| -- C954010.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 a requeue within an accept statement does not block. |
| -- This test uses: Requeue to an entry in a different task |
| -- Parameterless call |
| -- Requeue with abort |
| -- |
| -- TEST DESCRIPTION: |
| -- In the Distributor task, requeue two successive calls on the entries |
| -- of two separate target tasks. Verify that the target tasks are |
| -- run in parallel proving that the first requeue does not block |
| -- while the first target rendezvous takes place. |
| -- |
| -- 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. |
| -- |
| -- This test is directed towards the BLOCKING of the REQUEUE only |
| -- If the original caller does not block, the outcome of the test will |
| -- not be affected. If the original caller does not continue after |
| -- the return, the test will not pass. |
| -- If the requeue gets placed on the wrong entry a failing test could |
| -- pass (eg. if the first message is delivered to the second |
| -- computation task and the second message to the first) - a check for |
| -- this condition is made in other tests |
| -- |
| -- |
| -- CHANGE HISTORY: |
| -- 06 Dec 94 SAIC ACVC 2.0 |
| -- |
| --! |
| |
| with Report; |
| with ImpDef; |
| |
| procedure C954010 is |
| |
| -- Mechanism to count the number of Message tasks completed |
| protected TC_Tasks_Completed is |
| procedure Increment; |
| function Count return integer; |
| private |
| Number_Complete : integer := 0; |
| end TC_Tasks_Completed; |
| -- |
| TC_Expected_To_Complete : constant integer := 2; |
| |
| |
| task type Message_Task; |
| type acc_Message_Task is access Message_Task; |
| |
| task Line_Driver is |
| entry Start; |
| end Line_Driver; |
| |
| task Distributor is |
| entry Input; |
| end Distributor; |
| |
| task Credit_Computation is |
| entry Input; |
| end Credit_Computation; |
| |
| task Debit_Computation is |
| entry Input; |
| entry TC_Artificial_Rendezvous_1; -- test purposes only |
| entry TC_Artificial_Rendezvous_2; -- test purposes only |
| end Debit_Computation; |
| |
| |
| -- Mechanism to count the number of Message tasks completed |
| 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 and sends this to a Distributor |
| -- for appropriate disposal around the network of tasks |
| -- Such a 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 |
| |
| begin |
| |
| accept Start; -- Wait for trigger from main |
| |
| for i in 1..2 loop |
| declare |
| -- create a new message task |
| N : acc_Message_Task := new Message_Task; |
| begin |
| -- preparation code |
| null; -- stub |
| |
| end; -- declare |
| end loop; |
| |
| exception |
| when others => |
| Report.Failed ("Unexpected exception in Line_Driver"); |
| end Line_Driver; |
| |
| |
| task body Message_Task is |
| begin |
| -- Queue up on Distributor's Input queue |
| Distributor.Input; |
| |
| -- After the required computations have been performed |
| -- return the message appropriately (probably to an output |
| -- line driver |
| null; -- stub |
| |
| -- Increment to show completion of this task |
| TC_Tasks_Completed.Increment; |
| |
| exception |
| when others => |
| Report.Failed ("Unexpected exception in Message_Task"); |
| |
| end Message_Task; |
| |
| |
| -- Dispose each input message to the appropriate computation tasks |
| -- Normally this would be according to some parameters in the entry |
| -- but this simple test is using parameterless entries. |
| -- |
| task body Distributor is |
| Last_was_for_Credit_Computation : Boolean := false; -- switch |
| begin |
| loop |
| select |
| accept Input do |
| -- Determine to which task the message should be |
| -- distributed |
| -- For this test arbitrarily send the first to |
| -- Credit_Computation and the second to Debit_Computation |
| if Last_was_for_Credit_Computation then |
| requeue Debit_Computation.Input with abort; |
| else |
| Last_was_for_Credit_Computation := true; |
| requeue Credit_Computation.Input with abort; |
| end if; |
| end Input; |
| or |
| terminate; |
| end select; |
| end loop; |
| |
| exception |
| when others => |
| Report.Failed ("Unexpected exception in Distributor"); |
| end Distributor; |
| |
| |
| -- Computation task. After the computation is performed the rendezvous |
| -- in the original message task is completed. |
| task body Credit_Computation is |
| begin |
| loop |
| select |
| accept Input do |
| -- Perform the computations required for this message |
| -- |
| null; -- stub |
| |
| -- For the test: |
| -- Artificially rendezvous with Debit_Computation. |
| -- If the first requeue in Distributor has blocked |
| -- waiting for the current rendezvous to complete then the |
| -- second message will not be sent to Debit_Computation |
| -- which will still be waiting on its Input accept. |
| -- This task will HANG |
| -- |
| Debit_Computation.TC_Artificial_Rendezvous_1; |
| -- |
| end Input; |
| or |
| terminate; |
| end select; |
| end loop; |
| exception |
| when others => |
| Report.Failed ("Unexpected exception in Credit_Computation"); |
| end Credit_Computation; |
| |
| |
| -- Computation task. After the computation is performed the rendezvous |
| -- in the original message task is completed. |
| task body Debit_Computation is |
| Message_Count : integer := 0; |
| TC_AR1_is_complete : Boolean := false; |
| begin |
| loop |
| select |
| accept Input do |
| -- Perform the computations required for this message |
| null; -- stub |
| end Input; |
| Message_Count := Message_Count + 1; |
| or |
| -- Guard until the rendezvous with the message for this task |
| -- has completed |
| when Message_Count > 0 => |
| accept TC_Artificial_Rendezvous_1; -- see comments in |
| -- Credit_Computation above |
| TC_AR1_is_complete := true; |
| or |
| -- Completion rendezvous with the main procedure |
| when TC_AR1_is_complete => |
| accept TC_Artificial_Rendezvous_2; |
| or |
| terminate; |
| end select; |
| end loop; |
| exception |
| when others => |
| Report.Failed ("Unexpected exception in Debit_Computation"); |
| |
| |
| end Debit_Computation; |
| |
| |
| begin -- c954010 |
| Report.Test ("C954010", "Requeue in an accept body does not block"); |
| |
| Line_Driver.Start; |
| |
| -- Ensure that both messages were delivered to the computation tasks |
| -- This shows that both requeues were effective. |
| -- |
| Debit_Computation.TC_Artificial_Rendezvous_2; |
| |
| -- Ensure that the message tasks completed |
| while (TC_Tasks_Completed.Count < TC_Expected_To_Complete) loop |
| delay ImpDef.Minimum_Task_Switch; |
| end loop; |
| |
| Report.Result; |
| |
| end C954010; |
