src/Pure/PIDE/execution.ML
author wenzelm
Fri Jul 12 11:07:02 2013 +0200 (2013-07-12 ago)
changeset 52605 a2a805549c74
parent 52604 src/Pure/PIDE/exec.ML@ff2f0818aebc
child 52606 0d68d108d7e0
permissions -rw-r--r--
clarified module name;
     1 (*  Title:      Pure/PIDE/execution.ML
     2     Author:     Makarius
     3 
     4 Global management of command execution fragments.
     5 *)
     6 
     7 signature EXECUTION =
     8 sig
     9   type context
    10   val no_context: context
    11   val drop_context: context -> unit
    12   val fresh_context: unit -> context
    13   val is_running: context -> bool
    14   val running: context -> Document_ID.exec -> bool
    15   val finished: Document_ID.exec -> bool -> unit
    16   val is_stable: Document_ID.exec -> bool
    17   val peek_running: Document_ID.exec -> Future.group option
    18   val purge_canceled: unit -> unit
    19   val terminate_all: unit -> unit
    20 end;
    21 
    22 structure Execution: EXECUTION =
    23 struct
    24 
    25 (* global state *)
    26 
    27 datatype context = Context of Document_ID.generic;
    28 val no_context = Context Document_ID.none;
    29 
    30 type status = Future.group option;  (*SOME group: running, NONE: canceled*)
    31 val state = Synchronized.var "Execution.state" (no_context, Inttab.empty: status Inttab.table);
    32 
    33 
    34 (* unique execution context *)
    35 
    36 fun drop_context context =
    37   Synchronized.change state
    38     (apfst (fn context' => if context = context' then no_context else context'));
    39 
    40 fun fresh_context () =
    41   let
    42     val context = Context (Document_ID.make ());
    43     val _ = Synchronized.change state (apfst (K context));
    44   in context end;
    45 
    46 fun is_running context = context = fst (Synchronized.value state);
    47 
    48 
    49 (* registered execs *)
    50 
    51 fun running context exec_id =
    52   Synchronized.guarded_access state
    53     (fn (current_context, execs) =>
    54       let
    55         val cont = context = current_context;
    56         val execs' =
    57           if cont then
    58             Inttab.update_new (exec_id, SOME (Future.the_worker_group ())) execs
    59               handle Inttab.DUP dup => error ("Duplicate execution " ^ Document_ID.print dup)
    60           else execs;
    61       in SOME (cont, (current_context, execs')) end);
    62 
    63 fun finished exec_id stable =
    64   Synchronized.change state
    65     (apsnd (fn execs =>
    66       if not (Inttab.defined execs exec_id) then
    67         error ("Attempt to finish unknown execution: " ^ Document_ID.print exec_id)
    68       else if stable then Inttab.delete exec_id execs
    69       else Inttab.update (exec_id, NONE) execs));
    70 
    71 fun is_stable exec_id =
    72   not (Par_Exn.is_interrupted (Future.join_results (Goal.peek_futures exec_id))) andalso
    73   (case Inttab.lookup (snd (Synchronized.value state)) exec_id of
    74     NONE => true
    75   | SOME status => is_some status);
    76 
    77 fun peek_running exec_id =
    78   (case Inttab.lookup (snd (Synchronized.value state)) exec_id of
    79     SOME (SOME group) => SOME group
    80   | _ => NONE);
    81 
    82 fun purge_canceled () =
    83   Synchronized.guarded_access state
    84     (fn (context, execs) =>
    85       let
    86         val canceled = Inttab.fold (fn (exec_id, NONE) => cons exec_id | _ => I) execs [];
    87         val execs' = fold Inttab.delete canceled execs;
    88       in SOME ((), (context, execs')) end);
    89 
    90 fun terminate_all () =
    91   let
    92     val groups =
    93       Inttab.fold (fn (_, SOME group) => cons group | _ => I)
    94         (snd (Synchronized.value state)) [];
    95     val _ = List.app Future.cancel_group groups;
    96     val _ = List.app Future.terminate groups;
    97   in () end;
    98 
    99 end;
   100