1------------------------------------------------------------------------------
2--                                                                          --
3--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
4--                                                                          --
5--                 S Y S T E M . T A S K _ P R I M I T I V E S              --
6--                                                                          --
7--                                  S p e c                                 --
8--                                                                          --
9--          Copyright (C) 1991-2020, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNARL 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 3,  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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNARL was developed by the GNARL team at Florida State University.       --
28-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This is a NT (native) version of this package
33
34with System.OS_Interface;
35with System.Win32;
36
37package System.Task_Primitives is
38   pragma Preelaborate;
39
40   type Lock is limited private;
41   --  Should be used for implementation of protected objects
42
43   type RTS_Lock is limited private;
44   --  Should be used inside the runtime system. The difference between Lock
45   --  and the RTS_Lock is that the later one serves only as a semaphore so
46   --  that do not check for ceiling violations.
47
48   type Suspension_Object is limited private;
49   --  Should be used for the implementation of Ada.Synchronous_Task_Control
50
51   type Task_Body_Access is access procedure;
52   --  Pointer to the task body's entry point (or possibly a wrapper
53   --  declared local to the GNARL).
54
55   type Private_Data is limited private;
56   --  Any information that the GNULLI needs maintained on a per-task basis.
57   --  A component of this type is guaranteed to be included in the
58   --  Ada_Task_Control_Block.
59
60   subtype Task_Address is System.Address;
61   Task_Address_Size : constant := Standard'Address_Size;
62   --  Type used for task addresses and its size
63
64   Alternate_Stack_Size : constant := 0;
65   --  No alternate signal stack is used on this platform
66
67private
68
69   type Lock is record
70      Mutex          : aliased System.OS_Interface.CRITICAL_SECTION;
71      Priority       : Integer;
72      Owner_Priority : Integer;
73   end record;
74
75   type Condition_Variable is new System.Win32.HANDLE;
76
77   type RTS_Lock is new System.OS_Interface.CRITICAL_SECTION;
78
79   type Suspension_Object is record
80      State : Boolean;
81      pragma Atomic (State);
82      --  Boolean that indicates whether the object is open. This field is
83      --  marked Atomic to ensure that we can read its value without locking
84      --  the access to the Suspension_Object.
85
86      Waiting : Boolean;
87      --  Flag showing if there is a task already suspended on this object
88
89      L : aliased System.OS_Interface.CRITICAL_SECTION;
90      --  Protection for ensuring mutual exclusion on the Suspension_Object
91
92      CV : aliased Win32.HANDLE;
93      --  Condition variable used to queue threads until condition is signaled
94   end record;
95
96   type Private_Data is limited record
97      Thread : aliased Win32.HANDLE;
98      pragma Atomic (Thread);
99      --  Thread field may be updated by two different threads of control.
100      --  (See, Enter_Task and Create_Task in s-taprop.adb).
101      --  They put the same value (thr_self value). We do not want to
102      --  use lock on those operations and the only thing we have to
103      --  make sure is that they are updated in atomic fashion.
104
105      Thread_Id : aliased Win32.DWORD;
106      --  Used to provide a better tasking support in gdb
107
108      CV : aliased Condition_Variable;
109      --  Condition Variable used to implement Sleep/Wakeup
110
111      L : aliased RTS_Lock;
112      --  Protection for all components is lock L
113   end record;
114
115end System.Task_Primitives;
116