Move values the mainmenu caches to dedicated files (#14433)

builtin/mainmenu/common.lua

@@ -18,6 +18,26 @@
 -- Global menu data
 menudata = {}
 
+-- located in user cache path, for remembering this like e.g. last update check
+cache_settings = Settings(core.get_cache_path() .. DIR_DELIM .. "common.conf")
+
+--- Checks if the given key contains a timestamp less than a certain age.
+--- Pair this with a call to `cache_settings:set(key, tostring(os.time()))`
+--- after successfully refreshing the cache.
+--- @param key Name of entry in cache_settings
+--- @param max_age Age to check against, in seconds
+--- @return true if the max age is not reached
+function check_cache_age(key, max_age)
+	local time_now = os.time()
+	local time_checked = tonumber(cache_settings:get(key)) or 0
+	return time_now - time_checked < max_age
+end
+
+function core.on_before_close()
+	-- called before the menu is closed, either exit or to join a game
+	cache_settings:write()
+end
+
 -- Local cached values
 local min_supp_proto, max_supp_proto
 
@@ -27,6 +47,16 @@ function common_update_cached_supp_proto()
 end
 common_update_cached_supp_proto()
 
+-- Other global functions
+
+function core.sound_stop(handle, ...)
+	return handle:stop(...)
+end
+
+function os.tmpname()
+	error('do not use') -- instead: core.get_temp_path()
+end
+
 -- Menu helper functions
 
 local function render_client_count(n)
@@ -140,11 +170,6 @@ function render_serverlist_row(spec)
 
 	return table.concat(details, ",")
 end
----------------------------------------------------------------------------------
-os.tmpname = function()
-	error('do not use') -- instead use core.get_temp_path()
-end
---------------------------------------------------------------------------------
 
 function menu_render_worldlist()
 	local retval = {}