src/Pure/PIDE/document.ML

re-assign prints of unchanged eval only -- avoid crash of new_exec;

(*  Title:      Pure/PIDE/document.ML
    Author:     Makarius

Document as collection of named nodes, each consisting of an editable
list of commands, associated with asynchronous execution process.
*)

signature DOCUMENT =
sig
  type node_header = string * Thy_Header.header * string list
  datatype node_edit =
    Clear |    (* FIXME unused !? *)
    Edits of (Document_ID.command option * Document_ID.command option) list |
    Deps of node_header |
    Perspective of Document_ID.command list
  type edit = string * node_edit
  type state
  val init_state: state
  val define_command: Document_ID.command -> string -> string -> state -> state
  val remove_versions: Document_ID.version list -> state -> state
  val discontinue_execution: state -> unit
  val cancel_execution: state -> unit
  val start_execution: state -> unit
  val timing: bool Unsynchronized.ref
  val update: Document_ID.version -> Document_ID.version -> edit list -> state ->
    (Document_ID.command * Document_ID.exec list) list * state
  val state: unit -> state
  val change_state: (state -> state) -> unit
end;

structure Document: DOCUMENT =
struct

(** document structure **)

fun err_dup kind id = error ("Duplicate " ^ kind ^ ": " ^ Document_ID.print id);
fun err_undef kind id = error ("Undefined " ^ kind ^ ": " ^ Document_ID.print id);

type node_header = string * Thy_Header.header * string list;
type perspective = Inttab.set * Document_ID.command option;
structure Entries = Linear_Set(type key = Document_ID.command val ord = int_ord);

abstype node = Node of
 {header: node_header,  (*master directory, theory header, errors*)
  perspective: perspective,  (*visible commands, last visible command*)
  entries: Command.exec option Entries.T * bool,  (*command entries with excecutions, stable*)
  result: Command.eval option}  (*result of last execution*)
and version = Version of node String_Graph.T  (*development graph wrt. static imports*)
with

fun make_node (header, perspective, entries, result) =
  Node {header = header, perspective = perspective, entries = entries, result = result};

fun map_node f (Node {header, perspective, entries, result}) =
  make_node (f (header, perspective, entries, result));

fun make_perspective command_ids : perspective =
  (Inttab.make_set command_ids, try List.last command_ids);

val no_header = ("", Thy_Header.make ("", Position.none) [] [], ["Bad theory header"]);
val no_perspective = make_perspective [];

val empty_node = make_node (no_header, no_perspective, (Entries.empty, true), NONE);
val clear_node =
  map_node (fn (header, _, _, _) => (header, no_perspective, (Entries.empty, true), NONE));


(* basic components *)

fun set_header header =
  map_node (fn (_, perspective, entries, result) => (header, perspective, entries, result));

fun get_header (Node {header = (master, header, errors), ...}) =
  if null errors then (master, header)
  else error (cat_lines errors);

fun read_header node span =
  let
    val (dir, {name = (name, _), imports, keywords}) = get_header node;
    val {name = (_, pos), imports = imports', ...} = Thy_Header.read_tokens span;
  in (dir, Thy_Header.make (name, pos) (map #1 imports ~~ map #2 imports') keywords) end;

fun get_perspective (Node {perspective, ...}) = perspective;
fun set_perspective ids =
  map_node (fn (header, _, entries, result) => (header, make_perspective ids, entries, result));

val visible_command = Inttab.defined o #1 o get_perspective;
val visible_last = #2 o get_perspective;
val visible_node = is_some o visible_last

fun map_entries f =
  map_node (fn (header, perspective, (entries, stable), result) =>
    (header, perspective, (f entries, stable), result));
fun get_entries (Node {entries = (entries, _), ...}) = entries;

fun entries_stable stable =
  map_node (fn (header, perspective, (entries, _), result) =>
    (header, perspective, (entries, stable), result));
fun stable_entries (Node {entries = (_, stable), ...}) = stable;

fun iterate_entries f = Entries.iterate NONE f o get_entries;
fun iterate_entries_after start f (Node {entries = (entries, _), ...}) =
  (case Entries.get_after entries start of
    NONE => I
  | SOME id => Entries.iterate (SOME id) f entries);

fun get_result (Node {result, ...}) = result;
fun set_result result =
  map_node (fn (header, perspective, entries, _) => (header, perspective, entries, result));

fun changed_result node node' =
  (case (get_result node, get_result node') of
    (SOME eval, SOME eval') => #exec_id eval <> #exec_id eval'
  | (NONE, NONE) => false
  | _ => true);

fun finished_theory node =
  (case Exn.capture (Command.eval_result_state o the) (get_result node) of
    Exn.Res st => can (Toplevel.end_theory Position.none) st
  | _ => false);

fun get_node nodes name = String_Graph.get_node nodes name
  handle String_Graph.UNDEF _ => empty_node;
fun default_node name = String_Graph.default_node (name, empty_node);
fun update_node name f = default_node name #> String_Graph.map_node name f;


(* node edits and associated executions *)

datatype node_edit =
  Clear |
  Edits of (Document_ID.command option * Document_ID.command option) list |
  Deps of node_header |
  Perspective of Document_ID.command list;

type edit = string * node_edit;

val after_entry = Entries.get_after o get_entries;

fun lookup_entry node id =
  (case Entries.lookup (get_entries node) id of
    NONE => NONE
  | SOME (exec, _) => exec);

fun the_entry node id =
  (case Entries.lookup (get_entries node) id of
    NONE => err_undef "command entry" id
  | SOME (exec, _) => exec);

fun the_default_entry node (SOME id) = (id, the_default Command.no_exec (the_entry node id))
  | the_default_entry _ NONE = (Document_ID.none, Command.no_exec);

fun assign_entry (command_id, exec) node =
  if is_none (Entries.lookup (get_entries node) command_id) then node
  else map_entries (Entries.update (command_id, exec)) node;

fun reset_after id entries =
  (case Entries.get_after entries id of
    NONE => entries
  | SOME next => Entries.update (next, NONE) entries);

val edit_node = map_entries o fold
  (fn (id, SOME id2) => Entries.insert_after id (id2, NONE)
    | (id, NONE) => Entries.delete_after id #> reset_after id);


(* version operations *)

val empty_version = Version String_Graph.empty;

fun nodes_of (Version nodes) = nodes;
val node_of = get_node o nodes_of;

fun cycle_msg names = "Cyclic dependency of " ^ space_implode " via " (map quote names);

fun edit_nodes (name, node_edit) (Version nodes) =
  Version
    (case node_edit of
      Clear => update_node name clear_node nodes
    | Edits edits => update_node name (edit_node edits) nodes
    | Deps (master, header, errors) =>
        let
          val imports = map fst (#imports header);
          val errors1 =
            (Thy_Header.define_keywords header; errors)
              handle ERROR msg => errors @ [msg];
          val nodes1 = nodes
            |> default_node name
            |> fold default_node imports;
          val nodes2 = nodes1
            |> String_Graph.Keys.fold
                (fn dep => String_Graph.del_edge (dep, name)) (String_Graph.imm_preds nodes1 name);
          val (nodes3, errors2) =
            (String_Graph.add_deps_acyclic (name, imports) nodes2, errors1)
              handle String_Graph.CYCLES cs => (nodes2, errors1 @ map cycle_msg cs);
        in String_Graph.map_node name (set_header (master, header, errors2)) nodes3 end
    | Perspective perspective => update_node name (set_perspective perspective) nodes);

fun put_node (name, node) (Version nodes) =
  Version (update_node name (K node) nodes);

end;



(** main state -- document structure and execution process **)

type execution =
 {version_id: Document_ID.version,
  group: Future.group,
  running: bool Unsynchronized.ref};

val no_execution =
 {version_id = Document_ID.none,
  group = Future.new_group NONE,
  running = Unsynchronized.ref false};

abstype state = State of
 {versions: version Inttab.table,  (*version id -> document content*)
  commands: (string * Token.T list lazy) Inttab.table,  (*command id -> named command span*)
  execution: execution}  (*current execution process*)
with

fun make_state (versions, commands, execution) =
  State {versions = versions, commands = commands, execution = execution};

fun map_state f (State {versions, commands, execution}) =
  make_state (f (versions, commands, execution));

val init_state =
  make_state (Inttab.make [(Document_ID.none, empty_version)], Inttab.empty, no_execution);

fun execution_of (State {execution, ...}) = execution;


(* document versions *)

fun define_version version_id version =
  map_state (fn (versions, commands, _) =>
    let
      val versions' = Inttab.update_new (version_id, version) versions
        handle Inttab.DUP dup => err_dup "document version" dup;
      val execution' =
       {version_id = version_id,
        group = Future.new_group NONE,
        running = Unsynchronized.ref true};
    in (versions', commands, execution') end);

fun the_version (State {versions, ...}) version_id =
  (case Inttab.lookup versions version_id of
    NONE => err_undef "document version" version_id
  | SOME version => version);

fun delete_version version_id versions =
  Inttab.delete version_id versions
    handle Inttab.UNDEF _ => err_undef "document version" version_id;


(* commands *)

fun define_command command_id name text =
  map_state (fn (versions, commands, execution) =>
    let
      val id = Document_ID.print command_id;
      val span =
        Lazy.lazy (fn () =>
          Position.setmp_thread_data (Position.id_only id)
            (fn () => Thy_Syntax.parse_tokens (Keyword.get_lexicons ()) (Position.id id) text) ());
      val _ =
        Position.setmp_thread_data (Position.id_only id)
          (fn () => Output.status (Markup.markup_only Markup.accepted)) ();
      val commands' =
        Inttab.update_new (command_id, (name, span)) commands
          handle Inttab.DUP dup => err_dup "command" dup;
    in (versions, commands', execution) end);

fun the_command (State {commands, ...}) command_id =
  (case Inttab.lookup commands command_id of
    NONE => err_undef "command" command_id
  | SOME command => command);

val the_command_name = #1 oo the_command;

end;


(* remove_versions *)

fun remove_versions version_ids state = state |> map_state (fn (versions, _, execution) =>
  let
    val _ =
      member (op =) version_ids (#version_id execution) andalso
        error ("Attempt to remove execution version " ^ Document_ID.print (#version_id execution));

    val versions' = fold delete_version version_ids versions;
    val commands' =
      (versions', Inttab.empty) |->
        Inttab.fold (fn (_, version) => nodes_of version |>
          String_Graph.fold (fn (_, (node, _)) => node |>
            iterate_entries (fn ((_, command_id), _) =>
              SOME o Inttab.insert (K true) (command_id, the_command state command_id))));
  in (versions', commands', execution) end);



(** document execution **)

val discontinue_execution = execution_of #> (fn {running, ...} => running := false);
val cancel_execution = execution_of #> (fn {group, ...} => Future.cancel_group group);
val terminate_execution = execution_of #> (fn {group, ...} => Future.terminate group);

fun start_execution state =
  let
    val {version_id, group, running} = execution_of state;
    val _ =
      if not (! running) orelse Task_Queue.is_canceled group then []
      else
        nodes_of (the_version state version_id) |> String_Graph.schedule
          (fn deps => fn (name, node) =>
            if not (visible_node node) andalso finished_theory node then
              Future.value ()
            else
              (singleton o Future.forks)
                {name = "theory:" ^ name, group = SOME (Future.new_group (SOME group)),
                  deps = map (Future.task_of o #2) deps, pri = ~2, interrupts = false}
                (fn () =>
                  iterate_entries (fn (_, opt_exec) => fn () =>
                    (case opt_exec of
                      SOME exec => if ! running then SOME (Command.execute exec) else NONE
                    | NONE => NONE)) node ()));
  in () end;



(** document update **)

(* exec state assignment *)

type assign_update = Command.exec option Inttab.table;  (*command id -> exec*)

val assign_update_empty: assign_update = Inttab.empty;
fun assign_update_null (tab: assign_update) = Inttab.is_empty tab;
fun assign_update_defined (tab: assign_update) command_id = Inttab.defined tab command_id;
fun assign_update_apply (tab: assign_update) node = Inttab.fold assign_entry tab node;

fun assign_update_new upd (tab: assign_update) =
  Inttab.update_new upd tab
    handle Inttab.DUP dup => err_dup "exec state assignment" dup;

fun assign_update_result (tab: assign_update) =
  Inttab.fold (fn (command_id, exec) => cons (command_id, Command.exec_ids exec)) tab [];


(* update *)

val timing = Unsynchronized.ref false;
fun timeit msg e = cond_timeit (! timing) msg e;

local

fun make_required nodes =
  let
    val all_visible =
      String_Graph.fold (fn (a, (node, _)) => visible_node node ? cons a) nodes []
      |> String_Graph.all_preds nodes
      |> map (rpair ()) |> Symtab.make;

    val required =
      Symtab.fold (fn (a, ()) =>
        exists (Symtab.defined all_visible) (String_Graph.immediate_succs nodes a) ?
          Symtab.update (a, ())) all_visible Symtab.empty;
  in Symtab.defined required end;

fun init_theory deps node span =
  let
    (* FIXME provide files via Isabelle/Scala, not master_dir *)
    val (dir, header) = read_header node span;
    val master_dir =
      (case try Url.explode dir of
        SOME (Url.File path) => path
      | _ => Path.current);
    val imports = #imports header;
    val parents =
      imports |> map (fn (import, _) =>
        (case Thy_Info.lookup_theory import of
          SOME thy => thy
        | NONE =>
            Toplevel.end_theory (Position.file_only import)
              (case get_result (snd (the (AList.lookup (op =) deps import))) of
                NONE => Toplevel.toplevel
              | SOME eval => Command.eval_result_state eval)));
    val _ = Position.reports (map #2 imports ~~ map Theory.get_markup parents);
  in Thy_Load.begin_theory master_dir header parents end;

fun check_theory full name node =
  is_some (Thy_Info.lookup_theory name) orelse
  can get_header node andalso (not full orelse is_some (get_result node));

fun last_common state node0 node =
  let
    fun update_flags prev (visible, initial) =
      let
        val visible' = visible andalso prev <> visible_last node;
        val initial' = initial andalso
          (case prev of
            NONE => true
          | SOME command_id => not (Keyword.is_theory_begin (the_command_name state command_id)));
      in (visible', initial') end;

    fun get_common ((prev, command_id), opt_exec) (_, same, flags, assign_update) =
      if same then
        let
          val flags' = update_flags prev flags;
          val same' =
            (case (lookup_entry node0 command_id, opt_exec) of
              (SOME (eval0, _), SOME (eval, _)) => Command.same_eval (eval0, eval)
            | _ => false);
          val assign_update' = assign_update |> same' ?
            (case opt_exec of
              SOME (eval, prints) =>
                let
                  val command_visible = visible_command node command_id;
                  val command_name = the_command_name state command_id;
                in
                  (case Command.print command_visible command_name eval prints of
                    SOME prints' => assign_update_new (command_id, SOME (eval, prints'))
                  | NONE => I)
                end
            | NONE => I);
        in SOME (prev, same', flags', assign_update') end
      else NONE;
    val (common, same, flags, assign_update') =
      iterate_entries get_common node (NONE, true, (true, true), assign_update_empty);
    val (common', flags') =
      if same then
        let val last = Entries.get_after (get_entries node) common
        in (last, update_flags last flags) end
      else (common, flags);
  in (assign_update', common', flags') end;

fun illegal_init _ = error "Illegal theory header after end of theory";

fun new_exec state proper_init command_visible command_id' (assign_update, command_exec, init) =
  if not proper_init andalso is_none init then NONE
  else
    let
      val (_, (eval, _)) = command_exec;
      val (command_name, span) = the_command state command_id' ||> Lazy.force;

      val eval' = Command.eval (fn () => the_default illegal_init init span) span eval;
      val prints' = perhaps (Command.print command_visible command_name eval') [];
      val exec' = (eval', prints');

      val assign_update' = assign_update_new (command_id', SOME exec') assign_update;
      val init' = if Keyword.is_theory_begin command_name then NONE else init;
    in SOME (assign_update', (command_id', (eval', prints')), init') end;
in

fun update old_version_id new_version_id edits state =
  let
    val old_version = the_version state old_version_id;
    val new_version = timeit "Document.edit_nodes" (fn () => fold edit_nodes edits old_version);

    val nodes = nodes_of new_version;
    val is_required = make_required nodes;

    val _ = timeit "Document.terminate_execution" (fn () => terminate_execution state);
    val updated = timeit "Document.update" (fn () =>
      nodes |> String_Graph.schedule
        (fn deps => fn (name, node) =>
          (singleton o Future.forks)
            {name = "Document.update", group = NONE,
              deps = map (Future.task_of o #2) deps, pri = 0, interrupts = false}
            (fn () =>
              let
                val imports = map (apsnd Future.join) deps;
                val imports_changed = exists (#3 o #1 o #2) imports;
                val node_required = is_required name;
              in
                if imports_changed orelse AList.defined (op =) edits name orelse
                  not (stable_entries node) orelse not (finished_theory node)
                then
                  let
                    val node0 = node_of old_version name;
                    val init = init_theory imports node;
                    val proper_init =
                      check_theory false name node andalso
                      forall (fn (name, (_, node)) => check_theory true name node) imports;

                    val (print_execs, common, (still_visible, initial)) =
                      if imports_changed then (assign_update_empty, NONE, (true, true))
                      else last_common state node0 node;
                    val common_command_exec = the_default_entry node common;

                    val (updated_execs, (command_id', (eval', _)), _) =
                      (print_execs, common_command_exec, if initial then SOME init else NONE)
                      |> (still_visible orelse node_required) ?
                        iterate_entries_after common
                          (fn ((prev, id), _) => fn res =>
                            if not node_required andalso prev = visible_last node then NONE
                            else new_exec state proper_init (visible_command node id) id res) node;

                    val assigned_execs =
                      (node0, updated_execs) |-> iterate_entries_after common
                        (fn ((_, command_id0), exec0) => fn res =>
                          if is_none exec0 then NONE
                          else if assign_update_defined updated_execs command_id0 then SOME res
                          else SOME (assign_update_new (command_id0, NONE) res));

                    val last_exec =
                      if command_id' = Document_ID.none then NONE else SOME command_id';
                    val result =
                      if is_none last_exec orelse is_some (after_entry node last_exec) then NONE
                      else SOME eval';

                    val node' = node
                      |> assign_update_apply assigned_execs
                      |> entries_stable (assign_update_null updated_execs)
                      |> set_result result;
                    val assigned_node = SOME (name, node');
                    val result_changed = changed_result node0 node';
                  in
                    ((assign_update_result assigned_execs, assigned_node, result_changed), node')
                  end
                else (([], NONE, false), node)
              end))
      |> Future.joins |> map #1);

    val state' = state
      |> define_version new_version_id (fold put_node (map_filter #2 updated) new_version);
  in (maps #1 updated, state') end;

end;



(** global state **)

val global_state = Synchronized.var "Document.global_state" init_state;

fun state () = Synchronized.value global_state;
val change_state = Synchronized.change global_state;

end;