Re: Make istreambuf_iterator::_M_sbuf immutable and add debug checks

[François Dumont <frs dot dumont at gmail dot com>]

Hi

    Any final decision regarding this patch ?

François


On 23/10/2017 21:08, François Dumont wrote:
> Hi
>
>      I completed execution of all tests and found one test impacted by 
> this patch.
>
>      It is a good example of the impact of the patch. Users won't be 
> able to build a istreambuf_iterator at a point where the underlying 
> streambuf is at end-of-stream and then put some data in the streambuf 
> and then use the iterator. This is similar to what Petr was proposing, 
> some eof iterator becoming valid again through an operation on the 
> streambuf. I would prefer we forbid it completely or we accept it 
> completely but current middle way situation is strange.
>
>      The fix is easy, let the compiler build the streambuf_iterator 
> when needed. Even if patch is not accepted I think we should keep the 
> change on the test which is fragile.
>
> François
>
>
> On 13/10/2017 19:14, François Dumont wrote:
> > Hi
> >
> >      Here is the last patch I will propose for istreambuf_iterator. 
> > This is mostly to remove the mutable keyword on _M_sbuf.
> >
> >      To do so I had to reset _M_sbuf in valid places that is to say 
> > constructors and increment operators. Despite that we might still 
> > have eof iterators with _M_sbuf not null when you have for instance 
> > several iterator instance but only increment one. It seems fine to me 
> > because even in this case iterator will still be considered as eof 
> > and using several istreambuf_iterator to go through a given streambuf 
> > is not usual.
> >
> >      As _M_sbuf is immutable I have been able to restore the simple 
> > call to _M_at_eof() in the increment operators debug check.
> >
> > Ok to commit after successful tests ?
> >
> > François