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|
(************************************************************************)
(* * The Coq Proof Assistant / The Coq Development Team *)
(* v * INRIA, CNRS and contributors - Copyright 1999-2018 *)
(* <O___,, * (see CREDITS file for the list of authors) *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(* * (see LICENSE file for the text of the license) *)
(************************************************************************)
let not_ready_msg = ref (fun name ->
Pp.strbrk("The value you are asking for ("^name^") is not ready yet. "^
"Please wait or pass "^
"the \"-async-proofs off\" option to CoqIDE to disable "^
"asynchronous script processing and don't pass \"-quick\" to "^
"coqc."))
let not_here_msg = ref (fun name ->
Pp.strbrk("The value you are asking for ("^name^") is not available "^
"in this process. If you really need this, pass "^
"the \"-async-proofs off\" option to CoqIDE to disable "^
"asynchronous script processing and don't pass \"-quick\" to "^
"coqc."))
let customize_not_ready_msg f = not_ready_msg := f
let customize_not_here_msg f = not_here_msg := f
exception NotReady of string
exception NotHere of string
let _ = CErrors.register_handler (function
| NotReady name -> !not_ready_msg name
| NotHere name -> !not_here_msg name
| _ -> raise CErrors.Unhandled)
type fix_exn = Exninfo.iexn -> Exninfo.iexn
let id x = prerr_endline "Future: no fix_exn.\nYou have probably created a Future.computation from a value without passing the ~fix_exn argument. You probably want to chain with an already existing future instead."; x
module UUID = struct
type t = int
let invalid = 0
let fresh =
let count = ref invalid in
fun () -> incr count; !count
let compare = compare
let equal = (==)
end
module UUIDMap = Map.Make(UUID)
module UUIDSet = Set.Make(UUID)
type 'a assignement = [ `Val of 'a | `Exn of Exninfo.iexn | `Comp of 'a computation]
(* Val is not necessarily a final state, so the
computation restarts from the state stocked into Val *)
and 'a comp =
| Delegated of (unit -> unit)
| Closure of (unit -> 'a)
| Val of 'a
| Exn of Exninfo.iexn (* Invariant: this exception is always "fixed" as in fix_exn *)
and 'a comput =
| Ongoing of string * (UUID.t * fix_exn * 'a comp ref) CEphemeron.key
| Finished of 'a
and 'a computation = 'a comput ref
let unnamed = "unnamed"
let create ?(name=unnamed) ?(uuid=UUID.fresh ()) f x =
ref (Ongoing (name, CEphemeron.create (uuid, f, Pervasives.ref x)))
let get x =
match !x with
| Finished v -> unnamed, UUID.invalid, id, ref (Val v)
| Ongoing (name, x) ->
try let uuid, fix, c = CEphemeron.get x in name, uuid, fix, c
with CEphemeron.InvalidKey ->
name, UUID.invalid, id, ref (Exn (NotHere name, Exninfo.null))
type 'a value = [ `Val of 'a | `Exn of Exninfo.iexn ]
let is_over kx = let _, _, _, x = get kx in match !x with
| Val _ | Exn _ -> true
| Closure _ | Delegated _ -> false
let is_val kx = let _, _, _, x = get kx in match !x with
| Val _ -> true
| Exn _ | Closure _ | Delegated _ -> false
let is_exn kx = let _, _, _, x = get kx in match !x with
| Exn _ -> true
| Val _ | Closure _ | Delegated _ -> false
let peek_val kx = let _, _, _, x = get kx in match !x with
| Val v -> Some v
| Exn _ | Closure _ | Delegated _ -> None
let uuid kx = let _, id, _, _ = get kx in id
let from_val ?(fix_exn=id) v = create fix_exn (Val v)
let from_here ?(fix_exn=id) v = create fix_exn (Val v)
let fix_exn_of ck = let _, _, fix_exn, _ = get ck in fix_exn
let create_delegate ?(blocking=true) ~name fix_exn =
let assignement signal ck = fun v ->
let _, _, fix_exn, c = get ck in
assert (match !c with Delegated _ -> true | _ -> false);
begin match v with
| `Val v -> c := Val v
| `Exn e -> c := Exn (fix_exn e)
| `Comp f -> let _, _, _, comp = get f in c := !comp end;
signal () in
let wait, signal =
if not blocking then (fun () -> raise (NotReady name)), ignore else
let lock = Mutex.create () in
let cond = Condition.create () in
(fun () -> Mutex.lock lock; Condition.wait cond lock; Mutex.unlock lock),
(fun () -> Mutex.lock lock; Condition.broadcast cond; Mutex.unlock lock) in
let ck = create ~name fix_exn (Delegated wait) in
ck, assignement signal ck
(* TODO: get rid of try/catch to be stackless *)
let rec compute ck : 'a value =
let _, _, fix_exn, c = get ck in
match !c with
| Val x -> `Val x
| Exn (e, info) -> `Exn (e, info)
| Delegated wait -> wait (); compute ck
| Closure f ->
try
let data = f () in
c := Val data; `Val data
with e ->
let e = CErrors.push e in
let e = fix_exn e in
match e with
| (NotReady _, _) -> `Exn e
| _ -> c := Exn e; `Exn e
let force x = match compute x with
| `Val v -> v
| `Exn e -> Exninfo.iraise e
let chain ck f =
let name, uuid, fix_exn, c = get ck in
create ~uuid ~name fix_exn (match !c with
| Closure _ | Delegated _ -> Closure (fun () -> f (force ck))
| Exn _ as x -> x
| Val v -> Val (f v))
let create fix_exn f = create fix_exn (Closure f)
let replace kx y =
let _, _, _, x = get kx in
match !x with
| Exn _ -> x := Closure (fun () -> force y)
| _ -> CErrors.anomaly
(Pp.str "A computation can be replaced only if is_exn holds.")
let chain x f =
let y = chain x f in
if is_over x then ignore(force y);
y
let join kx =
let v = force kx in
kx := Finished v;
v
let sink kx = if is_val kx then ignore(join kx)
let split2 x =
chain x (fun x -> fst x), chain x (fun x -> snd x)
let map2 f x l =
CList.map_i (fun i y ->
let xi = chain x (fun x ->
try List.nth x i
with Failure _ | Invalid_argument _ ->
CErrors.anomaly (Pp.str "Future.map2 length mismatch.")) in
f xi y) 0 l
let print f kx =
let open Pp in
let name, uid, _, x = get kx in
let uid =
if UUID.equal uid UUID.invalid then str "[#:" ++ str name ++ str "]"
else str "[" ++ int uid ++ str":" ++ str name ++ str "]"
in
match !x with
| Delegated _ -> str "Delegated" ++ uid
| Closure _ -> str "Closure" ++ uid
| Val x -> str "PureVal" ++ uid ++ spc () ++ hov 0 (f x)
| Exn (e, _) -> str "Exn" ++ uid ++ spc () ++ hov 0 (str (Printexc.to_string e))
|
