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------------------------------------------------------------------------------

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--         S Y S T E M . T A S K I N G . T A S K _ A T T R I B U T E S      --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--             Copyright (C) 1991-1994, Florida State University            --

--                     Copyright (C) 1995-2008, AdaCore                     --

--                                                                          --

-- 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,  51  Franklin  Street,  Fifth  Floor, --

-- Boston, MA 02110-1301, 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.     --

--                                                                          --

------------------------------------------------------------------------------

with Ada.Unchecked_Conversion;

with System.Task_Primitives.Operations;

with System.Tasking.Initialization;

package body System.Tasking.Task_Attributes is

   use Task_Primitives.Operations;

   use Tasking.Initialization;

   function To_Access_Address is new Ada.Unchecked_Conversion

     (Access_Node, Access_Address);

   --  Store pointer to indirect attribute list

   --------------

   -- Finalize --

   --------------

   procedure Finalize (X : in out Instance) is

      Q, To_Be_Freed : Access_Node;

      Self_Id        : constant Task_Id := Self;

   begin

      --  Defer abort. Note that we use the nestable versions of Defer_Abort

      --  and Undefer_Abort, because abort can already deferred when this is

      --  called during finalization, which would cause an assert failure

      --  in Defer_Abort.

      Defer_Abort_Nestable (Self_Id);

      Lock_RTS;

      --  Remove this instantiation from the list of all instantiations

      declare

         P : Access_Instance;

         Q : Access_Instance := All_Attributes;

      begin

         while Q /= null and then Q /= X'Unchecked_Access loop

            P := Q; Q := Q.Next;

         end loop;

         pragma Assert (Q /= null);

         if P = null then

            All_Attributes := Q.Next;

         else

            P.Next := Q.Next;

         end if;

      end;

      if X.Index /= 0 then

         --  Free location of this attribute, for reuse

         In_Use := In_Use and not (2**Natural (X.Index));

         --  There is no need for finalization in this case, since controlled

         --  types are too big to fit in the TCB.

      else

         --  Remove nodes for this attribute from the lists of all tasks,

         --  and deallocate the nodes. Deallocation does finalization, if

         --  necessary.

         declare

            C : System.Tasking.Task_Id := All_Tasks_List;

            P : Access_Node;

         begin

            while C /= null loop

               Write_Lock (C);

               Q := To_Access_Node (C.Indirect_Attributes);

               while Q /= null

                 and then Q.Instance /= X'Unchecked_Access

               loop

                  P := Q;

                  Q := Q.Next;

               end loop;

               if Q /= null then

                  if P = null then

                     C.Indirect_Attributes := To_Access_Address (Q.Next);

                  else

                     P.Next := Q.Next;

                  end if;

                  --  Can't Deallocate now since we are holding RTS_Lock

                  Q.Next := To_Be_Freed;

                  To_Be_Freed := Q;

               end if;

               Unlock (C);

               C := C.Common.All_Tasks_Link;

            end loop;

         end;

      end if;

      Unlock_RTS;

      while To_Be_Freed /= null loop

         Q := To_Be_Freed;

         To_Be_Freed := To_Be_Freed.Next;

         X.Deallocate.all (Q);

      end loop;

      Undefer_Abort_Nestable (Self_Id);

   exception

      when others =>

         null;

         pragma Assert (False,

           "Exception in task attribute instance finalization");

   end Finalize;

   -------------------------

   -- Finalize Attributes --

   -------------------------

   --  This is to be called just before the ATCB is deallocated.

   --  It relies on the caller holding T.L write-lock on entry.

   procedure Finalize_Attributes (T : Task_Id) is

      P : Access_Node;

      Q : Access_Node := To_Access_Node (T.Indirect_Attributes);

   begin

      --  Deallocate all the indirect attributes of this task

      while Q /= null loop

         P := Q;

         Q := Q.Next; P.Instance.Deallocate.all (P);

      end loop;

      T.Indirect_Attributes := null;

   exception

      when others =>

         null;

         pragma Assert (False,

           "Exception in per-task attributes finalization");

   end Finalize_Attributes;

   ---------------------------

   -- Initialize Attributes --

   ---------------------------

   --  This is to be called by System.Tasking.Stages.Create_Task

   procedure Initialize_Attributes (T : Task_Id) is

      P       : Access_Instance;

      Self_Id : constant Task_Id := Self;

   begin

      Defer_Abort (Self_Id);

      Lock_RTS;

      --  Initialize all the direct-access attributes of this task

      P := All_Attributes;

      while P /= null loop

         if P.Index /= 0 then

            T.Direct_Attributes (P.Index) :=

              Direct_Attribute_Element

                (System.Storage_Elements.To_Address (P.Initial_Value));

         end if;

         P := P.Next;

      end loop;

      Unlock_RTS;

      Undefer_Abort (Self_Id);

   exception

      when others =>

         null;

         pragma Assert (False);

   end Initialize_Attributes;

end System.Tasking.Task_Attributes;