.x)
+	set:bind(3, pos.y)
+	set:bind(4, pos.z)
+	set:step()
+	return true
+end
+
+local function get_block(number)
+	get:reset()
+	get:bind(1, number)
+	if get:step() == ROW then
+		return {x = get:get_value(2), y = get:get_value(3), z = get:get_value(4)}
+	end
+end
+
+local function del_block(number)
+	db:exec("DELETE FROM numbers WHERE number="..number..";")
+end
+
+-------------------------------------------------------------------
+-- Migration from mod storage
+-------------------------------------------------------------------
+local Version = storage:get_int("Version") or 0
+local NextNumber = 0
+
+if Version == 0 then
+	Version = 4
+end
+if Version == 3 then
+	Version = 4
+	NextNumber = storage:get_int("NextNumber")
+	for i = 1, NextNumber do
+		local number = tostring(i)
+		if storage:contains(number) then
+			local pos = minetest.string_to_pos(storage:get_string(number))
+			set_block(number, pos)
+			storage:set_string(number, "")
+		end
+	end
+elseif Version == 4 then
+	NextNumber = storage:get_int("NextNumber")
+else
+	error("[] Invalid version number for 'number to pos mapping' table!")
+end
+
+
+-------------------------------------------------------------------
+-- API functions
+-------------------------------------------------------------------
+local api = {}
+
+function api.get_nodepos(number)
+	return get_block(number)
+end
+
+function api.set_nodepos(number, pos)
+	set_block(number, pos)
+end
+
+function api.add_nodepos(pos)
+	local num = tostring(NextNumber)
+	NextNumber = NextNumber + 1
+	storage:set_int("NextNumber", NextNumber)
+	set_block(num, pos)
+	return num
+end
+
+function api.del_nodepos(number)
+	del_block(number)
+end
+
+-- delete invalid entries
+function api.delete_invalid_entries(node_def)
+	minetest.log("info", "[TechAge] Data maintenance started")
+	for id, num, x, y, z in db:urows('SELECT * FROM numbers') do
+		local pos = {x = x, y = y, z = z}
+		local name = techage.get_node_lvm(pos).name
+		if not node_def[name] then
+			del_block(num)
+		end
+	end
+	minetest.log("info", "[TechAge] Data maintenance finished")
+end
+
+return api