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221 | -- --
-- package Copyright (c) Dmitry A. Kazakov --
-- Synchronization.Interprocess. Luebeck --
-- Mutexes Spring, 2018 --
-- Interface --
-- Last revision : 01:09 01 May 2018 --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public License as --
-- published by the Free Software Foundation; either version 2 of --
-- the License, or (at your option) any later version. This library --
-- is distributed in the hope that it will be useful, but WITHOUT --
-- 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 along with --
-- this library; if not, write to the Free Software Foundation, --
-- Inc., 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. --
--____________________________________________________________________--
with Ada.Exceptions; use Ada.Exceptions;
with Ada.IO_Exceptions; use Ada.IO_Exceptions;
with System.Address_To_Access_Conversions;
package body Synchronization.Interprocess.Mutexes is
procedure Check (Message : String; Code : DWORD := GetLastError) is
begin
if Code = ERROR_INVALID_HANDLE then
Raise_Exception
( Status_Error'Identity,
Message & "Mutex is not initialized or already finalized"
);
else
Raise_From_LastError (Data_Error'Identity, Message, Code);
end if;
end Check;
procedure Finalize (Object : in out Holder) is
begin
Release (Object.Resource.all);
end Finalize;
procedure Finalize (Object : in out Mutex) is
Result : BOOL;
begin
if Object.External /= INVALID_HANDLE_VALUE then
Result := CloseHandle (Object.External);
Object.External := INVALID_HANDLE_VALUE;
end if;
Synchronization.Interprocess.Finalize
( Abstract_Shared_Object (Object)
);
end Finalize;
function Get_Size (Object : Mutex) return Storage_Count is
begin
return Round (HANDLE'Max_Size_In_Storage_Elements);
end Get_Size;
function Get_Timeout (Object : Mutex) return Duration is
begin
return Duration (Long_Float (Object.Timeout) / 1000.0);
end Get_Timeout;
procedure Grab (Object : in out Mutex) is
begin
if Object.Owner = Current_Task then
Object.Count := Object.Count + 1;
else
case WaitForSingleObject (Object.External, 0) is
when WAIT_ABANDONED | WAIT_OBJECT_0 =>
Object.Owner := Current_Task;
Object.Count := 1;
when WAIT_TIMEOUT =>
return;
when others =>
Check ("Grab mutex fault: ");
end case;
end if;
end Grab;
procedure Initialize (Object : in out Holder) is
begin
Seize (Object.Resource.all);
end Initialize;
function Is_Mine (Object : Mutex) return Boolean is
begin
return Object.Owner = Current_Task;
end Is_Mine;
function Is_Owned (Object : Mutex) return Boolean is
Result : BOOL;
begin
return Object.Owner /= Null_Task_Id;
end Is_Owned;
procedure Map
( Object : in out Mutex;
Shared : in out Abstract_Shared_Environment'Class;
Location : System.Address;
Size : Storage_Count;
Owner : Boolean
) is
package Conversions is
new System.Address_To_Access_Conversions (HANDLE);
This : HANDLE renames Conversions.To_Pointer (Location).all;
begin
if Owner then
Object.External := CreateMutex;
if Object.External = 0 then
Object.External := INVALID_HANDLE_VALUE;
Raise_From_LastError
( Data_Error'Identity,
"Mutex creation fault: ",
GetLastError
);
end if;
This := Object.External;
else
if ( 0
= DuplicateHandle
( SourceProcessHandle => Shared.Server,
SourceHandle => This,
TargetProcessHandle => GetCurrentProcess,
TargetHandle =>
Object.External'Unchecked_Access
) )
then
Raise_From_LastError
( Data_Error'Identity,
"Cannot duplicate a handle to the mutex: ",
GetLastError
);
end if;
end if;
end Map;
procedure Release (Object : in out Mutex) is
begin
if Object.Owner = Current_Task then
Object.Count := Object.Count - 1;
if Object.Count = 0 then
Object.Owner := Null_Task_Id;
if 0 = ReleaseMutex (Object.External) then
Object.Owner := Null_Task_Id;
declare
Code : constant DWORD := GetLastError;
begin
Check ("Release mutex fault: ", Code);
end;
end if;
end if;
elsif Object.Owner = Null_Task_Id then
Raise_Exception
( Ownership_Error'Identity,
"Mutex is not owned"
);
else
Raise_Exception
( Ownership_Error'Identity,
"Mutex is owned by anothers task"
);
end if;
end Release;
procedure Seize (Object : in out Mutex) is
begin
if Object.Owner = Current_Task then
Object.Count := Object.Count + 1;
else
case WaitForSingleObject (Object.External, Object.Timeout) is
when WAIT_ABANDONED | WAIT_OBJECT_0 =>
Object.Owner := Current_Task;
Object.Count := 1;
when WAIT_TIMEOUT =>
Raise_Exception (Timeout_Error'Identity, "Timed out");
when others =>
Check ("Seize mutex fault: ");
end case;
end if;
end Seize;
procedure Seize (Object : in out Mutex; Timeout : Duration) is
begin
if Object.Owner = Current_Task then
Object.Count := Object.Count + 1;
else
case WaitForSingleObject
( Object.External,
Milliseconds (Timeout)
) is
when WAIT_ABANDONED | WAIT_OBJECT_0 =>
Object.Owner := Current_Task;
Object.Count := 1;
when WAIT_TIMEOUT =>
Raise_Exception (Timeout_Error'Identity, "Timed out");
when others =>
Check ("Seize mutex fault: ");
end case;
end if;
end Seize;
procedure Set_Timeout
( Object : in out Mutex;
Timeout : Duration
) is
begin
Object.Timeout := Milliseconds (Timeout);
end Set_Timeout;
end Synchronization.Interprocess.Mutexes;
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