c954012.a

来自「linux下编程用 编译软件」· A 代码 · 共 497 行 · 第 1/2 页

-- C954012.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 a requeue within an accept body to another entry in the same task
--     Specifically, check a call with parameters and a requeue with abort.
--
-- TEST DESCRIPTION:
--      One transaction is sent through to check the paths. After
--      processing this the Credit task sets the "overloaded" indicator.  Once
--      this indicator is set the Distributor queues low priority transactions
--      on a Wait_for_Underload queue in the same task using a requeue.  The
--      Distributor still delivers high priority transactions.  After two high
--      priority transactions have been processed by the Credit task it clears
--      the overload condition.  The low priority transactions should now be
--      delivered.
--
--      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    Fixed shared global variable problem for
--                          ACVC 2.0.1
--      14 Mar 03   RLB     Fixed a race condition and an incorrect termination
--                          condition in the test.
--!

with Report;
with ImpDef;
with Ada.Calendar;

procedure C954012 is

   function "=" (X,Y: Ada.Calendar.Time) return Boolean
                                                   renames Ada.Calendar."=";

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


   -- This is used as an "initializing" time for the messages as they are
   -- created.  As they pass through the Distributor they get a time_stamp
   -- of the current time. An arbitrary base time is chosen.
   --    TC: this fact is used, incidentally, to check that the messages have,
   --    indeed, passed through the Distributor as expected.
   --
   Base_Time : Ada.Calendar.Time := Ada.Calendar.Time_of(1959,3,9);


   -- Mechanism to count the number of Credit Message tasks completed
   protected TC_Tasks_Completed is
      procedure Increment;
      function  Count return integer;
   private
      Number_Complete : integer := 0;
   end TC_Tasks_Completed;

   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);
   -- Handshaking mechanism between the Line Driver and the Credit task
   TC_First_Message_Has_Arrived : Shared_Boolean (False);
   Credit_Overloaded : Shared_Boolean (False);

   TC_Credit_Messages_Expected  : constant integer := 5;

   type Transaction_Code is (Credit, Debit);
   type Transaction_Priority is (High, Low);

   type Transaction_Record;
   type acc_Transaction_Record is access Transaction_Record;
   type Transaction_Record is
      record
         ID               : integer := 0;
         Code             : Transaction_Code := Debit;
         Priority         : Transaction_Priority := High;
         Account_Number   : integer := 0;
         Stock_Number     : integer := 0;
         Quantity         : integer := 0;
         Return_Value     : integer := 0;
         Message_Count    : integer := 0;          -- for test
         Time_Stamp       : Ada.Calendar.Time := Base_Time;
      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);
      entry Wait_for_Underload (Transaction : acc_Transaction_Record);
      entry TC_Credit_OK;
   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;


   -- Mechanism to count the number of Message tasks completed (Credit)
   protected body TC_Tasks_Completed is
      procedure Increment is
      begin
         Number_Complete := Number_Complete + 1;
      end Increment;

      function Count return integer is
      begin
         return Number_Complete;
      end Count;
   end TC_Tasks_Completed;


   -- 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 the required number of dummy messages needed for
   --      this test and allow it to terminate at that point.  Artificially
   --      alternate High and Low priority Credit transactions for this test.
   --
   task body Line_Driver is
      Current_ID       : integer := 1;
      Current_Priority : Transaction_Priority := High;

      -- Artificial: number of messages required for this test
      type TC_Trans_Range is range 1..6;

      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.Priority := Current_Priority;

            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 Transaction_Numb in TC_Trans_Range loop  -- TC: limit the loop
         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 Transaction_Numb = TC_Trans_Range'first then
               -- Send the first Credit message
               Build_Credit_Record ( Next_Transaction );
               Next_Message_Task.Accept_Transaction ( Next_Transaction );
               -- TC: Wait until the first message has been received by the
               -- Credit task and it has set the Overload indicator for the
               -- Distributor
               while not TC_First_Message_Has_Arrived.Value loop
                  delay ImpDef.Minimum_Task_Switch;
               end loop;
            elsif Transaction_Numb = TC_Trans_Range'last then
               -- For this test send the last transaction to the Debit task
               -- to improve the mix
               Build_Debit_Record( Next_Transaction );
               Next_Message_Task.Accept_Transaction ( Next_Transaction );
            else
               -- TC: Alternate high and low priority transactions