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-- 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;
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