-- C974004.A -- -- -- Grant of Unlimited Rights -- -- Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687, -- F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained -- unlimited rights in the software and documentation contained herein. -- Unlimited rights are defined in DFAR 252.227-7013(a)(19). By making -- this public release, the Government intends to confer upon all -- recipients unlimited rights equal to those held by the Government. -- These rights include rights to use, duplicate, release or disclose the -- released technical data and computer software in whole or in part, in -- any manner and for any purpose whatsoever, and to have or permit others -- to do so. -- -- DISCLAIMER -- -- ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR -- DISCLOSED ARE AS IS. THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED -- WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE -- SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE -- OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A -- PARTICULAR PURPOSE OF SAID MATERIAL. --* -- -- OBJECTIVE: -- Check that the abortable part of an asynchronous select statement -- is aborted if it does not complete before the triggering statement -- completes, where the triggering statement is a task entry call, -- the entry call is queued, and the entry call completes by propagating -- an exception and that the sequence of statements of the triggering -- alternative is not executed after the abortable part is left and that -- the exception propagated by the entry call is re-raised immediately -- following the asynchronous select. -- -- TEST DESCRIPTION: -- Declare a main procedure containing an asynchronous select with a task -- entry call as triggering statement. Force the entry call to be -- queued by having the task call a procedure, prior to the corresponding -- accept statement, which simulates a routine waiting for user input -- (with a delay). -- -- Simulate a time-consuming routine in the abortable part by calling a -- procedure containing an infinite loop. Meanwhile, simulate input by -- the user (the delay expires), which causes the task to execute the -- accept statement corresponding to the triggering entry call. Raise -- an exception in the accept statement which is not handled by the task, -- and which is thus propagated to the caller. -- -- -- CHANGE HISTORY: -- 06 Dec 94 SAIC ACVC 2.0 -- --! package C974004_0 is -- Automated teller machine abstraction. -- Flags for testing purposes: Count : Integer := 1234; -- Global to defeat -- optimization. Propagated_From_Task : exception; type Key_Enum is (None, Cancel, Deposit, Withdraw); type Card_Number_Type is private; type Card_PIN_Type is private; type ATM_Card_Type is private; Transaction_Canceled : exception; task type ATM_Keyboard_Task is entry Cancel_Pressed; end ATM_Keyboard_Task; procedure Read_Card (Card : in out ATM_Card_Type); procedure Validate_Card (Card : in ATM_Card_Type); procedure Perform_Transaction (Card : in ATM_Card_Type); private type Card_Number_Type is range 1 .. 9999; type Card_PIN_Type is range 100 .. 999; type ATM_Card_Type is record Number : Card_Number_Type; PIN : Card_PIN_Type; end record; end C974004_0; --==================================================================-- with Report; with ImpDef; package body C974004_0 is procedure Listen_For_Input (Key : out Key_Enum) is begin -- Simulate the situation where a user waits a bit for the card to -- be validated, then presses cancel before it completes. -- Delay long enough to force queuing of Keyboard.Cancel_Pressed. delay ImpDef.Clear_Ready_Queue; if Report.Equal (3, 3) then -- Always true. Key := Cancel; end if; end Listen_For_Input; -- One of these gets created as "Keyboard" for each transaction -- task body ATM_Keyboard_Task is Key_Pressed : Key_Enum := None; begin loop -- Force entry calls to be Listen_For_Input (Key_Pressed); -- queued, then set guard to -- true. select when (Key_Pressed = Cancel) => -- Guard is now true, so accept accept Cancel_Pressed do -- queued entry call. null; --:::: user code for cancel -- Now simulate an unexpected exception arising in the -- user code raise Propagated_From_Task; -- Propagate an exception. end Cancel_Pressed; Report.Failed ("Exception not propagated in ATM_Keyboard_Task"); -- User has canceled the transaction so we exit the -- loop and allow the task to terminate exit; else Key_Pressed := None; end select; end loop; exception when Propagated_From_Task => null; -- This is the expected test behavior when others => Report.Failed ("Unexpected Exception in ATM_Keyboard_Task"); end ATM_Keyboard_Task; procedure Read_Card (Card : in out ATM_Card_Type) is begin Card.Number := 9999; Card.PIN := 111; end Read_Card; procedure Validate_Card (Card : in ATM_Card_Type) is begin -- Simulate an exceedingly long validation activity. loop -- Infinite loop. Count := (Count + 1) mod Integer (Card.PIN); -- Synch. point to allow transfer of control to Keyboard -- task during this simulation delay ImpDef.Minimum_Task_Switch; exit when not Report.Equal (Count, Count); -- Always false. end loop; end Validate_Card; procedure Perform_Transaction (Card : in ATM_Card_Type) is begin Report.Failed ("Exception not re-raised immediately following " & "asynchronous select"); if Count = 1234 then -- Initial value is unchanged Report.Failed ("Abortable part did not execute"); end if; end Perform_Transaction; end C974004_0; --==================================================================-- with Report; with C974004_0; -- Automated teller machine abstraction. use C974004_0; procedure C974004 is Card_Data : ATM_Card_Type; begin -- Main program. Report.Test ("C974004", "Asynchronous Select: Trigger is queued on a " & "task entry and is completed first by an " & "exception"); Read_Card (Card_Data); begin declare -- Create the task for this transaction Keyboard : C974004_0.ATM_Keyboard_Task; begin -- -- -- Asynchronous select is tested here -- -- -- select Keyboard.Cancel_Pressed; -- Entry call initially queued, so -- abortable part starts. raise Transaction_Canceled; -- Should not be executed. then abort Validate_Card (Card_Data); -- Keyboard.Cancel_Pressed is accepted -- and propagates an exception before -- this call finishes; it is then -- aborted. -- Check that the whole of the abortable part is aborted, not -- just the statement in the abortable part that was executing -- at the time Report.Failed ("Abortable part not aborted"); end select; -- The propagated exception is -- re-raised here; control passes to -- the exception handler. Perform_Transaction(Card_Data); -- Should not be reached. exception when Transaction_Canceled => Report.Failed ("Triggering alternative sequence of statements " & "executed"); when Propagated_From_Task => -- This is the expected test path if Count = 1234 then -- Initial value is unchanged Report.Failed ("Abortable part did not execute"); end if; when Tasking_Error => Report.Failed ("Tasking_Error raised"); when others => Report.Failed ("Wrong exception raised"); end; exception when Propagated_From_Task => Report.Failed ("Correct exception raised at wrong level"); when others => Report.Failed ("Wrong exception raised at wrong level"); end; Report.Result; end C974004;