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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      --

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--                                  S p e c                                 --

--                                                                          --

--             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.     --

--                                                                          --

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--  This package provides support for the body of Ada.Task_Attributes

with Ada.Finalization;

with System.Storage_Elements;

package System.Tasking.Task_Attributes is

   type Attribute is new Integer;

   --  A stand-in for the generic formal type of Ada.Task_Attributes

   --  in the following declarations.

   type Node;

   type Access_Node is access all Node;

   --  This needs comments ???

   function To_Access_Node is new Ada.Unchecked_Conversion

     (Access_Address, Access_Node);

   --  Used to fetch pointer to indirect attribute list. Declaration is in

   --  spec to avoid any problems with aliasing assumptions.

   type Dummy_Wrapper;

   type Access_Dummy_Wrapper is access all Dummy_Wrapper;

   pragma No_Strict_Aliasing (Access_Dummy_Wrapper);

   --  Needed to avoid possible incorrect aliasing situations from

   --  instantiation of Unchecked_Conversion in body of Ada.Task_Attributes.

   for Access_Dummy_Wrapper'Storage_Size use 0;

   --  Access_Dummy_Wrapper is a stand-in for the generic type Wrapper defined

   --  in Ada.Task_Attributes. The real objects allocated are always

   --  of type Wrapper, no Dummy_Wrapper objects are ever created.

   type Deallocator is access procedure (P : in out Access_Node);

   --  Called to deallocate an Wrapper. P is a pointer to a Node within

   type Instance;

   type Access_Instance is access all Instance;

   type Instance is new Ada.Finalization.Limited_Controlled with record

      Deallocate    : Deallocator;

      Initial_Value : aliased System.Storage_Elements.Integer_Address;

      Index : Direct_Index;

      --  The index of the TCB location used by this instantiation, if it is

      --  stored in the TCB, otherwise zero.

      Next : Access_Instance;

      --  Next instance in All_Attributes list

   end record;

   procedure Finalize (X : in out Instance);

   type Node is record

      Wrapper  : Access_Dummy_Wrapper;

      Instance : Access_Instance;

      Next     : Access_Node;

   end record;

   --  The following type is a stand-in for the actual wrapper type, which is

   --  different for each instantiation of Ada.Task_Attributes.

   type Dummy_Wrapper is record

      Dummy_Node : aliased Node;

      Value : aliased Attribute;

      --  The generic formal type, may be controlled

   end record;

   for Dummy_Wrapper'Alignment use Standard'Maximum_Alignment;

   --  A number of unchecked conversions involving Dummy_Wrapper_Access

   --  sources are performed in other units (e.g. Ada.Task_Attributes).

   --  Ensure that the designated object is always strictly enough aligned.

   In_Use : Direct_Index_Vector := 0;

   --  Set True for direct indices that are already used (True??? type???)

   All_Attributes : Access_Instance;

   --  A linked list of all indirectly access attributes, which includes all

   --  those that require finalization.

   procedure Initialize_Attributes (T : Task_Id);

   --  Initialize all attributes created via Ada.Task_Attributes for T. This

   --  must be called by the creator of the task, inside Create_Task, via

   --  soft-link Initialize_Attributes_Link. On entry, abort must be deferred

   --  and the caller must hold no locks

   procedure Finalize_Attributes (T : Task_Id);

   --  Finalize all attributes created via Ada.Task_Attributes for T.

   --  This is to be called by the task after it is marked as terminated

   --  (and before it actually dies), inside Vulnerable_Free_Task, via the

   --  soft-link Finalize_Attributes_Link. On entry, abort must be deferred

   --  and T.L must be write-locked.

end System.Tasking.Task_Attributes;