Add ObjectState class. Closes #1515

mods/lord/Core/base_classes/src/base_classes.lua

@@ -1,15 +1,18 @@
-local Event = require("base_classes.Event")
-local Form  = require("base_classes.Form")
+local Event       = require("base_classes.Event")
+local Form        = require("base_classes.Form")
+local ObjectState = require("base_classes.ObjectState")
 
 
 base_classes = {} -- luacheck: ignore unused global variable base_classes
 
 local function register_api()
 	_G.base_classes = {
 		--- @type base_classes.Event
-		Event = Event,
+		Event       = Event,
 		--- @type base_classes.Form
-		Form  = Form,
+		Form        = Form,
+		--- @type base_classes.ObjectState
+		ObjectState = ObjectState,
 	}
 end
 

mods/lord/Core/base_classes/src/base_classes/ObjectState.lua

@@ -0,0 +1,53 @@
+local Storage = require("base_classes.ObjectState.Storage")
+
+
+--- @class base_classes.ObjectState
+local ObjectState = {
+	--- @private
+	--- @type table<string,any>
+	state_table = nil,
+}
+
+--- @param object table  Table of all state entries
+--- @return base_classes.ObjectState
+function ObjectState:new(object)
+	local class = self
+
+	self = setmetatable({}, { __index = class })
+	self:load(object)
+
+	return self
+end
+
+--- @param name string
+--- @return any
+function ObjectState:get_entry(name)
+	return self.state_table[name]
+end
+
+--- @param name  string
+--- @param value any
+--- @return base_classes.ObjectState
+function ObjectState:set_entry(name, value)
+	self.state_table[name] = value
+
+	return self
+end
+--- @param name string
+--- @return base_classes.ObjectState
+function ObjectState:del_entry(name)
+	return self:set_entry(name, nil)
+end
+
+--- @param object ObjectRef
+--- @return boolean
+function ObjectState:save(object)
+	return Storage.set_state_of(object, self.state_table)
+end
+
+--- @param object Player|Entity
+function ObjectState:load(object)
+	self.state_table = Storage.get_state_of(object)
+end
+
+return ObjectState

mods/lord/Core/base_classes/src/base_classes/ObjectState/Storage.lua

@@ -0,0 +1,46 @@
+--- @static
+--- @class base_classes.ObjectState.Storage
+local Storage = {}
+
+--- Obtains `ObjectState` from meta or object properties depending on whether `object` is a player or not
+--- @param object Player|Entity
+--- @return table
+function Storage.get_state_of(object)
+	if not object then
+		return
+	end
+
+	return object:is_player()
+		and minetest.deserialize(object:get_meta():get("object_state") or "return {}")
+		or  object:get_luaentity().object_state or {}
+end
+
+--- Obtains `ObjectState` from meta or object properties depending on whether `object` is a player or not
+---
+--- @param object       Player|Entity   a player or an entity to apply `ObjectState` to
+--- @param state_table  table
+---
+--- @return boolean  success or not
+function Storage.set_state_of(object, state_table)
+	if not object then
+		return false
+	end
+
+	local state_string = minetest.serialize(state_table)
+
+	if object:is_player() then
+		local meta = object:get_meta()
+		meta:set_string("object_state", state_string)
+	else
+		local entity = object:get_luaentity()
+		if not entity then
+			return false
+		end
+		entity.object_state = state_table
+	end
+
+	return true
+end
+
+
+return Storage