| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- |
| -- -- |
| -- SYSTEM.TASKING.PROTECTED_OBJECTS.ENTRIES -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1998-2004, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNARL is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 2, or (at your option) any later ver- -- |
| -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNARL; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- |
| -- MA 02111-1307, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- unit, or you link this unit with other files to produce an executable, -- |
| -- this unit does not by itself cause the resulting executable to be -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- GNARL was developed by the GNARL team at Florida State University. -- |
| -- Extensive contributions were provided by Ada Core Technologies, Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package contains all the simple primitives related to |
| -- Protected_Objects with entries (i.e init, lock, unlock). |
| |
| -- The handling of protected objects with no entries is done in |
| -- System.Tasking.Protected_Objects, the complex routines for protected |
| -- objects with entries in System.Tasking.Protected_Objects.Operations. |
| -- The split between Entries and Operations is needed to break circular |
| -- dependencies inside the run time. |
| |
| -- Note: the compiler generates direct calls to this interface, via Rtsfind. |
| |
| with Ada.Exceptions; |
| -- used for Exception_Occurrence_Access |
| -- Raise_Exception |
| |
| with System.Task_Primitives.Operations; |
| -- used for Initialize_Lock |
| -- Write_Lock |
| -- Unlock |
| -- Get_Priority |
| -- Wakeup |
| |
| with System.Tasking.Initialization; |
| -- used for Defer_Abort, |
| -- Undefer_Abort, |
| -- Change_Base_Priority |
| |
| pragma Elaborate_All (System.Tasking.Initialization); |
| -- this insures that tasking is initialized if any protected objects are |
| -- created. |
| |
| with System.Parameters; |
| -- used for Single_Lock |
| |
| package body System.Tasking.Protected_Objects.Entries is |
| |
| package STPO renames System.Task_Primitives.Operations; |
| |
| use Parameters; |
| use Task_Primitives.Operations; |
| use Ada.Exceptions; |
| |
| ---------------- |
| -- Local Data -- |
| ---------------- |
| |
| Locking_Policy : Character; |
| pragma Import (C, Locking_Policy, "__gl_locking_policy"); |
| |
| -------------- |
| -- Finalize -- |
| -------------- |
| |
| procedure Finalize (Object : in out Protection_Entries) is |
| Entry_Call : Entry_Call_Link; |
| Caller : Task_Id; |
| Ceiling_Violation : Boolean; |
| Self_ID : constant Task_Id := STPO.Self; |
| Old_Base_Priority : System.Any_Priority; |
| |
| begin |
| if Object.Finalized then |
| return; |
| end if; |
| |
| STPO.Write_Lock (Object.L'Unrestricted_Access, Ceiling_Violation); |
| |
| if Single_Lock then |
| Lock_RTS; |
| end if; |
| |
| if Ceiling_Violation then |
| -- Dip our own priority down to ceiling of lock. |
| -- See similar code in Tasking.Entry_Calls.Lock_Server. |
| |
| STPO.Write_Lock (Self_ID); |
| Old_Base_Priority := Self_ID.Common.Base_Priority; |
| Self_ID.New_Base_Priority := Object.Ceiling; |
| Initialization.Change_Base_Priority (Self_ID); |
| STPO.Unlock (Self_ID); |
| |
| if Single_Lock then |
| Unlock_RTS; |
| end if; |
| |
| STPO.Write_Lock (Object.L'Unrestricted_Access, Ceiling_Violation); |
| |
| if Ceiling_Violation then |
| Raise_Exception (Program_Error'Identity, "Ceiling Violation"); |
| end if; |
| |
| if Single_Lock then |
| Lock_RTS; |
| end if; |
| |
| Object.Old_Base_Priority := Old_Base_Priority; |
| Object.Pending_Action := True; |
| end if; |
| |
| -- Send program_error to all tasks still queued on this object. |
| |
| for E in Object.Entry_Queues'Range loop |
| Entry_Call := Object.Entry_Queues (E).Head; |
| |
| while Entry_Call /= null loop |
| Caller := Entry_Call.Self; |
| Entry_Call.Exception_To_Raise := Program_Error'Identity; |
| |
| STPO.Write_Lock (Caller); |
| Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done); |
| STPO.Unlock (Caller); |
| |
| exit when Entry_Call = Object.Entry_Queues (E).Tail; |
| Entry_Call := Entry_Call.Next; |
| end loop; |
| end loop; |
| |
| Object.Finalized := True; |
| |
| if Single_Lock then |
| Unlock_RTS; |
| end if; |
| |
| STPO.Unlock (Object.L'Unrestricted_Access); |
| |
| STPO.Finalize_Lock (Object.L'Unrestricted_Access); |
| end Finalize; |
| |
| ------------------------------------- |
| -- Has_Interrupt_Or_Attach_Handler -- |
| ------------------------------------- |
| |
| function Has_Interrupt_Or_Attach_Handler |
| (Object : Protection_Entries_Access) |
| return Boolean |
| is |
| pragma Warnings (Off, Object); |
| begin |
| return False; |
| end Has_Interrupt_Or_Attach_Handler; |
| |
| ----------------------------------- |
| -- Initialize_Protection_Entries -- |
| ----------------------------------- |
| |
| procedure Initialize_Protection_Entries |
| (Object : Protection_Entries_Access; |
| Ceiling_Priority : Integer; |
| Compiler_Info : System.Address; |
| Entry_Bodies : Protected_Entry_Body_Access; |
| Find_Body_Index : Find_Body_Index_Access) |
| is |
| Init_Priority : Integer := Ceiling_Priority; |
| Self_ID : constant Task_Id := STPO.Self; |
| |
| begin |
| if Init_Priority = Unspecified_Priority then |
| Init_Priority := System.Priority'Last; |
| end if; |
| |
| if Locking_Policy = 'C' |
| and then Has_Interrupt_Or_Attach_Handler (Object) |
| and then Init_Priority not in System.Interrupt_Priority |
| then |
| -- Required by C.3.1(11) |
| |
| raise Program_Error; |
| end if; |
| |
| Initialization.Defer_Abort (Self_ID); |
| Initialize_Lock (Init_Priority, Object.L'Access); |
| Initialization.Undefer_Abort (Self_ID); |
| Object.Ceiling := System.Any_Priority (Init_Priority); |
| Object.Compiler_Info := Compiler_Info; |
| Object.Pending_Action := False; |
| Object.Call_In_Progress := null; |
| Object.Entry_Bodies := Entry_Bodies; |
| Object.Find_Body_Index := Find_Body_Index; |
| |
| for E in Object.Entry_Queues'Range loop |
| Object.Entry_Queues (E).Head := null; |
| Object.Entry_Queues (E).Tail := null; |
| end loop; |
| end Initialize_Protection_Entries; |
| |
| ------------------ |
| -- Lock_Entries -- |
| ------------------ |
| |
| procedure Lock_Entries |
| (Object : Protection_Entries_Access; Ceiling_Violation : out Boolean) |
| is |
| begin |
| if Object.Finalized then |
| Raise_Exception |
| (Program_Error'Identity, "Protected Object is finalized"); |
| end if; |
| |
| -- If pragma Detect_Blocking is active then Program_Error must |
| -- be raised if this potentially blocking operation is called from |
| -- a protected action, and the protected object nesting level |
| -- must be increased. |
| |
| if Detect_Blocking then |
| declare |
| Self_Id : constant Task_Id := STPO.Self; |
| begin |
| if Self_Id.Common.Protected_Action_Nesting > 0 then |
| Ada.Exceptions.Raise_Exception |
| (Program_Error'Identity, "potentially blocking operation"); |
| else |
| -- We are entering in a protected action, so that we |
| -- increase the protected object nesting level. |
| |
| Self_Id.Common.Protected_Action_Nesting := |
| Self_Id.Common.Protected_Action_Nesting + 1; |
| end if; |
| end; |
| end if; |
| |
| -- The lock is made without defering abortion. |
| |
| -- Therefore the abortion has to be deferred before calling this |
| -- routine. This means that the compiler has to generate a Defer_Abort |
| -- call before the call to Lock. |
| |
| -- The caller is responsible for undeferring abortion, and compiler |
| -- generated calls must be protected with cleanup handlers to ensure |
| -- that abortion is undeferred in all cases. |
| |
| pragma Assert (STPO.Self.Deferral_Level > 0); |
| Write_Lock (Object.L'Access, Ceiling_Violation); |
| end Lock_Entries; |
| |
| procedure Lock_Entries (Object : Protection_Entries_Access) is |
| Ceiling_Violation : Boolean; |
| |
| begin |
| Lock_Entries (Object, Ceiling_Violation); |
| |
| if Ceiling_Violation then |
| Raise_Exception (Program_Error'Identity, "Ceiling Violation"); |
| end if; |
| end Lock_Entries; |
| |
| ---------------------------- |
| -- Lock_Read_Only_Entries -- |
| ---------------------------- |
| |
| procedure Lock_Read_Only_Entries (Object : Protection_Entries_Access) is |
| Ceiling_Violation : Boolean; |
| |
| begin |
| if Object.Finalized then |
| Raise_Exception |
| (Program_Error'Identity, "Protected Object is finalized"); |
| end if; |
| |
| -- If pragma Detect_Blocking is active then Program_Error must be |
| -- raised if this potentially blocking operation is called from a |
| -- protected action, and the protected object nesting level must |
| -- be increased. |
| |
| if Detect_Blocking then |
| declare |
| Self_Id : constant Task_Id := STPO.Self; |
| begin |
| if Self_Id.Common.Protected_Action_Nesting > 0 then |
| Ada.Exceptions.Raise_Exception |
| (Program_Error'Identity, "potentially blocking operation"); |
| else |
| -- We are entering in a protected action, so that we |
| -- increase the protected object nesting level. |
| |
| Self_Id.Common.Protected_Action_Nesting := |
| Self_Id.Common.Protected_Action_Nesting + 1; |
| end if; |
| end; |
| end if; |
| |
| Read_Lock (Object.L'Access, Ceiling_Violation); |
| |
| if Ceiling_Violation then |
| Raise_Exception (Program_Error'Identity, "Ceiling Violation"); |
| end if; |
| end Lock_Read_Only_Entries; |
| |
| -------------------- |
| -- Unlock_Entries -- |
| -------------------- |
| |
| procedure Unlock_Entries (Object : Protection_Entries_Access) is |
| begin |
| -- We are exiting from a protected action, so that we decrease the |
| -- protected object nesting level (if pragma Detect_Blocking is |
| -- active). |
| |
| if Detect_Blocking then |
| declare |
| Self_Id : constant Task_Id := Self; |
| begin |
| -- Cannot call this procedure without being within a protected |
| -- action. |
| |
| pragma Assert (Self_Id.Common.Protected_Action_Nesting > 0); |
| |
| Self_Id.Common.Protected_Action_Nesting := |
| Self_Id.Common.Protected_Action_Nesting - 1; |
| end; |
| end if; |
| |
| Unlock (Object.L'Access); |
| end Unlock_Entries; |
| |
| end System.Tasking.Protected_Objects.Entries; |
