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-- C954014.A

--

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--

-- OBJECTIVE:

--     Check that a requeue is not canceled and that the requeueing

--     task is unaffected when a calling task is aborted. Check that the

--     abort is deferred until the entry call is complete.

--     Specifically, check requeue to an entry in a different task,

--     requeue where the entry call has parameters, and requeue

--     without the abort option.

--

-- TEST DESCRIPTION

--     In the Driver create a task that places a call on the

--     Distributor.  In the Distributor requeue this call on the Credit task.

--     Abort the calling task when it is known to be in rendezvous with the

--     Credit task. (We arrange this by using artificial synchronization

--     points in the Driver and the accept body of the Credit task) Ensure

--     that the abort is deferred (the task is not terminated) until the

--     accept body completes.   Afterwards, send one extra message through

--     the Distributor to check that the requeueing task has not been

--     disrupted.

--

--     This series of tests uses a simulation of a transaction driven

--     processing system.  Line Drivers accept input from an external source

--     and build them into transaction records.  These records are then

--     encapsulated in message tasks which remain extant for the life of the

--     transaction in the system.  The message tasks put themselves on the

--     input queue of a Distributor which, from information in the

--     transaction and/or system load conditions forwards them to other

--     operating tasks. These in turn might forward the transactions to yet

--     other tasks for further action.  The routing is, in real life, dynamic

--     and unpredictable at the time of message generation.  All rerouting in

--     this  model is done by means of requeues.

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--      25 Nov 95   SAIC    Replaced global variables with protected objects

--                          for ACVC 2.0.1.

--

--!

with Report;

with ImpDef;

procedure C954014 is

   -- Arbitrary test values

   Credit_Return : constant := 1;

   Debit_Return  : constant := 2;

   protected type Shared_Boolean (Initial_Value : Boolean := False) is

      procedure Set_True;

      procedure Set_False;

      function  Value return Boolean;

   private

      Current_Value : Boolean := Initial_Value;

   end Shared_Boolean;

   protected body Shared_Boolean is

      procedure Set_True is

      begin

         Current_Value := True;

      end Set_True;

      procedure Set_False is

      begin

         Current_Value := False;

      end Set_False;

      function Value return Boolean is

      begin

         return Current_Value;

      end Value;

   end Shared_Boolean;

   TC_Debit_Message_Complete  : Shared_Boolean (False);

   -- Synchronization flags for handshaking between the Line_Driver

   -- and the Accept body in the Credit Task

   TC_Handshake_A : Shared_Boolean (False);

   TC_Handshake_B : Shared_Boolean (False);

   TC_Handshake_C : Shared_Boolean (False);

   TC_Handshake_D : Shared_Boolean (False);

   TC_Handshake_E : Shared_Boolean (False);

   TC_Handshake_F : Shared_Boolean (False);

   type Transaction_Code is (Credit, Debit);

   type Transaction_Record;

   type acc_Transaction_Record is access Transaction_Record;

   type Transaction_Record is

      record

         ID               : integer := 0;

         Code             : Transaction_Code := Debit;

         Account_Number   : integer := 0;

         Stock_Number     : integer := 0;

         Quantity         : integer := 0;

         Return_Value     : integer := 0;

         TC_Message_Count : integer := 0;

         TC_Thru_Distrib  : Boolean;

      end record;

   task type Message_Task is

      entry Accept_Transaction (In_Transaction : acc_Transaction_Record);

   end Message_Task;

   type acc_Message_Task is access Message_Task;

   task Line_Driver is

      entry start;

   end Line_Driver;

   task Distributor is

      entry Input(Transaction : acc_Transaction_Record);

   end Distributor;

   task Credit_Computation is

      entry Input(Transaction : acc_Transaction_Record);

   end Credit_Computation;

   task Debit_Computation is

      entry Input(Transaction : acc_Transaction_Record);

   end Debit_Computation;

   -- Assemble messages received from an external source

   --   Creates a message task for each. The message tasks remain extant

   --   for the life of the messages in the system.

   --      TC: The Line Driver task would normally be designed to loop

   --      continuously creating the messages as input is received.  Simulate

   --      this  but limit it to two dummy messages for this test and use

   --      special artificial handshaking checks with the Credit accept body

   --      to control the test. Allow it to terminate at the end

   --

   task body Line_Driver is

      Current_ID : integer := 1;

      TC_First_message_sent: Boolean := false;

      procedure Build_Credit_Record

                              ( Next_Transaction : acc_Transaction_Record ) is

         Dummy_Account : constant integer := 100;

      begin

            Next_Transaction.ID := Current_ID;

            Next_Transaction.Code := Credit;

            Next_Transaction.Account_Number := Dummy_Account;

            Current_ID := Current_ID + 1;

      end Build_Credit_Record;

      procedure Build_Debit_Record

                              ( Next_Transaction : acc_Transaction_Record ) is

         Dummy_Account : constant integer := 200;

      begin

            Next_Transaction.ID := Current_ID;

            Next_Transaction.Code := Debit;

            Next_Transaction.Account_Number := Dummy_Account;

            Current_ID := Current_ID + 1;

      end Build_Debit_Record;

   begin

      accept Start;       -- Wait for trigger from main

      for i in 1..2 loop  -- TC: arbitrarily limit to one credit message

                          --     and one debit, then complete

         declare

            -- Create a task for the next message

            Next_Message_Task : acc_Message_Task := new Message_Task;

            -- Create a record for it

            Next_Transaction : acc_Transaction_Record :=

                                                   new Transaction_Record;

         begin

            if not TC_First_Message_Sent then

               -- send out the first message which will be aborted

               Build_Credit_Record ( Next_Transaction );

               Next_Message_Task.Accept_Transaction ( Next_Transaction );

               TC_First_Message_Sent := true;

               -- Wait for Credit task to get into the accept body

               --   The call from the Message Task has been requeued by

               --   the distributor

               while not TC_Handshake_A.Value loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               -- Abort the calling task; the Credit task is guaranteed to

               -- be in the accept body

               abort Next_Message_Task.all;     -- We are still in this declare

                                                -- block

               -- Inform the Credit task that the abort has been initiated

               TC_Handshake_B.Set_True;

               -- Now wait for the "acknowledgment" from the Credit task

               -- this ensures a complete task switch (at least)

               while not TC_Handshake_C.Value loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               -- The aborted task must not terminate till the accept body

               -- has completed

               if Next_Message_Task'terminated then

                  Report.Failed ("The abort was not deferred");

               end if;

               -- Inform the Credit task that the termination has been checked

               TC_Handshake_D.Set_True;

               -- Now wait for the completion of the accept body in the

               -- Credit task

               while not TC_Handshake_E.Value loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               while not ( Next_Message_Task'terminated ) loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               -- Indicate to the Main program that this section is complete

               TC_Handshake_F.Set_True;

            else

               -- The main part of the test is complete. Send one Debit message

               -- as further exercise of the Distributor to ensure it has not

               -- been affected by the abort of the requeue;

               Build_Debit_Record ( Next_Transaction );

               Next_Message_Task.Accept_Transaction ( Next_Transaction );

            end if;

         end;   -- declare

      end loop;

   exception

      when others =>

         Report.Failed ("Unexpected exception in Line_Driver");

   end Line_Driver;

   task body Message_Task is

      TC_Original_Transaction_Code : Transaction_Code;

      This_Transaction : acc_Transaction_Record := new Transaction_Record;

   begin

      accept Accept_Transaction (In_Transaction : acc_Transaction_Record) do

         This_Transaction.all := In_Transaction.all;

      end Accept_Transaction;

      -- Note the original code to ensure correct return

      TC_Original_Transaction_Code := This_Transaction.Code;

      -- Queue up on Distributor's Input queue

      Distributor.Input ( This_Transaction );

      -- This task will now wait for the requeued rendezvous

      -- to complete before proceeding

      -- After the required computations have been performed

      -- return the Transaction_Record appropriately (probably to an output

      -- line driver)

      null;            -- stub

      -- For the test check that the return values are as expected

      if TC_Original_Transaction_Code /= This_Transaction.Code then

         -- Incorrect rendezvous

         Report.Failed ("Message Task: Incorrect code returned");

      end if;

      if This_Transaction.Code = Credit then

         -- The only Credit message was the one that should have been aborted

         Report.Failed ("Abort was not effective");

      else

         if This_Transaction.Return_Value     /= Debit_Return or

            This_Transaction.TC_Message_Count /= 1            or not

            This_Transaction.TC_Thru_Distrib       then

               Report.Failed ("Expected path not traversed");

         end if;

         TC_Debit_Message_Complete.Set_True;

      end if;

   exception

      when others =>

         Report.Failed ("Unexpected exception in Message_Task");

   end Message_Task;

   -- Dispose each input Transaction_Record to the appropriate

   -- computation tasks

   --

   task body Distributor is

   begin

      loop

         select

            accept Input (Transaction : acc_Transaction_Record) do

               -- Indicate that the  message did pass through the

               -- Distributor Task

               Transaction.TC_Thru_Distrib := true;

               -- Pass this transaction on the appropriate computation

               -- task

               case Transaction.Code is

                  when Credit =>

                     requeue Credit_Computation.Input;   -- without abort

                  when Debit =>

                     requeue Debit_Computation.Input;    -- without abort

               end case;

            end Input;

         or

            terminate;

         end select;

      end loop;

   exception

      when others =>

         Report.Failed ("Unexpected exception in Distributor");

   end Distributor;

   -- Computation task.

   --   Note:  After the computation is performed in this task and the

   --          accept body is completed the rendezvous in the original

   --          message task is completed.

   task body Credit_Computation is

      Message_Count   : integer := 0;

   begin

      loop

         select

            accept Input ( Transaction : acc_Transaction_Record) do

               -- Perform the computations required for this transaction

               --

               null;     -- stub

               -- The rest of this code is for Test Control

               --

               if not Transaction.TC_Thru_Distrib then

                  Report.Failed

                         ("Credit Task: Wrong queue, Distributor bypassed");

               end if;

               if Transaction.code /= Credit then

                  Report.Failed

                         ("Credit Task: Requeue delivered to the wrong queue");

               end if;

               -- for the test plug a known value and count

               Transaction.Return_Value := Credit_Return;

               -- one, and only one message should pass through

               if Message_Count /= 0 then

                  Report.Failed ("Aborted Requeue was not canceled -1");

               end if;

               Message_Count := Message_Count + 1;

               Transaction.TC_Message_Count := Message_Count;

               -- Having done the basic housekeeping we now need to signal

               -- that we are in the accept body of the credit task.  The

               -- message has arrived and the Line Driver may now abort the

               -- calling task

               TC_Handshake_A.Set_True;

               -- Now wait for the Line Driver to inform us the calling

               -- task has been aborted

               while not TC_Handshake_B.Value loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               -- The abort has taken place

               -- Inform the Line Driver that we are still running in the

               -- accept body

               TC_Handshake_C.Set_True;

               -- Now wait for the Line Driver to digest this information

               while not TC_Handshake_D.Value loop

                  delay ImpDef.Minimum_Task_Switch;

               end loop;

               -- The Line driver has checked that the caller is not terminated

               -- We can now complete the accept

            end Input;

            -- We are out of the accept

            TC_Handshake_E.Set_True;

         or

            terminate;

         end select;

      end loop;

   exception

      when others =>

         Report.Failed ("Unexpected exception in Credit_Computation");

   end Credit_Computation;

   -- Computation task.

   --   Note:  After the computation is performed in this task and the

   --          accept body is completed the rendezvous in the original

   --          message task is completed.

   task body Debit_Computation is

      Message_Count   : integer := 0;

   begin

      loop

         select

            accept Input (Transaction : acc_Transaction_Record) do

               -- Perform the computations required for this message

               --

               null;      -- stub

               -- The rest of this code is for Test Control

               --

               if not Transaction.TC_Thru_Distrib then

                  Report.Failed

                         ("Debit Task: Wrong queue, Distributor bypassed");

               end if;

               if Transaction.code /= Debit then

                  Report.Failed

                         ("Debit Task: Requeue delivered to the wrong queue");

               end if;

               -- for the test plug a known value and count

               Transaction.Return_Value := Debit_Return;

               -- one, and only one, message should pass through

               Message_Count := Message_Count + 1;

               Transaction.TC_Message_Count := Message_Count;

            end Input;

         or

            terminate;

         end select;

      end loop;

   exception

      when others =>

         Report.Failed ("Unexpected exception in Debit_Computation");

   end Debit_Computation;

begin -- c954014

   Report.Test ("C954014", "Abort a task that has a call" &

                                          " requeued_without_abort");

   Line_Driver.Start;   -- Start the test

   -- Wait for the message tasks to complete before reporting the result

   --

   while not (TC_Handshake_F.Value                  -- abort not effective?

              and TC_Debit_Message_Complete.Value   -- Distributor affected?

              and TC_Handshake_E.Value ) loop       -- accept not completed?

      delay ImpDef.Minimum_Task_Switch;

   end loop;

   Report.Result;

end C954014;