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module Id_map = Map.Make (String)
type cell_status = Idle | Queued | Running
type history = {
past : Doc.t list;
future : Doc.t list;
count : int;
capacity : int;
}
let empty_history capacity = { past = []; future = []; count = 0; capacity }
let take n xs =
let rec loop acc n = function
| [] -> List.rev acc
| _ when n <= 0 -> List.rev acc
| x :: rest -> loop (x :: acc) (n - 1) rest
in
loop [] n xs
let push_history doc h =
let past = doc :: h.past in
if h.count >= h.capacity then
{ h with past = take h.capacity past; future = []; count = h.capacity }
else { h with past; future = []; count = h.count + 1 }
type t = {
doc : Doc.t;
last_checkpoint : Doc.t;
statuses : cell_status Id_map.t;
history : history;
}
let create ?(history_capacity = 100) doc =
{
doc;
last_checkpoint = doc;
statuses = Id_map.empty;
history = empty_history history_capacity;
}
let doc s = s.doc
let cell_status id s =
match Id_map.find_opt id s.statuses with Some st -> st | None -> Idle
let can_undo s = s.history.past <> []
let can_redo s = s.history.future <> []
let update_source cell_id source s =
match Doc.find cell_id s.doc with
| Some c ->
let doc = Doc.replace cell_id (Cell.set_source source c) s.doc in
{ s with doc }
| None -> s
let checkpoint s =
if s.doc == s.last_checkpoint then s
else
let history = push_history s.last_checkpoint s.history in
{ s with last_checkpoint = s.doc; history }
let with_history_push f s =
let s = checkpoint s in
let history = push_history s.doc s.history in
let doc = f s.doc in
{ s with doc; last_checkpoint = doc; history }
let insert_cell ~pos cell s = with_history_push (Doc.insert ~pos cell) s
let remove_cell cell_id s = with_history_push (Doc.remove cell_id) s
let move_cell cell_id ~pos s = with_history_push (Doc.move cell_id ~pos) s
let clear_outputs cell_id s =
let doc = Doc.update cell_id Cell.clear_outputs s.doc in
{ s with doc }
let clear_all_outputs s =
let doc = Doc.clear_all_outputs s.doc in
{ s with doc }
let set_cell_kind cell_id kind s =
match Doc.find cell_id s.doc with
| Some c ->
with_history_push
(fun doc ->
let src = Cell.source c in
let id = Cell.id c in
let attrs = Cell.attrs c in
let c' =
match kind with
| `Code -> Cell.code ~id ~attrs src
| `Text -> Cell.text ~id ~attrs src
in
Doc.replace cell_id c' doc)
s
| None -> s
let set_cell_attrs cell_id attrs s =
match Doc.find cell_id s.doc with
| Some c ->
with_history_push
(fun doc -> Doc.replace cell_id (Cell.set_attrs attrs c) doc)
s
| None -> s
let mark_running cell_id s =
{ s with statuses = Id_map.add cell_id Running s.statuses }
let mark_queued cell_id s =
{ s with statuses = Id_map.add cell_id Queued s.statuses }
let mark_idle cell_id s =
{ s with statuses = Id_map.add cell_id Idle s.statuses }
let apply_output cell_id output s =
let doc = Doc.update cell_id (Cell.append_output output) s.doc in
{ s with doc }
let finish_execution cell_id ~success:_ s =
let doc = Doc.update cell_id Cell.increment_execution_count s.doc in
{ s with doc; statuses = Id_map.add cell_id Idle s.statuses }
let undo s =
match s.history.past with
| prev :: rest ->
let history =
{
s.history with
past = rest;
future = s.doc :: s.history.future;
count = s.history.count - 1;
}
in
{ s with doc = prev; last_checkpoint = prev; history }
| [] -> s
let redo s =
match s.history.future with
| next :: rest ->
let history =
{
s.history with
past = s.doc :: s.history.past;
future = rest;
count = s.history.count + 1;
}
in
{ s with doc = next; last_checkpoint = next; history }
| [] -> s
let reload doc s =
{
doc;
last_checkpoint = doc;
statuses = Id_map.empty;
history = empty_history s.history.capacity;
}