(*  Title:      Pure/Thy/thy_info.ML

     ID:         $Id$

     Author:     Markus Wenzel, TU Muenchen

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

 file dependencies.

 *)

 signature BASIC_THY_INFO =

 sig

   val theory: string -> theory

   val touch_thy: string -> unit

   val remove_thy: string -> unit

 end;

 signature THY_INFO =

 sig

   include BASIC_THY_INFO

   datatype action = Update | Outdate | Remove

   val str_of_action: action -> string

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

   val 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 the_theory: string -> theory -> theory

   val get_parents: string -> string list

   val loaded_files: string -> Path.T list

   val touch_child_thys: string -> unit

   val touch_all_thys: unit -> unit

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

   val use: string -> unit

   val time_use: string -> unit

   val pretend_use_thy_only: string -> unit

   val use_thys: string list -> unit

   val use_thy: string -> unit

   val time_use_thy: string -> unit

   val update_thy: string -> unit

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

   val end_theory: theory -> theory

   val finish: unit -> unit

   val register_theory: theory -> unit

   val pretty_theory: theory -> Pretty.T

 end;

 structure ThyInfo: 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 = ref ([]: (action -> string -> unit) list);

 in

   fun add_hook f = CRITICAL (fn () => 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 master = (Path.T * File.ident) * (Path.T * File.ident) option;

 type deps =

   {outdated: bool,              (*entry considered outdated*)

     master: master option,      (*master dependencies for thy + attached ML file*)

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

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

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

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

 fun make_deps outdated master text parents files : deps =

   {outdated = outdated, master = master, text = text, parents = parents, files = files};

 fun init_deps master text parents files =

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

 fun master_idents (NONE: master option) = []

   | master_idents (SOME ((_, thy_id), NONE)) = [thy_id]

   | master_idents (SOME ((_, thy_id), SOME (_, ml_id))) = [thy_id, ml_id];

 fun master_dir (NONE: master option) = 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 = ref (Graph.empty: thy Graph.T);

 in

   fun get_thys () = ! database;

   fun change_thys f = CRITICAL (fn () => Library.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));

 fun is_finished name = is_none (get_deps name);

 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]);

 (* pretty printing a theory *)

 local

 fun relevant_names names =

   let

     val (finished, unfinished) =

       List.filter (fn name => name = Context.draftN orelse known_thy name) names

       |> List.partition (fn name => name <> Context.draftN andalso is_finished name);

   in (if not (null finished) then [List.last finished] else []) @ unfinished end;

 in

 fun pretty_theory thy =

   Pretty.str_list "{" "}" (relevant_names (Context.names_of thy));

 end;

 (* 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]));

 fun the_theory name thy =

   if Context.theory_name thy = name then thy

   else get_theory name;

 val _ = ML_Context.value_antiq "theory"

   (Scan.lift Args.name

     >> (fn name => (name ^ "_thy", "ThyInfo.theory " ^ ML_Syntax.print_string name))

   || Scan.succeed ("thy", "ML_Context.the_context ()"));

 (** thy operations **)

 (* maintain 'outdated' flag *)

 local

 fun is_outdated name =

   (case lookup_deps name of

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

   | _ => false);

 fun outdate_thy name =

   if is_finished name orelse is_outdated name then ()

   else CRITICAL (fn () =>

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

     make_deps true master text parents files)); perform Outdate name));

 fun check_unfinished name =

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

   else SOME name;

 in

 fun touch_thys names =

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

 fun touch_thy name = touch_thys [name];

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

 fun touch_all_thys () = List.app outdate_thy (get_names ());

 end;

 (* check 'finished' state *)

 fun check_unfinished fail name =

   if known_thy name andalso is_finished name then

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

   else ();

 (* load_file *)

 local

 fun provide path name info (deps as SOME {outdated, 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 outdated 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) (ML_Context.get_context ()) of

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

   | SOME name =>

       (case lookup_deps name of

         SOME deps =>

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

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

 in

 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;

 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 really ml time initiators dir name =

   let

     val _ =

       if really then priority ("Loading theory " ^ quote name ^ required_by " " initiators)

       else priority ("Registering theory " ^ quote name);

     val (master_path, text, files) =

       (case get_deps name of

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

           (master_path, text, files)

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

     val _ = touch_thy name;

     val _ =

       if really then

         ThyLoad.load_thy dir name (Position.path master_path) text ml (time orelse ! Output.timing)

       else ();

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

     val _ =

       if null missing_files then ()

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

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

   in

     CRITICAL (fn () =>

      (change_deps name

         (Option.map (fn {master, parents, files, ...} => make_deps false master [] parents files));

       perform Update name))

   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 ThyLoad.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 ml strict dir name =

   (case lookup_deps name of

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

   | NONE =>

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

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

   | SOME (deps as SOME {outdated, master, text, parents, files}) =>

       if not strict andalso can get_theory name then (true, deps, parents)

       else

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

           if master_idents master <> master_idents master'

           then

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

               ThyLoad.deps_thy dir name ml;

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

           else

             let

               val checked_files = map (check_ml master') files;

               val current = not outdated andalso forall (is_some o snd) checked_files;

               val deps' = SOME (make_deps (not current) master' text parents checked_files);

             in (current, deps', parents) end

         end);

 in

 fun require_thys really ml time strict keep_strict initiators dir strs tasks =

   fold_map (require_thy really ml time strict keep_strict initiators dir) strs tasks

   |>> forall I

 and require_thy really ml time strict keep_strict 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 (fst tasks)) name of

       SOME task => (Task.is_finished task, tasks)

     | NONE =>

         let

           val (current, deps, parents) = check_deps ml strict 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', tasks_len')) =

             require_thys true true time (strict andalso keep_strict) keep_strict

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

           val all_current = current andalso parents_current;

           val thy = if all_current orelse not really then SOME (get_theory name) else NONE;

           val _ = change_thys (new_deps name parent_names (deps, thy));

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

            (if all_current then Task.Finished

             else Task.Task (fn () => load_thy really ml time initiators dir' name));

           val tasks_len'' = if all_current then tasks_len' else tasks_len' + 1;

         in (all_current, (tasks_graph'', tasks_len'')) end)

   end;

 end;

 (* variations on use_thy -- scheduling required theories *)

 local

 fun schedule_seq tasks =

   Graph.topological_order tasks

   |> List.app (fn name => (case Graph.get_node tasks name of Task.Task f => f () | _ => ()));

 fun max_task (task as (_, (Task.Task _, _))) NONE = SOME task

   | max_task (task as (_, (Task.Task _, m))) (task' as SOME (_, (_, m'))) =

       if m > m' then SOME task else task'

   | max_task _ task' = task';

 fun next_task G =

   let

     val tasks = Graph.minimals G |> map (fn name =>

       (name, (Graph.get_node G name, length (Graph.imm_succs G name))))

     val finished = filter (Task.is_finished o fst o snd) tasks;

   in

     if not (null finished) then next_task (Graph.del_nodes (map fst finished) G)

     else if null tasks then ((Task.Finished, I), G)

     else

       (case fold max_task tasks NONE of

         NONE => ((Task.Running, I), G)

       | SOME (name, (task, _)) =>

           ((task, Graph.del_nodes [name]), Graph.map_node name (K Task.Running) G))

   end;

 fun schedule_tasks (tasks, n) =

   let val m = ! Multithreading.max_threads in

     if m <= 1 orelse n <= 1 then schedule_seq tasks

     else if Multithreading.self_critical () then

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

       schedule_seq tasks)

     else

       (case Multithreading.schedule (Int.min (m, n)) next_task tasks of

         [] => ()

       | exns => raise Exn.EXCEPTIONS (exns, ""))

   end;

 fun gen_use_thy' req dir arg =

   let val (_, tasks) = req [] dir arg (Graph.empty, 0)

   in schedule_tasks tasks end;

 fun gen_use_thy req str =

   let val name = base_name str in

     check_unfinished warning name;

     gen_use_thy' req Path.current str;

     CRITICAL (fn () => ML_Context.set_context (SOME (Context.Theory (get_theory name))))

   end;

 in

 val quiet_update_thys    = gen_use_thy' (require_thys true true false true true);

 val pretend_use_thy_only = gen_use_thy' (require_thy false false false true false) Path.current;

 val use_thys             = gen_use_thy' (require_thys true true false true false) Path.current;

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

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

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

 end;

 (* 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

       priority (loader_msg "removing" succs);

       CRITICAL (fn () => (List.app (perform Remove) succs; change_thys (Graph.del_nodes succs)))

     end;

 (* begin / end theory *)

 fun check_uses name uses =

   let val illegal = map (fn ext => Path.ext ext (Path.basic name)) ("" :: ThyLoad.ml_exts) in

     (case find_first (member (op =) illegal o Path.base o Path.expand o #1) uses of

       NONE => ()

     | SOME (path, _) => error ("Illegal use of theory ML file: " ^ quote (Path.implode path)))

   end;

 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 quiet_update_thys dir parents else ();

     (* FIXME tmp *)

     val _ = CRITICAL (fn () =>

       ML_Context.set_context (SOME (Context.Theory (get_theory (List.last parent_names)))));

     val _ = check_uses name uses;

     val theory =

       Theory.begin_theory name (map get_theory parent_names)

       |> Present.begin_theory dir uses;

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

     val ((), theory') =

       ML_Context.pass_context (Context.Theory theory) (List.app (load_file false)) uses_now

       ||> Context.the_theory;

   in theory' end;

 fun end_theory theory =

   let

     val name = Context.theory_name theory;

     val theory' = Theory.end_theory theory;

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

   in 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 = 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;

 val _ = register_theory ProtoPure.thy;

 (*final declarations of this structure*)

 val theory = get_theory;

 val names = get_names;

 end;

 structure BasicThyInfo: BASIC_THY_INFO = ThyInfo;

 open BasicThyInfo;