| -- C974005.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 Tasking_Error is raised at the point of an entry call |
| -- which is the triggering statement of an asynchronous select, if |
| -- the entry call is queued, but the task containing the entry completes |
| -- before it can be accepted or canceled. |
| -- |
| -- Check that the abortable part is aborted if it does not complete |
| -- before the triggering statement completes. |
| -- |
| -- Check that the sequence of statements of the triggering alternative |
| -- is not executed. |
| -- |
| -- 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 is NOT the input expected by the |
| -- guard on the accept statement. The entry remains closed, and the |
| -- task completes its execution. Since the entry was not accepted before |
| -- its task completed, Tasking_Error is raised at the point of the entry |
| -- call. |
| -- |
| -- |
| -- CHANGE HISTORY: |
| -- 06 Dec 94 SAIC ACVC 2.0 |
| -- |
| --! |
| |
| package C974005_0 is -- Automated teller machine abstraction. |
| |
| |
| -- Flags for testing purposes: |
| |
| Count : Integer := 1234; |
| |
| 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 C974005_0; |
| |
| |
| --==================================================================-- |
| |
| |
| with Report; |
| with ImpDef; |
| |
| package body C974005_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 a transaction key (NOT Cancel). |
| |
| -- Delay long enough to force queuing of Keyboard.Cancel_Pressed. |
| delay ImpDef.Clear_Ready_Queue; |
| |
| if Report.Equal (3, 3) then -- Always true. |
| Key := Deposit; -- Cancel is NOT pressed. |
| end if; |
| end Listen_For_Input; |
| |
| |
| task body ATM_Keyboard_Task is |
| Key_Pressed : Key_Enum := None; |
| begin |
| |
| -- Note: no loop. If the user does not press Cancel, the task completes. |
| -- In this model of the keyboard monitor, the user only gets one chance |
| -- to cancel the card validation. |
| -- Force entry |
| Listen_For_Input (Key_Pressed); -- calls to be |
| -- queued, but do |
| -- NOT set guard |
| -- to true. |
| select |
| when (Key_Pressed = Cancel) => -- Guard is false, |
| accept Cancel_Pressed do -- so entry call |
| Report.Failed ("Accept statement executed"); -- remains queued. |
| end Cancel_Pressed; |
| else -- Else alternative |
| Key_Pressed := None; -- executed, then |
| end select; -- task ends. |
| exception |
| 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 |
| -- Additional analysis added to aid developers |
| Report.Failed ("Abortable part did not execute"); |
| end if; |
| end Perform_Transaction; |
| |
| |
| end C974005_0; |
| |
| |
| --==================================================================-- |
| |
| |
| with Report; |
| |
| with C974005_0; -- Automated teller machine abstraction. |
| use C974005_0; |
| |
| procedure C974005 is |
| |
| Card_Data : ATM_Card_Type; |
| |
| begin -- Main program. |
| |
| Report.Test ("C974005", "ATC: trigger is queued but task terminates" & |
| " before call is serviced"); |
| |
| Read_Card (Card_Data); |
| |
| begin |
| |
| declare |
| Keyboard : C974005_0.ATM_Keyboard_Task; |
| begin |
| |
| -- -- |
| -- Asynchronous select is tested here -- |
| -- -- |
| |
| select |
| Keyboard.Cancel_Pressed; -- Entry call initially queued, so |
| -- abortable part starts. |
| |
| -- Tasking_Error raised here when |
| -- Keyboard completes before entry |
| -- call can be accepted, and before |
| -- abortable part completes. |
| |
| raise Transaction_Canceled; -- Should not be executed. |
| then abort |
| Validate_Card (Card_Data); -- Keyboard task completes before |
| -- Keyboard.Cancel_Pressed is |
| -- accepted, and before this call |
| -- finishes. Tasking_Error is raised |
| -- at the point of the entry call, |
| -- and this call is 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; |
| Perform_Transaction (Card_Data); -- Should not be reached. |
| exception |
| when Transaction_Canceled => |
| Report.Failed ("Triggering alternative sequence of statements " & |
| "executed"); |
| when Tasking_Error => |
| if Count = 1234 then |
| Report.Failed ("Abortable part did not execute"); |
| end if; |
| when others => |
| Report.Failed ("Wrong exception raised"); |
| end; |
| |
| exception |
| when Tasking_Error => |
| Report.Failed ("Correct exception raised at wrong level"); |
| when others => |
| Report.Failed ("Wrong exception raised at wrong level"); |
| end; |
| |
| Report.Result; |
| |
| end C974005; |
