New timer design.

I could honestly not make much sense of the timer implementation
that was here. Instead I've implemented the type of timer algorithm
that I've used before, and tested it instead.

The concept is extremely simple: all timers are put in an ordered
list. We check every server tick if any of the timers have
elapsed, and execute the function associated with this timer.

We know that many timers by themselves cause new timers to be
added to this list, so we iterate *backwards* over the timer
list. This means that new timers being added while timers are
being executed, can never be executed in the same function pass,
as they are always appended to the table *after* the end of
the table, which we will never reach in the current pass over
all the table elements.

We switch time keeping to minetest.get_us_time(). dtime is
likely unreliable and we have our own high-res timer that we
can fix if it is indeed broken. This removes the need to do
any sort of time keeping.
This commit is contained in:
Auke Kok 2016-01-21 01:07:38 -08:00 committed by ShadowNinja
parent 4ac1e9bccb
commit ad884f23d4
2 changed files with 37 additions and 63 deletions

@ -4,74 +4,48 @@
-- Misc. API functions
--
local timers = {}
local mintime
local function update_timers(delay)
mintime = false
local sub = 0
for index = 1, #timers do
index = index - sub
local timer = timers[index]
timer.time = timer.time - delay
if timer.time <= 0 then
core.set_last_run_mod(timer.mod_origin)
timer.func(unpack(timer.args or {}))
table.remove(timers, index)
sub = sub + 1
elseif mintime then
mintime = math.min(mintime, timer.time)
else
mintime = timer.time
local jobs = {}
local time = 0.0
local last = 0.0
core.register_globalstep(function(dtime)
local new = core.get_us_time() / 1000000
if new > last then
time = time + (new - last)
else
-- Overflow, we may lose a little bit of time here but
-- only 1 tick max, potentially running timers slightly
-- too early.
time = time + new
end
last = new
if #jobs < 1 then
return
end
-- Iterate backwards so that we miss any new timers added by
-- a timer callback, and so that we don't skip the next timer
-- in the list if we remove one.
for i = #jobs, 1, -1 do
local job = jobs[i]
if time >= job.expire then
core.set_last_run_mod(job.mod_origin)
job.func(unpack(job.arg))
table.remove(jobs, i)
end
end
end
local timers_to_add
local function add_timers()
for _, timer in ipairs(timers_to_add) do
table.insert(timers, timer)
end
timers_to_add = false
end
local delay = 0
core.register_globalstep(function(dtime)
if not mintime then
-- abort if no timers are running
return
end
if timers_to_add then
add_timers()
end
delay = delay + dtime
if delay < mintime then
return
end
update_timers(delay)
delay = 0
end)
function core.after(time, func, ...)
function core.after(after, func, ...)
assert(tonumber(time) and type(func) == "function",
"Invalid core.after invocation")
if not mintime then
mintime = time
timers_to_add = {{
time = time+delay,
func = func,
args = {...},
mod_origin = core.get_last_run_mod(),
}}
return
end
mintime = math.min(mintime, time)
timers_to_add = timers_to_add or {}
timers_to_add[#timers_to_add+1] = {
time = time+delay,
func = func,
args = {...},
mod_origin = core.get_last_run_mod(),
}
table.insert(jobs, {
func = func,
expire = time + after,
arg = {...},
mod_origin = core.get_last_run_mod()
})
end
function core.check_player_privs(player_or_name, ...)

@ -2242,7 +2242,7 @@ These functions return the leftover itemstack.
### Timing
* `minetest.after(time, func, ...)`
* Call the function `func` after `time` seconds
* Call the function `func` after `time` seconds, may be fractional
* Optional: Variable number of arguments that are passed to `func`
### Server