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114 | -- --
-- package Copyright (c) Dmitry A. Kazakov --
-- GLib.Object.Weak_References Luebeck --
-- Implementation Spring, 2007 --
-- --
-- Last revision : 22:45 07 Apr 2016 --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public License as --
-- published by the Free Software Foundation; either version 2 of --
-- the License, or (at your option) any later version. This library --
-- is distributed in the hope that it will be useful, but WITHOUT --
-- 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 along with --
-- this library; if not, write to the Free Software Foundation, --
-- Inc., 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. --
--____________________________________________________________________--
with System.Address_To_Access_Conversions;
package body GLib.Object.Weak_References is
package Address_To_Access is
new System.Address_To_Access_Conversions (Weak_Reference'Class);
use Address_To_Access;
procedure Adjust (Reference : in out Weak_Reference) is
begin
if Reference.Object /= null then
Weak_Ref
( Reference.Object,
Notifier_Ptr,
Weak_Reference'Class (Reference)'Address
);
end if;
end Adjust;
procedure Finalize (Reference : in out Weak_Reference)
renames Invalidate;
function Get (Reference : Weak_Reference)
return access Object_Type'Class is
begin
return Reference.Object;
end Get;
procedure Invalidate (Reference : in out Weak_Reference) is
begin
if Reference.Object /= null then
Weak_Unref
( Reference.Object,
Notifier_Ptr,
Weak_Reference'Class (Reference)'Address
);
Reference.Object := null;
end if;
end Invalidate;
function Is_Valid (Reference : Weak_Reference) return Boolean is
begin
return Reference.Object /= null;
end Is_Valid;
function Ref (Object : not null access Object_Type'Class)
return Weak_Reference is
Reference : Weak_Reference;
begin
Weak_Ref
( Object,
Notifier_Ptr,
Weak_Reference'Class (Reference)'Address
);
Reference.Object := Object.all'Access;
return Reference;
end Ref;
procedure Notifier
( Data : System.Address;
Where_The_Object_Was : System.Address
) is
Ptr : constant Object_Pointer := To_Pointer (Data);
begin
if Ptr /= null then
Ptr.Object := null;
Ptr.Notify;
end if;
end Notifier;
procedure Set
( Reference : in out Weak_Reference;
Object : not null access Object_Type'Class
) is
begin
if Object /= Reference.Object then
Invalidate (Reference);
end if;
Weak_Ref
( Object,
Notifier_Ptr,
Weak_Reference'Class (Reference)'Address
);
Reference.Object := Object.all'Access;
end Set;
end GLib.Object.Weak_References;
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