jvgsingleinstance.pas

East make Tray Icon in delphi

{-----------------------------------------------------------------------------
The contents of this file are subject to the Mozilla Public License
Version 1.1 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.mozilla.org/MPL/MPL-1.1.html

Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either expressed or implied. See the License for
the specific language governing rights and limitations under the License.

The Original Code is: JvgSingleInstance.PAS, released on 2003-01-15.

The Initial Developer of the Original Code is Andrey V. Chudin,  [chudin att yandex dott ru]
Portions created by Andrey V. Chudin are Copyright (C) 2003 Andrey V. Chudin.
All Rights Reserved.

Contributor(s):
Michael Beck [mbeck att bigfoot dott com].
Burov Dmitry, translation of russian text.

You may retrieve the latest version of this file at the Project JEDI's JVCL home page,
located at http://jvcl.sourceforge.net

Known Issues:
-----------------------------------------------------------------------------}
// $Id: JvgSingleInstance.pas,v 1.18 2005/02/17 10:21:21 marquardt Exp $

unit JvgSingleInstance;

{$I jvcl.inc}

interface

uses
  {$IFDEF USEJVCL}
  {$IFDEF UNITVERSIONING}
  JclUnitVersioning,
  {$ENDIF UNITVERSIONING}
  Windows, Classes, SyncObjs, SysUtils, Forms,
  JvComponent;
  {$ELSE}
  Windows, Classes, SyncObjs, SysUtils, Forms;
  {$ENDIF USEJVCL}

type
  {$IFDEF USEJVCL}
  TJvgSingleInstance = class(TJvComponent)
  {$ELSE}
  TJvgSingleInstance = class(TComponent)
  {$ENDIF USEJVCL}
  private
    FCheckEvent: TEvent;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  end;

{$IFDEF USEJVCL}
{$IFDEF UNITVERSIONING}
const
  UnitVersioning: TUnitVersionInfo = (
    RCSfile: '$RCSfile: JvgSingleInstance.pas,v $';
    Revision: '$Revision: 1.18 $';
    Date: '$Date: 2005/02/17 10:21:21 $';
    LogPath: 'JVCL\run'
  );
{$ENDIF UNITVERSIONING}
{$ENDIF USEJVCL}

implementation

{$IFDEF USEJVCL}
uses
  JvResources, JvConsts;
{$ENDIF USEJVCL}

{$IFNDEF USEJVCL}
resourcestring
  RsOneInstanceOfThisProgramIsAlreadyRu = 'One instance of this program is already running. A second instance launch is not allowed.';
  RsSecondInstanceLaunchOfs = 'Second instance launch of %s';
{$ENDIF !USEJVCL}

{ semaphore

var
  hs: THandle;
begin
  hs := CreateSemaphore(nil, 0, 2, 'MyProgSemaphore');
  if GetLastError = ERROR_ALREADY_EXISTS then
    Halt;
  Application.Initialize;
  Application.CreateForm(TForm1, Form1);
  Application.Run;
  ReleaseSemaphore(hs, 2, 0);
end.
}

{ mutex

const
  SAppMutex = 'SomeName';

var
  Mtx: THandle;
  Wait: Longint;

begin
  Application.Initialize;
  Mtx := CreateMutex(nil, True, PChar(SAppMutex));
  try
    Wait := WaitForSingleObject(Mtx, 0);
    if (Wait <> WAIT_TIMEOUT) then
    begin
      OpenMutex(SYNCHRONIZE, False, PChar(SAppMutex));
      try
        Application.CreateForm(TfrmMain, frmMain);
        Application.Run;
      finally
        ReleaseMutex(Mtx);
      end;
    end
    else
      Exit;
  finally
    CloseHandle(Mtx);
  end;
end.
}

constructor TJvgSingleInstance.Create(AOwner: TComponent);
var
  S1, S2: string;
begin
  inherited Create(AOwner);
  if csDesigning in ComponentState then
    Exit;
  FCheckEvent := TEvent.Create(nil, False, True, ParamStr(0));
  if FCheckEvent.WaitFor(10) <> wrSignaled then
  begin
    S1 := RsOneInstanceOfThisProgramIsAlreadyRu;
    S2 := Format(RsSecondInstanceLaunchOfs, [ExtractFileName(ParamStr(0))]);
    Application.MessageBox(PChar(S1), PChar(S2), MB_ICONSTOP or MB_OK);
    Halt;
  end;
end;

destructor TJvgSingleInstance.Destroy;
begin
  FCheckEvent.Free;
  inherited Destroy;
end;

{$IFDEF USEJVCL}
{$IFDEF UNITVERSIONING}
initialization
  RegisterUnitVersion(HInstance, UnitVersioning);

finalization
  UnregisterUnitVersion(HInstance);
{$ENDIF UNITVERSIONING}
{$ENDIF USEJVCL}

end.