Race condition with data loss in ReadWritePart

[Ingo Klöcker]

On Sunday 24 February 2008, Martin Pley wrote:
> Am Sonntag, 24. Februar 2008 13:18:17 schrieb Ingo Klöcker:
> > On Saturday 23 February 2008, Martin Pley wrote:
> > > > I noticed a race condition with data loss in ReadWritePart:
> > > >
> > > > Try to open a non-local-file from a slow or offline server.
> > > > Then, instead of waiting for the file, just open another local
> > > > file. Now, when you delete the part, the file is deleted(!).
> > > >
> > > > If I see it correctly, this is because m_bTemp is set to "true"
> > > > while opening the remote file. And when you open the local file
> > > > it will not be set to false again.
> > >
> > > It's actually not a race condition. I reimplemented
> > > ReadWritePart::closeURL() without setting m_bTemp to false. And
> > > when I delete the part, ~ReadOnlyPart calls
> > > ReadOnlyPart::closeURL(), which deletes the file.
> > >
> > > Perhaps one should add a warning to the documentation of
> > > closeURL().
> >
> > There's no need for adding a warning. We just need to call
> > closeURL() from ~ReadWritePart.
>
> IMO this is not a good idea. You would get a
> save-or-ignore-messagebox in the destructor. But saveFile() might not
> exist anymore because the destuctor of the derived class was already
> called. One should be carefull with calling virtual methods from
> constructor or destructor.

True.

> However, in my case this would not help at all.

After having a quick look at the code to me the problem seems to be that 
m_bTemp is not set to false in ReadOnlyPart::openURL() in

  if ( d->m_url.isLocalFile() )
  { ... }

while it's set to true in the corresponding else-branch. This would help 
in your case, right?


Regards,
Ingo
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