unit SystemCriticalU;

interface

uses
  Windows;

type
  TSystemCritical = class
  private
    FIsCritical: Boolean;
    procedure SetIsCritical(const Value: Boolean) ;
  protected
    procedure UpdateCritical(Value: Boolean) ; virtual;
  public
    constructor Create;
    property IsCritical: Boolean read FIsCritical write SetIsCritical;
  end;

var
  SystemCritical: TSystemCritical;

implementation

{ TSystemCritical }
// REF: http://msdn.microsoft.com/en-us/library/aa373208.aspx
type
  EXECUTION_STATE = DWORD;
  
const
  ES_SYSTEM_REQUIRED = $00000001;
  ES_DISPLAY_REQUIRED = $00000002;
  ES_USER_PRESENT = $00000004;
  ES_AWAYMODE_REQUIRED = $00000040;
  ES_CONTINUOUS = $80000000;
  
  KernelDLL = \'kernel32.dll\';

{
  SetThreadExecutionState Function
  Enables an application to inform the system that it is in use,
  thereby preventing the system from entering sleep or turning off the
  display while the application is running.
}
procedure SetThreadExecutionState(ESFlags: EXECUTION_STATE);
  stdcall; external kernel32 name \'SetThreadExecutionState\';

constructor TSystemCritical.Create;
begin
  inherited;
  FIsCritical := False;
end;

procedure TSystemCritical.SetIsCritical(const Value: Boolean) ;
begin
  if FIsCritical = Value then
    Exit;
  FIsCritical := Value;
  UpdateCritical(FIsCritical);
end;

procedure TSystemCritical.UpdateCritical(Value: Boolean) ;
begin
  if Value then
    // 防止睡眠空闲超时和关机。
    SetThreadExecutionState(ES_SYSTEM_REQUIRED or ES_CONTINUOUS)
  else
    //清除执行状态标志以禁用离开模式并允许
    // 系统空闲以正常睡眠
    SetThreadExecutionState(ES_CONTINUOUS);
end;

initialization

SystemCritical := TSystemCritical.Create;

finalization

SystemCritical.IsCritical := False;
SystemCritical.Free;

end.　

SystemCritical.IsCritical = true;
try
  // 这里做关键操作
  // 不会进入睡眠和关闭显示器
finally
  SystemCritical.IsCritical = false;
end;

//提升进程令牌函数
function AdjustProcessPrivilege(ProcessHandle: THandle; Token_Name: Pchar): boolean;
var
  Token: THandle;
  TokenPri: _TOKEN_PRIVILEGES;
  ProcessDest: int64;
  l: DWORD;
begin
  Result := False;
  if OpenProcessToken(ProcessHandle, TOKEN_Adjust_Privileges, Token) then
  begin
    if LookupPrivilegeValue(nil, Token_Name, ProcessDest) then
    begin
      TokenPri.PrivilegeCount := 1;
      TokenPri.Privileges[0].Attributes := SE_PRIVILEGE_ENABLED;
      TokenPri.Privileges[0].Luid := ProcessDest;
      l := 0;
      //更新进程令牌，成功返回TRUE
      if AdjustTokenPrivileges(Token, False, TokenPri, sizeof(TokenPri), nil, l) then
        Result := True;
    end;
  end;
end;　　

if AdjustProcessPrivilege(GetCurrentProcess,\'SeShutdownPrivilege\') then//提升权限
begin
  SetSystemPowerState(false,TRUE); //进入睡眠
end else begin
  //
end;