Re: [Qemu-devel] [PATCH 3/3] qapi: convert sendkey

[Daniel P. Berrange]

On Fri, May 25, 2012 at 10:06:11AM -0300, Luiz Capitulino wrote:
> On Fri, 25 May 2012 08:34:54 +0100
> "Daniel P. Berrange" <address@hidden> wrote:
> 
> > On Fri, May 25, 2012 at 02:20:33PM +0800, Amos Kong wrote:
> > > On 25/05/12 11:51, Eric Blake wrote:
> > > >On 05/24/2012 09:32 PM, Amos Kong wrote:
> > > >>Convert 'sendkey' to use. do_sendkey() depends on some variables
> > > >>in monitor.c, so reserve qmp_sendkey() to monitor.c
> > > >>Rename 'string' to 'keys', rename 'hold_time' to 'hold-time'
> > > >>
> > > >>Signed-off-by: Amos Kong<address@hidden>
> > > >
> > > >>+##
> > > >>+# @sendkey:
> > > >>+#
> > > >>+# Send keys to VM.
> > > >>+#
> > > >>+# @keys: key sequence
> > > >>+# @hold-time: time to delay key up events
> > > >>+#
> > > >>+# Returns: Nothing on success
> > > >>+#          If key is unknown or redundant, QERR_INVALID_PARAMETER
> > > >>+#          If key is invalid, QERR_INVALID_PARAMETER_VALUE
> > > >>+#
> > > >>+# Notes: Send @var{keys} to the emulator. @var{keys} could be the name 
> > > >>of the
> > > >>+#        key or the raw value in either decimal or hexadecimal  
> > > >>format. Use
> > > >>+#        @code{-} to press several keys simultaneously.
> > > >>+#
> > > >>+# Since: 0.14.0
> > > >>+##
> > > >>+{ 'command': 'sendkey', 'data': {'keys': 'str', '*hold-time': 'int'} }
> > > >
> > > >Rather than making 'keys' a free-form string where qemu then has to
> > > >parse '-' to separate keys, should we instead make it a JSON array?  For
> > > >example,
> > > 
> > > 
> > > Anthony, Luiz, Daniel,  what's your opinion?
> > 
> > Using a JSON array for the key names does seem like the most
> > natural way to model this. A good rule of thumb is that the
> > implementation of a command should not need to further
> > parse the individual parameter values. Using a magic string
> > encoding instead of the JSON array requires such extra special
> > case parsing.
> 
> That's true, and I agree this is better.
> 
> Just would like to point out that we can't go too far on improving
> HMP-inherited commands, as our goal here is to convert most (or every single)
> HMP commands to QMP. If we go far on improving commands, we'll get stuck as we
> did some time ago.
> 
> Btw, I remember someone saying that when libvirt wants to use a HMP command it
> first checks if the command exists in QMP before using passthrough. In that 
> case,
> how will libvirt behave if we change the arguments?

We're not talking about changing the args of the existing HMP command,
and libvirt has no code for a QMP version of sendkey, so there's no
compatibility issue.

Daniel
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