1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K I N G . P R O T E C T E D _ O B J E C T S . --
6 -- O P E R A T I O N S --
10 -- Copyright (C) 1998-2005, Free Software Foundation, Inc. --
12 -- GNARL is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
21 -- Boston, MA 02110-1301, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. --
31 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
33 ------------------------------------------------------------------------------
35 -- This package contains all the extended primitives related to
36 -- Protected_Objects with entries.
38 -- The handling of protected objects with no entries is done in
39 -- System.Tasking.Protected_Objects, the simple routines for protected
40 -- objects with entries in System.Tasking.Protected_Objects.Entries.
42 -- The split between Entries and Operations is needed to break circular
43 -- dependencies inside the run time.
45 -- This package contains all primitives related to Protected_Objects.
46 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
49 -- Used for Exception_ID
53 with System.Task_Primitives.Operations;
54 -- used for Initialize_Lock
60 with System.Tasking.Entry_Calls;
61 -- used for Wait_For_Completion
62 -- Wait_Until_Abortable
63 -- Wait_For_Completion_With_Timeout
65 with System.Tasking.Initialization;
66 -- Used for Defer_Abort,
68 -- Change_Base_Priority
70 pragma Elaborate_All (System.Tasking.Initialization);
71 -- This insures that tasking is initialized if any protected objects are
74 with System.Tasking.Queuing;
76 -- Broadcast_Program_Error
77 -- Select_Protected_Entry_Call
81 with System.Tasking.Rendezvous;
82 -- used for Task_Do_Or_Queue
84 with System.Tasking.Utilities;
85 -- used for Exit_One_ATC_Level
87 with System.Tasking.Debug;
90 with System.Parameters;
91 -- used for Single_Lock
94 with System.Traces.Tasking;
95 -- used for Send_Trace_Info
97 with System.Restrictions;
98 -- used for Run_Time_Restrictions
100 package body System.Tasking.Protected_Objects.Operations is
102 package STPO renames System.Task_Primitives.Operations;
109 use System.Restrictions;
110 use System.Restrictions.Rident;
112 use System.Traces.Tasking;
114 -----------------------
115 -- Local Subprograms --
116 -----------------------
118 procedure Update_For_Queue_To_PO
119 (Entry_Call : Entry_Call_Link;
120 With_Abort : Boolean);
121 pragma Inline (Update_For_Queue_To_PO);
122 -- Update the state of an existing entry call to reflect
123 -- the fact that it is being enqueued, based on
124 -- whether the current queuing action is with or without abort.
125 -- Call this only while holding the PO's lock.
126 -- It returns with the PO's lock still held.
128 procedure Requeue_Call
130 Object : Protection_Entries_Access;
131 Entry_Call : Entry_Call_Link;
132 With_Abort : Boolean);
133 -- Handle requeue of Entry_Call.
134 -- In particular, queue the call if needed, or service it immediately
137 ---------------------------------
138 -- Cancel_Protected_Entry_Call --
139 ---------------------------------
141 -- Compiler interface only. Do not call from within the RTS.
142 -- This should have analogous effect to Cancel_Task_Entry_Call,
143 -- setting the value of Block.Cancelled instead of returning
144 -- the parameter value Cancelled.
146 -- The effect should be idempotent, since the call may already
147 -- have been dequeued.
160 -- X : protected_entry_index := 1;
161 -- B80b : communication_block;
162 -- communication_blockIP (B80b);
167 -- procedure _clean is
169 -- if enqueued (B80b) then
170 -- cancel_protected_entry_call (B80b);
175 -- protected_entry_call (rTV!(r)._object'unchecked_access, X,
176 -- null_address, asynchronous_call, B80b, objectF => 0);
177 -- if enqueued (B80b) then
184 -- when _abort_signal =>
185 -- abort_undefer.all;
188 -- if not cancelled (B80b) then
193 -- If the entry call completes after we get into the abortable part,
194 -- Abort_Signal should be raised and ATC will take us to the at-end
195 -- handler, which will call _clean.
197 -- If the entry call returns with the call already completed,
198 -- we can skip this, and use the "if enqueued()" to go past
199 -- the at-end handler, but we will still call _clean.
201 -- If the abortable part completes before the entry call is Done,
202 -- it will call _clean.
204 -- If the entry call or the abortable part raises an exception,
205 -- we will still call _clean, but the value of Cancelled should not matter.
207 -- Whoever calls _clean first gets to decide whether the call
208 -- has been "cancelled".
210 -- Enqueued should be true if there is any chance that the call
211 -- is still on a queue. It seems to be safe to make it True if
212 -- the call was Onqueue at some point before return from
213 -- Protected_Entry_Call.
215 -- Cancelled should be true iff the abortable part completed
216 -- and succeeded in cancelling the entry call before it completed.
219 -- The need for Enqueued is less obvious.
220 -- The "if enqueued ()" tests are not necessary, since both
221 -- Cancel_Protected_Entry_Call and Protected_Entry_Call must
222 -- do the same test internally, with locking. The one that
223 -- makes cancellation conditional may be a useful heuristic
224 -- since at least 1/2 the time the call should be off-queue
225 -- by that point. The other one seems totally useless, since
226 -- Protected_Entry_Call must do the same check and then
227 -- possibly wait for the call to be abortable, internally.
229 -- We can check Call.State here without locking the caller's mutex,
230 -- since the call must be over after returning from Wait_For_Completion.
231 -- No other task can access the call record at this point.
233 procedure Cancel_Protected_Entry_Call
234 (Block : in out Communication_Block) is
236 Entry_Calls.Try_To_Cancel_Entry_Call (Block.Cancelled);
237 end Cancel_Protected_Entry_Call;
243 function Cancelled (Block : Communication_Block) return Boolean is
245 return Block.Cancelled;
248 -------------------------
249 -- Complete_Entry_Body --
250 -------------------------
252 procedure Complete_Entry_Body (Object : Protection_Entries_Access) is
254 Exceptional_Complete_Entry_Body (Object, Ada.Exceptions.Null_Id);
255 end Complete_Entry_Body;
261 function Enqueued (Block : Communication_Block) return Boolean is
263 return Block.Enqueued;
266 -------------------------------------
267 -- Exceptional_Complete_Entry_Body --
268 -------------------------------------
270 procedure Exceptional_Complete_Entry_Body
271 (Object : Protection_Entries_Access;
272 Ex : Ada.Exceptions.Exception_Id)
274 procedure Transfer_Occurrence
275 (Target : Ada.Exceptions.Exception_Occurrence_Access;
276 Source : Ada.Exceptions.Exception_Occurrence);
277 pragma Import (C, Transfer_Occurrence, "__gnat_transfer_occurrence");
279 Entry_Call : constant Entry_Call_Link := Object.Call_In_Progress;
282 (Debug.Trace (STPO.Self, "Exceptional_Complete_Entry_Body", 'P'));
284 -- We must have abort deferred, since we are inside
285 -- a protected operation.
287 if Entry_Call /= null then
288 -- The call was not requeued.
290 Entry_Call.Exception_To_Raise := Ex;
292 if Ex /= Ada.Exceptions.Null_Id then
294 (Entry_Call.Self.Common.Compiler_Data.Current_Excep'Access,
295 STPO.Self.Common.Compiler_Data.Current_Excep);
298 -- Wakeup_Entry_Caller will be called from PO_Do_Or_Queue or
299 -- PO_Service_Entries on return.
302 if Runtime_Traces then
303 Send_Trace_Info (PO_Done, Entry_Call.Self);
305 end Exceptional_Complete_Entry_Body;
311 procedure PO_Do_Or_Queue
313 Object : Protection_Entries_Access;
314 Entry_Call : Entry_Call_Link;
315 With_Abort : Boolean)
317 E : constant Protected_Entry_Index :=
318 Protected_Entry_Index (Entry_Call.E);
319 Barrier_Value : Boolean;
322 -- When the Action procedure for an entry body returns, it is either
323 -- completed (having called [Exceptional_]Complete_Entry_Body) or it
324 -- is queued, having executed a requeue statement.
327 Object.Entry_Bodies (
328 Object.Find_Body_Index (Object.Compiler_Info, E)).
329 Barrier (Object.Compiler_Info, E);
331 if Barrier_Value then
333 -- Not abortable while service is in progress.
335 if Entry_Call.State = Now_Abortable then
336 Entry_Call.State := Was_Abortable;
339 Object.Call_In_Progress := Entry_Call;
342 (Debug.Trace (Self_ID, "PODOQ: start entry body", 'P'));
343 Object.Entry_Bodies (
344 Object.Find_Body_Index (Object.Compiler_Info, E)).Action (
345 Object.Compiler_Info, Entry_Call.Uninterpreted_Data, E);
347 if Object.Call_In_Progress /= null then
349 -- Body of current entry served call to completion
351 Object.Call_In_Progress := null;
357 STPO.Write_Lock (Entry_Call.Self);
358 Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done);
359 STPO.Unlock (Entry_Call.Self);
366 Requeue_Call (Self_ID, Object, Entry_Call, With_Abort);
369 elsif Entry_Call.Mode /= Conditional_Call
370 or else not With_Abort
373 if Run_Time_Restrictions.Set (Max_Entry_Queue_Length)
375 Run_Time_Restrictions.Value (Max_Entry_Queue_Length) <=
376 Queuing.Count_Waiting (Object.Entry_Queues (E))
378 -- This violates the Max_Entry_Queue_Length restriction,
379 -- raise Program_Error.
381 Entry_Call.Exception_To_Raise := Program_Error'Identity;
387 STPO.Write_Lock (Entry_Call.Self);
388 Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done);
389 STPO.Unlock (Entry_Call.Self);
395 Queuing.Enqueue (Object.Entry_Queues (E), Entry_Call);
396 Update_For_Queue_To_PO (Entry_Call, With_Abort);
399 -- Conditional_Call and With_Abort
405 STPO.Write_Lock (Entry_Call.Self);
406 pragma Assert (Entry_Call.State >= Was_Abortable);
407 Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Cancelled);
408 STPO.Unlock (Entry_Call.Self);
417 Queuing.Broadcast_Program_Error (Self_ID, Object, Entry_Call);
420 ------------------------
421 -- PO_Service_Entries --
422 ------------------------
424 procedure PO_Service_Entries
426 Object : Entries.Protection_Entries_Access;
427 Unlock_Object : Boolean := True)
429 E : Protected_Entry_Index;
431 Entry_Call : Entry_Call_Link;
435 Queuing.Select_Protected_Entry_Call (Self_ID, Object, Entry_Call);
437 exit when Entry_Call = null;
439 E := Protected_Entry_Index (Entry_Call.E);
441 -- Not abortable while service is in progress.
443 if Entry_Call.State = Now_Abortable then
444 Entry_Call.State := Was_Abortable;
447 Object.Call_In_Progress := Entry_Call;
450 if Runtime_Traces then
451 Send_Trace_Info (PO_Run, Self_ID,
452 Entry_Call.Self, Entry_Index (E));
456 (Debug.Trace (Self_ID, "POSE: start entry body", 'P'));
457 Object.Entry_Bodies (
458 Object.Find_Body_Index (Object.Compiler_Info, E)).Action (
459 Object.Compiler_Info, Entry_Call.Uninterpreted_Data, E);
462 Queuing.Broadcast_Program_Error
463 (Self_ID, Object, Entry_Call);
466 if Object.Call_In_Progress = null then
468 (Self_ID, Object, Entry_Call, Entry_Call.Requeue_With_Abort);
469 exit when Entry_Call.State = Cancelled;
472 Object.Call_In_Progress := null;
473 Caller := Entry_Call.Self;
479 STPO.Write_Lock (Caller);
480 Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done);
481 STPO.Unlock (Caller);
489 if Unlock_Object then
490 Unlock_Entries (Object);
492 end PO_Service_Entries;
494 ---------------------
495 -- Protected_Count --
496 ---------------------
498 function Protected_Count
499 (Object : Protection_Entries'Class;
500 E : Protected_Entry_Index)
504 return Queuing.Count_Waiting (Object.Entry_Queues (E));
507 --------------------------
508 -- Protected_Entry_Call --
509 --------------------------
511 -- Compiler interface only. Do not call from within the RTS.
520 -- X : protected_entry_index := 1;
521 -- B85b : communication_block;
522 -- communication_blockIP (B85b);
524 -- protected_entry_call (rTV!(r)._object'unchecked_access, X,
525 -- null_address, conditional_call, B85b, objectF => 0);
526 -- if cancelled (B85b) then
533 -- See also Cancel_Protected_Entry_Call for code expansion of asynchronous
536 -- The initial part of this procedure does not need to lock the the calling
537 -- task's ATCB, up to the point where the call record first may be queued
538 -- (PO_Do_Or_Queue), since before that no other task will have access to
541 -- If this is a call made inside of an abort deferred region, the call
542 -- should be never abortable.
544 -- If the call was not queued abortably, we need to wait until it is before
545 -- proceeding with the abortable part.
547 -- There are some heuristics here, just to save time for frequently
548 -- occurring cases. For example, we check Initially_Abortable to try to
549 -- avoid calling the procedure Wait_Until_Abortable, since the normal case
550 -- for async. entry calls is to be queued abortably.
552 -- Another heuristic uses the Block.Enqueued to try to avoid calling
553 -- Cancel_Protected_Entry_Call if the call can be served immediately.
555 procedure Protected_Entry_Call
556 (Object : Protection_Entries_Access;
557 E : Protected_Entry_Index;
558 Uninterpreted_Data : System.Address;
560 Block : out Communication_Block)
562 Self_ID : constant Task_Id := STPO.Self;
563 Entry_Call : Entry_Call_Link;
564 Initially_Abortable : Boolean;
565 Ceiling_Violation : Boolean;
569 (Debug.Trace (Self_ID, "Protected_Entry_Call", 'P'));
571 if Runtime_Traces then
572 Send_Trace_Info (PO_Call, Entry_Index (E));
575 if Self_ID.ATC_Nesting_Level = ATC_Level'Last then
577 (Storage_Error'Identity, "not enough ATC nesting levels");
580 -- If pragma Detect_Blocking is active then Program_Error must be
581 -- raised if this potentially blocking operation is called from a
585 and then Self_ID.Common.Protected_Action_Nesting > 0
587 Ada.Exceptions.Raise_Exception
588 (Program_Error'Identity, "potentially blocking operation");
591 Initialization.Defer_Abort (Self_ID);
592 Lock_Entries (Object, Ceiling_Violation);
594 if Ceiling_Violation then
596 -- Failed ceiling check
598 Initialization.Undefer_Abort (Self_ID);
602 Block.Self := Self_ID;
603 Self_ID.ATC_Nesting_Level := Self_ID.ATC_Nesting_Level + 1;
605 (Debug.Trace (Self_ID, "PEC: entered ATC level: " &
606 ATC_Level'Image (Self_ID.ATC_Nesting_Level), 'A'));
608 Self_ID.Entry_Calls (Self_ID.ATC_Nesting_Level)'Access;
609 Entry_Call.Next := null;
610 Entry_Call.Mode := Mode;
611 Entry_Call.Cancellation_Attempted := False;
613 if Self_ID.Deferral_Level > 1 then
614 Entry_Call.State := Never_Abortable;
616 Entry_Call.State := Now_Abortable;
619 Entry_Call.E := Entry_Index (E);
620 Entry_Call.Prio := STPO.Get_Priority (Self_ID);
621 Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
622 Entry_Call.Called_PO := To_Address (Object);
623 Entry_Call.Called_Task := null;
624 Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id;
626 PO_Do_Or_Queue (Self_ID, Object, Entry_Call, With_Abort => True);
627 Initially_Abortable := Entry_Call.State = Now_Abortable;
628 PO_Service_Entries (Self_ID, Object);
630 -- Try to prevent waiting later (in Try_To_Cancel_Protected_Entry_Call)
631 -- for completed or cancelled calls. (This is a heuristic, only.)
633 if Entry_Call.State >= Done then
635 -- Once State >= Done it will not change any more.
641 STPO.Write_Lock (Self_ID);
642 Utilities.Exit_One_ATC_Level (Self_ID);
643 STPO.Unlock (Self_ID);
649 Block.Enqueued := False;
650 Block.Cancelled := Entry_Call.State = Cancelled;
651 Initialization.Undefer_Abort (Self_ID);
652 Entry_Calls.Check_Exception (Self_ID, Entry_Call);
656 -- In this case we cannot conclude anything,
657 -- since State can change concurrently.
661 -- Now for the general case.
663 if Mode = Asynchronous_Call then
665 -- Try to avoid an expensive call.
667 if not Initially_Abortable then
670 Entry_Calls.Wait_Until_Abortable (Self_ID, Entry_Call);
673 Entry_Calls.Wait_Until_Abortable (Self_ID, Entry_Call);
677 elsif Mode < Asynchronous_Call then
679 -- Simple_Call or Conditional_Call
683 Entry_Calls.Wait_For_Completion (Entry_Call);
686 STPO.Write_Lock (Self_ID);
687 Entry_Calls.Wait_For_Completion (Entry_Call);
688 STPO.Unlock (Self_ID);
691 Block.Cancelled := Entry_Call.State = Cancelled;
694 pragma Assert (False);
698 Initialization.Undefer_Abort (Self_ID);
699 Entry_Calls.Check_Exception (Self_ID, Entry_Call);
700 end Protected_Entry_Call;
706 procedure Requeue_Call
708 Object : Protection_Entries_Access;
709 Entry_Call : Entry_Call_Link;
710 With_Abort : Boolean)
712 New_Object : Protection_Entries_Access;
713 Ceiling_Violation : Boolean;
715 E : Protected_Entry_Index;
718 New_Object := To_Protection (Entry_Call.Called_PO);
720 if New_Object = null then
722 -- Call is to be requeued to a task entry
728 Result := Rendezvous.Task_Do_Or_Queue
729 (Self_Id, Entry_Call,
730 With_Abort => Entry_Call.Requeue_With_Abort);
733 Queuing.Broadcast_Program_Error
734 (Self_Id, Object, Entry_Call, RTS_Locked => True);
742 -- Call should be requeued to a PO
744 if Object /= New_Object then
746 -- Requeue is to different PO
748 Lock_Entries (New_Object, Ceiling_Violation);
750 if Ceiling_Violation then
751 Object.Call_In_Progress := null;
752 Queuing.Broadcast_Program_Error
753 (Self_Id, Object, Entry_Call);
756 PO_Do_Or_Queue (Self_Id, New_Object, Entry_Call, With_Abort);
757 PO_Service_Entries (Self_Id, New_Object);
761 -- Requeue is to same protected object
763 if Entry_Call.Requeue_With_Abort
764 and then Entry_Call.Cancellation_Attempted
766 -- If this is a requeue with abort and someone tried
767 -- to cancel this call, cancel it at this point.
769 Entry_Call.State := Cancelled;
774 or else Entry_Call.Mode /= Conditional_Call
776 E := Protected_Entry_Index (Entry_Call.E);
778 if Run_Time_Restrictions.Set (Max_Entry_Queue_Length)
780 Run_Time_Restrictions.Value (Max_Entry_Queue_Length) <=
781 Queuing.Count_Waiting (Object.Entry_Queues (E))
783 -- This violates the Max_Entry_Queue_Length restriction,
784 -- raise Program_Error.
786 Entry_Call.Exception_To_Raise := Program_Error'Identity;
792 STPO.Write_Lock (Entry_Call.Self);
793 Initialization.Wakeup_Entry_Caller
794 (Self_Id, Entry_Call, Done);
795 STPO.Unlock (Entry_Call.Self);
802 (New_Object.Entry_Queues (E), Entry_Call);
803 Update_For_Queue_To_PO (Entry_Call, With_Abort);
807 PO_Do_Or_Queue (Self_Id, New_Object, Entry_Call, With_Abort);
813 ----------------------------
814 -- Protected_Entry_Caller --
815 ----------------------------
817 function Protected_Entry_Caller
818 (Object : Protection_Entries'Class) return Task_Id is
820 return Object.Call_In_Progress.Self;
821 end Protected_Entry_Caller;
823 -----------------------------
824 -- Requeue_Protected_Entry --
825 -----------------------------
827 -- Compiler interface only. Do not call from within the RTS.
836 -- procedure rPT__E10b (O : address; P : address; E :
837 -- protected_entry_index) is
838 -- type rTVP is access rTV;
840 -- _object : rTVP := rTVP!(O);
843 -- rR : protection renames _object._object;
844 -- vP : integer renames _object.v;
845 -- bP : boolean renames _object.b;
849 -- requeue_protected_entry (rR'unchecked_access, rR'
850 -- unchecked_access, 2, false, objectF => 0, new_objectF =>
854 -- complete_entry_body (_object._object'unchecked_access, objectF =>
859 -- abort_undefer.all;
860 -- exceptional_complete_entry_body (_object._object'
861 -- unchecked_access, current_exception, objectF => 0);
865 procedure Requeue_Protected_Entry
866 (Object : Protection_Entries_Access;
867 New_Object : Protection_Entries_Access;
868 E : Protected_Entry_Index;
869 With_Abort : Boolean)
871 Entry_Call : constant Entry_Call_Link := Object.Call_In_Progress;
875 (Debug.Trace (STPO.Self, "Requeue_Protected_Entry", 'P'));
876 pragma Assert (STPO.Self.Deferral_Level > 0);
878 Entry_Call.E := Entry_Index (E);
879 Entry_Call.Called_PO := To_Address (New_Object);
880 Entry_Call.Called_Task := null;
881 Entry_Call.Requeue_With_Abort := With_Abort;
882 Object.Call_In_Progress := null;
883 end Requeue_Protected_Entry;
885 -------------------------------------
886 -- Requeue_Task_To_Protected_Entry --
887 -------------------------------------
889 -- Compiler interface only.
899 -- accept_call (1, A79b);
901 -- requeue_task_to_protected_entry (rTV!(r)._object'
902 -- unchecked_access, 2, false, new_objectF => 0);
905 -- complete_rendezvous;
907 -- when all others =>
908 -- exceptional_complete_rendezvous (get_gnat_exception);
911 procedure Requeue_Task_To_Protected_Entry
912 (New_Object : Protection_Entries_Access;
913 E : Protected_Entry_Index;
914 With_Abort : Boolean)
916 Self_ID : constant Task_Id := STPO.Self;
917 Entry_Call : constant Entry_Call_Link := Self_ID.Common.Call;
920 Initialization.Defer_Abort (Self_ID);
922 -- We do not need to lock Self_ID here since the call is not abortable
923 -- at this point, and therefore, the caller cannot cancel the call.
925 Entry_Call.Needs_Requeue := True;
926 Entry_Call.Requeue_With_Abort := With_Abort;
927 Entry_Call.Called_PO := To_Address (New_Object);
928 Entry_Call.Called_Task := null;
929 Entry_Call.E := Entry_Index (E);
930 Initialization.Undefer_Abort (Self_ID);
931 end Requeue_Task_To_Protected_Entry;
933 ---------------------
934 -- Service_Entries --
935 ---------------------
937 procedure Service_Entries (Object : Protection_Entries_Access) is
938 Self_ID : constant Task_Id := STPO.Self;
940 PO_Service_Entries (Self_ID, Object);
943 --------------------------------
944 -- Timed_Protected_Entry_Call --
945 --------------------------------
947 -- Compiler interface only. Do not call from within the RTS.
949 procedure Timed_Protected_Entry_Call
950 (Object : Protection_Entries_Access;
951 E : Protected_Entry_Index;
952 Uninterpreted_Data : System.Address;
955 Entry_Call_Successful : out Boolean)
957 Self_Id : constant Task_Id := STPO.Self;
958 Entry_Call : Entry_Call_Link;
959 Ceiling_Violation : Boolean;
963 if Self_Id.ATC_Nesting_Level = ATC_Level'Last then
964 Raise_Exception (Storage_Error'Identity,
965 "not enough ATC nesting levels");
968 -- If pragma Detect_Blocking is active then Program_Error must be
969 -- raised if this potentially blocking operation is called from a
973 and then Self_Id.Common.Protected_Action_Nesting > 0
975 Ada.Exceptions.Raise_Exception
976 (Program_Error'Identity, "potentially blocking operation");
979 if Runtime_Traces then
980 Send_Trace_Info (POT_Call, Entry_Index (E), Timeout);
983 Initialization.Defer_Abort (Self_Id);
984 Lock_Entries (Object, Ceiling_Violation);
986 if Ceiling_Violation then
987 Initialization.Undefer_Abort (Self_Id);
991 Self_Id.ATC_Nesting_Level := Self_Id.ATC_Nesting_Level + 1;
993 (Debug.Trace (Self_Id, "TPEC: exited to ATC level: " &
994 ATC_Level'Image (Self_Id.ATC_Nesting_Level), 'A'));
996 Self_Id.Entry_Calls (Self_Id.ATC_Nesting_Level)'Access;
997 Entry_Call.Next := null;
998 Entry_Call.Mode := Timed_Call;
999 Entry_Call.Cancellation_Attempted := False;
1001 if Self_Id.Deferral_Level > 1 then
1002 Entry_Call.State := Never_Abortable;
1004 Entry_Call.State := Now_Abortable;
1007 Entry_Call.E := Entry_Index (E);
1008 Entry_Call.Prio := STPO.Get_Priority (Self_Id);
1009 Entry_Call.Uninterpreted_Data := Uninterpreted_Data;
1010 Entry_Call.Called_PO := To_Address (Object);
1011 Entry_Call.Called_Task := null;
1012 Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id;
1014 PO_Do_Or_Queue (Self_Id, Object, Entry_Call, With_Abort => True);
1015 PO_Service_Entries (Self_Id, Object);
1020 STPO.Write_Lock (Self_Id);
1023 -- Try to avoid waiting for completed or cancelled calls.
1025 if Entry_Call.State >= Done then
1026 Utilities.Exit_One_ATC_Level (Self_Id);
1031 STPO.Unlock (Self_Id);
1034 Entry_Call_Successful := Entry_Call.State = Done;
1035 Initialization.Undefer_Abort (Self_Id);
1036 Entry_Calls.Check_Exception (Self_Id, Entry_Call);
1040 Entry_Calls.Wait_For_Completion_With_Timeout
1041 (Entry_Call, Timeout, Mode, Yielded);
1046 STPO.Unlock (Self_Id);
1049 -- ??? Do we need to yield in case Yielded is False
1051 Initialization.Undefer_Abort (Self_Id);
1052 Entry_Call_Successful := Entry_Call.State = Done;
1053 Entry_Calls.Check_Exception (Self_Id, Entry_Call);
1054 end Timed_Protected_Entry_Call;
1056 ----------------------------
1057 -- Update_For_Queue_To_PO --
1058 ----------------------------
1060 -- Update the state of an existing entry call, based on
1061 -- whether the current queuing action is with or without abort.
1062 -- Call this only while holding the server's lock.
1063 -- It returns with the server's lock released.
1065 New_State : constant array (Boolean, Entry_Call_State)
1066 of Entry_Call_State :=
1068 (Never_Abortable => Never_Abortable,
1069 Not_Yet_Abortable => Now_Abortable,
1070 Was_Abortable => Now_Abortable,
1071 Now_Abortable => Now_Abortable,
1073 Cancelled => Cancelled),
1075 (Never_Abortable => Never_Abortable,
1076 Not_Yet_Abortable => Not_Yet_Abortable,
1077 Was_Abortable => Was_Abortable,
1078 Now_Abortable => Now_Abortable,
1080 Cancelled => Cancelled)
1083 procedure Update_For_Queue_To_PO
1084 (Entry_Call : Entry_Call_Link;
1085 With_Abort : Boolean)
1087 Old : constant Entry_Call_State := Entry_Call.State;
1090 pragma Assert (Old < Done);
1092 Entry_Call.State := New_State (With_Abort, Entry_Call.State);
1094 if Entry_Call.Mode = Asynchronous_Call then
1095 if Old < Was_Abortable and then
1096 Entry_Call.State = Now_Abortable
1102 STPO.Write_Lock (Entry_Call.Self);
1104 if Entry_Call.Self.Common.State = Async_Select_Sleep then
1105 STPO.Wakeup (Entry_Call.Self, Async_Select_Sleep);
1108 STPO.Unlock (Entry_Call.Self);
1116 elsif Entry_Call.Mode = Conditional_Call then
1117 pragma Assert (Entry_Call.State < Was_Abortable);
1120 end Update_For_Queue_To_PO;
1122 end System.Tasking.Protected_Objects.Operations;