Quelle stm.ml Sprache: SML

(************************************************************************)
(*         *      The Rocq Prover / The Rocq Development Team           *)
(*  v      *         Copyright INRIA, CNRS and contributors             *)
(* <O___,, * (see version control and CREDITS file for authors & dates) *)
(*   \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)         *)
(************************************************************************)

(* enable in case of stm problems  *)
(* let stm_debug () = CDebug.(get_flag misc) *)
let stm_debug = ref false

let stm_pr_err s  = Format.eprintf "%s] %s\n%!"     (Spawned.process_id ()) s
let stm_pp_err pp = Format.eprintf "%s] @[%a@]\n%!" (Spawned.process_id ()) Pp.pp_with pp

let stm_prerr_endline s = if !stm_debug then begin stm_pr_err (s ()) end else ()
let stm_pperr_endline s = if !stm_debug then begin stm_pp_err (s ()) end else ()

let stm_prerr_debug   s = if CDebug.(get_flag misc) then begin stm_pr_err (s ()) end else ()

open Pp
open CErrors
open Names
open Feedback
open Vernacexpr
open Vernacextend

module PG_compat = Vernacstate.Declare [@@ocaml.warning "-3"]

let is_vtkeep = function VtKeep _ -> true | _ -> false
let get_vtkeep = function VtKeep x -> x | _ -> assert false

module AsyncOpts = struct

  type cache = Force
  type async_proofs = APoff | APonLazy | APon
  type tac_error_filter = FNone | FOnly of string list | FAll

  type stm_opt = {
    spawn_args : string list;

    async_proofs_n_workers : int;
    async_proofs_n_tacworkers : int;

    async_proofs_cache : cache option;
    async_proofs_mode : async_proofs;

    async_proofs_private_flags : string option;
    async_proofs_never_reopen_branch : bool;

    async_proofs_tac_error_resilience : tac_error_filter;
    async_proofs_cmd_error_resilience : bool;
    async_proofs_delegation_threshold : float;

    async_proofs_worker_priority : CoqworkmgrApi.priority;
  }

  let default_opts ~spawn_args = {
    spawn_args;

    async_proofs_n_workers = 1;
    async_proofs_n_tacworkers = 2;

    async_proofs_cache = None;

    async_proofs_mode = APoff;

    async_proofs_private_flags = None;
    async_proofs_never_reopen_branch = false;

    async_proofs_tac_error_resilience = FOnly [ "curly" ];
    async_proofs_cmd_error_resilience = true;
    async_proofs_delegation_threshold = 0.03;

    async_proofs_worker_priority = CoqworkmgrApi.Low;
  }

  let cur_opt : stm_opt option ref = ref None
  let set_cur_opt o = assert (Option.is_empty !cur_opt); cur_opt := Some o
  let cur_opt () = match !cur_opt with
    | Some o -> o
    | None ->
      anomaly Pp.(str "Incorrect stm init: accessing options before they are set.")
end

open AsyncOpts

let async_proofs_is_master opt =
  opt.async_proofs_mode = APon &&
  !Flags.async_proofs_worker_id = "master"

let execution_error ?loc state_id msg =
    feedback ~id:state_id (Message (Error, loc, [], msg))

module Hooks = struct

let state_computed = ref (fun ~doc:_ state_id ~in_cache ->
    feedback ~id:state_id Processed)

let state_ready = ref (fun ~doc:_ state_id -> ())

let forward_feedback =
  let m = Mutex.create () in
  ref (function
    | { doc_id = did; span_id = id; route; contents } ->
        CThread.with_lock m ~scope:(fun () -> feedback ~did ~id ~route contents))

let unreachable_state = ref (fun ~doc:_ _ _ -> ())

let document_add = ref (fun _ _ -> ())

let document_edit = ref (fun _ -> ())

let sentence_exec = ref (fun _ -> ())

end

let async_proofs_workers_extra_env = ref [||]

type aast = {
  verbose : bool;
  indentation : int;
  strlen : int;
  mutable expr : vernac_control; (* mutable: Proof using hinted by aux file *)
}
let pr_ast { expr; indentation } = Pp.(int indentation ++ str " " ++ Ppvernac.pr_vernac expr)

(* Commands piercing opaque (probably should be using the vernactypes system instead) *)
let may_pierce_opaque = function
  | VernacSynPure (VernacPrint _) -> true
  | VernacSynterp (VernacExtend ({ ext_plugin = "rocq-runtime.plugins.extraction" }, _)) -> true
  | _ -> false

type depth = int
type 'branch branch_type_gen =
  | Master
  | Proof of depth
  | Edit of
      Stateid.t * Stateid.t  * Vernacextend.vernac_qed_type * 'branch

module Kind =
struct
  type 'a t = 'a branch_type_gen
  let master = Master
end

module Vcs_ = Vcs.Make(Stateid.Self)(Kind)
type future_proof = Declare.Proof.closed_proof_output option Future.computation

type branch_type = Vcs_.Branch.t Kind.t
(* TODO 8.7 : split commands and tactics, since this type is too messy now *)
type cqueue = MainQueue | SkipQueue
type cmd_t = {
  ctac : bool; (* is a tactic *)
  ceff : bool; (* is a side-effecting command in the middle of a proof *)
  cast : aast;
  cids : Names.Id.t list;
  cblock : proof_block_name option;
  cqueue : cqueue;
  cancel_switch : AsyncTaskQueue.cancel_switch; }
type fork_t = aast * Vcs_.Branch.t * opacity_guarantee * Names.Id.t list
type qed_t = {
  qast : aast;
  keep : vernac_qed_type;
  mutable fproof : (future_proof option * AsyncTaskQueue.cancel_switch) option;
  brname : Vcs_.Branch.t;
  brinfo : Vcs_.branch_info
}
type seff_t = ReplayCommand of aast | CherryPickEnv
type alias_t = Stateid.t * aast

type transaction =
  | Cmd    of cmd_t
  | Fork   of fork_t
  | Qed    of qed_t
  | Sideff of seff_t
  | Alias  of alias_t
  | Noop
type step =
  | SCmd    of cmd_t
  | SFork   of fork_t * Stateid.t option
  | SQed    of qed_t * Stateid.t
  | SSideff of seff_t * Stateid.t
  | SAlias  of alias_t

type visit = { step : step; next : Stateid.t }

let mkTransTac cast cblock cqueue =
  Cmd { ctac = true; cast; cblock; cqueue; cids = []; ceff = false; cancel_switch = ref false }

let mkTransCmd cast cids ceff cqueue =
  Cmd { ctac = false; cast; cblock = None; cqueue; cids; ceff; cancel_switch = ref false }

type cached_state =
  | EmptyState
  | ParsingState of Procq.frozen_t
  | FullState of Vernacstate.t
  | ErrorState of Procq.frozen_t option * Exninfo.iexn
type branch = Vcs_.Branch.t * Vcs_.branch_info
type backup = { mine : branch; others : branch list }

module DynBlockData : Dyn.S = Dyn.Make ()

(* Clusters of nodes implemented as Dag properties.  While Dag and Vcs impose
* no constraint on properties, here we impose boxes to be non overlapping.
* Such invariant makes sense for the current kinds of boxes (proof blocks and
* entire proofs) but may make no sense and dropped/refined in the future.
* Such invariant is useful to detect broken proof block detection code *)
type box =
  | ProofTask of pt
  | ProofBlock of static_block_declaration * proof_block_name
and pt = { (* TODO: inline records in OCaml 4.03 *)
  lemma : Stateid.t;
  qed   : Stateid.t;
}
and static_block_declaration = {
  block_start : Stateid.t;
  block_stop  : Stateid.t;
  dynamic_switch : Stateid.t;
  carry_on_data : DynBlockData.t;
}

(* Functions that work on a Vcs with a specific branch type *)
module Vcs_aux : sig

  val proof_nesting : ('t,'i,'c) Vcs_.t -> int
  val find_proof_at_depth :
          ('t, 'i,'c) Vcs_.t -> int ->
      Vcs_.Branch.t * Vcs_.branch_info
  exception Expired
  val visit : (transaction,'i,'c) Vcs_.t -> Vcs_.Dag.node -> visit

end = struct (* {{{ *)

  let proof_nesting vcs =
    List.fold_left max 0
      (CList.map_filter
        (function
         | { Vcs_.kind = Proof n } -> Some n
         | { Vcs_.kind = Edit _ } -> Some 1
         | _ -> None)
        (List.map (Vcs_.get_branch vcs) (Vcs_.branches vcs)))

  let find_proof_at_depth vcs pl =
    try List.find (function
          | _, { Vcs_.kind = Proof n } -> Int.equal n pl
          | _, { Vcs_.kind = Edit _ } -> anomaly(Pp.str "find_proof_at_depth")
          | _ -> false)
        (List.map (fun h -> h, Vcs_.get_branch vcs h) (Vcs_.branches vcs))
    with Not_found -> failwith "find_proof_at_depth"

  exception Expired
  let visit vcs id =
    if Stateid.equal id Stateid.initial then
      anomaly(Pp.str "Visiting the initial state id.")
    else if Stateid.equal id Stateid.dummy then
      anomaly(Pp.str "Visiting the dummy state id.")
    else
    try
      match Vcs_.Dag.from_node (Vcs_.dag vcs) id with
      | [n, Cmd x] -> { step = SCmd x; next = n }
      | [n, Alias x] -> { step = SAlias x; next = n }
      | [n, Fork x] -> { step = SFork (x,None); next = n }
      | [n, Fork x; p, Noop] -> { step = SFork (x,Some p); next = n }
      | [p, Noop; n, Fork x] -> { step = SFork (x,Some p); next = n }
      | [n, Qed x; p, Noop]
      | [p, Noop; n, Qed x] -> { step = SQed (x,p); next = n }
      | [n, Sideff CherryPickEnv; p, Noop]
      | [p, Noop; n, Sideff CherryPickEnv]-> { step = SSideff (CherryPickEnv, p); next = n }
      | [n, Sideff (ReplayCommand x); p, Noop]
      | [p, Noop; n, Sideff (ReplayCommand x)]-> { step = SSideff(ReplayCommand x,p); next = n }
      | [n, Sideff (ReplayCommand x)]-> {step = SSideff(ReplayCommand x, Stateid.dummy); next=n}
      | _ -> anomaly (Pp.str ("Malformed VCS at node "^Stateid.to_string id^"."))
    with Not_found -> raise Expired

end (* }}} *)

(*************************** THE DOCUMENT *************************************)
(******************************************************************************)

(* The main document type associated to a VCS *)
type stm_doc_type =
  | VoDoc       of string
  | VosDoc      of string
  | Interactive of Coqargs.top

(* Dummy until we land the functional interp patch + fixed start_library *)
type doc = int
let dummy_doc : doc = 0

(* Imperative wrap around VCS to obtain _the_ VCS that is the
* representation of the document Rocq is currently processing *)
module VCS : sig

  exception Expired

  module Branch : (module type of Vcs_.Branch with type t = Vcs_.Branch.t)
  type id = Stateid.t
  type branch_info = Vcs_.branch_info = {
    kind : branch_type;
    root : id;
    pos  : id;
  }

  type vcs = (transaction, state_info, box) Vcs_.t
  and state_info = { (* TODO: Make this record private to VCS *)
    mutable n_reached : int;      (* debug cache: how many times was computed *)
    mutable n_goals : int;        (* open goals: indentation *)
    mutable state : cached_state; (* state value *)
    mutable proof_mode : Pvernac.proof_mode option;
    mutable vcs_backup : vcs option * backup option;
  }

  val init : stm_doc_type -> id -> Procq.frozen_t -> doc
  (* val get_type : unit -> stm_doc_type *)
  val set_ldir : Names.DirPath.t -> unit
  val get_ldir : unit -> Names.DirPath.t

  val is_interactive : unit -> bool
  val is_vos_doc : unit -> bool

  val current_branch : unit -> Branch.t
  val checkout : Branch.t -> unit
  val branches : unit -> Branch.t list
  val get_branch : Branch.t -> branch_info
  val get_branch_pos : Branch.t -> id
  val new_node : ?id:Stateid.t -> Pvernac.proof_mode option -> unit -> id
  val merge : id -> ours:transaction -> ?into:Branch.t -> Branch.t -> unit
  val rewrite_merge : id -> ours:transaction -> at:id -> Branch.t -> unit
  val delete_branch : Branch.t -> unit
  val commit : id -> transaction -> unit
  val mk_branch_name : aast -> Branch.t
  val edit_branch : Branch.t
  val branch : ?root:id -> ?pos:id -> Branch.t -> branch_type -> unit
  val reset_branch : Branch.t -> id -> unit
  val reachable : id -> Stateid.Set.t
  val cur_tip : unit -> id

  val get_info : id -> state_info
  val reached : id -> unit
  val goals : id -> int -> unit
  val set_state : id -> cached_state -> unit
  val get_state : id -> cached_state
  val set_parsing_state : id -> Procq.frozen_t -> unit
  val get_parsing_state : id -> Procq.frozen_t option
  val get_proof_mode : id -> Pvernac.proof_mode option

  (* cuts from start -> stop, raising Expired if some nodes are not there *)
  val slice : block_start:id -> block_stop:id -> vcs
  val nodes_in_slice : block_start:id -> block_stop:id -> Stateid.t list

  val create_proof_task_box : id list -> qed:id -> block_start:id -> unit
  val create_proof_block : static_block_declaration -> string -> unit
  val box_of : id -> box list
  val delete_boxes_of : id -> unit
  val proof_task_box_of : id -> pt option

  val proof_nesting : unit -> int
  val checkout_shallowest_proof_branch : unit -> unit
  val propagate_sideff : action:seff_t -> Stateid.t list
  val propagate_qed : unit -> unit

  val gc : unit -> unit

  val visit : id -> visit

  val print : ?now:bool -> unit -> unit

  val backup : unit -> vcs
  val restore : vcs -> unit

end = struct (* {{{ *)

  include Vcs_
  exception Expired = Vcs_aux.Expired

  open Printf

  type vcs = (transaction, state_info, box) t
  and state_info = { (* TODO: Make this record private to VCS *)
    mutable n_reached : int;      (* debug cache: how many times was computed *)
    mutable n_goals : int;        (* open goals: indentation *)
    mutable state : cached_state; (* state value *)
    mutable proof_mode : Pvernac.proof_mode option;
    mutable vcs_backup : vcs option * backup option;
  }
  let default_info proof_mode =
    {
      n_reached = 0; n_goals = 0;
      state = EmptyState;
      proof_mode;
      vcs_backup = (None,None);
    }

  let print_dag vcs () =

    (* Due to threading, be wary that this will be called from the
       toplevel with we_are_parsing set to true, as indeed, the
       toplevel is waiting for input . What a race! XD

       In case you are hitting the race enable stm_debug.
    *)
    if !stm_debug then Flags.in_synterp_phase := false;

    let fname =
      "stm_" ^ Str.global_replace (Str.regexp " ") "_" (Spawned.process_id ()) in
    let string_of_transaction = function
      | Cmd { cast = t } | Fork (t, _,_,_) ->
          (try Pp.string_of_ppcmds (pr_ast t) with e when CErrors.noncritical e -> "ERR")
      | Sideff (ReplayCommand t) ->
          sprintf "Sideff(%s)"
            (try Pp.string_of_ppcmds (pr_ast t) with e when CErrors.noncritical e -> "ERR")
      | Sideff CherryPickEnv -> "EnvChange"
      | Noop -> " "
      | Alias (id,_) -> sprintf "Alias(%s)" (Stateid.to_string id)
      | Qed { qast } -> Pp.string_of_ppcmds (pr_ast qast) in
    let is_green id =
      match get_info vcs id with
      | Some { state = FullState _ } -> true
      | _ -> false in
    let is_red id =
      match get_info vcs id with
      | Some { state = ErrorState _ } -> true
      | _ -> false in
    let head = current_branch vcs in
    let heads =
      List.map (fun x -> x, (get_branch vcs x).pos) (branches vcs) in
    let graph = dag vcs in
    let quote s =
      Str.global_replace (Str.regexp "\n") "
"
       (Str.global_replace (Str.regexp "<") "<"
        (Str.global_replace (Str.regexp ">") ">"
         (Str.global_replace (Str.regexp "\"") """
          (Str.global_replace (Str.regexp "&") "&"
           (String.sub s 0 (min (String.length s) 20)))))) in
    let fname_dot, fname_ps =
      let f = "/tmp/" ^ Filename.basename fname in
      f ^ ".dot", f ^ ".pdf" in
    let node id = "s" ^ Stateid.to_string id in
    let edge tr =
      sprintf "<12\" FACE=\"sans\">%s>"
        (quote (string_of_transaction tr)) in
    let node_info id =
      match get_info vcs id with
      | None -> ""
      | Some info ->
          sprintf "<12\">%s" (Stateid.to_string id) ^
          sprintf " 11\">r:%d g:%d>"
            info.n_reached info.n_goals in
    let color id =
      if is_red id then "red" else if is_green id then "green" else "white" in
    let nodefmt oc id =
      fprintf oc "%s [label=%s,style=filled,fillcolor=%s];\n"
        (node id) (node_info id) (color id) in

    let ids = ref Stateid.Set.empty in
    let boxes = ref [] in
    (* Fill in *)
    Dag.iter graph (fun from _ _ l ->
      ids := Stateid.Set.add from !ids;
      List.iter (fun box -> boxes := box :: !boxes)
        (Dag.property_of graph from);
      List.iter (fun (dest, _) ->
        ids := Stateid.Set.add dest !ids;
        List.iter (fun box -> boxes := box :: !boxes)
          (Dag.property_of graph dest))
      l);
    boxes := CList.sort_uniquize Dag.Property.compare !boxes;

    let oc = open_out fname_dot in
    output_string oc "digraph states {\n";
    Dag.iter graph (fun from cf _ l ->
      List.iter (fun (dest, trans) ->
       fprintf oc "%s -> %s [xlabel=%s,labelfloat=true];\n"
           (node from) (node dest) (edge trans)) l
    );

    let contains b1 b2 =
      Stateid.Set.subset
        (Dag.Property.having_it b2) (Dag.Property.having_it b1) in
    let same_box = Dag.Property.equal in
    let outerboxes boxes =
       List.filter (fun b ->
         not (List.exists (fun b1 ->
           not (same_box b1 b) && contains b1 b) boxes)
         ) boxes in
    let rec rec_print b =
      boxes := CList.remove same_box b !boxes;
      let sub_boxes = List.filter (contains b) (outerboxes !boxes) in
      fprintf oc "subgraph cluster_%s {\n" (Dag.Property.to_string b);
      List.iter rec_print sub_boxes;
      Stateid.Set.iter (fun id ->
        if Stateid.Set.mem id !ids then begin
          ids := Stateid.Set.remove id !ids;
          nodefmt oc id
        end)
        (Dag.Property.having_it b);
      match Dag.Property.data b with
      | ProofBlock ({ dynamic_switch = id }, lbl) ->
          fprintf oc "label=\"%s (test:%s)\";\n" lbl (Stateid.to_string id);
          fprintf oc "color=red; }\n"
      | ProofTask _ -> fprintf oc "color=blue; }\n"
      in
    List.iter rec_print (outerboxes !boxes);
    Stateid.Set.iter (nodefmt oc) !ids;

    List.iteri (fun i (b,id) ->
      let shape = if Branch.equal head b then "box3d" else "box" in
      fprintf oc "b%d -> %s;\n" i (node id);
      fprintf oc "b%d [shape=%s,label=\"%s\"];\n" i shape
        (Branch.to_string b);
    ) heads;

    output_string oc "}\n";
    close_out oc;
    ignore(Sys.command
      ("dot -Tpdf -Gcharset=latin1 " ^ fname_dot ^ " -o" ^ fname_ps))

  let vcs : vcs ref = ref (empty Stateid.dummy)

  let doc_type = ref (Interactive (Coqargs.TopLogical ""))
  let ldir = ref Names.DirPath.empty

  let init dt id ps =
    doc_type := dt;
    vcs := empty id;
    let info = { (default_info None) with state = ParsingState ps } in
    vcs := set_info !vcs id info;
    dummy_doc

  let set_ldir ld =
    ldir := ld

  let get_ldir () = !ldir
  (* let get_type () = !doc_type *)

  let is_interactive () =
    match !doc_type with
    | Interactive _ -> true
    | _ -> false

  let is_vos_doc () =
    match !doc_type with
    | VosDoc _ -> true
    | _ -> false

  let current_branch () = current_branch !vcs

  let checkout head = vcs := checkout !vcs head
  let branches () = branches !vcs
  let get_branch head = get_branch !vcs head
  let get_branch_pos head = (get_branch head).pos
  let new_node ?(id=Stateid.fresh ()) proof_mode () =
    assert(Vcs_.get_info !vcs id = None);
    vcs := set_info !vcs id (default_info proof_mode);
    id
  let merge id ~ours ?into branch =
    vcs := merge !vcs id ~ours ~theirs:Noop ?into branch
  let delete_branch branch = vcs := delete_branch !vcs branch
  let reset_branch branch id = vcs := reset_branch !vcs branch id
  let commit id t = vcs := commit !vcs id t
  let rewrite_merge id ~ours ~at branch =
    vcs := rewrite_merge !vcs id ~ours ~theirs:Noop ~at branch
  let reachable id = reachable !vcs id
  let mk_branch_name { expr = x } = Branch.make
    (match x.CAst.v.Vernacexpr.expr with
    | VernacSynPure (VernacDefinition (_,({CAst.v=Name i},_),_)) -> Id.to_string i
    | VernacSynPure (VernacStartTheoremProof (_,[({CAst.v=i},_),_])) -> Id.to_string i
    | VernacSynPure (VernacInstance (({CAst.v=Name i},_),_,_,_,_)) -> Id.to_string i
    | _ -> "branch")
  let edit_branch = Branch.make "edit"
  let branch ?root ?pos name kind = vcs := branch !vcs ?root ?pos name kind
  let get_info id =
    match get_info !vcs id with
    | Some x -> x
    | None -> raise Vcs_aux.Expired
  let set_state id s =
    let info = get_info id in
    info.state <- s;
    let is_full_state_valid = match s with
      | FullState _ -> true
      | EmptyState | ErrorState _ | ParsingState _ -> false
    in
    if async_proofs_is_master (cur_opt()) && is_full_state_valid then
      !Hooks.state_ready ~doc:dummy_doc (* XXX should be taken in input *) id

  let get_state id = (get_info id).state

  let get_parsing_state id =
    stm_pperr_endline (fun () -> str "retrieve parsing state state " ++ str (Stateid.to_string id) ++ str " }}}");
    match (get_info id).state with
    | FullState s -> Some Vernacstate.(Synterp.parsing s.synterp)
    | ParsingState s -> Some s
    | ErrorState (s,_) -> s
    | EmptyState -> None

  let set_parsing_state id ps =
    let info = get_info id in
    let new_state =
      match info.state with
      | FullState s -> assert false
      | ParsingState s -> assert false
      | ErrorState _ -> assert false
      | EmptyState -> ParsingState ps
    in
    info.state <- new_state

  let get_proof_mode id = (get_info id).proof_mode

  let reached id =
    let info = get_info id in
    info.n_reached <- info.n_reached + 1
  let goals id n = (get_info id).n_goals <- n
  let cur_tip () = get_branch_pos (current_branch ())

  let proof_nesting () = Vcs_aux.proof_nesting !vcs

  let checkout_shallowest_proof_branch () =
    if List.mem edit_branch (Vcs_.branches !vcs) then begin
      checkout edit_branch
    end else
      let pl = proof_nesting () in
      try
        let branch = fst @@ Vcs_aux.find_proof_at_depth !vcs pl in
        checkout branch
      with Failure _ ->
        checkout Branch.master

  (* copies the transaction on every open branch *)
  let propagate_sideff ~action =
    List.map (fun b ->
      checkout b;
      let proof_mode = get_proof_mode @@ get_branch_pos b in
      let id = new_node proof_mode () in
      merge id ~ours:(Sideff action) ~into:b Branch.master;
      id)
    (List.filter (fun b -> not (Branch.equal b Branch.master)) (branches ()))

  let propagate_qed () =
    List.iter (fun b ->
      checkout b;
      let proof_mode = get_proof_mode @@ get_branch_pos b in
      let id = new_node proof_mode () in
      let parsing = Option.get @@ get_parsing_state (get_branch_pos b) in
      merge id ~ours:(Sideff CherryPickEnv) ~into:b Branch.master;
      set_parsing_state id parsing)
    (List.filter (fun b -> not (Branch.equal b Branch.master)) (branches ()))

  let visit id = Vcs_aux.visit !vcs id

  let nodes_in_slice ~block_start ~block_stop =
    let rec aux id =
      if Stateid.equal id block_start then [] else
      match visit id with
      | { next = n; step = SCmd x } -> (id,Cmd x) :: aux n
      | { next = n; step = SAlias x } -> (id,Alias x) :: aux n
      | { next = n; step = SSideff (ReplayCommand x,_) } ->
           (id,Sideff (ReplayCommand x)) :: aux n
      | _ -> anomaly Pp.(str("Cannot slice from "^ Stateid.to_string block_start ^
                         " to "^Stateid.to_string block_stop^"."))
    in aux block_stop

  (* [slice] copies a slice of the DAG, keeping only the last known valid state.
     When it copies a state, it drops the libobjects and keeps only the structure. *)
  let slice ~block_start ~block_stop =
    let l = nodes_in_slice ~block_start ~block_stop in
    let copy_info v id =
      let info = get_info id in
      Vcs_.set_info v id
        { info with state = EmptyState;
                    vcs_backup = None,None } in
    let make_shallow = function
      | FullState st -> FullState (Vernacstate.Stm.make_shallow st)
      | x -> x
    in
    let copy_info_w_state v id =
      let info = get_info id in
      Vcs_.set_info v id { info with state = make_shallow info.state; vcs_backup = None,None } in
    let copy_proof_blockes v =
      let nodes = Vcs_.Dag.all_nodes (Vcs_.dag v) in
      let props =
        Stateid.Set.fold (fun n pl -> Vcs_.property_of !vcs n @ pl) nodes [] in
      let props = CList.sort_uniquize Vcs_.Dag.Property.compare props in
      List.fold_left (fun v p ->
        Vcs_.create_property v
          (Stateid.Set.elements (Vcs_.Dag.Property.having_it p))
          (Vcs_.Dag.Property.data p)) v props
    in
    let v = Vcs_.empty block_start in
    let v = copy_info v block_start in
    let v = List.fold_right (fun (id,tr) v ->
      let v = Vcs_.commit v id tr in
      let v = copy_info v id in
      v) l v in
    (* Stm should have reached the beginning of proof *)
    assert (match get_state block_start
            with FullState _ -> true | _  -> false);
    (* We put in the new dag the most recent state known to master *)
    let rec fill id =
      match get_state id with
      | EmptyState | ErrorState _ | ParsingState _ -> fill (Vcs_aux.visit v id).next
      | FullState _ -> copy_info_w_state v id
    in
    let v = fill block_stop in
    (* We put in the new dag the first state (since Qed shall run on it,
     * see check_task_aux) *)
    let v = copy_info_w_state v block_start in
    copy_proof_blockes v

  let nodes_in_slice ~block_start ~block_stop =
    List.rev (List.map fst (nodes_in_slice ~block_start ~block_stop))

  let topo_invariant l =
    let all = List.fold_right Stateid.Set.add l Stateid.Set.empty in
    List.for_all
      (fun x ->
         let props = property_of !vcs x in
         let sets = List.map Dag.Property.having_it props in
         List.for_all (fun s -> Stateid.Set.(subset s all || subset all s)) sets)
      l

  let create_proof_task_box l ~qed ~block_start:lemma =
    if not (topo_invariant l) then anomaly Pp.(str "overlapping boxes.");
    vcs := create_property !vcs l (ProofTask { qed; lemma })
  let create_proof_block ({ block_start; block_stop} as decl) name =
    let l = nodes_in_slice ~block_start ~block_stop in
    if not (topo_invariant l) then anomaly Pp.(str "overlapping boxes.");
    vcs := create_property !vcs l (ProofBlock (decl, name))
  let box_of id = List.map Dag.Property.data (property_of !vcs id)
  let delete_boxes_of id =
    List.iter (fun x -> vcs := delete_property !vcs x) (property_of !vcs id)
  let proof_task_box_of id =
    match
      CList.map_filter (function ProofTask x -> Some x | _ -> None) (box_of id)
    with
    | [] -> None
    | [x] -> Some x
    | _ -> anomaly Pp.(str "node with more than 1 proof task box.")

  let gc () =
    let old_vcs = !vcs in
    let new_vcs, erased_nodes = gc old_vcs in
    Stateid.Set.iter (fun id ->
        match (Vcs_aux.visit old_vcs id).step with
        | SQed ({ fproof = Some (_, cancel_switch) }, _)
        | SCmd { cancel_switch } ->
             cancel_switch := true
        | _ -> ())
      erased_nodes;
    vcs := new_vcs

  module NB : sig (* Non blocking Sys.command *)

    val command : now:bool -> (unit -> unit) -> unit

  end = struct

    let m = Mutex.create ()
    let c = Condition.create ()
    let job = ref None
    let worker = ref None

    let set_last_job j =
      CThread.with_lock m ~scope:(fun () ->
          job := Some j;
          Condition.signal c)

    let get_last_job () =
      CThread.with_lock m ~scope:(fun () ->
          while Option.is_empty !job do Condition.wait c m; done;
          match !job with
          | None -> assert false
          | Some x -> job := None; x)

    let run_command () =
      try while true do get_last_job () () done
      with e -> () (* No failure *)

    let command ~now job =
      if now then job ()
      else begin
        set_last_job job;
        if Option.is_empty !worker then
          worker := Some (CThread.create run_command ())
      end

  end

  let print ?(now=false) () =
    if CDebug.(get_flag misc) then NB.command ~now (print_dag !vcs)

  let backup () = !vcs
  let restore v = vcs := v

end (* }}} *)

type state = Valid of Vernacstate.t option | Expired | Error of exn

let state_of_id ~doc id =
  try match VCS.get_state id with
    | FullState s -> Valid (Some s)
    | ErrorState (_,(e,_)) -> Error e
    | EmptyState | ParsingState _ -> Valid None
  with VCS.Expired -> Expired

let () =
  Stateid.set_is_valid (fun ~doc id -> state_of_id ~doc id <> Expired)

(****** A cache: fills in the nodes of the VCS document with their value ******)
module State : sig

  type t

  val freeze : unit -> t
  val unfreeze : t -> unit

  (** The function is from unit, so it uses the current state to define
      a new one.  I.e. one may been to install the right state before
      defining a new one.
      Warning: an optimization in installed_cached requires that state
      modifying functions are always executed using this wrapper. *)
  val define :
    doc:doc ->
    ?safe_id:Stateid.t ->
    ?redefine:bool -> ?cache:bool ->
    ?feedback_processed:bool -> (unit -> unit) -> Stateid.t -> unit

  val install_cached : Stateid.t -> unit
  (* val install_parsing_state : Stateid.t -> unit *)
  val is_cached : ?cache:bool -> Stateid.t -> bool
  val is_cached_and_valid : ?cache:bool -> Stateid.t -> bool

  val exn_on : Stateid.t -> valid:Stateid.t -> Exninfo.iexn -> Exninfo.iexn

  (* to send states across worker/master *)
  val get_cached : Stateid.t -> Vernacstate.t

  type partial_state =
    | Full of Vernacstate.t
    | ProofOnly of Stateid.t * Vernacstate.Stm.pstate

  val assign : Stateid.t -> partial_state -> unit

  (* Handlers for initial state, prior to document creation. *)
  val register_root_state : unit -> unit
  val restore_root_state : unit -> unit

  val purify : ('a -> 'b) -> 'a -> 'b

end = struct (* {{{ *)

  type t = { id : Stateid.t; vernac_state : Vernacstate.t }

  (* cur_id holds Stateid.dummy in case the last attempt to define a state
   * failed, so the global state may contain garbage *)
  let cur_id = ref Stateid.dummy
  let freeze () = { id = !cur_id; vernac_state = Vernacstate.freeze_full_state () }
  let unfreeze st =
    Vernacstate.unfreeze_full_state st.vernac_state;
    cur_id := st.id

  let invalidate_cur_state () = cur_id := Stateid.dummy

  type partial_state =
    | Full of Vernacstate.t
    | ProofOnly of Stateid.t * Vernacstate.Stm.pstate

  let cache_state id =
    VCS.set_state id (FullState (Vernacstate.freeze_full_state ()))

  let freeze_invalid id iexn =
    let ps = VCS.get_parsing_state id in
    VCS.set_state id (ErrorState (ps,iexn))

  let is_cached ?(cache=false) id only_valid =
    if Stateid.equal id !cur_id then
      try match VCS.get_info id with
        | ({ state = EmptyState } | { state = ParsingState _ }) when cache -> cache_state id; true
        | _ -> true
      with VCS.Expired -> false
    else
      try match VCS.get_state id with
        | EmptyState | ParsingState _ -> false
        | FullState _ -> true
        | ErrorState _ -> not only_valid
      with VCS.Expired -> false

  let is_cached_and_valid ?cache id = is_cached ?cache id true
  let is_cached ?cache id = is_cached ?cache id false

  let install_cached id =
    match VCS.get_state id with
    | FullState s ->
       Vernacstate.unfreeze_full_state s;
       cur_id := id

    | ErrorState (_,ie) ->
       Exninfo.iraise ie

    | EmptyState | ParsingState _ ->
      (* rocq compile has a 1 slot cache and only for valid states *)
      if (VCS.is_interactive ()) || not (Stateid.equal id !cur_id) then
        anomaly Pp.(str "installing a non cached state.")

  (*
  let install_parsing_state id =
    if not (Stateid.equal id !cur_id) then begin
      Vernacstate.Parser.install @@ VCS.get_parsing_state id
    end
     *)

  let get_cached id =
    try match VCS.get_state id with
    | FullState s -> s
    | _ -> anomaly Pp.(str "not a cached state.")
    with VCS.Expired -> anomaly Pp.(str "not a cached state (expired).")

  let assign id what =
    if VCS.get_state id <> EmptyState then () else
    try match what with
    | Full s ->
         let s =
           try
            let prev = (VCS.visit id).next in
            if is_cached_and_valid prev
            then
              let open Vernacstate in
              { s with interp = { s.interp with
                lemmas = PG_compat.copy_terminators
                           ~src:((get_cached prev).interp.lemmas) ~tgt:s.interp.lemmas }}
            else s
           with VCS.Expired -> s in
         VCS.set_state id (FullState s)
    | ProofOnly(ontop,pstate) ->
         if is_cached_and_valid ontop then
           let s = get_cached ontop in
           let s = Vernacstate.Stm.set_pstate s pstate in
           VCS.set_state id (FullState s)
    with VCS.Expired -> ()

  let exn_on id ~valid (e, info) =
    match Stateid.get info with
    | Some _ -> (e, info)
    | None ->
        let loc = Loc.get_loc info in
        execution_error ?loc id (iprint (e, info));
        (e, Stateid.add info ~valid id)

  (* [define] puts the system in state [id] calling [f ()] *)
  (* [safe_id] is the last known valid state before execution *)
  let define ~doc ?safe_id ?(redefine=false) ?(cache=false) ?(feedback_processed=true)
        f id
  =
    feedback ~id:id (ProcessingIn !Flags.async_proofs_worker_id);
    let str_id = Stateid.to_string id in
    if is_cached id && not redefine then
      anomaly Pp.(str"defining state "++str str_id++str" twice.");
    try
      stm_prerr_endline (fun () -> "defining "^str_id^" (cache="^
        if cache then "Y)" else "N)");
      f ();
      if cache then cache_state id;
      stm_prerr_endline (fun () -> "setting cur id to "^str_id);
      cur_id := id;
      if feedback_processed then
        !Hooks.state_computed~doc id ~in_cache:false;
      VCS.reached id;
      if PG_compat.there_are_pending_proofs () then
        VCS.goals id (PG_compat.get_open_goals ())
    with e ->
      let (e, info) = Exninfo.capture e in
      let good_id = !cur_id in
      invalidate_cur_state ();
      VCS.reached id;
      let ie =
        match Stateid.get info, safe_id with
        | None, None -> (exn_on id ~valid:good_id (e, info))
        | None, Some good_id -> (exn_on id ~valid:good_id (e, info))
        | Some _, None -> (e, info)
        | Some (_,at), Some id -> (e, Stateid.add info ~valid:id at) in
      if cache then freeze_invalid id ie;
      !Hooks.unreachable_state ~doc id ie;
      Exninfo.iraise ie

  let init_state = ref None

  let register_root_state () =
    init_state := Some (Vernacstate.freeze_full_state ())

  let restore_root_state () =
    cur_id := Stateid.dummy;
    Vernacstate.unfreeze_full_state (Option.get !init_state)

  (* Protect against state changes *)
  let purify f x =
    let st = freeze () in
    try
      let res = f x in
      Vernacstate.Interp.invalidate_cache ();
      unfreeze st;
      res
    with e ->
      let e = Exninfo.capture e in
      Vernacstate.Interp.invalidate_cache ();
      unfreeze st;
      Exninfo.iraise e

end (* }}} *)

(* Wrapper for the proof-closing special path for Qed *)
let stm_qed_delay_proof ?route ~proof ~id ~st ~loc ~control pending : Vernacstate.Interp.t =
  set_id_for_feedback ?route dummy_doc id;
  Vernacinterp.interp_qed_delayed_proof ~proof ~st ~control (CAst.make ?loc pending)

(* Wrapper for Vernacentries.interp to set the feedback id *)
(* It is currently called 19 times, this number should be certainly
   reduced... *)
let stm_vernac_interp ?route id st { verbose; expr } : Vernacstate.t =
  (* The Stm will gain the capability to interpret commmads affecting
     the whole document state, such as backtrack, etc... so we start
     to design the stm command interpreter now *)
  set_id_for_feedback ?route dummy_doc id;
  Aux_file.record_in_aux_set_at ?loc:expr.CAst.loc ();
  (* We need to check if a command should be filtered from
   * vernac_entries, as it cannot handle it. This should go away in
   * future refactorings.
  *)
  let is_filtered_command = function
    VernacSynPure (VernacResetName _ | VernacResetInitial | VernacBack _
    | VernacRestart | VernacUndo _ | VernacUndoTo _
    | VernacAbortAll) -> true
    | _ -> false
  in
  (* XXX unsupported attributes *)
  let cmd = expr.CAst.v.expr in
  if is_filtered_command cmd then
    (stm_pperr_endline Pp.(fun () -> str "ignoring " ++ Ppvernac.pr_vernac expr); st)
  else begin
    stm_pperr_endline Pp.(fun () -> str "interpreting " ++ Ppvernac.pr_vernac expr);
    Vernacinterp.(interp ~intern:fs_intern ?verbosely:(Some verbose) ~st expr)
  end

(****************************** CRUFT *****************************************)
(******************************************************************************)

(* The backtrack module simulates the classic behavior of a linear document *)
module Backtrack : sig

  val record : unit -> unit

  (* we could navigate the dag, but this ways easy *)
  val branches_of : Stateid.t -> backup

  (* Returns the state that the command should backtract to *)
  val undo_vernac_classifier : vernac_control -> doc:doc -> Stateid.t
  val get_prev_proof : doc:doc -> Stateid.t -> Proof.t option
  val get_proof : doc:doc -> Stateid.t -> Proof.t option

end = struct (* {{{ *)

  let record () =
    List.iter (fun current_branch ->
      let mine = current_branch, VCS.get_branch current_branch in
      let info = VCS.get_info (VCS.get_branch_pos current_branch) in
      let others =
        CList.map_filter (fun b ->
          if Vcs_.Branch.equal b current_branch then None
          else Some(b, VCS.get_branch b)) (VCS.branches ()) in
      let backup = if fst info.vcs_backup <> None then fst info.vcs_backup
        else Some (VCS.backup ()) in
      let branches = if snd info.vcs_backup <> None then snd info.vcs_backup
        else Some { mine; others } in
      info.vcs_backup <- backup, branches)
    [VCS.current_branch (); VCS.Branch.master]

  let branches_of id =
    let info = VCS.get_info id in
    match info.vcs_backup with
    | _, None ->
       anomaly Pp.(str"Backtrack.branches_of "++str(Stateid.to_string id)++
                   str": a state with no vcs_backup.")
    | _, Some x -> x

  type ('a, 'b) cont = Stop of 'a | Cont of 'b

  let rec fold_until f acc id =
    let next acc =
      if id = Stateid.initial then raise Not_found
      else fold_until f acc (VCS.visit id).next in
    let info = VCS.get_info id in
    match info.vcs_backup with
    | None, _ -> next acc
    | Some vcs, _ ->
        let ids, tactic, undo =
          if id = Stateid.initial || id = Stateid.dummy then [],false,0 else
          match VCS.visit id with
          | { step = SFork ((_,_,_,l),_) } -> l, false,0
          | { step = SCmd { cids = l; ctac } } -> l, ctac,0
          | { step = SAlias (_,{ expr }) } when not (Vernacprop.has_query_control expr) ->
          begin match expr.CAst.v.expr with
                | VernacSynPure (VernacUndo n) -> [], false, n
                | _ -> [],false,0
          end
          | _ -> [],false,0 in
        match f acc (id, vcs, ids, tactic, undo) with
        | Stop x -> x
        | Cont acc -> next acc

  let undo_costly_in_batch_mode =
    CWarnings.create ~name:"undo-batch-mode" Pp.(fun v ->
        str "Command" ++ spc() ++ quote (Ppvernac.pr_vernac v) ++
        strbrk (" is not recommended in batch mode. In particular, going back in the document" ^
             " is not efficient in batch mode due to Rocq not caching previous states for memory optimization reasons." ^
             " If your use is intentional, you may want to disable this warning and pass" ^
             " the \"-async-proofs-cache force\" option to Rocq."))

  let back_tactic n (id,_,_,tactic,undo) =
    let value = (if tactic then 1 else 0) - undo in
    if Int.equal n 0 then Stop id else Cont (n-value)

  let get_proof ~doc id =
    match state_of_id ~doc id with
    | Valid (Some vstate) ->
      Option.map (Vernacstate.LemmaStack.with_top ~f:Declare.Proof.get) vstate.Vernacstate.interp.lemmas
    | _ -> None

  let undo_vernac_classifier v ~doc =
    if not (VCS.is_interactive ()) && (cur_opt()).async_proofs_cache <> Some Force
    then undo_costly_in_batch_mode v;
    try
      match v.CAst.v.expr with
      | VernacSynPure VernacResetInitial ->
          Stateid.initial
      | VernacSynPure (VernacResetName {CAst.v=name}) ->
          let id = VCS.cur_tip () in
          (try
            let oid =
              fold_until (fun b (id,_,label,_,_) ->
                if b then Stop id else Cont (List.mem name label))
              false id in
            oid
          with Not_found ->
            id)
      | VernacSynPure (VernacBack n) ->
          let id = VCS.cur_tip () in
          let oid = fold_until (fun n (id,_,_,_,_) ->
            if Int.equal n 0 then Stop id else Cont (n-1)) n id in
          oid
      | VernacSynPure (VernacUndo n) ->
          let id = VCS.cur_tip () in
          let oid = fold_until back_tactic n id in
          oid
      | VernacSynPure (VernacUndoTo _
        | VernacRestart as e) ->
          let m = match e with VernacUndoTo m -> m | _ -> 0 in
          let id = VCS.cur_tip () in
          let vcs =
            match (VCS.get_info id).vcs_backup with
            | None, _ -> anomaly Pp.(str"Backtrack: tip with no vcs_backup.")
            | Some vcs, _ -> vcs in
          let cb, _ =
            try Vcs_aux.find_proof_at_depth vcs (Vcs_aux.proof_nesting vcs)
            with Failure _ -> raise PG_compat.NoCurrentProof in
          let n = fold_until (fun n (_,vcs,_,_,_) ->
            if List.mem cb (Vcs_.branches vcs) then Cont (n+1) else Stop n)
            0 id in
          let oid = fold_until (fun n (id,_,_,_,_) ->
            if Int.equal n 0 then Stop id else Cont (n-1)) (n-m-1) id in
          oid
      | VernacSynPure VernacAbortAll ->
          let id = VCS.cur_tip () in
          let oid = fold_until (fun () (id,vcs,_,_,_) ->
            match Vcs_.branches vcs with [_] -> Stop id | _ -> Cont ())
            () id in
          oid
      | _ -> anomaly Pp.(str "incorrect VtMeta classification")
    with
    | Not_found ->
       CErrors.user_err
        Pp.(str "Cannot undo.")

  let get_prev_proof ~doc id =
    try
      let np = get_proof ~doc id in
      match np with
      | None -> None
      | Some cp ->
        let rec search did =
          let did = fold_until back_tactic 1 did in
          match get_proof ~doc did with
          | None -> None
          | Some rv ->
            if Evar.Set.equal (Proof.all_goals rv) (Proof.all_goals cp)
            then search did
            else Some rv
        in
        search id
    with Not_found | PG_compat.NoCurrentProof -> None

end (* }}} *)

let get_prev_proof = Backtrack.get_prev_proof
let get_proof = Backtrack.get_proof

let hints = ref Aux_file.empty_aux_file
let set_compilation_hints file =
  hints := Aux_file.load_aux_file_for file

let get_hint_ctx loc =
  let s = Aux_file.get ?loc !hints "context_used" in
  let ids = List.map Names.Id.of_string (Str.split (Str.regexp " ") s) in
  let ids = List.map (fun id -> CAst.make id) ids in
  match ids with
  | [] -> SsEmpty
  | x :: xs ->
    List.fold_left (fun a x -> SsUnion (SsSingl x,a)) (SsSingl x) xs

let get_hint_bp_time proof_name =
  try float_of_string (Aux_file.get !hints proof_name)
  with Not_found -> 1.0

let record_pb_time ?loc proof_name time =
  let proof_build_time = Printf.sprintf "%.3f" time in
  Aux_file.record_in_aux_at ?loc "proof_build_time" proof_build_time;
  if proof_name <> "" then begin
    Aux_file.record_in_aux_at proof_name proof_build_time;
    hints := Aux_file.set !hints proof_name proof_build_time
  end

(****************** proof structure for error recovery ************************)
(******************************************************************************)

type document_node = {
  indentation : int;
  ast : Vernacexpr.vernac_control;
  id : Stateid.t;
}

type document_view = {
  entry_point : document_node;
  prev_node : document_node -> document_node option;
}

type static_block_detection =
  document_view -> static_block_declaration option

type recovery_action = {
  base_state : Stateid.t;
  goals_to_admit : Evar.t list;
  recovery_command : Vernacexpr.vernac_control option;
}

type block_classification = ValidBlock of recovery_action | Leaks

type dynamic_block_error_recovery =
  doc -> static_block_declaration -> block_classification

let proof_block_delimiters = ref []

let register_proof_block_delimiter name static dynamic =
  if List.mem_assoc name !proof_block_delimiters then
    CErrors.user_err Pp.(str "Duplicate block delimiter " ++ str name ++ str ".");
  proof_block_delimiters := (name, (static,dynamic)) :: !proof_block_delimiters

let mk_doc_node id = function
  | { step = SCmd { ctac; cast = { indentation; expr }}; next } when ctac ->
       Some { indentation; ast = expr; id }
  | { step = SSideff (ReplayCommand { indentation; expr }, _); next } ->
       Some { indentation; ast = expr; id }
  | _ -> None
let prev_node { id } =
  let id = (VCS.visit id).next in
  mk_doc_node id (VCS.visit id)
let cur_node id = mk_doc_node id (VCS.visit id)

let is_block_name_enabled name =
  match (cur_opt()).async_proofs_tac_error_resilience with
  | FNone -> false
  | FAll -> true
  | FOnly l -> List.mem name l

let detect_proof_block id name =
  let name = match name with None -> "indent" | Some x -> x in
  if is_block_name_enabled name &&
     (async_proofs_is_master (cur_opt()) || Flags.async_proofs_is_worker ())
  then (
  match cur_node id with
  | None -> ()
  | Some entry_point -> try
      let static, _ = List.assoc name !proof_block_delimiters in
      begin match static { prev_node; entry_point } with
      | None -> ()
      | Some ({ block_start; block_stop } as decl) ->
          VCS.create_proof_block decl name
      end
    with Not_found ->
      CErrors.user_err
        Pp.(str "Unknown proof block delimiter " ++ str name ++ str ".")
  )
(****************************** THE SCHEDULER *********************************)
(******************************************************************************)

(* Unused module warning doesn't understand [module rec] *)
[@@@ocaml.warning "-60"]
module rec ProofTask : sig

  type competence = Stateid.t list
  type task_build_proof = {
    t_exn_info : Stateid.exn_info;
    t_start    : Stateid.t;
    t_stop     : Stateid.t;
    t_drop     : bool;
    t_states   : competence;
    t_assign   : Declare.Proof.closed_proof_output option Future.assignment -> unit;
    t_loc      : Loc.t option;
    t_uuid     : Future.UUID.t;
    t_name     : string }

  type task =
    | BuildProof of task_build_proof
    | States of Stateid.t list

  type request =
  | ReqBuildProof of (Future.UUID.t,VCS.vcs) Stateid.request * bool * competence
  | ReqStates of Stateid.t list

  include AsyncTaskQueue.Task
  with type task := task
   and type competence := competence
   and type request := request

  val build_proof_here :
    doc:doc ->
    ?loc:Loc.t ->
    drop_pt:bool ->
    Stateid.exn_info -> Stateid.t ->
      Declare.Proof.closed_proof_output option Future.computation

end = struct (* {{{ *)

  let forward_feedback msg = !Hooks.forward_feedback msg

  type competence = Stateid.t list
  type task_build_proof = {
    t_exn_info : Stateid.exn_info;
    t_start    : Stateid.t;
    t_stop     : Stateid.t;
    t_drop     : bool;
    t_states   : competence;
    t_assign   : Declare.Proof.closed_proof_output option Future.assignment -> unit;
    t_loc      : Loc.t option;
    t_uuid     : Future.UUID.t;
    t_name     : string }

  type task =
    | BuildProof of task_build_proof
    | States of Stateid.t list

  type worker_status = Fresh | Old of competence

  type request =
  | ReqBuildProof of (Future.UUID.t,VCS.vcs) Stateid.request * bool * competence
  | ReqStates of Stateid.t list

  type error = {
    e_error_at    : Stateid.t;
    e_safe_id     : Stateid.t;
    e_msg         : Pp.t;
    e_loc         : Loc.t option;
    e_safe_states : Stateid.t list }

  type response =
    | RespBuiltProof of Declare.Proof.closed_proof_output option * float
    | RespError of error
    | RespStates of (Stateid.t * State.partial_state) list

  let name = "proof"
  let extra_env () = !async_proofs_workers_extra_env

  let task_match age t =
    match age, t with
    | Fresh, BuildProof { t_states } -> true
    | Old my_states, States l ->
        List.for_all (fun x -> CList.mem_f Stateid.equal x my_states) l
    | _ -> false

  let name_of_task = function
    | BuildProof t -> "proof: " ^ t.t_name
    | States l -> "states: " ^ String.concat "," (List.map Stateid.to_string l)
  let name_of_request = function
    | ReqBuildProof(r,_,_) -> "proof: " ^ r.Stateid.name
    | ReqStates l -> "states: "^String.concat "," (List.map Stateid.to_string l)

  let request_of_task age = function
    | States l -> Some (ReqStates l)
    | BuildProof {
        t_exn_info;t_start;t_stop;t_loc;t_uuid;t_name;t_states;t_drop
      } ->
        assert(age = Fresh);
        try Some (ReqBuildProof ({
          Stateid.exn_info = t_exn_info;
          stop = t_stop;
          document = VCS.slice ~block_start:t_start ~block_stop:t_stop;
          loc = t_loc;
          uuid = t_uuid;
          name = t_name }, t_drop, t_states))
        with VCS.Expired -> None

  let use_response (s : worker_status) t r =
    match s, t, r with
    | Old c, States _, RespStates l ->
        List.iter (fun (id,s) -> State.assign id s) l; `End
    | Fresh, BuildProof { t_assign; t_loc; t_name; t_states; t_drop },
              RespBuiltProof (pl, time) ->
        feedback (InProgress ~-1);
        t_assign (`Val pl);
        record_pb_time ?loc:t_loc t_name time;
        if t_drop then `Stay(t_states,[States t_states])
        else `End
    | Fresh, BuildProof { t_assign; t_loc; t_name; t_states },
            RespError { e_error_at; e_safe_id = valid; e_loc; e_msg; e_safe_states } ->
        feedback (InProgress ~-1);
        let info = match e_loc with
          | Some loc -> Loc.add_loc Exninfo.null loc
          | None -> Exninfo.null
        in
        let info = Stateid.add ~valid info e_error_at in
        let e = (AsyncTaskQueue.RemoteException e_msg, info) in
        t_assign (`Exn e);
        `Stay(t_states,[States e_safe_states])
    | _ -> assert false

  let on_task_cancellation_or_expiration_or_slave_death = function
    | None -> ()
    | Some (States _) -> ()
    | Some (BuildProof { t_start = start; t_assign }) ->
        let s = "Worker dies or task expired" in
        let info = Stateid.add ~valid:start Exninfo.null start in
        let e = (AsyncTaskQueue.RemoteException (Pp.strbrk s), info) in
        t_assign (`Exn e);
        execution_error start (Pp.strbrk s);
        feedback (InProgress ~-1)

  let build_proof_here_fun ~doc ?loc ~drop_pt ~id eop =
    let wall_clock1 = Unix.gettimeofday () in
    Reach.known_state ~doc ~cache:(VCS.is_interactive ()) eop;
    let wall_clock2 = Unix.gettimeofday () in
    Aux_file.record_in_aux_at ?loc "proof_build_time"
      (Printf.sprintf "%.3f" (wall_clock2 -. wall_clock1));
    let p = if drop_pt then None else Some (PG_compat.return_proof ()) in
    if drop_pt then feedback ~id Complete;
    p

  let build_proof_here ~doc ?loc ~drop_pt exn_info eop =
    Future.create ~fix_exn:(Some exn_info) (fun () -> build_proof_here_fun ~doc ?loc ~drop_pt ~id:exn_info.Stateid.id eop)

  let perform_buildp { Stateid.exn_info; stop; document; loc } drop my_states =
    try
      VCS.restore document;
      VCS.print ();
      let proof, time =
        let wall_clock = Unix.gettimeofday () in
        let proof =
          try
            build_proof_here_fun ~doc:dummy_doc (* XXX should be document *)
              ?loc ~drop_pt:drop ~id:exn_info.Stateid.id stop
          with exn ->
            let iexn = Exninfo.capture exn in
            let iexn = State.exn_on exn_info.Stateid.id ~valid:exn_info.Stateid.valid iexn in
            Exninfo.iraise iexn
        in
        proof, Unix.gettimeofday () -. wall_clock in
      (* We typecheck the proof with the kernel (in the worker) to spot
       * the few errors tactics don't catch, like the "fix" tactic building
       * a bad fixpoint *)
      (* STATE: We use the current installed imperative state *)
      let st = State.freeze () in
      let () = match proof with
        | None -> (* drop *) ()
        | Some proof ->
          (* Unfortunately close_future_proof and friends are not pure so we need
             to set the state manually here *)
          State.unfreeze st;
          let pobject =
            PG_compat.close_future_proof ~feedback_id:stop (Future.from_val proof) in

          let st = Vernacstate.freeze_full_state () in
          let opaque = Opaque in
          try
            let _pstate =
              stm_qed_delay_proof ~st ~id:stop
                ~proof:pobject ~loc ~control:[] (Proved (opaque,None)) in
            ()
          with exn ->
            (* If [stm_qed_delay_proof] fails above we need to use the
               exn callback in the same way than build_proof_here;
               actually [fix_exn] there does more more than just
               modifying exn info, it also updates the STM state *)
            let iexn = Exninfo.capture exn in
            let iexn = State.exn_on exn_info.Stateid.id ~valid:exn_info.Stateid.valid iexn in
            Exninfo.iraise iexn
      in
      (* STATE: Restore the state XXX: handle exn *)
      State.unfreeze st;
      RespBuiltProof(proof,time)
    with
    | e when CErrors.noncritical e || e = Stack_overflow ->
        let e, info = Exninfo.capture e in
        (* This can happen if the proof is broken.  The error has also been
         * signalled as a feedback, hence we can silently recover *)
        let e_error_at, e_safe_id = match Stateid.get info with
          | Some (safe, err) -> err, safe
          | None -> Stateid.dummy, Stateid.dummy in
        let e_msg = iprint (e, info) in
        stm_pperr_endline Pp.(fun () -> str "failed with the following exception: " ++ fnl () ++ e_msg);
        let e_safe_states = List.filter State.is_cached_and_valid my_states in
        RespError { e_error_at; e_safe_id; e_msg; e_loc = Loc.get_loc info; e_safe_states }

  let perform_states query =
    if query = [] then [] else
    let is_tac e = match Vernac_classifier.classify_vernac e with
    | VtProofStep _ -> true
    | _ -> false
    in
    let initial =
      let rec aux id =
        try match VCS.visit id with { next } -> aux next
        with VCS.Expired -> id in
      aux (List.hd query) in
    let get_state seen id =
      let prev =
        try
          let { next = prev; step } = VCS.visit id in
          if State.is_cached_and_valid prev && List.mem prev seen
          then Some (prev, State.get_cached prev, step)
          else None
        with VCS.Expired -> None in
      let this =
        if State.is_cached_and_valid id then Some (State.get_cached id) else None in
      match prev, this with
      | _, None -> None
      | Some (prev, o, SCmd { cast = { expr }}), Some n
        when is_tac expr && Vernacstate.Stm.same_env o n -> (* A pure tactic *)
          Some (id, State.ProofOnly (prev, Vernacstate.Stm.pstate n))
      | Some _, Some s ->
        if CDebug.(get_flag misc) then msg_debug (Pp.str "STM: sending back a fat state");
          Some (id, State.Full s)
      | _, Some s -> Some (id, State.Full s) in
    let rec aux seen = function
      | [] -> []
      | id :: rest ->
          match get_state seen id with
          | None -> aux seen rest
          | Some stuff -> stuff :: aux (id :: seen) rest in
    aux [initial] query

  let perform = function
    | ReqBuildProof (bp,drop,states) -> perform_buildp bp drop states
    | ReqStates sl -> RespStates (perform_states sl)

  let on_marshal_error s = function
    | States _ ->
      msg_warning Pp.(strbrk("Marshalling error: "^s^". "^
                             "The system state could not be sent to the master process."))
    | BuildProof { t_exn_info; t_stop; t_assign; t_loc; t_drop = drop_pt } ->
      msg_warning Pp.(strbrk("Marshalling error: "^s^". "^
                             "The system state could not be sent to the worker process. "^
                             "Falling back to local, lazy, evaluation."));
      t_assign(`Comp(fun () -> build_proof_here_fun ~doc:dummy_doc (* XXX should be stored in a closure, it is the same doc that was used to generate the task *) ?loc:t_loc ~drop_pt ~id:t_exn_info.Stateid.id t_stop));
      feedback (InProgress ~-1)

end (* }}} *)

(* Slave processes (if initialized, otherwise local lazy evaluation) *)
and Slaves : sig

  (* (eventually) remote calls *)
  val build_proof
    : doc:doc
    -> ?loc:Loc.t
    -> drop_pt:bool
    -> exn_info:Stateid.exn_info
    -> block_start:Stateid.t
    -> block_stop:Stateid.t
    -> name:string
    -> unit
    -> future_proof * AsyncTaskQueue.cancel_switch

  (* blocking function that waits for the task queue to be empty *)
  val wait_all_done : unit -> unit

  (* initialize the whole machinery (optional) *)
  val init : spawn_args:string list -> CoqworkmgrApi.priority -> unit

  type 'a tasks = (('a,VCS.vcs) Stateid.request * bool) list
  val dump_snapshot : unit -> Future.UUID.t tasks

  val cancel_worker : WorkerPool.worker_id -> unit

  val reset_task_queue : unit -> unit

end = struct (* {{{ *)

  module TaskQueue = AsyncTaskQueue.MakeQueue(ProofTask) ()

  let queue = ref None
  let init ~spawn_args priority =
    if async_proofs_is_master (cur_opt()) then
      queue := Some (TaskQueue.create ~spawn_args (cur_opt()).async_proofs_n_workers priority)
    else
      queue := Some (TaskQueue.create ~spawn_args 0 priority)

  let build_proof ~doc ?loc ~drop_pt ~exn_info ~block_start ~block_stop ~name:pname () =
    let cancel_switch = ref false in
    let n_workers = TaskQueue.n_workers (Option.get !queue) in
    if Int.equal n_workers 0 && not (VCS.is_vos_doc ()) then
      ProofTask.build_proof_here ~doc ?loc ~drop_pt exn_info block_stop, cancel_switch
    else
      let f, t_assign = Future.create_delegate ~name:pname (Some exn_info) in
      let t_uuid = Future.uuid f in
      if n_workers > 0 then feedback (InProgress 1);
      let task = ProofTask.(BuildProof {
        t_exn_info = exn_info; t_start = block_start; t_stop = block_stop; t_assign; t_drop = drop_pt;
        t_loc = loc; t_uuid; t_name = pname;
        t_states = VCS.nodes_in_slice ~block_start ~block_stop }) in
      TaskQueue.enqueue_task (Option.get !queue) task ~cancel_switch;
      f, cancel_switch

  let wait_all_done () = TaskQueue.join (Option.get !queue)

  let cancel_worker n = TaskQueue.cancel_worker (Option.get !queue) n

  (* For external users this name is nicer than request *)
  type 'a tasks = (('a,VCS.vcs) Stateid.request * bool) list
  let dump_snapshot () =
    let tasks = TaskQueue.snapshot (Option.get !queue) in
    let reqs =
      CList.map_filter
        ProofTask.(fun x ->
             match request_of_task Fresh x with
             | Some (ReqBuildProof (r, b, _)) -> Some(r, b)
             | _ -> None)
        tasks in
    stm_prerr_endline (fun () -> Printf.sprintf "dumping %d tasks\n" (List.length reqs));
    reqs

  let reset_task_queue () = TaskQueue.clear (Option.get !queue)

end (* }}} *)

and QueryTask : sig

  type task = { t_where : Stateid.t; t_for : Stateid.t ; t_what : aast }
  include AsyncTaskQueue.Task with type task := task

end = struct (* {{{ *)

  type task =
    { t_where : Stateid.t; t_for : Stateid.t ; t_what : aast }

  type request =
    { r_where : Stateid.t ; r_for : Stateid.t ; r_what : aast; r_doc : VCS.vcs }
  type response = unit

  let name = "query"
  let extra_env _ = [||]
  type competence = unit
  type worker_status = Fresh | Old of competence

  let task_match _ _ = true

  let request_of_task _ { t_where; t_what; t_for } =
    try Some {
      r_where = t_where;
      r_for   = t_for;
      r_doc   = VCS.slice ~block_start:t_where ~block_stop:t_where;
      r_what  = t_what }
    with VCS.Expired -> None

  let use_response _ _ _ = `End

  let on_marshal_error _ _ =
    stm_pr_err ("Fatal marshal error in query");
    flush_all (); exit 1

  let on_task_cancellation_or_expiration_or_slave_death _ = ()

  let forward_feedback msg = !Hooks.forward_feedback msg

  let perform { r_where; r_doc; r_what; r_for } =
    VCS.restore r_doc;
    VCS.print ();
    Reach.known_state ~doc:dummy_doc (* XXX should be r_doc *) ~cache:false r_where;
    (* STATE *)
    let st = Vernacstate.freeze_full_state () in
    try
      (* STATE SPEC:
       * - start: r_where
       * - end  : after execution of r_what
       *)
      ignore(stm_vernac_interp r_for st { r_what with verbose = true });
      feedback ~id:r_for Processed
    with e when CErrors.noncritical e ->
      let e,_ as ie = Exninfo.capture e in
      let msg = iprint ie in
      let qf = Result.value ~default:[] (Quickfix.from_exception e) in
      feedback ~id:r_for (Message (Error, None, qf, msg))

  let name_of_task { t_what } = string_of_ppcmds (pr_ast t_what)
  let name_of_request { r_what } = string_of_ppcmds (pr_ast r_what)

end (* }}} *)

and Query : sig

  val init : CoqworkmgrApi.priority -> unit

end = struct (* {{{ *)

  module TaskQueue = AsyncTaskQueue.MakeQueue(QueryTask) ()

  let queue = ref None

  let init priority = queue := Some (TaskQueue.create 0 priority)

end (* }}} *)

(* Runs all transactions needed to reach a state *)
and Reach : sig

  val known_state :
    doc:doc -> ?redefine_qed:bool -> cache:bool ->
      Stateid.t -> unit

end = struct (* {{{ *)

let async_policy () =
  if Attributes.is_universe_polymorphism () then false (* FIXME this makes no sense, it is the default value of the attribute *)
  else if VCS.is_interactive () then
    (async_proofs_is_master (cur_opt()) || (cur_opt()).async_proofs_mode = APonLazy)
  else
    (VCS.is_vos_doc () || (cur_opt()).async_proofs_mode <> APoff)

let delegate name =
     get_hint_bp_time name >= (cur_opt()).async_proofs_delegation_threshold
  || VCS.is_vos_doc ()

type reason =
| Aborted
| Alias
| AlreadyEvaluated
| Doesn'tGuaranteeOpacity
| Immediate
| MutualProofs
| NestedProof
| NoPU_NoHint_NoES
| Policy
| Print
| Transparent
| Unknown

type sync_kind =
| Sync of string * reason
| ASync of Stateid.t * Stateid.t list * string * bool
| MaybeASync of Stateid.t * Stateid.t list * string * bool

let collect_proof keep cur hd brkind id =
stm_prerr_endline (fun () -> "Collecting proof ending at "^Stateid.to_string id);
let no_name = "" in
let name = function
   | [] -> no_name
   | id :: _ -> Names.Id.to_string id in
let loc = (snd cur).expr.CAst.loc in
let is_defined_expr = function
   | VernacSynPure (VernacEndProof (Proved (Transparent,_))) -> true
   | _ -> false in
let is_defined = function
   | _, { expr = e } -> is_defined_expr e.CAst.v.expr
                        && (not (Vernacprop.has_query_control e)) in
let has_default_proof_using = Option.has_some (Proof_using.get_default_proof_using ()) in
let proof_using_ast = function
   | VernacSynPure(VernacProof(_,Some _)) -> true
   | VernacSynPure(VernacProof(_,None)) -> has_default_proof_using
   | _ -> false
in
let proof_using_ast = function
   | Some (_, v) when proof_using_ast v.expr.CAst.v.expr
                      && (not (Vernacprop.has_query_control v.expr)) -> Some v
   | _ -> None in
let has_proof_using x = proof_using_ast x <> None in
let proof_no_using = function
   | VernacSynPure (VernacProof(t,None)) -> if has_default_proof_using then None else t
   | _ -> assert false
in
let proof_no_using = function
   | Some (_, v) -> proof_no_using v.expr.CAst.v.expr, v
   | _ -> assert false in
let has_proof_no_using = function
   | VernacSynPure (VernacProof(_,None)) -> not has_default_proof_using
   | _ -> false
in
let has_proof_no_using = function
   | Some (_, v) -> has_proof_no_using v.expr.CAst.v.expr
                    && (not (Vernacprop.has_query_control v.expr))
   | _ -> false in
let too_complex_to_delegate = function
   VernacSynterp (VernacDeclareModule _
    | VernacDefineModule _
    | VernacDeclareModuleType _
    | VernacInclude _
    | VernacRequire _
    | VernacImport _) -> true
   | ast -> may_pierce_opaque ast in
let parent = function Some (p, _) -> p | None -> assert false in
let is_empty = function ASync(_,[],_,_) | MaybeASync(_,[],_,_) -> true | _ -> false in
let rec collect last accn id =
    let view = VCS.visit id in
    match view.step with
    | (SSideff (ReplayCommand x,_) | SCmd { cast = x })
      when too_complex_to_delegate x.expr.CAst.v.expr ->
       Sync(no_name,Print)
    | SCmd { cast = x } -> collect (Some (id,x)) (id::accn) view.next
    | SSideff (ReplayCommand x,_) -> collect (Some (id,x)) (id::accn) view.next
    (* An Alias could jump everywhere... we hope we can ignore it*)
    | SAlias _ -> Sync (no_name,Alias)
    | SFork((_,_,_,_::_::_), _) ->
        Sync (no_name,MutualProofs)
    | SFork((_,_,Doesn'tGuaranteeOpacity,_), _) ->
        Sync (no_name,Doesn'tGuaranteeOpacity)
    | SFork((_,hd',GuaranteesOpacity,ids), _) when has_proof_using last ->
        assert (VCS.Branch.equal hd hd' || VCS.Branch.equal hd VCS.edit_branch);
        let name = name ids in
        ASync (parent last,accn,name,delegate name)
    | SFork((_, hd', GuaranteesOpacity, ids), _) when
       has_proof_no_using last && not (State.is_cached_and_valid (parent last)) &&
       VCS.is_vos_doc () ->
        assert (VCS.Branch.equal hd hd'||VCS.Branch.equal hd VCS.edit_branch);
        (try
          let name, hint = name ids, get_hint_ctx loc  in
          let t, v = proof_no_using last in
--> --------------------

--> maximum size reached

--> --------------------

quality94%

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