session.ml

(********************************************************************)
(*                                                                  *)
(*  The Why3 Verification Platform   /   The Why3 Development Team  *)
(*  Copyright 2010-2012   --   INRIA - CNRS - Paris-Sud University  *)
(*                                                                  *)
(*  This software is distributed under the terms of the GNU Lesser  *)
(*  General Public License version 2.1, with the special exception  *)
(*  on linking described in file LICENSE.                           *)
(*                                                                  *)
(********************************************************************)

open Debug
open Stdlib
open Ty
open Ident
open Decl
open Term
open Theory
open Task

module Mprover = Whyconf.Mprover
module Sprover = Whyconf.Sprover
module PHprover = Whyconf.Hprover
module C = Whyconf
module Tc = Termcode

let debug = Debug.register_info_flag "session"
  ~desc:"Pring@ debugging@ messages@ about@ Why3@ session@ \
         creation,@ reading@ and@ writing."

(** {2 Type definitions} *)

module PHstr = Hstr

type proof_attempt_status =
    | Unedited (** editor not yet run for interactive proof *)
    | JustEdited (** edited but not run yet *)
    | Interrupted (** external proof has never completed *)
    | Scheduled (** external proof attempt is scheduled *)
    | Running (** external proof attempt is in progress *)
    | Done of Call_provers.prover_result (** external proof done *)
    | InternalFailure of exn (** external proof aborted by internal error *)

type task_option = Task.task option

type ident_path =
  { ip_library : string list;
    ip_theory : string;
    ip_qualid : string list;
  }

let print_ident_path fmt ip =
  Format.fprintf fmt "%a.%s.%a"
    (Pp.print_list Pp.dot Pp.string) ip.ip_library
    ip.ip_theory
    (Pp.print_list Pp.dot Pp.string) ip.ip_qualid

let compare_ident_path x y =
  let c = Lists.compare String.compare x.ip_library y.ip_library in
  if c <> 0 then -c else (* in order to be bottom up *)
  let c = String.compare x.ip_theory y.ip_theory in
  if c <> 0 then c else
  let c = Lists.compare String.compare x.ip_qualid y.ip_qualid in
  c

module Pos = struct
  type t = ident_path
  let compare = compare_ident_path
  let equal x y = (x : t) = y
  let hash x = Hashtbl.hash (x : t)
end

module Mpos = Map.Make(Pos)
module Spos = Mpos.Set
module Hpos = XHashtbl.Make(Pos)

type meta_args = meta_arg list

module Mmeta_args = Map.Make(struct
  type t = meta_args

  let meta_arg_id = function
    | MAty _  -> 0
    | MAts _  -> 1
    | MAls _  -> 2
    | MApr _  -> 3
    | MAstr _ -> 4
    | MAint _ -> 5

  let compare_meta_arg x y =
    match x,y with
  (** These hash are in fact tag *)
    | MAty  x, MAty  y -> compare (ty_hash x) (ty_hash y)
    | MAts  x, MAts  y -> compare (ts_hash x) (ts_hash y)
    | MAls  x, MAls  y -> compare (ls_hash x) (ls_hash y)
    | MApr  x, MApr  y -> compare (pr_hash x) (pr_hash y)
    | MAstr x, MAstr y -> String.compare x y
    | MAint x, MAint y -> compare x y
    | _ -> compare (meta_arg_id x) (meta_arg_id y)

  let compare = Lists.compare compare_meta_arg
end)
module Smeta_args = Mmeta_args.Set

type metas_args = Smeta_args.t Mstr.t

module Mmetas_args = Map.Make(struct
  type t = metas_args
  let compare = Mstr.compare Smeta_args.compare
end)

type idpos = {
  idpos_ts : ident_path Mts.t;
  idpos_ls : ident_path Mls.t;
  idpos_pr : ident_path Mpr.t;
}

let empty_idpos =
  {
    idpos_ts = Mts.empty;
    idpos_ls = Mls.empty;
    idpos_pr = Mpr.empty;
  }

(* dead code
let posid_of_idpos idpos =
  let posid = Mpos.empty in
  let posid = Mts.fold (fun ts pos ->
    Mpos.add pos (MAts ts)) idpos.idpos_ts posid  in
  let posid = Mls.fold (fun ls pos ->
    Mpos.add pos (MAls ls)) idpos.idpos_ls posid  in
  let posid = Mpr.fold (fun pr pos ->
    Mpos.add pos (MApr pr)) idpos.idpos_pr posid  in
  posid
*)

type expl = string option

type 'a goal =
  { mutable goal_key  : 'a;
    goal_name : Ident.ident;
    goal_expl : expl;
    goal_parent : 'a goal_parent;
    mutable goal_checksum : Tc.checksum;
    mutable goal_shape : Tc.shape;
    mutable goal_verified : bool;
    goal_task: task_option;
    mutable goal_expanded : bool;
    goal_external_proofs : 'a proof_attempt PHprover.t;
    goal_transformations : 'a transf PHstr.t;
    mutable goal_metas : 'a metas Mmetas_args.t;
  }

and 'a proof_attempt =
  { proof_key : 'a;
    mutable proof_prover : Whyconf.prover;
    proof_parent : 'a goal;
    mutable proof_state : proof_attempt_status;
    mutable proof_timelimit : int;
    mutable proof_memlimit : int;
    mutable proof_obsolete : bool;
    mutable proof_archived : bool;
    mutable proof_edited_as : string option;
  }

and 'a goal_parent =
  | Parent_theory of 'a theory
  | Parent_transf of 'a transf
  | Parent_metas  of 'a metas

and 'a metas =
  { mutable metas_key : 'a;
    metas_added : metas_args;
    metas_idpos : idpos;
    metas_parent : 'a goal;
    mutable metas_verified : bool;
    mutable metas_goal : 'a goal;
    (** Not mutated after the creation *)
    mutable metas_expanded : bool;
  }

and 'a transf =
    { mutable transf_key : 'a;
      transf_name : string;
      (** Why3 tranformation name *)
      transf_parent : 'a goal;
      mutable transf_verified : bool;
      mutable transf_goals : 'a goal list;
      (** Not mutated after the creation of the session *)
      mutable transf_expanded : bool;
    }

and 'a theory =
    { mutable theory_key : 'a;
      theory_name : Ident.ident;
      theory_parent : 'a file;
      mutable theory_goals : 'a goal list;
      mutable theory_verified : bool;
      mutable theory_expanded : bool;
    }

and 'a file =
    { mutable file_key : 'a;
      file_name : string;
      file_format : string option;
      file_parent : 'a session;
      mutable file_theories: 'a theory list;
      (** Not mutated after the creation *)
      mutable file_verified : bool;
      mutable file_expanded : bool;
    }

and 'a session =
    { session_files : 'a file PHstr.t;
      mutable session_shape_version : int;
      session_dir   : string; (** Absolute path *)
    }

type loaded_prover =
    { prover_config : Whyconf.config_prover;
      prover_driver : Driver.driver}

type loaded_provers = loaded_prover option PHprover.t

type 'a env_session =
    { env : Env.env;
      mutable whyconf : Whyconf.config;
      loaded_provers : loaded_provers;
      session : 'a session}

let update_env_session_config e c = e.whyconf <- c

(*************************)
(**       Iterators      *)
(*************************)
type 'a any =
  | File of 'a file
  | Theory of 'a theory
  | Goal of 'a goal
  | Proof_attempt of 'a proof_attempt
  | Transf of 'a transf
  | Metas of 'a metas

let rec goal_iter_proof_attempt f g =
  PHprover.iter (fun _ a -> f a) g.goal_external_proofs;
  PHstr.iter (fun _ t -> transf_iter_proof_attempt f t) g.goal_transformations;
  Mmetas_args.iter (fun _ t -> metas_iter_proof_attempt f t) g.goal_metas;

and transf_iter_proof_attempt f t =
  List.iter (goal_iter_proof_attempt f) t.transf_goals

and metas_iter_proof_attempt f t =
  goal_iter_proof_attempt f t.metas_goal

let theory_iter_proof_attempt f t =
  List.iter (goal_iter_proof_attempt f) t.theory_goals

let metas_iter_proof_attempt f m =
  goal_iter_proof_attempt f m.metas_goal

let file_iter_proof_attempt f t =
  List.iter (theory_iter_proof_attempt f) t.file_theories

let session_iter_proof_attempt f s =
  PHstr.iter (fun _ file -> file_iter_proof_attempt f file) s.session_files

let iter_proof_attempt f = function
    | Goal g -> goal_iter_proof_attempt f g
    | Theory th -> theory_iter_proof_attempt f th
    | File file -> file_iter_proof_attempt f file
    | Proof_attempt a -> f a
    | Transf tr -> transf_iter_proof_attempt f tr
    | Metas m -> metas_iter_proof_attempt f m

let rec goal_iter_leaf_goal ~unproved_only f g =
  if not (g.goal_verified && unproved_only) then
    let r = ref true in
    PHstr.iter
      (fun _ t -> r := false;
        List.iter (goal_iter_leaf_goal ~unproved_only f) t.transf_goals)
      g.goal_transformations;
    if !r then f g

(** iterators not reccursive *)
let iter_goal fp ft fm g =
  PHprover.iter (fun _ a -> fp a) g.goal_external_proofs;
  PHstr.iter (fun _ t -> ft t) g.goal_transformations;
  Mmetas_args.iter (fun _ t -> fm t) g.goal_metas

let iter_transf f t =
  List.iter (fun g -> f g) t.transf_goals

let iter_metas f t = f t.metas_goal

let goal_iter f g =
  PHprover.iter
    (fun _ a -> f (Proof_attempt a)) g.goal_external_proofs;
  PHstr.iter (fun _ t -> f (Transf t)) g.goal_transformations;
  Mmetas_args.iter (fun _ t -> f (Metas t)) g.goal_metas


let transf_iter f t =
  List.iter (fun g -> f (Goal g)) t.transf_goals

let metas_iter f t =
  f (Goal t.metas_goal)

let theory_iter f t =
  List.iter (fun g -> f (Goal g)) t.theory_goals

let file_iter f t =
  List.iter (fun th -> f (Theory th)) t.file_theories

let session_iter f s =
  PHstr.iter (fun _ file -> f (File file)) s.session_files

let iter f = function
    | Goal g -> goal_iter f g
    | Theory th -> theory_iter f th
    | File file -> file_iter f file
    | Proof_attempt _ -> ()
    | Transf tr -> transf_iter f tr
    | Metas m -> metas_iter f m

(** Print session *)


module PTreeT = struct
  type 'a t = | Any of 'a any | Session of 'a session
  let decomp = function
    | Any t ->
      let s = match t with
        | File f ->
          if f.file_verified
          then f.file_name
          else f.file_name^"?"
        | Theory th ->
          if th.theory_verified
          then th.theory_name.Ident.id_string
          else th.theory_name.Ident.id_string^"?"
        | Goal g ->
          if g.goal_verified
          then g.goal_name.Ident.id_string
          else g.goal_name.Ident.id_string^"?"
        | Proof_attempt pr ->
          Pp.sprintf_wnl "%a%s%s%s%s"
            Whyconf.print_prover pr.proof_prover
            (match pr.proof_state with
              | Done { Call_provers.pr_answer = Call_provers.Valid} -> ""
              | InternalFailure _ -> "!"
              | _ -> "?")
            (if pr.proof_obsolete || pr.proof_archived then " " else "")
            (if pr.proof_obsolete then "O" else "")
            (if pr.proof_archived then "A" else "")
        | Transf tr ->
          if tr.transf_verified
          then tr.transf_name
          else tr.transf_name^"?"
        | Metas metas ->
          if metas.metas_verified
          then "metas..."
          else "metas..."^"?"
      in
      let l = ref [] in
      iter (fun a -> l := (Any a)::!l) t;
      s,!l
    | Session s ->
      let l = ref [] in
      session_iter (fun a -> l := (Any a)::!l) s;
      Filename.basename s.session_dir,!l

end

module PTree = Print_tree.PMake(PTreeT)

let print_any fmt any = PTree.print fmt (PTreeT.Any any)

let print_session fmt s = PTree.print fmt (PTreeT.Session s)

(** 2 Create a session *)

let empty_session ?shape_version dir =
  let shape_version = match shape_version with
    | Some v -> v
    | None -> Termcode.current_shape_version
  in
  { session_files = PHstr.create 3;
    session_shape_version = shape_version;
    session_dir   = dir;
  }

let create_session ?shape_version project_dir =
  if not (Sys.file_exists project_dir) then
    begin
      dprintf debug
        "[Info] '%s' does not exists. Creating directory of that name \
 for the project@." project_dir;
      Unix.mkdir project_dir 0o777
    end;
  empty_session ?shape_version project_dir


(* dead code
let load_env_session ?(includes=[]) session conf_path_opt =
  let config = Whyconf.read_config conf_path_opt in
  let loadpath = (Whyconf.loadpath (Whyconf.get_main config)) @ includes in
  let env = Env.create_env loadpath in
  { session = session;
    env = env;
    whyconf = config;
    loaded_provers = PHprover.create 5;
  }
*)

(************************)
(* session accessor     *)
(************************)

(* dead code
let get_session_file file = file.file_parent

let get_session_theory th = get_session_file th.theory_parent

let rec get_session_goal goal =
  match goal.goal_parent with
    | Parent_transf trans -> get_session_trans trans
    | Parent_theory th    -> get_session_theory th
    | Parent_metas  metas -> get_session_metas metas


and get_session_trans transf = get_session_goal transf.transf_parent

and get_session_metas metas = get_session_goal metas.metas_parent

let get_session_proof_attempt pa = get_session_goal pa.proof_parent
*)

let get_used_provers session =
  let sprover = ref Sprover.empty in
  session_iter_proof_attempt
    (fun pa -> sprover := Sprover.add pa.proof_prover !sprover)
    session;
  !sprover

exception NoTask

let goal_task g = Opt.get_exn NoTask g.goal_task
let goal_task_option g = g.goal_task

let goal_expl g = Opt.get_def g.goal_name.Ident.id_string g.goal_expl

(************************)
(* saving state on disk *)
(************************)
open Format

let db_filename = "why3session.xml"
let session_dir_for_save = ref "."

let save_string fmt s =
  for i=0 to String.length s - 1 do
    match String.get s i with
      | '\"' -> pp_print_string fmt "&quot;"
      | '\'' -> pp_print_string fmt "&apos;"
      | '<' -> pp_print_string fmt "&lt;"
      | '>' -> pp_print_string fmt "&gt;"
      | '&' -> pp_print_string fmt "&amp;"
      | c -> pp_print_char fmt c
  done


let save_result fmt r =
  fprintf fmt "@\n<result status=\"%s\" time=\"%.2f\"/>"
    (match r.Call_provers.pr_answer with
       | Call_provers.Valid -> "valid"
       | Call_provers.Failure _ -> "failure"
       | Call_provers.Unknown _ -> "unknown"
       | Call_provers.HighFailure -> "highfailure"
       | Call_provers.Timeout -> "timeout"
       | Call_provers.OutOfMemory -> "outofmemory"
       | Call_provers.Invalid -> "invalid")
    r.Call_provers.pr_time

let save_status fmt s =
  match s with
    | Unedited ->
        fprintf fmt "@\n<unedited/>"
    | Scheduled | Running | Interrupted | JustEdited ->
        fprintf fmt "@\n<undone/>"
    | InternalFailure msg ->
        fprintf fmt "@\n<internalfailure reason=\"%a\"/>"
          save_string (Printexc.to_string msg)
    | Done r -> save_result fmt r


let opt lab fmt = function
  | None -> ()
  | Some s -> fprintf fmt "%s=\"%a\"@ " lab save_string s

let save_proof_attempt fmt (id,a) =
  fprintf fmt
    "@\n@[<v 1><proof@ prover=\"%i\"@ timelimit=\"%d\"@ \
memlimit=\"%d\"@ %aobsolete=\"%b\"@ archived=\"%b\">"
    id a.proof_timelimit a.proof_memlimit
    (opt "edited") a.proof_edited_as a.proof_obsolete
    a.proof_archived;
  save_status fmt a.proof_state;
  fprintf fmt "@]@\n</proof>"

let save_ident fmt id =
  fprintf fmt "name=\"%a\"" save_string id.Ident.id_string;
  match id.Ident.id_loc with
    | None -> ()
    | Some loc ->
      let file,lnum,cnumb,cnume = Loc.get loc in
      let file = Sysutil.relativize_filename !session_dir_for_save file in
      fprintf fmt
        "@ locfile=\"%a\"@ loclnum=\"%i\" loccnumb=\"%i\" loccnume=\"%i\""
        save_string file lnum cnumb cnume

let save_label fmt s =
  fprintf fmt "@\n@[<v 1><label@ name=\"%a\"/>@]" save_string s.Ident.lab_string

let rec save_goal provers fmt g =
  assert (Tc.string_of_shape g.goal_shape <> "");
  fprintf fmt
    "@\n@[<v 1><goal@ %a@ %asum=\"%a\"@ proved=\"%b\"@ \
expanded=\"%b\"@ shape=\"%a\">"
    save_ident g.goal_name
    (opt "expl") g.goal_expl
    save_string (Tc.string_of_checksum g.goal_checksum)
    g.goal_verified  g.goal_expanded
    save_string (Tc.string_of_shape g.goal_shape);
  Ident.Slab.iter (save_label fmt) g.goal_name.Ident.id_label;
  let l = PHprover.fold
    (fun _ a acc -> (Mprover.find a.proof_prover provers, a) :: acc)
    g.goal_external_proofs [] in
  let l = List.sort (fun (i1,_) (i2,_) -> compare i1 i2) l in
  List.iter (save_proof_attempt fmt) l;
  let l = PHstr.fold (fun _ t acc -> t :: acc) g.goal_transformations [] in
  let l = List.sort (fun t1 t2 -> compare t1.transf_name t2.transf_name) l in
  List.iter (save_trans provers fmt) l;
  Mmetas_args.iter (save_metas provers fmt) g.goal_metas;
  fprintf fmt "@]@\n</goal>"

and save_trans provers fmt t =
  fprintf fmt "@\n@[<v 1><transf@ name=\"%a\"@ proved=\"%b\"@ expanded=\"%b\">"
    save_string t.transf_name t.transf_verified t.transf_expanded;
  List.iter (save_goal provers fmt) t.transf_goals;
  fprintf fmt "@]@\n</transf>"

and save_metas provers fmt _ m =
  fprintf fmt "@\n@[<v 1><metas@ proved=\"%b\"@ expanded=\"%b\">"
    m.metas_verified m.metas_expanded;
  let save_pos fmt pos =
    fprintf fmt "@\n@[<v 1>ip_theory=\"%a\">" save_string pos.ip_theory;
    List.iter (fprintf fmt "@\n@[<v 1><ip_library@ name=\"%a\"/>@]" save_string)
      pos.ip_library;
    List.iter (fprintf fmt "@\n@[<v 1><ip_qualid@ name=\"%a\"/>@]" save_string)
      pos.ip_qualid;
    fprintf fmt "@]";
  in
  let save_ts_pos fmt ts pos =
    fprintf fmt "@\n@[<v 1><ts_pos@ name=\"%a\"@ arity=\"%i\"@ \
    id=\"%i\"@ %a</ts_pos>@]"
      save_string ts.ts_name.id_string (List.length ts.ts_args)
      (ts_hash ts) save_pos pos in
  let save_ls_pos fmt ls pos =
    (** TODO: add the signature? *)
    fprintf fmt "@\n@[<v 1><ls_pos@ name=\"%a\"@ id=\"%i\"@ %a</ls_pos>@]"
      save_string ls.ls_name.id_string
      (ls_hash ls) save_pos pos
  in
  let save_pr_pos fmt pr pos =
    fprintf fmt "@\n@[<v 1><pr_pos@ name=\"%a\"@ id=\"%i\"@ %a</pr_pos>@]"
      save_string pr.pr_name.id_string
      (pr_hash pr) save_pos pos
  in
  Mts.iter (save_ts_pos fmt) m.metas_idpos.idpos_ts;
  Mls.iter (save_ls_pos fmt) m.metas_idpos.idpos_ls;
  Mpr.iter (save_pr_pos fmt) m.metas_idpos.idpos_pr;
  Mstr.iter (fun s smeta_args ->
    Smeta_args.iter (save_meta_args fmt s) smeta_args) m.metas_added;
  save_goal provers fmt m.metas_goal;
  fprintf fmt "@]@\n</metas>"

and save_meta_args fmt s l =
  fprintf fmt "@\n@[<v 1><meta@ name=\"%a\">" save_string s;
  let save_meta_arg fmt = function
    | MAty ty -> fprintf fmt "@\n@[<v 1><meta_arg_ty/>";
      save_ty fmt ty;
      fprintf fmt "@]@\n</meta_arg_ty>"
    | MAts ts ->
      fprintf fmt "@\n@[<v 1><meta_arg_ts@ id=\"%i\"/>@]" (ts_hash ts)
    | MAls ls ->
      fprintf fmt "@\n@[<v 1><meta_arg_ls@ id=\"%i\"/>@]" (ls_hash ls)
    | MApr pr ->
      fprintf fmt "@\n@[<v 1><meta_arg_pr@ id=\"%i\"/>@]" (pr_hash pr)
    | MAstr s ->
      fprintf fmt "@\n@[<v 1><meta_arg_str@ val=\"%s\"/>@]" s
    | MAint i ->
      fprintf fmt "@\n@[<v 1><meta_arg_int@ val=\"%i\"/>@]" i
  in
  List.iter (save_meta_arg fmt) l;
  fprintf fmt "@]@\n</meta_args>"

and save_ty fmt ty =
  match ty.ty_node with
  | Tyvar tv ->
    fprintf fmt "@\n@[<v 1><ty_var@ id=\"%i\"/>@]" (tv_hash tv)
  | Tyapp (ts,l) ->
    fprintf fmt "@\n@[<v 1><ty_app@ id=\"%i\"/>" (ts_hash ts);
    List.iter (save_ty fmt) l;
    fprintf fmt "@]@\n</ty_app>"

let save_theory provers fmt t =
  fprintf fmt
    "@\n@[<v 1><theory@ %a@ verified=\"%b\"@ expanded=\"%b\">"
    save_ident t.theory_name
    t.theory_verified t.theory_expanded;
  Ident.Slab.iter (save_label fmt) t.theory_name.Ident.id_label;
  List.iter (save_goal provers fmt) t.theory_goals;
  fprintf fmt "@]@\n</theory>"

let save_file provers fmt _ f =
  fprintf fmt
    "@\n@[<v 1><file@ name=\"%a\"@ %averified=\"%b\"@ expanded=\"%b\">"
    save_string f.file_name (opt "format")
    f.file_format f.file_verified f.file_expanded;
  List.iter (save_theory provers fmt) f.file_theories;
  fprintf fmt "@]@\n</file>"

let save_prover fmt p (provers,id) =
  fprintf fmt "@\n@[<v 1><prover@ id=\"%i\"@ \
name=\"%a\"@ version=\"%a\"%a/>@]"
    id save_string p.C.prover_name save_string p.C.prover_version
    (fun fmt s -> if s <> "" then fprintf fmt "@ alternative=\"%a\""
        save_string s)
    p.C.prover_altern;
  Mprover.add p id provers, id+1

let save fname _config session =
  let ch = open_out fname in
  let fmt = formatter_of_out_channel ch in
  fprintf fmt "<?xml version=\"1.0\" encoding=\"UTF-8\"?>@\n";
  fprintf fmt "<!DOCTYPE why3session PUBLIC \"-//Why3//proof session v2//EN\" \"http://why3.lri.fr/why3session.dtd\">@\n";
(*
  let rel_file = Sysutil.relativize_filename !session_dir_for_save fname in
  fprintf fmt "@[<v 1><why3session@ name=\"%a\" shape_version=\"%d\">"
    save_string rel_file session.session_shape_version;
*)
  fprintf fmt "@[<v 1><why3session shape_version=\"%d\">"
    session.session_shape_version;
  let provers,_ = Sprover.fold (save_prover fmt) (get_used_provers session)
    (Mprover.empty,0) in
  PHstr.iter (save_file provers fmt) session.session_files;
  fprintf fmt "@]@\n</why3session>";
  fprintf fmt "@.";
  close_out ch

let save_session config session =
  let f = Filename.concat session.session_dir db_filename in
  Sysutil.backup_file f;
  session_dir_for_save := session.session_dir;
  save f config session

(*******************************)
(*          explanations       *)
(*******************************)

let expl_regexp = Str.regexp "expl:\\(.*\\)"

let check_expl lab acc =
  let lab = lab.Ident.lab_string in
  if Str.string_match expl_regexp lab 0
  then Some (Str.matched_group 1 lab)
  else acc

let check_expl lab =
  if Ident.Slab.mem Split_goal.stop_split lab then None
  else Ident.Slab.fold check_expl lab None

let rec get_expl_fmla acc f =
  if f.t_ty <> None then acc else
  let res = check_expl f.Term.t_label in
  if res = None then match f.t_node with
    | Term.Ttrue | Term.Tfalse | Term.Tapp _ -> acc
    | Term.Tbinop(Term.Timplies,_,f) -> get_expl_fmla acc f
    | Term.Tlet _ | Term.Tcase _ | Term.Tquant (Term.Tforall, _) ->
        Term.t_fold get_expl_fmla acc f
    | _ -> raise Exit
  else if acc = None then res else raise Exit

let get_expl_fmla f = try get_expl_fmla None f with Exit -> None

let goal_expl_task ~root task =
  let gid = (Task.task_goal task).Decl.pr_name in
  let info =
    let fmla = Task.task_goal_fmla task in
    let res = get_expl_fmla fmla in
    if res <> None || not root then res else check_expl gid.Ident.id_label
  in
  gid, info, task


(*****************************)
(*   update verified field   *)
(*****************************)
type 'a notify = 'a any -> unit
let notify : 'a notify = fun _ -> ()

let file_verified f =
  List.for_all (fun t -> t.theory_verified) f.file_theories

let theory_verified t =
  List.for_all (fun g -> g.goal_verified) t.theory_goals

let transf_verified t =
  List.for_all (fun g -> g.goal_verified) t.transf_goals

let metas_verified m = m.metas_goal.goal_verified

let proof_verified a =
  (not a.proof_obsolete) &&
    match a.proof_state with
      | Done { Call_provers.pr_answer = Call_provers.Valid} -> true
      | _ -> false

let goal_verified g =
    try
      PHprover.iter
        (fun _ a ->
          if proof_verified a
          then raise Exit)
        g.goal_external_proofs;
      PHstr.iter
        (fun _ t -> if t.transf_verified then raise Exit)
        g.goal_transformations;
      Mmetas_args.iter
        (fun _ t -> if t.metas_verified then raise Exit)
        g.goal_metas;
      false
    with Exit -> true

let check_file_verified notify f =
  let b = file_verified f in
  if f.file_verified <> b then begin
    f.file_verified <- b;
    notify (File f)
  end

let check_theory_proved notify t =
  let b = theory_verified t in
  if t.theory_verified <> b then begin
    t.theory_verified <- b;
    notify (Theory t);
    check_file_verified notify t.theory_parent
  end

let rec check_goal_proved notify g =
  let b = goal_verified g in
  if g.goal_verified <> b then begin
    g.goal_verified <- b;
    notify (Goal g);
    match g.goal_parent with
      | Parent_theory t -> check_theory_proved notify t
      | Parent_transf t -> check_transf_proved notify t
      | Parent_metas t -> check_metas_proved notify t
  end

and check_transf_proved notify t =
  let b = transf_verified t in
  if t.transf_verified <> b then begin
    t.transf_verified <- b;
    notify (Transf t);
    check_goal_proved notify t.transf_parent
  end


and check_metas_proved notify m =
  let b = metas_verified m in
  if m.metas_verified <> b then begin
    m.metas_verified <- b;
    notify (Metas m);
    check_goal_proved notify m.metas_parent
  end

(******************************)
(* raw additions to the model *)
(******************************)
type 'a keygen = ?parent:'a -> unit -> 'a

let add_external_proof
    ?(notify=notify)
    ~(keygen:'a keygen) ~obsolete
    ~archived ~timelimit ~memlimit ~edit (g:'a goal) p result =
  assert (edit <> Some "");
  let key = keygen ~parent:g.goal_key () in
  let a = { proof_prover = p;
            proof_parent = g;
            proof_key = key;
            proof_obsolete = obsolete;
            proof_archived = archived;
            proof_state = result;
            proof_timelimit = timelimit;
            proof_memlimit = memlimit;
            proof_edited_as = edit;
          }
  in
  PHprover.replace g.goal_external_proofs p a;
  check_goal_proved notify g;
  a

let remove_external_proof ?(notify=notify) a =
  let g = a.proof_parent in
  PHprover.remove g.goal_external_proofs a.proof_prover;
  check_goal_proved notify g


let set_proof_state ?(notify=notify) ~obsolete ~archived res a =
  a.proof_state <- res;
  a.proof_obsolete <- obsolete;
  a.proof_archived <- archived;
  notify (Proof_attempt a);
  check_goal_proved notify a.proof_parent

let change_prover a p =
  let g = a.proof_parent in
  PHprover.remove g.goal_external_proofs a.proof_prover;
  PHprover.add g.goal_external_proofs p a;
  a.proof_prover <- p;
  a.proof_obsolete <- true

let set_edited_as edited_as a = a.proof_edited_as <- edited_as

let set_timelimit timelimit a = a.proof_timelimit <- timelimit
let set_memlimit memlimit a = a.proof_memlimit <- memlimit

let set_obsolete ?(notify=notify) a =
  a.proof_obsolete <- true;
  notify (Proof_attempt a);
  check_goal_proved notify a.proof_parent

let set_archived a b = a.proof_archived <- b

let get_edited_as_abs session pr =
  Opt.map (Filename.concat session.session_dir) pr.proof_edited_as

(* [raw_add_goal parent name expl sum t] adds a goal to the given parent
   DOES NOT record the new goal in its parent, thus this should not be exported
*)
let raw_add_no_task ~(keygen:'a keygen) ~(expanded:bool) parent name expl sum shape =
  let parent_key = match parent with
    | Parent_theory mth -> mth.theory_key
    | Parent_transf mtr -> mtr.transf_key
    | Parent_metas  mms -> mms.metas_key
  in
  let key = keygen ~parent:parent_key () in
  let goal = { goal_name = name;
               goal_expl = expl;
               goal_parent = parent;
               goal_task = None ;
               goal_checksum = sum;
               goal_shape = shape;
               goal_key = key;
               goal_external_proofs = PHprover.create 7;
               goal_transformations = PHstr.create 3;
               goal_metas = Mmetas_args.empty;
               goal_verified = false;
               goal_expanded = expanded;
             }
  in
  goal

let raw_add_task ~version ~(keygen:'a keygen) ~(expanded:bool) parent name expl t =
  let parent_key = match parent with
    | Parent_theory mth -> mth.theory_key
    | Parent_transf mtr -> mtr.transf_key
    | Parent_metas  mms -> mms.metas_key
  in
  let key = keygen ~parent:parent_key () in
  let sum = Termcode.task_checksum ~version t in
  let shape = Termcode.t_shape_buf ~version
    (Task.task_goal_fmla t) in
  let goal = { goal_name = name;
               goal_expl = expl;
               goal_parent = parent;
               goal_task = Some t ;
               goal_checksum = sum;
               goal_shape = shape;
               goal_key = key;
               goal_external_proofs = PHprover.create 7;
               goal_transformations = PHstr.create 3;
               goal_metas = Mmetas_args.empty;
               goal_verified = false;
               goal_expanded = expanded;
             }
  in
  goal


(* [raw_add_transformation g name adds a transformation to the given goal g
   Adds no subgoals, thus this should not be exported
*)
let raw_add_transformation ~(keygen:'a keygen) ~(expanded:bool) g name =
  let parent = g.goal_key in
  let key = keygen ~parent () in
  let tr = { transf_name = name;
             transf_parent = g;
             transf_verified = false;
             transf_key = key;
             transf_goals = [];
             transf_expanded = expanded;
           }
  in
  PHstr.replace g.goal_transformations name tr;
  tr

let raw_add_metas ~(keygen:'a keygen) ~(expanded:bool) g added idpos =
  let parent = g.goal_key in
  let key = keygen ~parent () in
  let ms = { metas_added = added;
             metas_idpos = idpos;
             metas_parent = g;
             metas_verified = false;
             metas_key = key;
             metas_goal = g;
             metas_expanded = expanded;
           }
  in
  g.goal_metas <- Mmetas_args.add added ms g.goal_metas;
  ms

let raw_add_theory ~(keygen:'a keygen) ~(expanded:bool) mfile thname =
  let parent = mfile.file_key in
  let key = keygen ~parent () in
  let mth = { theory_name = thname;
              theory_key = key;
              theory_parent = mfile;
              theory_goals = [];
              theory_verified = false;
              theory_expanded = expanded;
            }
  in
  mth

let raw_add_file ~(keygen:'a keygen) ~(expanded:bool) session f fmt =
  let key = keygen () in
  let mfile = { file_name = f;
                file_key = key;
                file_format = fmt;
                file_theories = [];
                file_verified = false;
                file_expanded = expanded;
                file_parent  = session;
              }
  in
  PHstr.replace session.session_files f mfile;
  mfile


(****************************)
(*     session opening      *)
(****************************)

exception LoadError of Xml.element * string
(** LoadError (xml,messg) *)

let bool_attribute field r def =
  try
    match List.assoc field r.Xml.attributes with
      | "true" -> true
      | "false" -> false
      | _ -> assert false
  with Not_found -> def

let int_attribute_def field r def =
  try
    int_of_string (List.assoc field r.Xml.attributes)
  with Not_found | Invalid_argument _ -> def

let int_attribute field r =
  try
    int_of_string (List.assoc field r.Xml.attributes)
  with Not_found | Invalid_argument _ ->
    (** TODO: use real error *)
    eprintf "[Error] missing required attribute '%s' from element '%s'@."
      field r.Xml.name;
    assert false

let string_attribute_def field r def=
  try
    List.assoc field r.Xml.attributes
  with Not_found -> def

let string_attribute field r =
  try
    List.assoc field r.Xml.attributes
  with Not_found ->
    eprintf "[Error] missing required attribute '%s' from element '%s'@."