Re: [Qemu-devel] [PATCH 04/12] chardev: remove many local variables in qemu_chr_parse_socket

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

On Tue, Jan 15, 2019 at 01:33:25PM -0600, Eric Blake wrote:
> [adding Markus in relation to a QemuOpts observation]
> 
> On 1/15/19 8:52 AM, Daniel P. Berrangé wrote:
> > Now that all validation is separated off into a separate method,
> > we can directly populate the ChardevSocket struct from the
> > QemuOpts values, avoiding many local variables.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >  chardev/char-socket.c | 40 ++++++++++++++++++----------------------
> >  1 file changed, 18 insertions(+), 22 deletions(-)
> > 
> 
> > @@ -1216,26 +1208,30 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
> >      sock = backend->u.socket.data = g_new0(ChardevSocket, 1);
> >      qemu_chr_parse_common(opts, qapi_ChardevSocket_base(sock));
> >  
> > -    sock->has_nodelay = true;
> > -    sock->nodelay = do_nodelay;
> > +    sock->has_nodelay = qemu_opt_get(opts, "delay");
> > +    sock->nodelay = !qemu_opt_get_bool(opts, "delay", true);
> 
> Unrelated to this patch, but my recent proposal to make QemuOpts be a
> bit more typesafe:
> 
> https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg02042.html
> 
> does not like users calling qemu_opt_get() of an option that has an
> integer default (as opposed to a string default), even if the only
> reason the caller was doing it was to learn if the option is present.  I
> wonder if we should introduce
> 
> bool qemu_opt_has(QemuOpts *opts, const char *name)
> 
> and then replace existing callers which merely call qemu_opt_get() to
> learn whether an optional option was present/defaulted but without
> caring about its string value.  I also wonder if Coccinelle can be
> employed to determine which callers fit that bill (that is, detect when
> a const char * result is ignored or solely used in a bool context, vs.
> when it is actually used as a string parameter to another function
> and/or saved in a const char * variable).

Yes, if you're going to enforce type safety on qemu_opt_get, then
then we definitely need to have  qemu_opt_has()  function to check
for existance, as this is needed in other places too.


> 
> Now, on to actual review,
> 
> > +    /*
> > +     * We have different default to QMP for 'server', hence
> > +     * we can't just check for existance of 'server'
> 
> s/existance/existence/
> 
> > +     */
> >      sock->has_server = true;
> > -    sock->server = is_listen;
> > -    sock->has_telnet = true;
> > -    sock->telnet = is_telnet;
> > -    sock->has_tn3270 = true;
> > -    sock->tn3270 = is_tn3270;
> > -    sock->has_websocket = true;
> > -    sock->websocket = is_websock;
> > +    sock->server = qemu_opt_get_bool(opts, "server", false);
> > +    sock->has_telnet = qemu_opt_get(opts, "telnet");
> > +    sock->telnet = qemu_opt_get_bool(opts, "telnet", false);
> > +    sock->has_tn3270 = qemu_opt_get(opts, "tn3270");
> > +    sock->tn3270 = qemu_opt_get_bool(opts, "tn3270", false);
> > +    sock->has_websocket = qemu_opt_get(opts, "websocket");
> > +    sock->websocket = qemu_opt_get_bool(opts, "websocket", false);
> >      /*
> >       * We have different default to QMP for 'wait' when 'server'
> >       * is set, hence we can't just check for existance of 'wait'
> 
> but then again, you were copy-pasting an existing typo.

Both typos were from this series


Regards,
Daniel
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