-- C954011.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 
--     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 a requeue is placed on the correct entry; that the 
--      original caller waits for the completion of the requeued rendezvous;
--      that the original caller continues after the rendezvous.
--      Specifically, this test checks requeue to an entry in a different
--      task, requeue where the entry has parameters, and requeue with
--      abort.
--
-- TEST DESCRIPTION:
--      In the Distributor task, requeue two successive calls on the entries
--      of two separate target tasks.  Each task in each of the  paths adds 
--      identifying information in the transaction being passed.  This
--      information is checked by the Message tasks on completion ensuring that
--      the requeues have been placed on the correct queues.
--
--      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
--      26 Nov 95   SAIC    Fixed problems with shared global variables
--                          for ACVC 2.0.1
--
--!

with Report;
with ImpDef;
         
procedure C954011 is
 

   -- Arbitrary test values
   Credit_Return : constant := 1;
   Debit_Return  : constant := 2;

   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 := false;
      end record;

   protected type Message_Mgr is
      procedure Mark_Complete;
      function Is_Complete return Boolean;
   private
      Complete : Boolean := False;
   end Message_Mgr;

   protected body Message_Mgr is
      procedure Mark_Complete is
      begin
         Complete := True;
      end Mark_Complete;

      Function Is_Complete return Boolean is
      begin
         return Complete;
      end Is_Complete;
   end Message_Mgr;

   TC_Debit_Message  : Message_Mgr;
   TC_Credit_Message : Message_Mgr;


   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.
   --      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 allow it
   --      to terminate at that point
   --
   task body Line_Driver is
      Current_ID : integer := 1;
      TC_Last_was_for_credit : 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  -- arbitrarily limit to two messages for the test
         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 TC_Last_was_for_credit then
               Build_Debit_Record ( Next_Transaction );            
            else
               Build_Credit_Record( Next_Transaction );
               TC_Last_was_for_credit := true;
            end if;
            Next_Message_Task.Accept_Transaction ( Next_Transaction );  
         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

      
      -- The following is all Test Control Code

      -- 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
         if This_Transaction.Return_Value     /= Credit_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_Credit_Message.Mark_Complete;
      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.Mark_Complete;
      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
               -- Mark the message as having passed through the distributor
               Transaction.TC_Thru_Distrib := true;

               -- Pass this transaction on the appropriate computation
               -- task
               case Transaction.Code is 
                  when Credit =>
                     requeue Credit_Computation.Input with abort;
                  when Debit => 
                     requeue Debit_Computation.Input with 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

               -- For the test: 
               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
               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 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

               -- For the test: 
               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 -- c954011

   Report.Test ("C954011", "Requeue from task body to task entry");

   Line_Driver.Start;        -- Start the test

   -- Ensure that the message tasks complete before reporting the result
   while not (TC_Credit_Message.Is_Complete and 
              TC_Debit_Message.Is_Complete) loop
      delay ImpDef.Minimum_Task_Switch;
   end loop;

   Report.Result;

end C954011;