-- C954A01.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 if a task requeued without abort on a protected entry queue -- is aborted, the abort is deferred until the entry call completes, -- after which the task becomes completed. -- -- TEST DESCRIPTION: -- Declare a protected type which simulates a printer device driver -- (foundation code). -- -- Declare a task which simulates a printer server for multiple printers. -- -- For the protected type, declare an entry with a barrier that is set -- false by a protected procedure (which simulates starting a print job -- on the printer), and is set true by a second protected procedure (which -- simulates a handler called when the printer interrupts, indicating -- that printing is done). -- -- For the task, declare an entry whose corresponding accept statement -- contains a call to first protected procedure of the protected type -- (which sets the barrier of the protected entry to false), followed by -- a requeue with abort to the protected entry. Declare a second entry -- which does nothing. -- -- Declare a "requesting" task which calls the printer server task entry -- (and thus executes the requeue). Attempt to abort the requesting -- task. Verify that it is not aborted. Call the second protected -- procedure of the protected type (the interrupt handler) and verify that -- the protected entry completes for the requesting task. Verify that -- the requesting task is then aborted. -- -- TEST FILES: -- This test depends on the following foundation code: -- -- F954A00.A -- -- -- CHANGE HISTORY: -- 06 Dec 94 SAIC ACVC 2.0 -- 10 Oct 96 SAIC Added pragma elaborate. -- --! package C954A01_0 is -- Printer server abstraction. -- Simulate a system with multiple printers. The entry Print requests -- that data be printed on the next available printer. The entry call -- is accepted when a printer is available, and completes when printing -- is done. task Printer_Server is entry Print (File_Name : String); -- Test the requeue statement. entry Verify_Results; -- Artifice for test purposes. end Printer_Server; end C954A01_0; --==================================================================-- with Report; with ImpDef; with F954A00; -- Printer device abstraction. use F954A00; pragma Elaborate(F954A00); package body C954A01_0 is -- Printer server abstraction. task body Printer_Server is Printers_Busy : Boolean := True; Index : Printer_ID := 1; Print_Accepted : Boolean := False; begin loop -- Wait for a printer to become available: while Printers_Busy loop Printers_Busy := False; -- Exit loop if -- entry accepted. select Printer(Index).Done_Printing; -- Accepted immed. -- when printer is -- available. else Index := 1 + (Index mod Number_Of_Printers);-- Entry not immed. Printers_Busy := True; -- accepted; keep end select; -- looping. end loop; -- Value of Index -- at loop exit -- identifies the -- avail. printer. -- Wait for a print request or terminate: select accept Print (File_Name : String) do Print_Accepted := True; -- Allow -- Verify_Results -- to be accepted. Printer(Index).Start_Printing (File_Name); -- Begin printing on -- the available -- -- -- printer. -- Requeue is tested here -- -- -- -- Requeue caller so requeue Printer(Index).Done_Printing; -- server task free -- to accept other end Print; -- requests. or -- Guard ensures that Verify_Results cannot be accepted -- until after Print has been accepted. This avoids a -- race condition in the main program. when Print_Accepted => accept Verify_Results; -- Artifice for -- testing purposes. or terminate; end select; -- Allow other tasks to get control delay ImpDef.Minimum_Task_Switch; end loop; exception when others => Report.Failed ("Exception raised in Printer_Server task"); end Printer_Server; end C954A01_0; --==================================================================-- with Report; with ImpDef; with F954A00; -- Printer device abstraction. with C954A01_0; -- Printer server abstraction. use C954A01_0; use F954A00; procedure C954A01 is Long_Enough : constant Duration := ImpDef.Switch_To_New_Task; --==============================================-- task Print_Request; -- Send a print request. task body Print_Request is My_File : constant String := "MYFILE.DAT"; begin Printer_Server.Print (My_File); -- Invoke requeue statement. Report.Failed ("Task continued execution following entry call"); exception when others => Report.Failed ("Exception raised in Print_Request task"); end Print_Request; --==============================================-- begin -- Main program. Report.Test ("C954A01", "Requeue without abort - check that the abort " & "is deferred until after the rendezvous completes. (Task to PO)"); -- To pass this test, the following must be true: -- -- (A) The abort of Print_Request is deferred until after the -- Done_Printing entry body completes. -- (B) Print_Request aborts after the Done_Printing entry call -- completes. -- -- Call the entry Verify_Results. The entry call will not be accepted -- until after Print_Request has been requeued to Done_Printing. Printer_Server.Verify_Results; -- Accepted after Print_Request is -- requeued to Done_Printing. -- Simulate an application which needs access to the printer within -- a specified time, and which aborts the current printer job if time -- runs out. select Printer(1).Done_Printing; -- Wait for printer to come free. or delay Long_Enough; -- Print job took too long. abort Print_Request; -- Abort print job. end select; Printer_Server.Verify_Results; -- Abortion completion point: force -- abort to complete (if it's going -- to). -- Verify that the Done_Printing entry body has not yet completed, -- and thus that Print_Request has not been aborted. if Printer(1).Is_Done then Report.Failed ("Target entry of requeue executed prematurely"); elsif Print_Request'Terminated then Report.Failed ("Caller was aborted before entry was complete"); else Printer(1).Handle_Interrupt; -- Simulate a printer interrupt, -- signaling that printing is -- done. -- The Done_Printing entry body will complete before the next protected -- action is called (Printer(1).Is_Done). Verify (A) and (B): that the -- Print_Request is aborted. Printer_Server.Verify_Results; -- Abortion completion point: force -- Print_Request abort to complete. if not Printer(1).Is_Done then Report.Failed ("Target entry of requeue did not complete"); end if; if not Print_Request'Terminated then Report.Failed ("Task not aborted following completion of entry call"); abort Print_Request; -- Try to kill hung task. end if; end if; Report.Result; end C954A01;