(*  Title:      Pure/Thy/thy_info.ML

    ID:         $Id$

    Author:     Markus Wenzel, TU Muenchen

Theory loader database, including theory and file dependencies.

*)

signature BASIC_THY_INFO =

sig

  val theory: string -> theory

  val theory_of_sign: Sign.sg -> theory

  val theory_of_thm: thm -> theory

(*val use: string -> unit*)             (*exported later*)

  val time_use: string -> unit

  val touch_thy: string -> unit

  val use_thy: string -> unit

  val update_thy: string -> unit

  val remove_thy: string -> unit

  val time_use_thy: string -> unit

  val use_thy_only: string -> unit

end;

signature THY_INFO =

sig

  include BASIC_THY_INFO

  val names: unit -> string list

  val get_theory: string -> theory

  val put_theory: theory -> unit

  val get_preds: string -> string list

  val loaded_files: string -> (Path.T * File.info) list

  val load_file: bool -> Path.T -> unit

  val use_path: Path.T -> unit

  val use: string -> unit

  val begin_theory: string -> string list -> (Path.T * bool) list -> theory

  val end_theory: theory -> theory

  val finish: unit -> unit

  val register_theory: theory -> unit

end;

structure ThyInfo: THY_INFO =

struct

(** thy database **)

(* messages *)

fun gen_msg txt [] = txt

  | gen_msg txt names = txt ^ " " ^ commas_quote names;

fun loader_msg txt names = gen_msg ("Theory loader: " ^ txt) names;

val show_path = space_implode " via " o map quote;

fun cycle_msg name names = loader_msg ("cyclic dependency of " ^ show_path (name :: names)) [];

(* derived graph operations *)

fun add_deps name parents G =

  foldl (fn (H, parent) => Graph.add_edge_acyclic (parent, name) H) (G, parents)

    handle Graph.CYCLES namess => error (cat_lines (map (cycle_msg name) namess));

fun del_deps name G =

  foldl (fn (H, parent) => Graph.del_edge (parent, name) H) (G, Graph.imm_preds G name);

fun update_node name parents entry G =

  add_deps name parents

    (if can (Graph.get_node G) name then del_deps name G else Graph.new_node (name, entry) G);

(* thy database *)

type deps =

  {present: bool, outdated: bool,

    master: (Path.T * File.info) list, files: (Path.T * (Path.T * File.info) option) list};

fun make_deps present outdated master files =

  {present = present, outdated = outdated, master = master, files = files}: deps;

type thy = deps option * theory option;

local

  val database = ref (Graph.empty: thy Graph.T);

in

  fun get_thys () = ! database;

  fun change_thys f = database := (f (! database));

end;

(* access thy graph *)

fun thy_graph f x = f (get_thys ()) x;

fun get_names () = Graph.keys (get_thys ());

(* access thy *)

fun lookup_thy name = Some (thy_graph Graph.get_node name) handle Graph.UNDEFINED _ => None;

fun get_thy name =

  (case lookup_thy name of

    Some thy => thy

  | None => error (loader_msg "nothing known about theory" [name]));

fun change_thy name f = (get_thy name; change_thys (Graph.map_node name f));

(* access deps *)

val lookup_deps = apsome #1 o lookup_thy;

val get_deps = #1 o get_thy;

fun change_deps name f = change_thy name (fn (deps, x) => (f deps, x));

fun is_finished name = is_none (get_deps name);

fun get_files name = (case get_deps name of Some {files, ...} => files | _ => []);

val loaded_files = mapfilter #2 o get_files;

fun get_preds name =

  (thy_graph Graph.imm_preds name) handle Graph.UNDEFINED _ =>

    error (loader_msg "nothing known about theory" [name]);

(* access theory *)

fun get_theory name =

  (case get_thy name of

    (_, Some theory) => theory

  | _ => error (loader_msg "undefined theory entry for" [name]));

val theory_of_sign = get_theory o Sign.name_of;

val theory_of_thm = theory_of_sign o Thm.sign_of_thm;

fun put_theory theory =

  change_thy (PureThy.get_name theory) (fn (deps, _) => (deps, Some theory));

(** thy operations **)

(* maintain 'outdated' flag *)

fun is_outdated name =

  (case lookup_deps name of

    Some (Some {outdated, ...}) => outdated

  | _ => false);

fun outdate_thy name =

  if is_finished name then ()

  else change_deps name (apsome (fn {present, outdated = _, master, files} =>

    make_deps present true master files));

fun touch_thy name =

  if is_outdated name then ()

  else if is_finished name then warning (loader_msg "tried to touch finished theory" [name])

  else

    (case filter_out is_outdated (thy_graph Graph.all_succs [name]) \ name of

      [] => outdate_thy name

    | names =>

       (warning (loader_msg "the following theories become out-of-date:" names);

        seq outdate_thy names; outdate_thy name));

val untouch_deps = apsome (fn {present, outdated = _, master, files}: deps =>

  make_deps present false master files);

(* load_thy *)

fun required_by [] = ""

  | required_by initiators = " (required by " ^ show_path (rev initiators) ^ ")";

fun load_thy ml time initiators dir name parents =

  let

    val _ = if name mem_string initiators then error (cycle_msg name (rev initiators)) else ();

    val _ = writeln ("Loading theory " ^ quote name ^ required_by initiators);

    val _ = seq touch_thy (thy_graph Graph.all_succs [name]);

    val master = ThyLoad.load_thy dir name ml time;

    val files = get_files name;

    val missing_files = mapfilter (fn (path, None) => Some (Path.pack path) | _ => None) files;

  in

    if null missing_files then ()

    else warning (loader_msg "unresolved dependencies of theory" [name] ^

      "\nfile(s): " ^ commas_quote missing_files);

    change_deps name (fn _ => Some (make_deps true false master files))

  end;

(* load_file *)

fun run_file path =

  let

    fun provide name info (deps as Some {present, outdated, master, files}) =

          if exists (equal path o #1) files then

            Some (make_deps present outdated master (overwrite (files, (path, Some info))))

          else (warning (loader_msg "undeclared dependency of theory" [name] ^

            " on file: " ^ quote (Path.pack path)); deps)

      | provide _ _ None = None;

  in

    (case apsome PureThy.get_name (Context.get_context ()) of

      None => (ThyLoad.load_file path; ())

    | Some name =>

        if is_some (lookup_thy name) then change_deps name (provide name (ThyLoad.load_file path))

        else (ThyLoad.load_file path; ()))

  end;

fun load_file false path = run_file path

  | load_file true path =

      let val name = Path.pack path in

        timeit (fn () =>

         (writeln ("\n**** Starting file " ^ quote name ^ " ****");

          run_file path;

          writeln ("**** Finished file " ^ quote name ^ " ****\n")))

      end;

val use_path = load_file false;

val use = use_path o Path.unpack;

val time_use = load_file true o Path.unpack;

(* require_thy *)

fun init_deps master files = Some (make_deps false false master (map (rpair None) files));

fun load_deps dir name ml =

  let val (master, (parents, files)) = ThyLoad.deps_thy dir name ml

  in (Some (init_deps master files), parents) end;

fun file_current (_, None) = false

  | file_current (path, info) = info = ThyLoad.check_file path;

fun current_deps ml strict dir name =

  (case lookup_deps name of

    None => (false, load_deps dir name ml)

  | Some deps =>

      let val same_deps = (None, thy_graph Graph.imm_preds name) in

        (case deps of

          None => (true, same_deps)

        | Some {present, outdated, master, files} =>

            if present andalso not strict then (true, same_deps)

            else

              let val master' = ThyLoad.check_thy dir name ml in

                if master <> master' then (false, load_deps dir name ml)

                else (not outdated andalso forall file_current files, same_deps)

              end)

      end);

fun require_thy ml time strict keep_strict initiators prfx (visited, str) =

  let

    val path = Path.expand (Path.unpack str);

    val name = Path.pack (Path.base path);

  in

    if name mem_string visited then (visited, (true, name))

    else

      let

        val dir = Path.append prfx (Path.dir path);

        val req_parent =

          require_thy ml time (strict andalso keep_strict) keep_strict (name :: initiators) dir;

        val (current, (new_deps, parents)) = current_deps ml strict dir name handle ERROR =>

          error (loader_msg "The error(s) above occurred while examining theory" [name] ^

            (if null initiators then "" else "\n" ^ required_by initiators));

        val (visited', parent_results) = foldl_map req_parent (name :: visited, parents);

        val result =

          if current andalso forall #1 parent_results then true

          else

            ((case new_deps of

              Some deps => change_thys (update_node name parents (untouch_deps deps, None))

            | None => ());

              load_thy ml time initiators dir name parents;

              false);

      in (visited', (result, name)) end

  end;

fun gen_use_thy req s =

  let val (_, (_, name)) = req [] Path.current ([], s)

  in Context.context (get_theory name) end;

val weak_use_thy = gen_use_thy (require_thy true false false false);

val use_thy      = gen_use_thy (require_thy true false true false);

val update_thy   = gen_use_thy (require_thy true false true true);

val time_use_thy = gen_use_thy (require_thy true true true false);

val use_thy_only = gen_use_thy (require_thy false false true false);

(* remove_thy *)

fun remove_thy name =

  if is_finished name then error (loader_msg "cannot remove finished theory" [name])

  else

    let val succs = thy_graph Graph.all_succs [name] in

      writeln (loader_msg "removing" succs);

      change_thys (Graph.del_nodes succs)

    end;

(* begin / end theory *)

fun begin_theory name parents paths =

  let

    val _ =

      if is_some (lookup_thy name) andalso is_finished name then

        error (loader_msg "cannot change finished theory" [name])

      else ();

    val _ = (map Path.basic parents; seq weak_use_thy parents);

    val theory = PureThy.begin_theory name (map get_theory parents);

    val _ = change_thys (update_node name parents (init_deps [] [], Some theory));

    val use_paths = mapfilter (fn (x, true) => Some x | _ => None) paths;

  in Context.setmp (Some theory) (seq use_path) use_paths; theory end;

fun end_theory theory =

  let val theory' = PureThy.end_theory theory

  in put_theory theory'; theory' end;

(* finish all theories *)

fun finish () = change_thys (Graph.map_nodes (fn (_, entry) => (None, entry)));

(* register existing theories *)

fun register_theory theory =

  let

    val name = PureThy.get_name theory;

    val parents = Theory.parents_of theory;

    val parent_names = map PureThy.get_name parents;

    fun err txt bads =

      error (loader_msg txt bads ^ "\n" ^ gen_msg "cannot register theory" [name]);

    val nonfinished = filter_out is_finished parent_names;

    fun get_variant (x, y_name) =

      if Theory.eq_thy (x, get_theory y_name) then None

      else Some y_name;

    val variants = mapfilter get_variant (parents ~~ parent_names);

    fun register G =

      (Graph.new_node (name, (None, Some theory)) G

        handle Graph.DUPLICATE _ => err "duplicate theory entry" [])

      |> add_deps name parent_names;

  in

    if not (null nonfinished) then err "non-finished parent theories" nonfinished

    else if not (null variants) then err "different versions of parent theories" variants

    else change_thys register

  end;

(*final declarations of this structure*)

val theory = get_theory;

val names = get_names;

end;

structure BasicThyInfo: BASIC_THY_INFO = ThyInfo;

open BasicThyInfo;