Content ID caching in Lua (#12444)

* Cache content IDs in Lua

Co-authored-by: sfan5 <sfan5@live.de>

builtin/async/game.lua

@@ -13,9 +13,12 @@ end
 
 -- Import a bunch of individual files from builtin/game/
 local gamepath = core.get_builtin_path() .. "game" .. DIR_DELIM
+local commonpath = core.get_builtin_path() .. "common" .. DIR_DELIM
+
+local builtin_shared = {}
 
 dofile(gamepath .. "constants.lua")
-dofile(gamepath .. "item_s.lua")
+assert(loadfile(commonpath .. "item_s.lua"))(builtin_shared)
 dofile(gamepath .. "misc_s.lua")
 dofile(gamepath .. "features.lua")
 dofile(gamepath .. "voxelarea.lua")
@@ -57,3 +60,5 @@ setmetatable(core.registered_items, alias_metatable)
 setmetatable(core.registered_nodes, alias_metatable)
 setmetatable(core.registered_craftitems, alias_metatable)
 setmetatable(core.registered_tools, alias_metatable)
+
+builtin_shared.cache_content_ids()

builtin/common/item_s.lua

@@ -4,6 +4,8 @@
 -- Server or writable access to IGameDef on the engine side.
 -- (The '_s' stands for standalone.)
 
+local builtin_shared = ...
+
 --
 -- Item definition helpers
 --
@@ -177,3 +179,47 @@ function core.strip_param2_color(param2, paramtype2)
 	-- paramtype2 == "color" requires no modification.
 	return param2
 end
+
+-- Content ID caching
+
+local old_get_content_id = core.get_content_id
+local old_get_name_from_content_id = core.get_name_from_content_id
+
+local name2content = setmetatable({}, {
+	__index = function(self, name)
+		return old_get_content_id(name)
+	end,
+})
+
+local content2name = setmetatable({}, {
+	__index = function(self, id)
+		return old_get_name_from_content_id(id)
+	end,
+})
+
+function core.get_content_id(name)
+	return name2content[name]
+end
+
+function core.get_name_from_content_id(id)
+	return content2name[id]
+end
+
+-- Cache content IDs after they have stopped changing.
+function builtin_shared.cache_content_ids()
+	for name in pairs(core.registered_nodes) do
+		local id = old_get_content_id(name)
+		name2content[name] = id
+		content2name[id] = name
+	end
+	-- unknown is not in the registered node list.
+	local unknown_name = old_get_name_from_content_id(core.CONTENT_UNKNOWN)
+	name2content[unknown_name] = core.CONTENT_UNKNOWN
+	content2name[core.CONTENT_UNKNOWN] = unknown_name
+
+	for name in pairs(core.registered_aliases) do
+		if core.registered_nodes[name] then
+			name2content[name] = old_get_content_id(name)
+		end
+	end
+end

builtin/game/init.lua

@@ -8,7 +8,7 @@ local gamepath   = scriptpath .. "game".. DIR_DELIM
 local builtin_shared = {}
 
 dofile(gamepath .. "constants.lua")
-dofile(gamepath .. "item_s.lua")
+assert(loadfile(commonpath .. "item_s.lua"))(builtin_shared)
 assert(loadfile(gamepath .. "item.lua"))(builtin_shared)
 dofile(gamepath .. "register.lua")
 
@@ -37,4 +37,6 @@ dofile(gamepath .. "statbars.lua")
 dofile(gamepath .. "knockback.lua")
 dofile(gamepath .. "async.lua")
 
+core.after(0, builtin_shared.cache_content_ids)
+
 profiler = nil