------------------------------------------------------------------------------
-- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
+-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
--- SYSTEM.TASKING.PROTECTED_OBJECTS.SINGLE_ENTRY --
+-- SYSTEM.TASKING.PROTECTED_OBJECTS.SINGLE_ENTRY --
-- --
-- S p e c --
-- --
--- $Revision$
--- --
--- Copyright (C) 1991-2001 Florida State University --
+-- Copyright (C) 1992-2009, 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- --
+-- 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. 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. --
+-- 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. --
-- --
--- 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. --
+-- 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 --
+-- <http://www.gnu.org/licenses/>. --
-- --
--- GNARL was developed by the GNARL team at Florida State University. It is --
--- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
--- State University (http://www.gnat.com). --
+-- GNARL was developed by the GNARL team at Florida State University. --
+-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides an optimized version of Protected_Objects.Operations
-- and Protected_Objects.Entries making the following assumptions:
--
--- PO have only one entry
--- There is only one caller at a time (No_Entry_Queue)
--- There is no dynamic priority support (No_Dynamic_Priorities)
--- No Abort Statements
--- (No_Abort_Statements, Max_Asynchronous_Select_Nesting => 0)
--- PO are at library level
--- None of the tasks will terminate (no need for finalization)
+-- PO have only one entry
+-- There is only one caller at a time (No_Entry_Queue)
+-- There is no dynamic priority support (No_Dynamic_Priorities)
+-- No Abort Statements
+-- (No_Abort_Statements, Max_Asynchronous_Select_Nesting => 0)
+-- PO are at library level
+-- None of the tasks will terminate (no need for finalization)
--
-- This interface is intended to be used in the ravenscar profile, the
-- compiler is responsible for ensuring that the conditions mentioned above
---------------------------------
-- The compiler will expand in the GNAT tree the following construct:
- --
+
-- protected PO is
-- entry E;
-- procedure P;
-- private
-- Open : Boolean := False;
-- end PO;
- --
+
-- protected body PO is
-- entry E when Open is
-- ...variable declarations...
-- begin
-- ...B...
-- end E;
- --
+
-- procedure P is
-- ...variable declarations...
-- begin
-- ...C...
-- end P;
-- end PO;
- --
+
-- as follows:
- --
+
-- protected type poT is
-- entry e;
-- procedure p;
-- barrier => poPT__B2s'unrestricted_access,
-- action => poPT__E1s'unrestricted_access);
-- freeze poTV [
- -- procedure _init_proc (_init : in out poTV) is
+ -- procedure poTVIP (_init : in out poTV) is
-- begin
-- _init.open := false;
- -- _init_proc (_init._object);
+ -- object-init-proc (_init._object);
-- initialize_protection_entry (_init._object'unchecked_access,
-- unspecified_priority, _init'address, poTA'
-- unrestricted_access);
-- return;
- -- end _init_proc;
+ -- end poTVIP;
-- ]
-- po : poT;
- -- _init_proc (poTV!(po));
- --
+ -- poTVIP (poTV!(po));
+
-- function poPT__B2s (O : address; E : protected_entry_index) return
-- boolean is
-- type poTVP is access poTV;
-- begin
-- return open;
-- end poPT__B2s;
- --
+
-- procedure poPT__E1s (O : address; P : address; E :
-- protected_entry_index) is
-- type poTVP is access poTV;
-- unchecked_access, get_gnat_exception);
-- return;
-- end poPT__E1s;
- --
+
-- procedure poPT__pN (_object : in out poTV) is
-- poR : protection_entry renames _object._object;
-- openP : boolean renames _object.open;
-- ...C...
-- return;
-- end poPT__pN;
- --
+
-- procedure poPT__pP (_object : in out poTV) is
-- procedure _clean is
-- begin
-- 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 cals to Lock_Read_Only
+ -- 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.
-- barrier. This is used when the state of a protected object may have
-- changed, in particular after the execution of the statement sequence of
-- a protected procedure.
- -- This must be called with abortion deferred and with the corresponding
- -- object locked.
+ --
+ -- This must be called with abort deferred and with the corresponding
+ -- object locked. Object is unlocked on return.
procedure Protected_Single_Entry_Call
(Object : Protection_Entry_Access;
function Protected_Count_Entry (Object : Protection_Entry)
return Natural;
- -- Return the number of entry calls on Object (0 or 1).
+ -- Return the number of entry calls on Object (0 or 1)
function Protected_Single_Entry_Caller (Object : Protection_Entry)
- return Task_ID;
+ return Task_Id;
-- Return value of E'Caller, where E is the protected entry currently
-- being handled. This will only work if called from within an
-- entry body, as required by the LRM (C.7.1(14)).
private
type Protection_Entry is record
- L : aliased Task_Primitives.Lock;
- Compiler_Info : System.Address;
- Call_In_Progress : Entry_Call_Link;
- Ceiling : System.Any_Priority;
- Entry_Body : Entry_Body_Access;
- Entry_Queue : Entry_Call_Link;
+ Common : aliased Protection;
+ -- State of the protected object. This part is common to any protected
+ -- object, including those without entries.
+
+ Compiler_Info : System.Address;
+ -- Pointer to compiler-generated record representing protected object
+
+ Call_In_Progress : Entry_Call_Link;
+ -- Pointer to the entry call being executed (if any)
+
+ Entry_Body : Entry_Body_Access;
+ -- Pointer to executable code for the entry body of the protected type
+
+ Entry_Queue : Entry_Call_Link;
+ -- Place to store the waiting entry call (if any)
end record;
- pragma Volatile (Protection_Entry);
- for Protection_Entry'Alignment use Standard'Maximum_Alignment;
- -- Use maximum alignement so that one can convert a protection_entry_access
- -- to a task_id.
end System.Tasking.Protected_Objects.Single_Entry;
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