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FixInsight vs VCL

Of course I couldn’t resist analyzing Delphi VCL with FixInsight. All examples in this post are related to Delphi XE7 (version 21.0.17017.3725). I will try to choose the most interesting places and ignore minor issues like methods that are too long or nested “with” statements (have you ever thought how many nested “with” statement in VCL?).

W512 Odd ELSE-IF condition

    if Element = sbGroupStartInactive then
      LSrcRect := System.Types.Rect(0, 110, 22 - 2, 132)
    else if Element = sbGroupEndInactive then
      LSrcRect := System.Types.Rect(22, 110, 46 - 2, 132)
    else if Element = sbGroupEndInactive then
      LSrcRect := System.Types.Rect(47, 110, 70 - 2, 132)
    else
      LSrcRect := System.Types.Rect(71, 110, 95 - 2, 132);
    DrawButton(RibbonSkin.Bitmap, LSrcRect, Canvas, Rect, 2, 2, 255);

Pay attention to lines 809 and 811. These conditions are equal. There is obviously something wrong. How could we fix this?

Let’s look around:

  else if Element in [sbGroupStartInactive, sbGroupMiddleInactive,
    sbGroupEndInactive, sbGroupSingleInactive] then
  begin
    if Element = sbGroupStartInactive then
      LSrcRect := System.Types.Rect(0, 110, 22, 132)
    else if Element = sbGroupMiddleInactive then
      LSrcRect := System.Types.Rect(22, 110, 46, 132)
    else if Element = sbGroupEndInactive then
      LSrcRect := System.Types.Rect(47, 110, 70, 132)
    else
      LSrcRect := System.Types.Rect(71, 110, 95, 132);
    DrawButton(RibbonSkin.Bitmap, LSrcRect, Canvas, Rect, 2, 2, 255);
  end
  else if Element in [sbGroupStartSplitInactive, sbGroupMiddleSplitInactive,
    sbGroupEndSplitInactive, sbGroupSingleSplitInactive] then
  begin
    if Element = sbGroupStartInactive then
      LSrcRect := System.Types.Rect(0, 110, 22 - 2, 132)
    else if Element = sbGroupEndInactive then
      LSrcRect := System.Types.Rect(22, 110, 46 - 2, 132)
    else if Element = sbGroupEndInactive then
      LSrcRect := System.Types.Rect(47, 110, 70 - 2, 132)
    else
      LSrcRect := System.Types.Rect(71, 110, 95 - 2, 132);
    DrawButton(RibbonSkin.Bitmap, LSrcRect, Canvas, Rect, 2, 2, 255);
  end
  else if Element in [sbSmallSplitHoverSplit, sbSmallSplitPressedSplit,
    sbSmallSplitInactiveSplit] then

That’s even more interesting. Along with “Element in [sbGroupStartSplitInactive, sbGroupMiddleSplitInactive, sbGroupEndSplitInactive, sbGroupSingleSplitInactive]” condition (see line 804), that code looks even more strange. I guess it is a rought copy-paste of the code above (lines 794 – 802) and actually it is intended to look like this:

  else if Element in [sbGroupStartSplitInactive, sbGroupMiddleSplitInactive,
    sbGroupEndSplitInactive, sbGroupSingleSplitInactive] then
  begin
    if Element = sbGroupStartSplitInactive then
      LSrcRect := System.Types.Rect(0, 110, 22 - 2, 132)
    else if Element = sbGroupMiddleSplitInactive then
      LSrcRect := System.Types.Rect(22, 110, 46 - 2, 132)
    else if Element = sbGroupEndSplitInactive then
      LSrcRect := System.Types.Rect(47, 110, 70 - 2, 132)
    else
      LSrcRect := System.Types.Rect(71, 110, 95 - 2, 132);
    DrawButton(RibbonSkin.Bitmap, LSrcRect, Canvas, Rect, 2, 2, 255);
  end

I don’t have much experience with Ribbon controls, so the fix offered solely on the basis of common sense. Maybe someone can do it better.

OK, go ahead.

W507 THEN statement is equal to ELSE statement

It’s Ribbon again :)

procedure TRibbonDropDownButton.DrawBackground(var PaintRect: TRect);
var
  LPt: TPoint;
begin
  inherited;
  LPt := GetArrowPosition(PaintRect);
  if not Enabled then
    DrawArrow(LPt, clNone, clNone, -1)
  else
    DrawArrow(LPt, clNone, clNone, -1);
end;

No comments. Obviously, the code in “then” and “else” are the same. It’s not clear what was meant to be there.

A similar issue in another file:

      if Assigned(Clients[I].ActionBar) then
      begin
        if Assigned(ActionProc) then
          ActionProc(Clients[I])
        else
          Clients[I].Refresh;
        UpdateActionBar(Clients[I]);
      end
      else
      begin
        if Assigned(ActionProc) then
          ActionProc(Clients[I])
        else
          Clients[I].Refresh;
        UpdateActionBar(Clients[I]);
      end;

And one more:

        if Style <> csSimple then
          if DroppedDown then
            DrawFrameControl(C.Handle, R, DFC_SCROLL, DFCS_FLAT or DFCS_SCROLLCOMBOBOX)
          else
            DrawFrameControl(C.Handle, R, DFC_SCROLL, DFCS_FLAT or DFCS_SCROLLCOMBOBOX);

OK, next.

W503 Assignment right hand side is equal to its left hand side

function CheckPoint(const Point, Source: TPoint; Deviation,
  ErrorMargin: Integer): Double;
var
  Distance: Double;
  ErrorMarginDistance: Double;
  M, B: Double;
begin
  Deviation := Deviation;
  Distance := Sqrt(Sqr(Point.X - Source.X) + Sqr(Point.Y - Source.Y));
  ErrorMarginDistance := MulDiv(Deviation, ErrorMargin, 100);

This assignment either should be different or it is completely useless.

And one more:

procedure TScreenTipsWindow.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params do
  begin
    Style := WS_POPUP;
    WindowClass.Style := WindowClass.Style;
    if NewStyleControls then
      ExStyle := WS_EX_TOOLWINDOW;
    if CheckWin32Version(5, 1) then
      WindowClass.Style := WindowClass.Style or CS_DROPSHADOW;
    if NewStyleControls then
      ExStyle := WS_EX_TOOLWINDOW;
    AddBiDiModeExStyle(ExStyle);
  end;
end;

And last, but not least…

W504 Missing INHERITED call in destructor

There are too many messages of this type, so I’m not going to quote everything.

destructor TActiveXPropertyPage.Destroy;
begin
  FPropertyPageImpl.FPropertyPage.Free;
  FPropertyPageImpl.Free;
end;

There is no “inherited” call, ancestor’s destructor is never called.

Well, let’s finish. As I said at the beginning, I don’t want to nitpick, so I ignored minor issues. In the next episode, we may talk about FMX or RTL :)

Static analysis is cool, isn’t it?