Re: [Qemu-devel] [PATCH 4/4] qapi: Rename ChardevBackend member "memory" to "ringbuf"

[Amos Kong <akong@redhat.com>]

On Mon, Jul 01, 2013 at 10:10:40AM +0200, Markus Armbruster wrote:
> Amos Kong <akong@redhat.com> writes:
> 
> > On Fri, Jun 28, 2013 at 07:19:39PM +0200, Markus Armbruster wrote:
> >> Eric Blake <eblake@redhat.com> writes:
> >> 
> >> > On 06/27/2013 08:22 AM, Markus Armbruster wrote:
> >> >> Commit 1da48c6 called the new member "memory" after commit 3949e59
> >> >> standardized "ringbuf".  Rename for consistency.
> >> >> 
> >> >> However, member name "memory" is visible in QMP since 1.5.  It's
> >> >> undocumented just like the driver name.  Keep it working anyway.
> >> >> 
> >> >> Cc: qemu-stable@nongnu.org
> >> >> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> >> >> ---
> >> >>  qapi-schema.json |  6 ++++--
> >> >>  qemu-char.c      | 11 ++++++-----
> >> >>  2 files changed, 10 insertions(+), 7 deletions(-)
> >> >> 
> >> >> diff --git a/qapi-schema.json b/qapi-schema.json
> >> >> index 6445da6..b3df8a5 100644
> >> >> --- a/qapi-schema.json
> >> >> +++ b/qapi-schema.json
> >> >> @@ -3277,9 +3277,9 @@
> >> >>  ##
> >> >>  # @ChardevRingbuf:
> >> >>  #
> >> >> -# Configuration info for memory chardevs
> >> >> +# Configuration info for ring buffer chardevs.
> >> >>  #
> >> >> -# @size: #optional Ringbuffer size, must be power of two, default is 65536
> >> >> +# @size: #optional ring buffer size, must be power of two, default is 65536
> >> >>  #
> >> >>  # Since: 1.5
> >> >>  ##
> >> >> @@ -3310,6 +3310,8 @@
> >> >>                                         'spicevmc' : 'ChardevSpiceChannel',
> >> >>                                         'spiceport' : 'ChardevSpicePort',
> >> >>                                         'vc'     : 'ChardevVC',
> >> >> +                                       'ringbuf': 'ChardevRingbuf',
> >> >> +                                       # next one is just for compatibility
> >> >>                                         'memory' : 'ChardevRingbuf' } }
> >> >
> >> > Does JSON allow comments in the middle of content?  Is this going to
> >> > screw up Amos' work on introspection?  You may need to instead have a
> >> > comment before the open '{' stating that 'memory' is an alias within the
> >> > union for back-compat reasons.
> >
> > I didn't parse the json file by myself. I just used the parsed
> > dictionary. So it only needs to make qapi.py happy.
> >
> >> RFC 4627 doesn't do comments at all.
> >> 
> >> This file is parsed by scripts/qapi.py, which as far as I can tell
> >> ignores lines starting with '#' anywhere in the input.
> >
> > Not anywhere, only start with '#'
> 
> Isn't that what I said?
> 
> > | def parse_schema(fp):
> > |     exprs = []
> > |     raw_exprs = []
> > |     expr = ''
> > |     expr_eval = None
> > | 
> > |     for line in fp:
> > |         if line.startswith('#') or line == '\n':
> >
> >       # ignores lines starting with '#' anywhere
> >           if line.strip().startswith('#')   
> >
> > |             continue
> > | 
> >
> >
> > So we should not add this kind of comment for back-compat.
> 
> Now I'm confused.  My patch adds a line that starts with '#'.
> parse_schema() ignores it.  Works as designed.  Why do you think we
> shouldn't do that?

The comment line in your patch doen't start with '#', it starts with
blank-space. If we want qapi.py to process it, we need to do strip()
first.

-- 
			Amos.