Indy/Lib/System/IdAntiFreezeBase.pas

{
  $Project$
  $Workfile$
  $Revision$
  $DateUTC$
  $Id$

  This file is part of the Indy (Internet Direct) project, and is offered
  under the dual-licensing agreement described on the Indy website.
  (http://www.indyproject.org/)

  Copyright:
   (c) 1993-2005, Chad Z. Hower and the Indy Pit Crew. All rights reserved.
}
{
  $Log$
}
{
  Rev 1.5    8/17/2004 2:54:38 PM  JPMugaas
  Made ShouldUse virtual again.

  Rev 1.4    2004.06.16 8:08:52 PM  czhower
  Temp workaround for D.NET

  Rev 1.3    2004.03.01 11:27:54 AM  czhower
  Bug fix for checking of more than one AF

  Rev 1.2    2004.02.29 9:38:36 PM  czhower
  Bug fix for design mode.

  Rev 1.1    2004.02.03 3:15:50 PM  czhower
  Updates to move to System.

  Rev 1.0    2004.02.03 2:40:34 PM  czhower
  Move

  Rev 1.3    2004.01.20 10:03:20 PM  czhower
  InitComponent

  Rev 1.2    2003.10.01 12:30:02 PM  czhower
  .Net

  Rev 1.1    2003.10.01 1:12:32 AM  czhower
  .Net

  Rev 1.0    11/13/2002 08:37:44 AM  JPMugaas
}

unit IdAntiFreezeBase;

interface

{$I IdCompilerDefines.inc}

uses
  IdBaseComponent;

const
  ID_Default_TIdAntiFreezeBase_Active = True;
  ID_Default_TIdAntiFreezeBase_ApplicationHasPriority = True;
  ID_Default_TIdAntiFreezeBase_IdleTimeOut = 250;
  ID_Default_TIdAntiFreezeBase_OnlyWhenIdle = True;

type
  TIdAntiFreezeBase = class(TIdBaseComponent)
  protected
    FActive: Boolean;
    FApplicationHasPriority: Boolean;
    FIdleTimeOut: Integer;
    FOnlyWhenIdle: Boolean;
    //
    procedure InitComponent; override;
  public
    destructor Destroy; override;
    procedure Process; virtual; abstract;
    class procedure DoProcess(const AIdle: Boolean = True; const AOverride: Boolean = False);
    class function ShouldUse: Boolean;
    class procedure Sleep(ATimeout: Integer);
  published
    property Active: boolean read FActive write FActive
     default ID_Default_TIdAntiFreezeBase_Active;
    property ApplicationHasPriority: Boolean read FApplicationHasPriority
     write FApplicationHasPriority
     default ID_Default_TIdAntiFreezeBase_ApplicationHasPriority;
    property IdleTimeOut: integer read FIdleTimeOut write FIdleTimeOut
     default ID_Default_TIdAntiFreezeBase_IdleTimeOut;
    property OnlyWhenIdle: Boolean read FOnlyWhenIdle write FOnlyWhenIdle
     default ID_Default_TIdAntiFreezeBase_OnlyWhenIdle;
  end;

var
  GAntiFreeze: TIdAntiFreezeBase = nil;

implementation

uses
  //facilitate inlining only.
  {$IFDEF USE_INLINE}
    {$IFDEF DOTNET}
  System.Threading,
    {$ENDIF}
    {$IFDEF WINDOWS}
      {$IFDEF FPC}
  windows,
      {$ELSE}
  Windows,
      {$ENDIF}
    {$ENDIF}
  {$ENDIF}
  {$IFDEF USE_VCL_POSIX}
  Posix.SysSelect,
  Posix.SysTime,
  {$ENDIF}
  {$IFDEF KYLIXCOMPAT}
  Libc,
  {$ENDIF}
  IdGlobal,
  IdResourceStrings,
  IdException;

{ TIdAntiFreezeBase }

destructor TIdAntiFreezeBase.Destroy;
begin
  if GAntiFreeze = Self then begin
    GAntiFreeze := nil;
  end;
  inherited Destroy;
end;

class procedure TIdAntiFreezeBase.DoProcess(const AIdle: Boolean = True; const AOverride: Boolean = False);
begin
  if ShouldUse then begin
    if (not GAntiFreeze.OnlyWhenIdle) or AIdle or AOverride then begin
      GAntiFreeze.Process;
    end;
  end;
end;

procedure TIdAntiFreezeBase.InitComponent;
begin
  inherited InitComponent;
  if not IsDesignTime then begin
    if Assigned(GAntiFreeze) then begin
      raise EIdException.Create(RSAntiFreezeOnlyOne); // TODO: create a new Exception class for this
    end;
    GAntiFreeze := Self;
  end;
  FActive := ID_Default_TIdAntiFreezeBase_Active;
  FApplicationHasPriority := ID_Default_TIdAntiFreezeBase_ApplicationHasPriority;
  IdleTimeOut := ID_Default_TIdAntiFreezeBase_IdleTimeOut;
  FOnlyWhenIdle := ID_Default_TIdAntiFreezeBase_OnlyWhenIdle;
end;

class function TIdAntiFreezeBase.ShouldUse: Boolean;
begin
  Result := (GAntiFreeze <> nil) and InMainThread;
  if Result then begin
    Result := GAntiFreeze.Active;
  end;
end;

class procedure TIdAntiFreezeBase.Sleep(ATimeout: Integer);
begin
  if ShouldUse then begin
    while ATimeout > GAntiFreeze.IdleTimeOut do begin
      IndySleep(GAntiFreeze.IdleTimeOut);
      Dec(ATimeout, GAntiFreeze.IdleTimeOut);
      DoProcess;
    end;
    IndySleep(ATimeout);
    DoProcess;
  end else begin
    IndySleep(ATimeout);
  end;
end;

end.