Use hashing for more efficient groupcaps updating

This adds the metadata field "groupcaps_hash" to tools enchanted with
efficiency.  This value contains a hash of the groupcaps field in
tool_capabilities.  This value gets compared to the expected hash value
to determine if the tools tool_capabilities should be updated according
to commit af31f8189e8e5c2b.

This commit makes efficiency more efficient.
This commit is contained in:
Elias Åström 2021-03-15 19:32:43 +01:00
parent 3241dbbec5
commit 922bdbc601
3 changed files with 64 additions and 8 deletions

@ -405,3 +405,11 @@ function mcl_util.get_object_center(obj)
pos.y = pos.y + (ymax - ymin) / 2.0
return pos
end
-- Compute a hash value.
function mcl_util.hash(value)
-- minetest.get_password_hash is quite fast, even if it uses a
-- cryptographic hashing function (SHA-1). It is written in C++ and it
-- is probably hard to write a faster hashing function in Lua.
return minetest.get_password_hash("ryvnf", minetest.serialize(value))
end

@ -155,9 +155,7 @@ mcl_enchanting.enchantments.efficiency = {
description = S("Increases mining speed."),
curse = false,
on_enchant = function(itemstack, level)
local tool_capabilities = itemstack:get_tool_capabilities()
tool_capabilities.groupcaps = mcl_autogroup.get_groupcaps(itemstack:get_name(), level)
itemstack:get_meta():set_tool_capabilities(tool_capabilities)
mcl_enchanting.apply_efficiency(itemstack, level)
end,
requires_tool = false,
treasure = false,

@ -1,6 +1,53 @@
local S = minetest.get_translator("mcl_enchanting")
local F = minetest.formspec_escape
local efficiency_cache_table = {}
-- Get the efficiency groupcaps and hash for a tool and efficiency level. If
-- this function is called repeatedly with the same values it will return data
-- from a cache.
--
-- Returns a table with the following two fields:
-- values - the groupcaps table
-- hash - the hash of the groupcaps table
local function get_efficiency_groupcaps(toolname, level)
local toolcache = efficiency_cache_table[toolname]
if not toolcache then
toolcache = {}
efficiency_cache_table[toolname] = toolcache
end
local levelcache = toolcache[level]
if not levelcache then
levelcache = {}
levelcache.values = mcl_autogroup.get_groupcaps(toolname, level)
levelcache.hash = mcl_util.hash(levelcache.values)
toolcache[level] = levelcache
end
return levelcache
end
-- Apply efficiency enchantment to a tool. This will update the tools
-- tool_capabilities to give it new digging times. This function will be called
-- repeatedly to make sure the digging times stored in groupcaps stays in sync
-- when the digging times of nodes can change.
--
-- To make it more efficient it will first check a hash value to determine if
-- the tool needs to be updated.
function mcl_enchanting.apply_efficiency(itemstack, level)
local name = itemstack:get_name()
local groupcaps = get_efficiency_groupcaps(name, level)
local hash = itemstack:get_meta():get_string("groupcaps_hash")
if not hash or hash ~= groupcaps.hash then
local tool_capabilities = itemstack:get_tool_capabilities()
tool_capabilities.groupcaps = groupcaps.values
itemstack:get_meta():set_tool_capabilities(tool_capabilities)
itemstack:get_meta():set_string("groupcaps_hash", groupcaps.hash)
end
end
function mcl_enchanting.is_book(itemname)
return itemname == "mcl_books:book" or itemname == "mcl_enchanting:book_enchanted" or itemname == "mcl_books:book_enchanted"
end
@ -219,13 +266,16 @@ function mcl_enchanting.enchantments_snippet(_, _, itemstack)
end
end
-- Returns after_use callback function for enchanted items. The after_use
-- callback is used to check the tool_capabilities of enchanted tools to update
-- old enchanted tools with outdated digtimes in their tool_capabilities.
-- Returns the after_use callback function to use when registering an enchanted
-- item. The after_use callback is used to update the tool_capabilities of
-- efficiency enchanted tools with outdated digging times.
--
-- It does this by calling apply_efficiency to reapply the efficiency
-- enchantment. That function is written to use hash values to only update the
-- tool if neccessary.
--
-- This is neccessary for digging times of tools to be in sync when MineClone2
-- or mods change add new hardness values for nodes or when existing hardness
-- values are changed.
-- or mods add new hardness values.
local function get_after_use_callback(itemdef)
if itemdef.after_use then
-- If the tool already has an after_use, make sure to call that