Refactor actionqueue.lua (#501)

Reduce actionqueue complexity, thus faster execution
Improve code style
Add documentation/explanations
This commit is contained in:
DS 2020-01-06 21:59:02 +01:00 committed by SmallJoker
parent 9b58f8db29
commit 68c1729990

@ -1,96 +1,140 @@
mesecon.queue.actions={} -- contains all ActionQueue actions --[[
Mesecons uses something it calls an ActionQueue.
function mesecon.queue:add_function(name, func) The ActionQueue holds functions and actions.
mesecon.queue.funcs[name] = func Functions are added on load time with a specified name.
Actions are preserved over server restarts.
Each action consists of a position, the name of an added function to be called,
the params that should be used in this function call (additionally to the pos),
the time after which it should be executed, an optional overwritecheck and a
priority.
If time = 0, the action will be executed in the next globalstep, otherwise the
earliest globalstep when it will be executed is the after next globalstep.
It is guaranteed, that for two actions ac1, ac2 where ac1 ~= ac2,
ac1.time == ac2.time, ac1.priority == ac2.priority and ac1 was added earlier
than ac2, ac1 will be executed before ac2 (but in the same globalstep).
Note: Do not pass references in params, as they can not be preserved.
Also note: Some of the guarantees here might be dropped at some time.
]]
-- localize for speed
local queue = mesecon.queue
queue.actions = {} -- contains all ActionQueue actions
function queue:add_function(name, func)
queue.funcs[name] = func
end end
-- If add_action with twice the same overwritecheck and same position are called, the first one is overwritten -- If add_action with twice the same overwritecheck and same position are called, the first one is overwritten
-- use overwritecheck nil to never overwrite, but just add the event to the queue -- use overwritecheck nil to never overwrite, but just add the event to the queue
-- priority specifies the order actions are executed within one globalstep, highest first -- priority specifies the order actions are executed within one globalstep, highest first
-- should be between 0 and 1 -- should be between 0 and 1
function mesecon.queue:add_action(pos, func, params, time, overwritecheck, priority) function queue:add_action(pos, func, params, time, overwritecheck, priority)
-- Create Action Table: -- Create Action Table:
time = time or 0 -- time <= 0 --> execute, time > 0 --> wait time until execution time = time or 0 -- time <= 0 --> execute, time > 0 --> wait time until execution
priority = priority or 1 priority = priority or 1
local action = { pos=mesecon.tablecopy(pos), local action = {
pos = mesecon.tablecopy(pos),
func = func, func = func,
params = mesecon.tablecopy(params or {}), params = mesecon.tablecopy(params or {}),
time = time, time = time,
owcheck = (overwritecheck and mesecon.tablecopy(overwritecheck)) or nil, owcheck = (overwritecheck and mesecon.tablecopy(overwritecheck)) or nil,
priority=priority} priority = priority
}
local toremove = nil -- check if old action has to be overwritten / removed:
-- Otherwise, add the action to the queue if overwritecheck then
if overwritecheck then -- check if old action has to be overwritten / removed: for i, ac in ipairs(queue.actions) do
for i, ac in ipairs(mesecon.queue.actions) do if vector.equals(pos, ac.pos)
if(vector.equals(pos, ac.pos) and mesecon.cmpAny(overwritecheck, ac.owcheck) then
and mesecon.cmpAny(overwritecheck, ac.owcheck)) then -- remove the old action
toremove = i table.remove(queue.actions, i)
break break
end end
end end
end end
if (toremove ~= nil) then table.insert(queue.actions, action)
table.remove(mesecon.queue.actions, toremove)
end
table.insert(mesecon.queue.actions, action)
end end
-- execute the stored functions on a globalstep -- execute the stored functions on a globalstep
-- if however, the pos of a function is not loaded (get_node_or_nil == nil), do NOT execute the function -- if however, the pos of a function is not loaded (get_node_or_nil == nil), do NOT execute the function
-- this makes sure that resuming mesecons circuits when restarting minetest works fine -- this makes sure that resuming mesecons circuits when restarting minetest works fine (hm, where do we do this?)
-- However, even that does not work in some cases, that's why we delay the time the globalsteps -- However, even that does not work in some cases, that's why we delay the time the globalsteps
-- start to be execute by 5 seconds -- start to be execute by 4 seconds
local get_highest_priority = function (actions)
local highestp = -1
local highesti
for i, ac in ipairs(actions) do
if ac.priority > highestp then
highestp = ac.priority
highesti = i
end
end
return highesti local function globalstep_func(dtime)
end local actions = queue.actions
-- split into two categories:
local m_time = 0 -- actions_now: actions to execute now
local resumetime = mesecon.setting("resumetime", 4) -- queue.actions: actions to execute later
minetest.register_globalstep(function (dtime)
m_time = m_time + dtime
-- don't even try if server has not been running for XY seconds; resumetime = time to wait
-- after starting the server before processing the ActionQueue, don't set this too low
if (m_time < resumetime) then return end
local actions = mesecon.tablecopy(mesecon.queue.actions)
local actions_now = {} local actions_now = {}
queue.actions = {}
mesecon.queue.actions = {} for _, ac in ipairs(actions) do
-- sort actions into two categories:
-- those toexecute now (actions_now) and those to execute later (mesecon.queue.actions)
for i, ac in ipairs(actions) do
if ac.time > 0 then if ac.time > 0 then
ac.time = ac.time - dtime -- executed later -- action ac is to be executed later
table.insert(mesecon.queue.actions, ac) -- ~> insert into queue.actions
ac.time = ac.time - dtime
table.insert(queue.actions, ac)
else else
-- action ac is to be executed now
-- ~> insert into actions_now
table.insert(actions_now, ac) table.insert(actions_now, ac)
end end
end end
while(#actions_now > 0) do -- execute highest priorities first, until all are executed -- stable-sort the executed actions after their priority
local hp = get_highest_priority(actions_now) -- some constructions might depend on the execution order, hence we first
mesecon.queue:execute(actions_now[hp]) -- execute the actions that had a lower index in actions_now
table.remove(actions_now, hp) local old_action_order = {}
for i, ac in ipairs(actions_now) do
old_action_order[ac] = i
end
table.sort(actions_now, function(ac1, ac2)
if ac1.priority ~= ac2.priority then
return ac1.priority > ac2.priority
else
return old_action_order[ac1] < old_action_order[ac2]
end end
end) end)
function mesecon.queue:execute(action) -- execute highest priorities first, until all are executed
for _, ac in ipairs(actions_now) do
queue:execute(ac)
end
end
-- delay the time the globalsteps start to be execute by 4 seconds
do
local m_time = 0
local resumetime = mesecon.setting("resumetime", 4)
local globalstep_func_index = #minetest.registered_globalsteps + 1
minetest.register_globalstep(function(dtime)
m_time = m_time + dtime
-- don't even try if server has not been running for XY seconds; resumetime = time to wait
-- after starting the server before processing the ActionQueue, don't set this too low
if m_time < resumetime then
return
end
-- replace this globalstep function
minetest.registered_globalsteps[globalstep_func_index] = globalstep_func
end)
end
function queue:execute(action)
-- ignore if action queue function name doesn't exist, -- ignore if action queue function name doesn't exist,
-- (e.g. in case the action queue savegame was written by an old mesecons version) -- (e.g. in case the action queue savegame was written by an old mesecons version)
if mesecon.queue.funcs[action.func] then if queue.funcs[action.func] then
mesecon.queue.funcs[action.func](action.pos, unpack(action.params)) queue.funcs[action.func](action.pos, unpack(action.params))
end end
end end
@ -98,8 +142,8 @@ end
-- Store and read the ActionQueue to / from a file -- Store and read the ActionQueue to / from a file
-- so that upcoming actions are remembered when the game -- so that upcoming actions are remembered when the game
-- is restarted -- is restarted
mesecon.queue.actions = mesecon.file2table("mesecon_actionqueue") queue.actions = mesecon.file2table("mesecon_actionqueue")
minetest.register_on_shutdown(function() minetest.register_on_shutdown(function()
mesecon.table2file("mesecon_actionqueue", mesecon.queue.actions) mesecon.table2file("mesecon_actionqueue", queue.actions)
end) end)