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open Common_
type instant_s = float
type duration_s = float
type kind =
| Once
| Every of duration_s
type task = {
mutable deadline: instant_s;
mutable active: bool;
f: cancel_handle -> unit;
as_cancel_handle: cancel_handle;
kind: kind;
}
module Task_heap = Heap.Make (struct
type t = task
let[@inline] leq t1 t2 = t1.deadline <= t2.deadline
end)
type t = { mutable tasks: Task_heap.t }
(** accepted time diff for actions. *)
let epsilon_s = 0.000_001
type tick_res =
| Wait of float
| Run of (cancel_handle -> unit) * cancel_handle
| Empty
let[@inline] has_tasks self = not (Task_heap.is_empty self.tasks)
let[@inline] num_tasks self : int = Task_heap.size self.tasks
let[@inline] pop_task_ self : unit =
let tasks, _t = Task_heap.take_exn self.tasks in
self.tasks <- tasks
let run_after self delay f : cancel_handle =
let now = Time.monotonic_time_s () in
let deadline = now +. delay in
let rec task =
{
deadline;
f;
kind = Once;
active = true;
as_cancel_handle = { cancel = (fun () -> task.active <- false) };
}
in
self.tasks <- Task_heap.insert task self.tasks;
task.as_cancel_handle
let run_every self delay f : cancel_handle =
let now = Time.monotonic_time_s () in
let deadline = now +. delay in
let rec task =
{
deadline;
f;
kind = Every delay;
active = true;
as_cancel_handle = { cancel = (fun () -> task.active <- false) };
}
in
self.tasks <- Task_heap.insert task self.tasks;
task.as_cancel_handle
let rec next (self : t) : tick_res =
match Task_heap.find_min self.tasks with
| None -> Empty
| Some task when not task.active ->
pop_task_ self;
next self
| Some task ->
let now = Time.monotonic_time_s () in
let remaining_time_s = task.deadline -. now in
if remaining_time_s <= epsilon_s then (
pop_task_ self;
(match task.kind with
| Once -> ()
| Every dur ->
task.deadline <- now +. dur;
self.tasks <- Task_heap.insert task self.tasks);
Run (task.f, task.as_cancel_handle)
) else
Wait remaining_time_s
let create () = { tasks = Task_heap.empty }