Re: [PATCH 2/5] io/channel.c,io/channel-socket.c: Add yank feature

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, May 11, 2020 at 10:00:42PM +0200, Lukas Straub wrote:
> On Mon, 11 May 2020 12:51:46 +0100
> Daniel P. Berrangé <berrange@redhat.com> wrote:
> 
> > On Mon, May 11, 2020 at 01:14:41PM +0200, Lukas Straub wrote:
> > > Add qio_channel_set_yank function to channel and to channel-socket,
> > > which will register a yank function. The yank function calls
> > > shutdown() on the socket.
> > > 
> > > Signed-off-by: Lukas Straub <lukasstraub2@web.de>
> > > ---
> > >  Makefile.objs               |  1 +
> > >  include/io/channel-socket.h |  1 +
> > >  include/io/channel.h        | 12 ++++++++++++
> > >  io/channel-socket.c         | 29 +++++++++++++++++++++++++++++
> > >  io/channel.c                |  9 +++++++++
> > >  5 files changed, 52 insertions(+)  
> > 
> > Assuming we want the yank feature (which I'm not entirely convinced
> > of), then I don't think any of this addition should exist. The
> > QIOChannel class already provides a "qio_channel_shutdown" method
> > which can be invoked. The layer above which is using the QIOChannel
> > should be calling this existing qio_channel_shutdown method in
> > response to any yank request.  The I/O layer shouldn't have any
> > direct dependancy on the yank feature.
> 
> Having the code here simplifys the code in the other places.

This introduces a depedancy from the IO channel code into the system
emulator infra which is not desired. The goal is to keep the io/ module
isolated and as self-contained as possible.

I don't think it makes a significant difference to the yank code to
keep it out of the io layer, and simply call the QIOChannel objects
via their existing public API.

Regards,
Daniel
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