(*  Title:      Pure/Thy/thy_info.ML

    Author:     Markus Wenzel, TU Muenchen

Main part of theory loader database, including handling of theory and

file dependencies.

*)

signature THY_INFO =

sig

  datatype action = Update | Outdate | Remove

  val str_of_action: action -> string

  val add_hook: (action -> string -> unit) -> unit

  val get_names: unit -> string list

  val known_thy: string -> bool

  val check_known_thy: string -> bool

  val if_known_thy: (string -> unit) -> string -> unit

  val lookup_theory: string -> theory option

  val get_theory: string -> theory

  val is_finished: string -> bool

  val master_directory: string -> Path.T

  val loaded_files: string -> Path.T list

  val get_parents: string -> string list

  val touch_thy: string -> unit

  val touch_child_thys: string -> unit

  val thy_ord: theory * theory -> order

  val remove_thy: string -> unit

  val kill_thy: string -> unit

  val provide_file: Path.T -> string -> unit

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

  val exec_file: bool -> Path.T -> Context.generic -> Context.generic

  val use: string -> unit

  val time_use: string -> unit

  val use_thys: string list -> unit

  val use_thy: string -> unit

  val time_use_thy: string -> unit

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

  val end_theory: theory -> unit

  val register_thy: string -> unit

  val register_theory: theory -> unit

  val finish: unit -> unit

end;

structure Thy_Info: THY_INFO =

struct

(** theory loader actions and hooks **)

datatype action = Update | Outdate | Remove;

val str_of_action = fn Update => "Update" | Outdate => "Outdate" | Remove => "Remove";

local

  val hooks = Unsynchronized.ref ([]: (action -> string -> unit) list);

in

  fun add_hook f = CRITICAL (fn () => Unsynchronized.change hooks (cons f));

  fun perform action name = List.app (fn f => (try (fn () => f action name) (); ())) (! hooks);

end;

(** thy database **)

(* messages *)

fun loader_msg txt [] = "Theory loader: " ^ txt

  | loader_msg txt names = "Theory loader: " ^ txt ^ " " ^ commas_quote names;

val show_path = space_implode " via " o map quote;

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

(* derived graph operations *)

fun add_deps name parents G = Graph.add_deps_acyclic (name, parents) G

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

fun upd_deps name entry G =

  fold (fn parent => Graph.del_edge (parent, name)) (Graph.imm_preds G name) G

  |> Graph.map_node name (K entry);

fun new_deps name parents entry G =

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

  |> add_deps name parents;

(* thy database *)

type deps =

  {update_time: int,                      (*symbolic time of update; negative value means outdated*)

    master: (Path.T * File.ident) option, (*master dependencies for thy file*)

    text: string list,                    (*source text for thy*)

    parents: string list,                 (*source specification of parents (partially qualified)*)

      (*auxiliary files: source path, physical path + identifier*)

    files: (Path.T * (Path.T * File.ident) option) list};

fun make_deps update_time master text parents files : deps =

  {update_time = update_time, master = master, text = text, parents = parents, files = files};

fun init_deps master text parents files =

  SOME (make_deps ~1 master text parents (map (rpair NONE) files));

fun master_dir NONE = Path.current

  | master_dir (SOME (path, _)) = Path.dir path;

fun master_dir' (d: deps option) = the_default Path.current (Option.map (master_dir o #master) d);

fun master_dir'' d = the_default Path.current (Option.map master_dir' d);

fun base_name s = Path.implode (Path.base (Path.explode s));

type thy = deps option * theory option;

local

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

in

  fun get_thys () = ! database;

  fun change_thys f = CRITICAL (fn () => Unsynchronized.change database f);

end;

(* access thy graph *)

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

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

(* access thy *)

fun lookup_thy name =

  SOME (thy_graph Graph.get_node name) handle Graph.UNDEF _ => NONE;

val known_thy = is_some o lookup_thy;

fun check_known_thy name = known_thy name orelse (warning ("Unknown theory " ^ quote name); false);

fun if_known_thy f name = if check_known_thy name then f name else ();

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 = CRITICAL (fn () =>

  (get_thy name; change_thys (Graph.map_node name f)));

(* access deps *)

val lookup_deps = Option.map #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));

val is_finished = is_none o get_deps;

val master_directory = master_dir' o get_deps;

fun loaded_files name =

  (case get_deps name of

    NONE => []

  | SOME {master, files, ...} =>

      (case master of SOME (thy_path, _) => [thy_path] | NONE => []) @

      (map_filter (Option.map #1 o #2) files));

fun get_parents name =

  thy_graph Graph.imm_preds name handle Graph.UNDEF _ =>

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

(* access theory *)

fun lookup_theory name =

  (case lookup_thy name of

    SOME (_, SOME thy) => SOME thy

  | _ => NONE);

fun get_theory name =

  (case lookup_theory name of

    SOME theory => theory

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

(** thy operations **)

(* check state *)

fun check_unfinished fail name =

  if known_thy name andalso is_finished name then

    fail (loader_msg "cannot update finished theory" [name])

  else ();

fun check_files name =

  let

    val files = (case get_deps name of SOME {files, ...} => files | NONE => []);

    val missing_files = map_filter (fn (path, NONE) => SOME (Path.implode path) | _ => NONE) files;

    val _ = null missing_files orelse

      error (loader_msg "unresolved dependencies of theory" [name] ^

        " on file(s): " ^ commas_quote missing_files);

  in () end;

(* maintain update_time *)

local

fun is_outdated name =

  (case lookup_deps name of

    SOME (SOME {update_time, ...}) => update_time < 0

  | _ => false);

fun unfinished name =

  if is_finished name then (warning (loader_msg "tried to touch finished theory" [name]); NONE)

  else SOME name;

in

fun outdate_thy name =

  if is_finished name orelse is_outdated name then ()

  else CRITICAL (fn () =>

   (change_deps name (Option.map (fn {master, text, parents, files, ...} =>

    make_deps ~1 master text parents files)); perform Outdate name));

fun touch_thys names =

  List.app outdate_thy (thy_graph Graph.all_succs (map_filter unfinished names));

fun touch_thy name = touch_thys [name];

fun touch_child_thys name = touch_thys (thy_graph Graph.imm_succs name);

end;

(* management data *)

structure Management_Data = Theory_Data

(

  type T =

    Task_Queue.group option *   (*worker thread group*)

    int;                        (*abstract update time*)

  val empty = (NONE, 0);

  fun extend _ = empty;

  fun merge _ = empty;

);

val thy_ord = int_ord o pairself (#2 o Management_Data.get);

(* pending proofs *)

fun join_thy name =

  (case lookup_theory name of

    NONE => ()

  | SOME thy => PureThy.join_proofs thy);

fun cancel_thy name =

  (case lookup_theory name of

    NONE => ()

  | SOME thy =>

      (case #1 (Management_Data.get thy) of

        NONE => ()

      | SOME group => Future.cancel_group group));

(* remove theory *)

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];

      val _ = List.app cancel_thy succs;

      val _ = priority (loader_msg "removing" succs);

      val _ = CRITICAL (fn () =>

        (List.app (perform Remove) succs; change_thys (Graph.del_nodes succs)));

    in () end;

val kill_thy = if_known_thy remove_thy;

(* load_file *)

local

fun provide path name info (SOME {update_time, master, text, parents, files}) =

     (if AList.defined (op =) files path then ()

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

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

      SOME (make_deps update_time master text parents

        (AList.update (op =) (path, SOME info) files)))

  | provide _ _ _ NONE = NONE;

fun run_file path =

  (case Option.map (Context.theory_name o Context.the_theory) (Context.thread_data ()) of

    NONE => (Thy_Load.load_ml Path.current path; ())

  | SOME name =>

      (case lookup_deps name of

        SOME deps =>

          change_deps name (provide path name (Thy_Load.load_ml (master_dir' deps) path))

      | NONE => (Thy_Load.load_ml Path.current path; ())));

in

fun provide_file path name =

  let

    val dir = master_directory name;

    val _ = check_unfinished error name;

  in

    (case Thy_Load.check_file dir path of

      SOME path_info => change_deps name (provide path name path_info)

    | NONE => error ("Could not find file " ^ quote (Path.implode path)))

  end;

fun load_file time path =

  if time then

    let val name = Path.implode path in

      timeit (fn () =>

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

        run_file path;

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

    end

  else run_file path;

fun exec_file time path = ML_Context.exec (fn () => load_file time path);

val use = load_file false o Path.explode;

val time_use = load_file true o Path.explode;

end;

(* load_thy *)

fun required_by _ [] = ""

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

fun load_thy time upd_time initiators name =

  let

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

    val (pos, text, _) =

      (case get_deps name of

        SOME {master = SOME (master_path, _), text as _ :: _, files, ...} =>

          (Path.position master_path, text, files)

      | _ => error (loader_msg "corrupted dependency information" [name]));

    val _ = touch_thy name;

    val _ = CRITICAL (fn () =>

      change_deps name (Option.map (fn {master, text, parents, files, ...} =>

        make_deps upd_time master text parents files)));

    val after_load = Outer_Syntax.load_thy name pos text (time orelse ! Output.timing);

    val _ =

      CRITICAL (fn () =>

       (change_deps name

          (Option.map (fn {update_time, master, parents, files, ...} =>

            make_deps update_time master [] parents files));

        perform Update name));

  in after_load end;

(* scheduling loader tasks *)

datatype task = Task of (unit -> unit -> unit) | Finished | Running;

fun task_finished Finished = true | task_finished _ = false;

local

fun schedule_futures task_graph = uninterruptible (fn _ => fn () =>

  let

    val tasks = Graph.topological_order task_graph |> map_filter (fn name =>

      (case Graph.get_node task_graph name of Task body => SOME (name, body) | _ => NONE));

    val par_proofs = ! parallel_proofs >= 1;

    fun fork (name, body) tab =

      let

        val deps = Graph.imm_preds task_graph name

          |> map_filter (fn parent =>

            (case Symtab.lookup tab parent of SOME future => SOME (parent, future) | NONE => NONE));

        fun failed (parent, future) = if can Future.join future then NONE else SOME parent;

        val future = Future.fork_deps (map #2 deps) (fn () =>

          (case map_filter failed deps of

            [] => body ()

          | bad => error (loader_msg

              ("failed to load " ^ quote name ^ " (unresolved " ^ commas_quote bad ^ ")") [])));

        val future' =

          if par_proofs then future

          else Future.map (fn after_load => (after_load (); fn () => ())) future;

      in Symtab.update (name, future') tab end;

    val futures = fold fork tasks Symtab.empty;

    val failed = tasks |> maps (fn (name, _) =>

      let

        val after_load = Future.join (the (Symtab.lookup futures name));

        val _ = join_thy name;

        val _ = after_load ();

      in [] end handle exn => [(name, exn)]) |> rev;

    val _ = List.app (kill_thy o #1) failed;

    val _ = Exn.release_all (map (Exn.Exn o #2) failed);

  in () end) ();

fun schedule_seq tasks =

  Graph.topological_order tasks

  |> List.app (fn name =>

    (case Graph.get_node tasks name of

      Task body =>

        let val after_load = body ()

        in after_load () handle exn => (kill_thy name; reraise exn) end

    | _ => ()));

in

fun schedule_tasks tasks =

  if not (Multithreading.enabled ()) then schedule_seq tasks

  else if Multithreading.self_critical () then

     (warning (loader_msg "no multithreading within critical section" []);

      schedule_seq tasks)

  else schedule_futures tasks;

end;

(* require_thy -- checking database entries wrt. the file-system *)

local

fun check_ml master (src_path, info) =

  let val info' =

    (case info of NONE => NONE

    | SOME (_, id) =>

        (case Thy_Load.check_ml (master_dir master) src_path of NONE => NONE

        | SOME (path', id') => if id <> id' then NONE else SOME (path', id')))

  in (src_path, info') end;

fun check_deps dir name =

  (case lookup_deps name of

    SOME NONE => (true, NONE, get_parents name)

  | NONE =>

      let val {master, text, imports = parents, uses = files} = Thy_Load.deps_thy dir name

      in (false, init_deps (SOME master) text parents files, parents) end

  | SOME (SOME {update_time, master, text, parents, files}) =>

      let

        val (thy_path, thy_id) = Thy_Load.check_thy dir name;

        val master' = SOME (thy_path, thy_id);

      in

        if Option.map #2 master <> SOME thy_id then

          let val {text = text', imports = parents', uses = files', ...} =

            Thy_Load.deps_thy dir name;

          in (false, init_deps master' text' parents' files', parents') end

        else

          let

            val files' = map (check_ml master') files;

            val current = update_time >= 0 andalso can get_theory name

              andalso forall (is_some o snd) files';

            val update_time' = if current then update_time else ~1;

            val deps' = SOME (make_deps update_time' master' text parents files');

          in (current, deps', parents) end

      end);

fun read_text (SOME {update_time, master = master as SOME (path, _), text = _, parents, files}) =

  SOME (make_deps update_time master (explode (File.read path)) parents files);

in

fun require_thys time initiators dir strs tasks =

      fold_map (require_thy time initiators dir) strs tasks |>> forall I

and require_thy time initiators dir str tasks =

  let

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

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

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

    val _ = member (op =) initiators name andalso error (cycle_msg initiators);

  in

    (case try (Graph.get_node tasks) name of

      SOME task => (task_finished task, tasks)

    | NONE =>

        let

          val (current, deps, parents) = check_deps dir' name

            handle ERROR msg => cat_error msg

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

                required_by "\n" initiators);

          val parent_names = map base_name parents;

          val (parents_current, tasks_graph') =

            require_thys time (name :: initiators)

              (Path.append dir (master_dir' deps)) parents tasks;

          val all_current = current andalso parents_current;

          val _ = if not all_current andalso known_thy name then outdate_thy name else ();

          val entry =

            if all_current then (deps, SOME (get_theory name))

            else (read_text deps, NONE);

          val _ = change_thys (new_deps name parent_names entry);

          val upd_time = serial ();

          val tasks_graph'' = tasks_graph' |> new_deps name parent_names

           (if all_current then Finished

            else Task (fn () => load_thy time upd_time initiators name));

        in (all_current, tasks_graph'') end)

  end;

end;

(* use_thy etc. *)

local

fun gen_use_thy' req dir arg =

  schedule_tasks (snd (req [] dir arg Graph.empty));

fun gen_use_thy req str =

  let val name = base_name str in

    check_unfinished warning name;

    gen_use_thy' req Path.current str

  end;

in

val use_thys_dir = gen_use_thy' (require_thys false);

val use_thys = use_thys_dir Path.current;

val use_thy = gen_use_thy (require_thy false);

val time_use_thy = gen_use_thy (require_thy true);

end;

(* begin / end theory *)

fun begin_theory name parents uses int =

  let

    val parent_names = map base_name parents;

    val dir = master_dir'' (lookup_deps name);

    val _ = check_unfinished error name;

    val _ = if int then use_thys_dir dir parents else ();

    val theory = Theory.begin_theory name (map get_theory parent_names);

    val deps =

      if known_thy name then get_deps name

      else init_deps NONE [] parents (map #1 uses);

    val _ = change_thys (new_deps name parent_names (deps, NONE));

    val update_time = (case deps of NONE => 0 | SOME {update_time, ...} => update_time);

    val update_time = if update_time > 0 then update_time else serial ();

    val theory' = theory

      |> Management_Data.put (Future.worker_group (), update_time)

      |> Present.begin_theory update_time dir uses;

    val uses_now = map_filter (fn (x, true) => SOME x | _ => NONE) uses;

    val theory'' =

      fold (fn x => Context.theory_map (exec_file false x) o Theory.checkpoint) uses_now theory';

  in theory'' end;

fun end_theory theory =

  let

    val name = Context.theory_name theory;

    val _ = check_files name;

    val theory' = Theory.end_theory theory;

    val _ = change_thy name (fn (deps, _) => (deps, SOME theory'));

  in () end;

(* register existing theories *)

fun register_thy name =

  let

    val _ = priority ("Registering theory " ^ quote name);

    val thy = get_theory name;

    val _ = map get_theory (get_parents name);

    val _ = check_unfinished error name;

    val _ = touch_thy name;

    val master = #master (Thy_Load.deps_thy Path.current name);

    val upd_time = #2 (Management_Data.get thy);

  in

    CRITICAL (fn () =>

     (change_deps name (Option.map

       (fn {parents, files, ...} => make_deps upd_time (SOME master) [] parents files));

      perform Update name))

  end;

fun register_theory theory =

  let

    val name = Context.theory_name theory;

    val parents = Theory.parents_of theory;

    val parent_names = map Context.theory_name parents;

    fun err txt bads =

      error (loader_msg txt bads ^ "\ncannot register theory " ^ quote 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 = map_filter get_variant (parents ~~ parent_names);

    fun register G =

      (Graph.new_node (name, (NONE, SOME theory)) G

        handle Graph.DUP _ => 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 CRITICAL (fn () => (change_thys register; perform Update name))

  end;

(* finish all theories *)

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

end;