------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- A D A . C O N T A I N E R S . I N D E F I N I T E _ H O L D E R S -- -- -- -- S p e c -- -- -- -- Copyright (C) 2013-2015, Free Software Foundation, Inc. -- -- -- -- This specification is derived from the Ada Reference Manual for use with -- -- GNAT. The copyright notice above, and the license provisions that follow -- -- apply solely to the contents of the part following the private keyword. -- -- -- -- GNAT 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 3, or (at your option) any later ver- -- -- sion. GNAT 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. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- ------------------------------------------------------------------------------ -- This is an optimized version of Indefinite_Holders using copy-on-write. -- It is used on platforms that support atomic built-ins. private with Ada.Finalization; private with Ada.Streams; private with System.Atomic_Counters; generic type Element_Type (<>) is private; with function "=" (Left, Right : Element_Type) return Boolean is <>; package Ada.Containers.Indefinite_Holders is pragma Annotate (CodePeer, Skip_Analysis); pragma Preelaborate (Indefinite_Holders); pragma Remote_Types (Indefinite_Holders); type Holder is tagged private; pragma Preelaborable_Initialization (Holder); Empty_Holder : constant Holder; function "=" (Left, Right : Holder) return Boolean; function To_Holder (New_Item : Element_Type) return Holder; function Is_Empty (Container : Holder) return Boolean; procedure Clear (Container : in out Holder); function Element (Container : Holder) return Element_Type; procedure Replace_Element (Container : in out Holder; New_Item : Element_Type); procedure Query_Element (Container : Holder; Process : not null access procedure (Element : Element_Type)); procedure Update_Element (Container : in out Holder; Process : not null access procedure (Element : in out Element_Type)); type Constant_Reference_Type (Element : not null access constant Element_Type) is private with Implicit_Dereference => Element; type Reference_Type (Element : not null access Element_Type) is private with Implicit_Dereference => Element; function Constant_Reference (Container : aliased Holder) return Constant_Reference_Type; pragma Inline (Constant_Reference); function Reference (Container : aliased in out Holder) return Reference_Type; pragma Inline (Reference); procedure Assign (Target : in out Holder; Source : Holder); function Copy (Source : Holder) return Holder; procedure Move (Target : in out Holder; Source : in out Holder); private use Ada.Finalization; use Ada.Streams; type Element_Access is access all Element_Type; type Holder_Access is access all Holder; type Shared_Holder is record Counter : System.Atomic_Counters.Atomic_Counter; Element : Element_Access; end record; type Shared_Holder_Access is access all Shared_Holder; procedure Reference (Item : not null Shared_Holder_Access); -- Increment reference counter procedure Unreference (Item : not null Shared_Holder_Access); -- Decrement reference counter, deallocate Item when counter goes to zero procedure Read (Stream : not null access Ada.Streams.Root_Stream_Type'Class; Container : out Holder); procedure Write (Stream : not null access Ada.Streams.Root_Stream_Type'Class; Container : Holder); type Holder is new Ada.Finalization.Controlled with record Reference : Shared_Holder_Access; Busy : Natural := 0; end record; for Holder'Read use Read; for Holder'Write use Write; overriding procedure Adjust (Container : in out Holder); overriding procedure Finalize (Container : in out Holder); type Reference_Control_Type is new Controlled with record Container : Holder_Access; end record; overriding procedure Adjust (Control : in out Reference_Control_Type); pragma Inline (Adjust); overriding procedure Finalize (Control : in out Reference_Control_Type); pragma Inline (Finalize); type Constant_Reference_Type (Element : not null access constant Element_Type) is record Control : Reference_Control_Type := raise Program_Error with "uninitialized reference"; -- The RM says, "The default initialization of an object of -- type Constant_Reference_Type or Reference_Type propagates -- Program_Error." end record; procedure Write (Stream : not null access Root_Stream_Type'Class; Item : Constant_Reference_Type); for Constant_Reference_Type'Write use Write; procedure Read (Stream : not null access Root_Stream_Type'Class; Item : out Constant_Reference_Type); for Constant_Reference_Type'Read use Read; type Reference_Type (Element : not null access Element_Type) is record Control : Reference_Control_Type := raise Program_Error with "uninitialized reference"; -- The RM says, "The default initialization of an object of -- type Constant_Reference_Type or Reference_Type propagates -- Program_Error." end record; procedure Write (Stream : not null access Root_Stream_Type'Class; Item : Reference_Type); for Reference_Type'Write use Write; procedure Read (Stream : not null access Root_Stream_Type'Class; Item : out Reference_Type); for Reference_Type'Read use Read; Empty_Holder : constant Holder := (Controlled with null, 0); end Ada.Containers.Indefinite_Holders;