teleport_tube.lua: add checks for hash collisions in positions table

This commit is contained in:
thetaepsilon-gamedev 2017-12-22 17:57:00 +00:00
parent 57fc8c67f8
commit 91bd0c7e98

View File

@ -50,6 +50,11 @@ local function read_tube_db()
return tp_tube_db
end
-- debug formatter for coordinates used below
local fmt = function(pos)
return pos.x..", "..pos.y..", "..pos.z
end
-- updates or adds a tube
local function set_tube(pos, channel, can_receive)
local tubes = tp_tube_db or read_tube_db()
@ -63,6 +68,19 @@ local function set_tube(pos, channel, can_receive)
end
-- we haven't found any tp tube to update, so lets add it
-- but sanity check that the hash has not already been inserted.
-- if so, complain very loudly and refuse the update so the player knows something is amiss.
-- to catch regressions of https://github.com/minetest-mods/pipeworks/issues/166
local existing = tp_tube_db[hash]
if existing ~= nil then
local e = "error"
minetest.log(e, "pipeworks teleport tube update refused due to position hash collision")
minetest.log(e, "collided hash: "..hash)
minetest.log(e, "tried-to-place tube: "..fmt(pos))
minetest.log(e, "existing tube: "..fmt(existing))
return
end
tp_tube_db[hash] = {x=pos.x,y=pos.y,z=pos.z,channel=channel,cr=can_receive}
save_tube_db()
end