1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--    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     --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2011-2020, Free Software Foundation, Inc.         --
10--                                                                          --
11-- This specification is derived from the Ada Reference Manual for use with --
12-- GNAT. The copyright notice above, and the license provisions that follow --
13-- apply solely to the  contents of the part following the private keyword. --
14--                                                                          --
15-- GNAT is free software;  you can  redistribute it  and/or modify it under --
16-- terms of the  GNU General Public License as published  by the Free Soft- --
17-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
18-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
19-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
20-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
21--                                                                          --
22-- As a special exception under Section 7 of GPL version 3, you are granted --
23-- additional permissions described in the GCC Runtime Library Exception,   --
24-- version 3.1, as published by the Free Software Foundation.               --
25--                                                                          --
26-- You should have received a copy of the GNU General Public License and    --
27-- a copy of the GCC Runtime Library Exception along with this program;     --
28-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
29-- <http://www.gnu.org/licenses/>.                                          --
30------------------------------------------------------------------------------
31
32private with Ada.Finalization;
33private with Ada.Streams;
34private with Ada.Strings.Text_Output;
35
36generic
37   type Element_Type (<>) is private;
38   with function "=" (Left, Right : Element_Type) return Boolean is <>;
39
40package Ada.Containers.Indefinite_Holders is
41   pragma Annotate (CodePeer, Skip_Analysis);
42   pragma Preelaborate (Indefinite_Holders);
43   pragma Remote_Types (Indefinite_Holders);
44
45   type Holder is tagged private;
46   pragma Preelaborable_Initialization (Holder);
47
48   Empty_Holder : constant Holder;
49
50   function "=" (Left, Right : Holder) return Boolean;
51
52   function To_Holder (New_Item : Element_Type) return Holder;
53
54   function Is_Empty (Container : Holder) return Boolean;
55
56   procedure Clear (Container : in out Holder);
57
58   function Element (Container : Holder) return Element_Type;
59
60   procedure Replace_Element
61     (Container : in out Holder;
62      New_Item  : Element_Type);
63
64   procedure Query_Element
65     (Container : Holder;
66      Process   : not null access procedure (Element : Element_Type));
67
68   procedure Update_Element
69     (Container : in out Holder;
70      Process   : not null access procedure (Element : in out Element_Type));
71
72   type Constant_Reference_Type
73      (Element : not null access constant Element_Type) is private
74   with
75      Implicit_Dereference => Element;
76
77   type Reference_Type
78     (Element : not null access Element_Type) is private
79   with
80      Implicit_Dereference => Element;
81
82   function Constant_Reference
83     (Container : aliased Holder) return Constant_Reference_Type;
84   pragma Inline (Constant_Reference);
85
86   function Reference
87     (Container : aliased in out Holder) return Reference_Type;
88   pragma Inline (Reference);
89
90   procedure Assign (Target : in out Holder; Source : Holder);
91
92   function Copy (Source : Holder) return Holder;
93
94   procedure Move (Target : in out Holder; Source : in out Holder);
95
96   procedure Swap (Left, Right : in out Holder);
97
98private
99
100   use Ada.Finalization;
101   use Ada.Streams;
102
103   type Element_Access is access all Element_Type;
104
105   type Holder_Access is access all Holder;
106   for Holder_Access'Storage_Size use 0;
107
108   procedure Read
109     (Stream    : not null access Ada.Streams.Root_Stream_Type'Class;
110      Container : out Holder);
111
112   procedure Write
113     (Stream    : not null access Ada.Streams.Root_Stream_Type'Class;
114      Container : Holder);
115
116   type Holder is new Ada.Finalization.Controlled with record
117      Element : Element_Access;
118      Busy    : Natural := 0;
119   end record with Put_Image => Put_Image;
120
121   procedure Put_Image
122     (S : in out Ada.Strings.Text_Output.Sink'Class; V : Holder);
123
124   for Holder'Read use Read;
125   for Holder'Write use Write;
126
127   overriding procedure Adjust (Container : in out Holder);
128   overriding procedure Finalize (Container : in out Holder);
129
130   type Reference_Control_Type is new Controlled with
131   record
132      Container : Holder_Access;
133   end record;
134
135   overriding procedure Adjust (Control : in out Reference_Control_Type);
136   pragma Inline (Adjust);
137
138   overriding procedure Finalize (Control : in out Reference_Control_Type);
139   pragma Inline (Finalize);
140
141   type Constant_Reference_Type
142     (Element : not null access constant Element_Type) is
143      record
144         Control : Reference_Control_Type :=
145           raise Program_Error with "uninitialized reference";
146         --  The RM says, "The default initialization of an object of
147         --  type Constant_Reference_Type or Reference_Type propagates
148         --  Program_Error."
149      end record;
150
151   procedure Write
152     (Stream : not null access Root_Stream_Type'Class;
153      Item   : Constant_Reference_Type);
154
155   for Constant_Reference_Type'Write use Write;
156
157   procedure Read
158     (Stream : not null access Root_Stream_Type'Class;
159      Item   : out Constant_Reference_Type);
160
161   for Constant_Reference_Type'Read use Read;
162
163   type Reference_Type (Element : not null access Element_Type) is record
164      Control : Reference_Control_Type :=
165        raise Program_Error with "uninitialized reference";
166      --  The RM says, "The default initialization of an object of
167      --  type Constant_Reference_Type or Reference_Type propagates
168      --  Program_Error."
169   end record;
170
171   procedure Write
172     (Stream : not null access Root_Stream_Type'Class;
173      Item   : Reference_Type);
174
175   for Reference_Type'Write use Write;
176
177   procedure Read
178     (Stream : not null access Root_Stream_Type'Class;
179      Item   : out Reference_Type);
180
181   for Reference_Type'Read use Read;
182
183   Empty_Holder : constant Holder := (Controlled with null, 0);
184
185end Ada.Containers.Indefinite_Holders;
186