Re: [Qemu-devel] [PATCH 7/7] block: dump to monitor for bdrv_snapshot_dump() and bdrv_image_info_dump()

[Wenchao Xia]

于 2013-5-15 20:28, Luiz Capitulino 写道:
> On Wed, 15 May 2013 10:10:37 +0800
> Wenchao Xia <address@hidden> wrote:
>
> > 于 2013-5-6 21:22, Luiz Capitulino 写道:
> > > On Mon, 06 May 2013 10:09:43 +0800
> > > Wenchao Xia <address@hidden> wrote:
> > >
> > > > 于 2013-5-3 10:51, Wenchao Xia 写道:
> > > > > 于 2013-5-2 20:02, Luiz Capitulino 写道:
> > > > > > On Thu, 02 May 2013 10:05:08 +0800
> > > > > > Wenchao Xia <address@hidden> wrote:
> > > > > >
> > > > > > > 于 2013-4-30 3:05, Luiz Capitulino 写道:
> > > > > > > > On Fri, 26 Apr 2013 16:46:57 +0200
> > > > > > > > Stefan Hajnoczi <address@hidden> wrote:
> > > > > > > >
> > > > > > > > > On Fri, Apr 26, 2013 at 05:31:15PM +0800, Wenchao Xia wrote:
> > > > > > > > > > @@ -2586,10 +2585,12 @@ void do_info_snapshots(Monitor *mon, const
> > > > > > > > > > QDict *qdict)
> > > > > > > > > >          }
> > > > > > > > > >
> > > > > > > > > >          if (total > 0) {
> > > > > > > > > > -        monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf,
> > > > > > > > > > sizeof(buf), NULL));
> > > > > > > > > > +        bdrv_snapshot_dump(NULL);
> > > > > > > > > > +        monitor_printf(mon, "\n");
> > > > > > > > >
> > > > > > > > > Luiz: any issue with mixing monitor_printf(mon) and
> > > > > > > > > monitor_vprintf(cur_mon) calls?  I guess there was a reason for
> > > > > > > > > explicitly passing mon instead of relying on cur_mon.
> > > > > > > >
> > > > > > > > where are they being mixed?
> > > > > > >       bdrv_snapshot_dump() used a global variable "cur_mon" inside,
> > > > > > > instead
> > > > > > > of let caller pass in a explicit montior* "mon", I guess that is the
> > > > > > > question.
> > > > > >
> > > > > > I'd have to see the code to tell, but yes, what Stefan described is the
> > > > > > best practice for the Monitor.
> > > > >      I think this would not be a problem until qemu wants more than one
> > > > > human monitor console, and then we may require a data structure to tell
> > > > > where to output the string: stdout, *mon, or even stderr, and
> > > > > error_printf() also need to be changed.
> > > >      Luiz, what is your idea? I'd like to respin v2 if no issues for it.
> > >
> > > As I said before, I'd have to see the code to tell. But answering your comment,
> > > the code does support multiple monitors.
> > Hi Luiz,
> >     Sorry to ask again, do you think method above is OK now, waiting for
> > your confirm.
>
> Can you point me to the code in question?
Sure, it is

+
+/*
+ * Print to current monitor if we have one, else to stdout. It is 
similar with
+ * error_printf().
+ * TODO just like error_vprintf()
+ */
+void message_printf(const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    if (cur_mon) {
+        monitor_vprintf(cur_mon, fmt, ap);
+    } else {
+        vfprintf(stdout, fmt, ap);
+    }
+    va_end(ap);
+}

  This function used global variable cur_mon instead of input parameter,
similar to error_printf().

--
Best Regards

Wenchao Xia