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-- C974011.A

--

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--     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

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--     recipients unlimited rights  equal to those held by the Government.

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--     released technical data and computer software in whole or in part, in

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--                                    DISCLAIMER

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--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR

--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED

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--*

--

-- OBJECTIVE:

--      Check that the sequence of statements of the triggering alternative

--      of an asynchronous select statement is not executed if the triggering

--      statement is a task entry call and the entry is not accepted

--      before the abortable part completes.

--      Check that the call queued on the entry is cancelled

--

-- 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 (with a delay) a routine waiting

--      for user input

--

--      Once the call is known to be queued, complete the abortable part.

--      Check that the rendezvous (and thus the trigger) does not complete.

--      Then clear the barrier and check that the entry has been cancelled

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--      28 Nov 95   SAIC    Eliminated shared global variable for ACVC 2.0.1

--

--!

with ImpDef;

--

package C974011_0 is  -- Automated teller machine abstraction.

   type Key_Enum is (None, Cancel, Deposit, Withdraw);

   protected Key_PO is

      procedure Set (K : Key_Enum);

      function  Value return Key_Enum;

   private

      Current : Key_Enum := None;

   end Key_PO;

   -- Flags for testing purposes

   TC_Abortable_Part_Completed : Boolean := False;

   TC_Rendezvous_Entered       : Boolean := False;

   TC_Delay_Time : constant duration := ImpDef.Switch_To_New_Task;

   Count  : Integer := 1234;  -- Global to defeat optimization.

   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 C974011_0;

     --==================================================================--

with Report;

package body C974011_0 is

   protected body Key_PO is

      procedure Set (K : Key_Enum) is

      begin

         Current := K;

      end Set;

      function Value return Key_Enum is

      begin

        return Current;

      end Value;

   end Key_PO;

   procedure Listen_For_Input (Key : out Key_Enum) is

   begin

      -- Model the situation where the user does not press cancel thus

      -- allowing validation to complete

      delay TC_Delay_Time;  -- Long enough to force queuing on

                            -- Keyboard.Cancel_Pressed.

      Key := Key_PO.Value;

   end Listen_For_Input;

   -- One of these gets created as "Keyboard" for each transaction

   --

   task body ATM_Keyboard_Task is

      Key_Pressed : Key_Enum;

   begin

      loop

                                                           -- Force entry calls

         Listen_For_Input (Key_Pressed);                   -- to be queued,

         select

            when (Key_Pressed = Cancel) =>

               accept Cancel_Pressed do

                  TC_Rendezvous_Entered := True;

               end Cancel_Pressed;

               -- User has cancelled the transaction so we exit the

               -- loop and allow the task to terminate

               exit;

         else

            delay ImpDef.Switch_To_New_Task;

         end select;

      end loop;

   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

      Count := (Count + 1) mod Integer (Card.PIN);

      -- Simulate a validation activity which is longer than the time

      -- taken in Listen_For_Input but not inordinately so.

      delay TC_Delay_Time * 2;

   end Validate_Card;

   procedure Perform_Transaction (Card : in ATM_Card_Type) is

   begin

      if TC_Rendezvous_Entered then

         Report.Failed ("Triggering statement completed");

      end if;

      if Count = 1234 then

         -- Initial value is unchanged

         Report.Failed ("Abortable part did not execute");

      end if;

      if not TC_Abortable_Part_Completed then

         Report.Failed ("Abortable part did not complete");

      end if;

   end Perform_Transaction;

end C974011_0;

     --==================================================================--

with Report;

with C974011_0;  -- Automated teller machine abstraction.

use  C974011_0;

procedure C974011 is

   Card_Data : ATM_Card_Type;

begin  -- Main program.

   Report.Test ("C974011", "Asynchronous Select: Trigger is queued on a " &

                            "task entry and the abortable part " &

                            "completes first");

   Read_Card (Card_Data);

   declare

      -- Create the task for this transaction

      Keyboard : C974011_0.ATM_Keyboard_Task;

   begin

      --                                    --

      -- Asynchronous select is tested here --

      --                                    --

      select

         Keyboard.Cancel_Pressed;      -- Entry call is initially queued, so

                                       -- abortable part starts.

         raise Transaction_Canceled;   -- This would be executed if we

                                       -- completed the rendezvous

      then abort

         Validate_Card (Card_Data);

         TC_Abortable_Part_Completed := true;

      end select;

      Perform_Transaction (Card_Data);

      -- Now clear the entry barrier to allow the rendezvous to complete

      -- if the triggering call has not been cancelled

      Key_PO.Set (Cancel);

      --

      delay TC_Delay_Time;  -- to allow it all to take place

      if TC_Rendezvous_Entered then

         Report.Failed ("Triggering Call was not cancelled");

      end if;

      abort Keyboard;    -- clean up.  (Note: the task will only exit the

                         -- loop and terminate if the call hanging on the

                         -- entry is executed.)

   exception

      when Transaction_Canceled =>

         Report.Failed ("Triggering alternative sequence of statements " &

                           "executed");

      when Others =>

         Report.Failed ("Unexpected exception in the Main");

   end;

   Report.Result;

end C974011;