-- 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;