1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--    S Y S T E M . F I N A L I Z A T I O N _ I M P L E M E N T A T I O N   --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2003 Free Software Foundation, Inc.          --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- Extensive contributions were provided by Ada Core Technologies Inc.      --
31--                                                                          --
32------------------------------------------------------------------------------
33
34with System.Finalization_Root;
35
36package System.Finalization_Implementation is
37pragma Elaborate_Body (Finalization_Implementation);
38
39   package SFR renames System.Finalization_Root;
40
41   ------------------------------------------------
42   -- Finalization Management Abstract Interface --
43   ------------------------------------------------
44
45   Global_Final_List : SFR.Finalizable_Ptr;
46   --  This list stores the controlled objects defined in library-level
47   --  packages. They will be finalized after the main program completion.
48
49   procedure Finalize_Global_List;
50   --  The procedure to be called in order to finalize the global list;
51
52   procedure Attach_To_Final_List
53     (L       : in out SFR.Finalizable_Ptr;
54      Obj     : in out SFR.Finalizable;
55      Nb_Link : Short_Short_Integer);
56   --  Attach finalizable object Obj to the linked list L. Nb_Link controls
57   --  the number of link of the linked_list, and can be either 0 for no
58   --  attachement, 1 for simple linked lists or 2 for doubly linked lists
59   --  or even 3 for a simple attachement of a whole array of elements.
60   --  Attachement to a simply linked list is not protected against
61   --  concurrent access and should only be used in contexts where it
62   --  doesn't matter, such as for objects allocated on the stack. In the
63   --  case of an attachment on a doubly linked list, L must not be null
64   --  and Obj will be inserted AFTER the first element and the attachment
65   --  is protected against concurrent call. Typically used to attach to
66   --  a dynamically allocated object to a List_Controller (whose first
67   --  element is always a dummy element)
68
69   procedure Finalize_List (L : SFR.Finalizable_Ptr);
70   --  Call Finalize on each element of the list L;
71
72   procedure Finalize_One (Obj  : in out SFR.Finalizable);
73   --  Call Finalize on Obj and remove its final list.
74
75   ---------------------
76   -- Deep Procedures --
77   ---------------------
78
79   procedure Deep_Tag_Initialize
80     (L : in out SFR.Finalizable_Ptr;
81      A : System.Address;
82      B : Short_Short_Integer);
83   --  Generic initialize for tagged objects with controlled components.
84   --  A is the address of the object, L the finalization list when it needs
85   --  to be attached and B the attachement level (see Attach_To_Final_List).
86
87   procedure Deep_Tag_Adjust
88     (L : in out SFR.Finalizable_Ptr;
89      A : System.Address;
90      B : Short_Short_Integer);
91   --  Generic adjust for tagged objects with controlled components.
92   --  A is the address of the object, L the finalization list when it needs
93   --  to be attached and B the attachement level (see Attach_To_Final_List).
94
95   procedure Deep_Tag_Finalize
96     (L : in out SFR.Finalizable_Ptr;
97      A : System.Address;
98      B : Boolean);
99   --  Generic finalize for tagged objects with controlled components.
100   --  A is the address of the object, L the finalization list when it needs
101   --  to be attached and B the attachement level (see Attach_To_Final_List).
102
103   procedure Deep_Tag_Attach
104     (L : in out SFR.Finalizable_Ptr;
105      A : System.Address;
106      B : Short_Short_Integer);
107   --  Generic attachement for tagged objects with controlled components.
108   --  A is the address of the object, L the finalization list when it needs
109   --  to be attached and B the attachement level (see Attach_To_Final_List).
110
111   -----------------------------
112   -- Record Controller Types --
113   -----------------------------
114
115   --  Definition of the types of the controller component that is included
116   --  in records containing controlled components. This controller is
117   --  attached to the finalization chain of the upper-level and carries
118   --  the pointer of the finalization chain for the lower level.
119
120   type Limited_Record_Controller is new SFR.Root_Controlled with record
121      F : SFR.Finalizable_Ptr;
122   end record;
123
124   procedure Initialize (Object : in out Limited_Record_Controller);
125   --  Does nothing.
126
127   procedure Finalize (Object : in out Limited_Record_Controller);
128   --  Finalize the controlled components of the enclosing record by
129   --  following the list starting at Object.F.
130
131   type Record_Controller is
132      new Limited_Record_Controller with record
133         My_Address : System.Address;
134      end record;
135
136   procedure Initialize (Object : in out Record_Controller);
137   --  Initialize the field My_Address to the Object'Address
138
139   procedure Adjust (Object : in out Record_Controller);
140   --  Adjust the components and their finalization pointers by substracting
141   --  by the offset of the target and the source addresses of the assignment.
142
143   --  Inherit Finalize from Limited_Record_Controller
144
145   procedure Detach_From_Final_List (Obj : in out SFR.Finalizable);
146   --  Remove the specified object from its Final list, which must be a
147   --  doubly linked list.
148
149end System.Finalization_Implementation;
150