Re: [boost] [smart_ptr] refactored enable_shared_from_this

From: Daniel Frey (d.frey_at_[hidden])
Date: 2008-04-26 09:56:51

On Sat, 2008-04-26 at 15:45 +0300, Peter Dimov wrote:
> Daniel Frey:
> >I refactored enable_shared_from_this in order to remove the _owner flag.
> > 
> > To test it, you need a small and straight-forward addition to
> > detail::weak_count: It needs .empty(), similar to detail::shared_count.
> 
> Are you sure that you need to test for emptiness instead of expiration?

I'm not sure, because I don't know what is expected. I initially
used .use_count() != 0, but it triggered a problem in
esft_constructor_test.cpp, line 131. I already asked Frank for more
information/documentation about what (the new) esft should support, but
he said that there is no documentation, instead he pointed me to the
regression tests, so I figured I need to make them pass. With .empty(),
they do.

When looking at the test case that fails with .use_count() != 0, I don't
really see why the call to shared_from_this() in line 130 should throw.
Shouldn't the call alone be legal? The only illegal thing I could spot
in this test case is, that after calling x.shared_from_this() no other
shared_ptr takes ownership of x.

Regards, Daniel

PS: I already committed the fix for the new shared_ptr's ctors. What
about adding the corresponding reset()? The refactored esft could use it
to simplify one line. And what's your opinion on documenting the new
interface? (You've seen the documentation thread?)