TSafeMe… BindMe

Forget Try-Finally to make sure your TObject instance destroyed completely on exit block procedure. TSafeMe makes your code clean without worrying with underlaying memory leaks.

Common try-finally pattern, is this your usual code?

function TXServer.ServiceDelete(const ServiceID: string): IXResponse;
var
  Q_SERVICES: TORM_Q_SERVICES;
begin
  Result := TXResponse.NewResponse();

  Q_SERVICES := TORM_Q_SERVICES.Create; // create new instance
  try
    try
      Q_SERVICES.SERVICE_ID.WhereValue := ServiceID;
      Q_SERVICES.Controller.Delete;
    except
      on E: Exception do
      begin
        Result.RESP_CODE := RC_ERROR;
        Result.RESP_MSG := E.Message;
      end;
    end;
  finally
    Q_SERVICES.Free; // then relese it
  end;
end;

Now compare with this one, see TSafeMe in action:

function TXServer.ServiceDelete(const ServiceID: string): IXResponse;
var
  Q_SERVICES: TORM_Q_SERVICES;
begin
  Result := TXResponse.NewResponse();
  TSafeMe.BindMe(TORM_Q_SERVICES.Create, Q_SERVICES);  // new instance and bind to TSafeMe

  try
    Q_SERVICES.SERVICE_ID.WhereValue := ServiceID;
    Q_SERVICES.Controller.Delete;
  except
    on E: Exception do
    begin
      Result.RESP_CODE := RC_ERROR;
      Result.RESP_MSG := E.Message;
    end;
  end;

  // no need release here, TSafeMe takes care for you
end;

function TXServer.ServiceUpdate(const ServiceID, ServiceName: string): IXResponse;
var
  Q_SERVICES: TORM_Q_SERVICES;
begin
  Result := TXResponse.NewResponse();
  TSafeMe.BindMe(TORM_Q_SERVICES.Create, Q_SERVICES);

  try
    Q_SERVICES.Controller.Edit;
    Q_SERVICES.SERVICE_ID.Value := ServiceID;
    Q_SERVICES.SERVICE_NAME.Value := ServiceName;
    Q_SERVICES.Controller.Post;
  except
    on E: Exception do
    begin
      Result.RESP_CODE := RC_ERROR;
      Result.RESP_MSG := E.Message;
    end;
  end;
end;

OK, here is another example, using common classes (as requested by b_squared):

procedure SafeMeInAction;
var
  MyStrings: TStrings;
  MyStream: TStream;
  MyComponent: TMyComponent; 
begin
  // new instances
  TSafeMe.BindMe(TStringList.Create, MyStrings);
  TSafeMe.BindMe(TStringStream.Create('Well this is the string data.'), MyStream);
  TSafeMe.BindMe(TMyComponent.Create(nil), MyComponent);

  // it is safe & ensure the instances will be destroyed once exit block procedure
  
  MyStrings.Add('One');
  MyStrings.Add(MyStream.DataString);
  MyStrings.Add(MyComponent.Name);

  // it is safe... even when exception occurred...

  raise Exception.Create('Ups something wrong here');
  MyStrings.Add('This never executed');

  // nice is it
  // bump... the instances destroyed as soon the program quit this block
end;

How this works? What a tricks inside this? Before I write the tips let me know your mind, write comment bellow about how this should achieved.

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