unit FDCRelauncher;

///  Simple mechanisms for restarting a service or application on exit.
///  Intended for use after .exe upgrades, etc.
///  Instructions:
///    1. Put the unit as early as possible in the main app uses section
///    2. Call one of the Restart procedures before exiting.
///
///  Written by Lars Fosdal, Tine SA, 15 OCT 2014, http://plus.lars.fosdal.com

interface
uses
  Windows, SysUtils, ShellAPI, CustomDebugOut;

  /// <summary> Restarts the application on exit, optionally passing extra arguments on the command line</summary>
  procedure RestartApplicationOnExit(const aExtraArguments: String = '');

  /// <summary> Restarts the service when it stops, using service name (without quotes)</summary>
  procedure RestartServiceOnExit(const ServiceName: String);

implementation

type
  TRestartOnExit = reference to procedure;

var
  RestartOnExit: TRestartOnExit;

procedure RestartServiceOnExit(const ServiceName: String);
begin
  RestartOnExit := procedure
  begin
    OutputDebugString(SysEvent + 'Restarting ' + ServiceName);
    try
      ShellExecute(0, 'open', pChar('cmd.exe'),
        pChar('/S /C net start "' + ServiceName + '"'), nil, SW_HIDE);
    except
      on E:Exception
      do begin
        OutputDebugString(BadShit + 'Restart Service Exception ' + E.ClassName + ' ' + E.Message);
      end;
    end;

  end;
end;

procedure RestartApplicationOnExit(const aExtraArguments: String);
var
  ExtraArguments: String;
begin
  ExtraArguments := Trim(aExtraArguments);

  RestartOnExit := procedure
  begin
    OutputDebugString(SysEvent + 'Restarting ' + ExtraArguments);
    try
      ShellExecute(0, 'open', pChar(ParamStr(0)),
        pChar('RestartApplicationOnExit='+IntToStr(GetCurrentProcessId) + ExtraArguments), nil, SW_NORMAL);
    except
      on E:Exception
      do begin
        OutputDebugString(BadShit + 'Restart Application Exception ' + E.ClassName + ' ' + E.Message);
      end;
    end;

  end;

end;

initialization
  RestartOnExit := nil;

finalization

  if Assigned(RestartOnExit)
   then RestartOnExit;

end.