FHandle in THandleStream better protected
lazarus / 7-LCL

----------------------------------------------------------------------
Borneq · 2009-12-27 14:25

I write class TFileStreamW which is similar to TFileStream but
argument filename is WideString insted of string
I want
constructor TFileStreamW.Create(const FileName: WideString; Mode:
Word);
begin
  if Mode = fmCreate then
  begin
    inherited Create(FileCreateW(FileName));
    if FHandle < 0 then
      raise EFCreateError.CreateResFmt(@SFCreateError, [FileName]);
  end
  else
  begin
    inherited Create(FileOpenW(FileName, Mode));
    if FHandle < 0 then
      raise EFOpenError.CreateResFmt(@SFOpenError, [FileName]);
  end;
end;

I must use FHandle but it is private in classesh.inc
Better if it will protected

----------------------------------------------------------------------
Marc · 2009-12-27 16:16

why not checking the result of FileCreateW(FileName) ?

----------------------------------------------------------------------
Borneq · 2009-12-27 17:57

Quote from: Marc on December 27, 2009, 05:16:30 pmwhy not checking the
result of FileCreateW(FileName) ?
Right!
Constructor will be:

constructor TFileStreamW.Create(const FileName: WideString; Mode:
Word);
var
  Handle: Integer;
begin
  if Mode = fmCreate then
  begin
    Handle := FileCreateW(FileName);
    if Handle < 0 then
      raise EFCreateError.CreateResFmt(@SFCreateError, [FileName]);
  end
  else
  begin
    Handle := FileOpenW(FileName, Mode);
    if Handle < 0 then
      raise EFOpenError.CreateResFmt(@SFOpenError, [FileName]);
  end;
  inherited Create(Handle);
end;

----------------------------------------------------------------------
Borneq · 2009-12-27 18:01

But..
How to close?

destructor TFileStreamW.Destroy;
begin
  if FHandle >= 0 then FileClose(FHandle);
  inherited Destroy;
end;

Must exists static variable indicating whether correctly open/create
operation passed

----------------------------------------------------------------------
Marc · 2009-12-27 18:05

Wouldn't the inherited handle stream close it ?

(otherwise keep a ref yourself)

----------------------------------------------------------------------
Borneq · 2009-12-27 19:31

Quote from: Marc on December 27, 2009, 07:05:53 pmWouldn't the
inherited handle stream close it ?
Yes,I noticed after sending message
Thanks