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

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2013-5-15 20:28, Luiz Capitulino 写道:
> On Wed, 15 May 2013 10:10:37 +0800
> Wenchao Xia <xiawenc@linux.vnet.ibm.com> wrote:
>
>> 于 2013-5-6 21:22, Luiz Capitulino 写道:
>>> On Mon, 06 May 2013 10:09:43 +0800
>>> Wenchao Xia <xiawenc@linux.vnet.ibm.com> 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 <xiawenc@linux.vnet.ibm.com> wrote:
>>>>>>
>>>>>>> 于 2013-4-30 3:05, Luiz Capitulino 写道:
>>>>>>>> On Fri, 26 Apr 2013 16:46:57 +0200
>>>>>>>> Stefan Hajnoczi <stefanha@gmail.com> 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