Question:

Question:
I have an interface-based timer (see code below). Is it safe to use it like this?

var
ATimer : ITimer;

ATimer := TTimer.Create(100);
ATimer.Start(procedure
begin
// Do something
ATimer.Stop;
ATimer := nil; // This will destroy the timer object. Bad idea?
end;)

It works well but I suspect it is not safe.

==========================================

ITimer = interface(IInvokable)
['{1C06BCF6-1C6D-473E-993F-2B231B17D4F5}']
function Start(const Action: TProc): ITimer;
function Stop: ITimer;
end;

{ ITimer implementation }
type
TTimer = class(TInterfacedObject, ITimer)
private var
FTimer: VCL.ExtCtrls.TTimer;
FAction: TProc;
private
procedure RunAction(Sender: TObject);
public
constructor Create(const Interval: Cardinal);
destructor Destroy; override;
class function New(const Interval: Cardinal): ITimer;
function Start(const Action: TProc): ITimer;
function Stop: ITimer;
end;


{ TTimer }

constructor TTimer.Create(const Interval: Cardinal);
begin
FTimer := VCL.ExtCtrls.TTimer.Create(nil);
FTimer.Enabled := False;
FTimer.Interval := Interval;
FTimer.OnTimer := RunAction;
end;

destructor TTimer.Destroy;
begin
FTimer.Free;
inherited;
end;

class function TTimer.New(const Interval: Cardinal): ITimer;
begin
Result := Create(Interval);
end;

procedure TTimer.RunAction(Sender: TObject);
begin
FAction;
end;

function TTimer.Start(const Action: TProc): ITimer;
begin
Result := Self;
FAction := Action;
FTimer.Enabled := True;
end;

function TTimer.Stop: ITimer;
begin
Result := Self;
FTimer.Enabled := False;
end;

(code from https://github.com/nunopicado/Reusable-Objects)


https://github.com/nunopicado/Reusable-Objects