[thirdparty/gcc.git] / gcc / ada / s-tpoben.ads

------------------------------------------------------------------------------
--                                                                          --
--               GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS                --
--                                                                          --
--                 SYSTEM.TASKING.PROTECTED_OBJECTS.ENTRIES                 --
--                                                                          --
--                                  S p e c                                 --
--                                                                          --
--          Copyright (C) 1992-2002, Free Software Foundation, Inc.         --
--                                                                          --
-- GNARL 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 2,  or (at your option) any later ver- --
-- sion. GNARL 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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNARL; see file COPYING.  If not, write --
-- to  the Free Software Foundation,  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.                                      --
--                                                                          --
-- GNARL was developed by the GNARL team at Florida State University.       --
-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
--                                                                          --
------------------------------------------------------------------------------

--  This package contains all the simple primitives related to
--  Protected_Objects with entries (i.e init, lock, unlock).
--  The handling of protected objects with no entries is done in
--  System.Tasking.Protected_Objects, the complex routines for protected
--  objects with entries in System.Tasking.Protected_Objects.Operations.
--  The split between Entries and Operations is needed to break circular
--  dependencies inside the run time.

--  Note: the compiler generates direct calls to this interface, via Rtsfind.
--  Any changes to this interface may require corresponding compiler changes.

with Ada.Finalization;
--  used for Limited_Controlled

with Unchecked_Conversion;

package System.Tasking.Protected_Objects.Entries is
   pragma Elaborate_Body;

   subtype Positive_Protected_Entry_Index is
     Protected_Entry_Index range  1 .. Protected_Entry_Index'Last;

   type Find_Body_Index_Access is access
     function
       (O : System.Address;
        E : Protected_Entry_Index)
        return Protected_Entry_Index;

   type Protected_Entry_Body_Array is
     array (Positive_Protected_Entry_Index range <>) of Entry_Body;
   --  This is an array of the executable code for all entry bodies of
   --  a protected type.

   type Protected_Entry_Body_Access is access all Protected_Entry_Body_Array;

   type Protected_Entry_Queue_Array is
     array (Protected_Entry_Index range <>) of Entry_Queue;

   --  This type contains the GNARL state of a protected object. The
   --  application-defined portion of the state (i.e. private objects)
   --  is maintained by the compiler-generated code.
   --  note that there is a simplified version of this type declared in
   --  System.Tasking.PO_Simple that handle the simple case (no entries).

   type Protection_Entries (Num_Entries : Protected_Entry_Index) is new
     Ada.Finalization.Limited_Controlled
   with record
      L                 : aliased Task_Primitives.Lock;
      --  The underlying lock associated with a Protection_Entries.
      --  Note that you should never (un)lock Object.L directly, but instead
      --  use Lock_Entries/Unlock_Entries.

      Compiler_Info     : System.Address;
      Call_In_Progress  : Entry_Call_Link;
      Ceiling           : System.Any_Priority;
      Old_Base_Priority : System.Any_Priority;
      Pending_Action    : Boolean;
      --  Flag indicating that priority has been dipped temporarily
      --  in order to avoid violating the priority ceiling of the lock
      --  associated with this protected object, in Lock_Server.
      --  The flag tells Unlock_Server or Unlock_And_Update_Server to
      --  restore the old priority to Old_Base_Priority. This is needed
      --  because of situations (bad language design?) where one
      --  needs to lock a PO but to do so would violate the priority
      --  ceiling.  For example, this can happen when an entry call
      --  has been requeued to a lower-priority object, and the caller
      --  then tries to cancel the call while its own priority is higher
      --  than the ceiling of the new PO.
      Finalized         : Boolean := False;
      --  Set to True by Finalize to make this routine idempotent.

      Entry_Bodies      : Protected_Entry_Body_Access;

      --  The following function maps the entry index in a call (which denotes
      --  the queue to the proper entry) into the body of the entry.

      Find_Body_Index   : Find_Body_Index_Access;
      Entry_Queues      : Protected_Entry_Queue_Array (1 .. Num_Entries);
   end record;

   --  No default initial values for this type, since call records
   --  will need to be re-initialized before every use.

   type Protection_Entries_Access is access all Protection_Entries'Class;
   --  See comments in s-tassta.adb about the implicit call to Current_Master
   --  generated by this declaration.

   function To_Address is
     new Unchecked_Conversion (Protection_Entries_Access, System.Address);
   function To_Protection is
     new Unchecked_Conversion (System.Address, Protection_Entries_Access);

   function Has_Interrupt_Or_Attach_Handler
     (Object : Protection_Entries_Access) return Boolean;
   --  Returns True if an Interrupt_Handler or Attach_Handler pragma applies
   --  to the protected object. That is to say this primitive returns False for
   --  Protection, but is overriden to return True when interrupt handlers are
   --  declared so the check required by C.3.1(11) can be implemented in
   --  System.Tasking.Protected_Objects.Initialize_Protection.

   procedure Initialize_Protection_Entries
     (Object           : Protection_Entries_Access;
      Ceiling_Priority : Integer;
      Compiler_Info    : System.Address;
      Entry_Bodies     : Protected_Entry_Body_Access;
      Find_Body_Index  : Find_Body_Index_Access);
   --  Initialize the Object parameter so that it can be used by the runtime
   --  to keep track of the runtime state of a protected object.

   procedure Lock_Entries (Object : Protection_Entries_Access);
   --  Lock a protected object for write access. Upon return, the caller
   --  owns the lock to this object, and no other call to Lock or
   --  Lock_Read_Only with the same argument will return until the
   --  corresponding call to Unlock has been made by the caller.
   --  Program_Error is raised in case of ceiling violation.

   procedure Lock_Entries
     (Object : Protection_Entries_Access; Ceiling_Violation : out Boolean);
   --  Same as above, but return the ceiling violation status instead of
   --  raising Program_Error.

   procedure Lock_Read_Only_Entries (Object : Protection_Entries_Access);
   --  Lock a protected object for read access. Upon return, the caller
   --  owns the lock for read access, and no other calls to Lock with the
   --  same argument will return until the corresponding call to Unlock
   --  has been made by the caller. Other calls to Lock_Read_Only may (but
   --  need not) return before the call to Unlock, and the corresponding
   --  callers will also own the lock for read access.
   --
   --  Note: we are not currently using this interface, it is provided
   --  for possible future use. At the current time, everyone uses Lock
   --  for both read and write locks.

   procedure Unlock_Entries (Object : Protection_Entries_Access);
   --  Relinquish ownership of the lock for the object represented by
   --  the Object parameter. If this ownership was for write access, or
   --  if it was for read access where there are no other read access
   --  locks outstanding, one (or more, in the case of Lock_Read_Only)
   --  of the tasks waiting on this lock (if any) will be given the
   --  lock and allowed to return from the Lock or Lock_Read_Only call.

private

   procedure Finalize (Object : in out Protection_Entries);
   --  Clean up a Protection object; in particular, finalize the associated
   --  Lock object.

end System.Tasking.Protected_Objects.Entries;
Commit	Line	Data
cacbc350 RK	1	------------------------------------------------------------------------------
cacbc350 RK	2	-- --
07fc65c4	3	-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
cacbc350	4	-- --
07fc65c4	5	-- SYSTEM.TASKING.PROTECTED_OBJECTS.ENTRIES --
cacbc350 RK	6	-- --
	7	-- S p e c --
	8	-- --
fbf5a39b	9	-- Copyright (C) 1992-2002, Free Software Foundation, Inc. --
cacbc350 RK	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 2, or (at your option) any later ver- --
	14	-- sion. GNARL 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 GNARL; 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	-- --
71ff80dc	29	-- GNARL was developed by the GNARL team at Florida State University. --
fbf5a39b	30	-- Extensive contributions were provided by Ada Core Technologies, Inc. --
cacbc350 RK	31	-- --
	32	------------------------------------------------------------------------------
	33
	34	-- This package contains all the simple primitives related to
	35	-- Protected_Objects with entries (i.e init, lock, unlock).
	36	-- The handling of protected objects with no entries is done in
	37	-- System.Tasking.Protected_Objects, the complex routines for protected
	38	-- objects with entries in System.Tasking.Protected_Objects.Operations.
	39	-- The split between Entries and Operations is needed to break circular
	40	-- dependencies inside the run time.
	41
	42	-- Note: the compiler generates direct calls to this interface, via Rtsfind.
	43	-- Any changes to this interface may require corresponding compiler changes.
	44
	45	with Ada.Finalization;
	46	-- used for Limited_Controlled
	47
	48	with Unchecked_Conversion;
	49
	50	package System.Tasking.Protected_Objects.Entries is
	51	pragma Elaborate_Body;
	52
	53	subtype Positive_Protected_Entry_Index is
	54	Protected_Entry_Index range 1 .. Protected_Entry_Index'Last;
	55
	56	type Find_Body_Index_Access is access
	57	function
	58	(O : System.Address;
	59	E : Protected_Entry_Index)
	60	return Protected_Entry_Index;
	61
	62	type Protected_Entry_Body_Array is
	63	array (Positive_Protected_Entry_Index range <>) of Entry_Body;
	64	-- This is an array of the executable code for all entry bodies of
	65	-- a protected type.
	66
	67	type Protected_Entry_Body_Access is access all Protected_Entry_Body_Array;
	68
	69	type Protected_Entry_Queue_Array is
	70	array (Protected_Entry_Index range <>) of Entry_Queue;
	71
	72	-- This type contains the GNARL state of a protected object. The
	73	-- application-defined portion of the state (i.e. private objects)
	74	-- is maintained by the compiler-generated code.
	75	-- note that there is a simplified version of this type declared in
	76	-- System.Tasking.PO_Simple that handle the simple case (no entries).
	77
	78	type Protection_Entries (Num_Entries : Protected_Entry_Index) is new
	79	Ada.Finalization.Limited_Controlled
	80	with record
	81	L : aliased Task_Primitives.Lock;
	82	-- The underlying lock associated with a Protection_Entries.
	83	-- Note that you should never (un)lock Object.L directly, but instead
	84	-- use Lock_Entries/Unlock_Entries.
	85
	86	Compiler_Info : System.Address;
	87	Call_In_Progress : Entry_Call_Link;
	88	Ceiling : System.Any_Priority;
	89	Old_Base_Priority : System.Any_Priority;
	90	Pending_Action : Boolean;
	91	-- Flag indicating that priority has been dipped temporarily
	92	-- in order to avoid violating the priority ceiling of the lock
	93	-- associated with this protected object, in Lock_Server.
	94	-- The flag tells Unlock_Server or Unlock_And_Update_Server to
95	-- restore the old priority to Old_Base_Priority. This is needed
96	-- because of situations (bad language design?) where one
97	-- needs to lock a PO but to do so would violate the priority
98	-- ceiling. For example, this can happen when an entry call
99	-- has been requeued to a lower-priority object, and the caller
100	-- then tries to cancel the call while its own priority is higher
101	-- than the ceiling of the new PO.
102	Finalized : Boolean := False;
103	-- Set to True by Finalize to make this routine idempotent.
104
105	Entry_Bodies : Protected_Entry_Body_Access;
106
107	-- The following function maps the entry index in a call (which denotes
108	-- the queue to the proper entry) into the body of the entry.
109
110	Find_Body_Index : Find_Body_Index_Access;
111	Entry_Queues : Protected_Entry_Queue_Array (1 .. Num_Entries);
112	end record;
cacbc350 RK	113
	114	-- No default initial values for this type, since call records
	115	-- will need to be re-initialized before every use.
	116
	117	type Protection_Entries_Access is access all Protection_Entries'Class;
	118	-- See comments in s-tassta.adb about the implicit call to Current_Master
	119	-- generated by this declaration.
	120
cacbc350 RK	121	function To_Address is
	122	new Unchecked_Conversion (Protection_Entries_Access, System.Address);
	123	function To_Protection is
	124	new Unchecked_Conversion (System.Address, Protection_Entries_Access);
	125
	126	function Has_Interrupt_Or_Attach_Handler
	127	(Object : Protection_Entries_Access) return Boolean;
	128	-- Returns True if an Interrupt_Handler or Attach_Handler pragma applies
	129	-- to the protected object. That is to say this primitive returns False for
	130	-- Protection, but is overriden to return True when interrupt handlers are
	131	-- declared so the check required by C.3.1(11) can be implemented in
	132	-- System.Tasking.Protected_Objects.Initialize_Protection.
	133
	134	procedure Initialize_Protection_Entries
	135	(Object : Protection_Entries_Access;
	136	Ceiling_Priority : Integer;
	137	Compiler_Info : System.Address;
	138	Entry_Bodies : Protected_Entry_Body_Access;
	139	Find_Body_Index : Find_Body_Index_Access);
	140	-- Initialize the Object parameter so that it can be used by the runtime
	141	-- to keep track of the runtime state of a protected object.
	142
	143	procedure Lock_Entries (Object : Protection_Entries_Access);
	144	-- Lock a protected object for write access. Upon return, the caller
	145	-- owns the lock to this object, and no other call to Lock or
	146	-- Lock_Read_Only with the same argument will return until the
	147	-- corresponding call to Unlock has been made by the caller.
	148	-- Program_Error is raised in case of ceiling violation.
	149
	150	procedure Lock_Entries
	151	(Object : Protection_Entries_Access; Ceiling_Violation : out Boolean);
	152	-- Same as above, but return the ceiling violation status instead of
	153	-- raising Program_Error.
	154
	155	procedure Lock_Read_Only_Entries (Object : Protection_Entries_Access);
	156	-- Lock a protected object for read access. Upon return, the caller
	157	-- owns the lock for read access, and no other calls to Lock with the
	158	-- same argument will return until the corresponding call to Unlock
	159	-- has been made by the caller. Other calls to Lock_Read_Only may (but
	160	-- need not) return before the call to Unlock, and the corresponding
	161	-- callers will also own the lock for read access.
	162	--
	163	-- Note: we are not currently using this interface, it is provided
	164	-- for possible future use. At the current time, everyone uses Lock
	165	-- for both read and write locks.
	166
	167	procedure Unlock_Entries (Object : Protection_Entries_Access);
	168	-- Relinquish ownership of the lock for the object represented by
	169	-- the Object parameter. If this ownership was for write access, or
	170	-- if it was for read access where there are no other read access
	171	-- locks outstanding, one (or more, in the case of Lock_Read_Only)
	172	-- of the tasks waiting on this lock (if any) will be given the
	173	-- lock and allowed to return from the Lock or Lock_Read_Only call.
	174
	175	private
	176
	177	procedure Finalize (Object : in out Protection_Entries);
	178	-- Clean up a Protection object; in particular, finalize the associated
	179	-- Lock object.
	180
	181	end System.Tasking.Protected_Objects.Entries;