tasks of canceled groups are considered "ready" -- enables to purge the queue from tasks depending on unfinished promises (also improves general reactivity);
shutdown: back to synchronous wait, which means no asynchronous interrupts within the loop;
1 (* Title: Pure/Concurrent/task_queue.ML
4 Ordered queue of grouped tasks.
11 val pri_of_task: task -> int
12 val str_of_task: task -> string
14 val new_group: group option -> group
15 val group_id: group -> int
16 val eq_group: group * group -> bool
17 val cancel_group: group -> exn -> unit
18 val is_canceled: group -> bool
19 val group_status: group -> exn list
20 val str_of_group: group -> string
23 val all_passive: queue -> bool
24 val status: queue -> {ready: int, pending: int, running: int, passive: int}
25 val cancel: group -> queue -> bool * queue
26 val cancel_all: queue -> group list * queue
27 val enqueue_passive: group -> queue -> task * queue
28 val enqueue: group -> task list -> int -> (bool -> bool) -> queue -> (task * bool) * queue
29 val extend: task -> (bool -> bool) -> queue -> queue option
30 val dequeue: Thread.thread -> queue -> (task * group * (bool -> bool) list) option * queue
31 val depend: task -> task list -> queue -> queue
32 val dequeue_towards: Thread.thread -> task list -> queue ->
33 (((task * group * (bool -> bool) list) option * task list) * queue)
34 val finish: task -> queue -> bool * queue
37 structure Task_Queue:> TASK_QUEUE =
42 datatype task = Task of int option * serial;
43 val dummy_task = Task (NONE, ~1);
44 fun new_task pri = Task (pri, serial ());
46 fun pri_of_task (Task (pri, _)) = the_default 0 pri;
47 fun str_of_task (Task (_, i)) = string_of_int i;
49 fun task_ord (Task t1, Task t2) = prod_ord (rev_order o option_ord int_ord) int_ord (t1, t2);
50 structure Task_Graph = Graph(type key = task val ord = task_ord);
55 datatype group = Group of
56 {parent: group option,
58 status: exn list Synchronized.var};
60 fun make_group (parent, id, status) = Group {parent = parent, id = id, status = status};
62 fun new_group parent = make_group (parent, serial (), Synchronized.var "group" []);
64 fun group_id (Group {id, ...}) = id;
65 fun eq_group (group1, group2) = group_id group1 = group_id group2;
67 fun group_ancestry (Group {parent, id, ...}) =
68 id :: (case parent of NONE => [] | SOME group => group_ancestry group);
73 fun cancel_group (Group {status, ...}) exn =
74 Synchronized.change status
77 Exn.Interrupt => if null exns then [exn] else exns
80 fun is_canceled (Group {parent, status, ...}) =
81 not (null (Synchronized.value status)) orelse
82 (case parent of NONE => false | SOME group => is_canceled group);
84 fun is_ready deps group = null deps orelse is_canceled group;
86 fun group_status (Group {parent, status, ...}) =
87 Synchronized.value status @
88 (case parent of NONE => [] | SOME group => group_status group);
90 fun str_of_group group =
91 (is_canceled group ? enclose "(" ")") (string_of_int (group_id group));
97 Job of (bool -> bool) list |
98 Running of Thread.thread |
101 type jobs = (group * job) Task_Graph.T;
103 fun get_group (jobs: jobs) task = #1 (Task_Graph.get_node jobs task);
104 fun get_job (jobs: jobs) task = #2 (Task_Graph.get_node jobs task);
105 fun set_job task job (jobs: jobs) = Task_Graph.map_node task (fn (group, _) => (group, job)) jobs;
107 fun add_job task dep (jobs: jobs) =
108 Task_Graph.add_edge (dep, task) jobs handle Task_Graph.UNDEF _ => jobs;
110 fun add_dep task dep (jobs: jobs) =
111 if Task_Graph.is_edge jobs (task, dep) then
112 raise Fail "Cyclic dependency of future tasks"
113 else add_job task dep jobs;
115 fun get_deps (jobs: jobs) task =
116 Task_Graph.imm_preds jobs task handle Task_Graph.UNDEF _ => [];
119 (* queue of grouped jobs *)
121 datatype result = Unknown | Result of task | No_Result;
123 datatype queue = Queue of
124 {groups: task list Inttab.table, (*groups with presently active members*)
125 jobs: jobs, (*job dependency graph*)
126 cache: result}; (*last dequeue result*)
128 fun make_queue groups jobs cache = Queue {groups = groups, jobs = jobs, cache = cache};
130 val empty = make_queue Inttab.empty Task_Graph.empty No_Result;
132 fun all_passive (Queue {jobs, ...}) =
133 Task_Graph.get_first NONE
134 ((fn Job _ => SOME () | Running _ => SOME () | Passive => NONE) o #2 o #1 o #2) jobs |> is_none;
139 fun status (Queue {jobs, ...}) =
142 Task_Graph.fold (fn (_, ((group, job), (deps, _))) => fn (x, y, z, w) =>
144 Job _ => if is_ready deps group then (x + 1, y, z, w) else (x, y + 1, z, w)
145 | Running _ => (x, y, z + 1, w)
146 | Passive => (x, y, z, w + 1)))
148 in {ready = x, pending = y, running = z, passive = w} end;
151 (* cancel -- peers and sub-groups *)
153 fun cancel group (Queue {groups, jobs, ...}) =
155 val _ = cancel_group group Exn.Interrupt;
156 val tasks = Inttab.lookup_list groups (group_id group);
158 fold (get_job jobs #> (fn Running t => insert Thread.equal t | _ => I)) tasks [];
159 val _ = List.app SimpleThread.interrupt running;
160 in (null running, make_queue groups jobs Unknown) end;
162 fun cancel_all (Queue {groups, jobs, ...}) =
164 fun cancel_job (group, job) (groups, running) =
165 (cancel_group group Exn.Interrupt;
167 Running t => (insert eq_group group groups, insert Thread.equal t running)
168 | _ => (groups, running)));
169 val (running_groups, running) = Task_Graph.fold (cancel_job o #1 o #2) jobs ([], []);
170 val _ = List.app SimpleThread.interrupt running;
171 in (running_groups, make_queue groups jobs Unknown) end;
176 fun enqueue_passive group (Queue {groups, jobs, cache}) =
178 val task = new_task NONE;
180 |> fold (fn gid => Inttab.cons_list (gid, task)) (group_ancestry group);
181 val jobs' = jobs |> Task_Graph.new_node (task, (group, Passive));
182 in (task, make_queue groups' jobs' cache) end;
184 fun enqueue group deps pri job (Queue {groups, jobs, cache}) =
186 val task = new_task (SOME pri);
188 |> fold (fn gid => Inttab.cons_list (gid, task)) (group_ancestry group);
190 |> Task_Graph.new_node (task, (group, Job [job]))
191 |> fold (add_job task) deps
192 |> fold (fold (add_job task) o get_deps jobs) deps;
193 val minimal = null (get_deps jobs' task);
197 if task_ord (last, task) = LESS
198 then cache else Unknown
200 in ((task, minimal), make_queue groups' jobs' cache') end;
202 fun extend task job (Queue {groups, jobs, cache}) =
203 (case try (get_job jobs) task of
204 SOME (Job list) => SOME (make_queue groups (set_job task (Job (job :: list)) jobs) cache)
210 fun dequeue thread (queue as Queue {groups, jobs, cache}) =
212 fun ready (task, ((group, Job list), (deps, _))) =
213 if is_ready deps group then SOME (task, group, rev list) else NONE
216 (case Task_Graph.get_first boundary ready jobs of
217 NONE => (NONE, make_queue groups jobs No_Result)
218 | SOME (result as (task, _, _)) =>
220 val jobs' = set_job task (Running thread) jobs;
221 val cache' = Result task;
222 in (SOME result, make_queue groups jobs' cache') end);
226 | Result last => deq (SOME last)
227 | No_Result => (NONE, queue))
231 (* dequeue_towards -- adhoc dependencies *)
233 fun depend task deps (Queue {groups, jobs, ...}) =
234 make_queue groups (fold (add_dep task) deps jobs) Unknown;
236 fun dequeue_towards thread deps (queue as Queue {groups, jobs, ...}) =
239 (case Task_Graph.get_node jobs task of
241 if is_ready (get_deps jobs task) group
242 then SOME (task, group, rev list)
245 val tasks = filter (can (Task_Graph.get_node jobs)) deps;
246 fun result (res as (task, _, _)) =
248 val jobs' = set_job task (Running thread) jobs;
249 val cache' = Unknown;
250 in ((SOME res, tasks), make_queue groups jobs' cache') end;
252 (case get_first ready tasks of
253 SOME res => result res
255 (case get_first (get_first ready o get_deps jobs) tasks of
256 SOME res => result res
257 | NONE => ((NONE, tasks), queue)))
263 fun finish task (Queue {groups, jobs, cache}) =
265 val group = get_group jobs task;
267 |> fold (fn gid => Inttab.remove_list (op =) (gid, task)) (group_ancestry group);
268 val jobs' = Task_Graph.del_node task jobs;
269 val maximal = null (Task_Graph.imm_succs jobs task);
270 val cache' = if maximal then cache else Unknown;
271 in (maximal, make_queue groups' jobs' cache') end;