Re: [Libevent-users] [PATCH] evbuffer_search_range fails when searching the last byte

[Nir Soffer <nirsof@xxxxxxxxx>]

On Jun 7, 2011, at 4:03 AM, Nick Mathewson wrote:

> On Mon, Jun 6, 2011 at 8:37 PM, Nir Soffer <nirsof@xxxxxxxxx> wrote:
> > Hi,
> >
> > I found that evbuffer_search_range fails when you try search the  
> > last byte
> > with a non null end pointer.
> >
> > You can work around this by checking the buffer length and calling
> > evbuffer_search() instead, or evbuffer_search_range with a null end  
> > pointer.
> >
> > I don't know how to fix it yet, but I added a failing test case :-)
>
> That doesn't look like the problem's with evbuffer_search_range:
> Instead of setting 'end' to the last byte in the buffer, you're
> setting it to one *after* the last byte in the buffer, which makes
> evbuffer_set_ptr() return -1.  If you get -1 from evbuffer_ptr_set(),
> you can't rely on the result.

True.

The test should check this. See attached patch.

> Arguably, evbuffer_ptr_set() should be able to represent not only
> every byte in the buffer, but also the point at the end of the buffer.
> But right now, it doesn't.

It will much useful like that :-)

> Here's another patch that might make stuff work.  Before I'd apply it,
> I'd like to have a look through everything that's using
> evbuffer_ptr_set() and evbuffer_ptr right now to make sure that
> nothing will freak out if it gets a pointer like this.
>
> What do you think?

Seem to work, but indeed need good review and probably more tests.

Attachment: 0002-Check-the-return-value-from-evbuffer_ptr_set.patch
Description: Binary data