source: trunk/Packages/Kernel/Kernel.Scheduler.pas

unit Kernel.Scheduler;

interface

uses
  Classes, SysUtils, Kernel.List, Kernel.Classes;

type
  TTask = class;
  TScheduler = class;

  TTaskEvent = procedure(Task: TTask) of object;

  TTaskState = (tsStopped, tsRunning, tsSuspended, tsWaiting);

  TWaitReason = (wrSleep, wrMessage);

  { TTask }

  TTask = class(TNamedObject)
    Scheduler: TScheduler;
    State: TTaskState;
    WaitReason: TWaitReason;
    WakeUpTime: TDateTime;
    Terminated: Boolean;
    EntryPoint: TTaskEvent;
    Messages: TObjectQueue; // TQueue<TIPMessage>
    procedure WaitForMessage;
    procedure Sleep(Duration: TDateTime);
    constructor Create; virtual;
    destructor Destroy; override;
  end;

  TTaskClass = class of TTask;

  { TScheduler }

  TScheduler = class
    TaskClass: TTaskClass;
    Tasks: TNamedObjects<TTask>;
    Running: Boolean;
    function GetCurrentTask: TTask; virtual;
    procedure Start; virtual;
    procedure Stop; virtual;
    function AddTask(Name: string; EntryPoint: TTaskEvent): TTask; virtual;
    procedure SwitchNext; virtual;
    constructor Create; virtual;
    destructor Destroy; override;
  end;

  TSchedulerClass = class of TScheduler;


implementation

{ TTask }

procedure TTask.WaitForMessage;
begin
  WaitReason := wrMessage;
  State := tsWaiting;
  Scheduler.SwitchNext;
end;

procedure TTask.Sleep(Duration: TDateTime);
begin
  WakeUpTime := Now + Duration;
  State := tsWaiting;
  WaitReason := wrSleep;
  Scheduler.SwitchNext;
end;

constructor TTask.Create;
begin
  Messages := TObjectQueue.Create;
end;

destructor TTask.Destroy;
begin
  FreeAndNil(Messages);
  inherited;
end;

{ TScheduler }

function TScheduler.GetCurrentTask: TTask;
begin
  Result := nil;
end;

procedure TScheduler.Start;
begin
  Running := True;
end;

procedure TScheduler.Stop;
begin
  Running := False;
end;

function TScheduler.AddTask(Name: string; EntryPoint: TTaskEvent): TTask;
var
  NewTask: TTask;
begin
  NewTask := TaskClass.Create;
  NewTask.Scheduler := Self;
  NewTask.Name := Name;
  NewTask.EntryPoint := EntryPoint;
  Tasks.Add(NewTask);
  Result := NewTask;
end;

procedure TScheduler.SwitchNext;
begin

end;

constructor TScheduler.Create;
begin
  TaskClass := TTask;
  Tasks := TNamedObjects<TTask>.Create;
end;

destructor TScheduler.Destroy;
begin
  if Running then Stop;
  Tasks.Free;
  inherited Destroy;
end;


end.