[libvirt] [PATCH 02/10] Support callbacks on virStream APIs in remote driver client

[Daniel P. Berrange]

On Mon, Nov 01, 2010 at 11:50:01AM -0600, Eric Blake wrote:
> On 11/01/2010 10:11 AM, Daniel P. Berrange wrote:
> > The current remote driver code for streams only supports
> > blocking I/O mode. This is fine for the usage with migration
> > but is a problem for more general use cases, in particular
> > bi-directional streams.
> > 
> > This adds supported for the stream callbacks and non-blocking
> > I/O. with the minor caveat is that it doesn't actually do
> > non-blocking I/O for sending stream data, only receiving it.
> > A future patch will try to do non-blocking sends, but this is
> > quite tricky to get right.
> > 
> > * src/remote/remote_driver.c: Allow non-blocking I/O for
> >   streams and support callbacks
> 
> > +
> > +static void
> > +remoteStreamEventTimer(int timer ATTRIBUTE_UNUSED, void *opaque)
> > +{
> > +    virStreamPtr st = opaque;
> > +    struct private_data *priv = st->conn->privateData;
> > +    struct private_stream_data *privst = st->privateData;
> > +
> > +    remoteDriverLock(priv);
> > +    if (privst->cb &&
> > +        (privst->cbEvents & VIR_STREAM_EVENT_READABLE) &&
> > +        privst->incomingOffset) {
> > +        virStreamEventCallback cb = privst->cb;
> > +        void *cbOpaque = privst->cbOpaque;
> > +        virFreeCallback cbFree = privst->cbFree;
> > +
> > +        privst->cbDispatch = 1;
> > +        remoteDriverUnlock(priv);
> > +        (cb)(st, VIR_STREAM_EVENT_READABLE, cbOpaque);
> 
> Any reason you aren't using the simpler style?
> 
>   cp(st, ...);

I prefer the '(cb)(st...)' style, because it makes it clearer that
'cb' is not a function name, but a function pointer.

Regards,
Daniel
-- 
|: Red Hat, Engineering, London    -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://deltacloud.org :|
|: http://autobuild.org        -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|