Re: [Qemu-devel] [PATCH v2 03/24] keyval: New keyval_parse()

[Markus Armbruster <armbru@redhat.com>]

Markus Armbruster <armbru@redhat.com> writes:

> Eric Blake <eblake@redhat.com> writes:
>
>> On 02/28/2017 03:26 PM, Markus Armbruster wrote:
>>> keyval_parse() parses KEY=VALUE,... into a QDict.  Works like
>>> qemu_opts_parse(), except:
>>> 
>>> * Returns a QDict instead of a QemuOpts (d'oh).
>>> 
>>> * Supports nesting, unlike QemuOpts: a KEY is split into key
>>>   fragments at '.' (dotted key convention; the block layer does
>>>   something similar on top of QemuOpts).  The key fragments are QDict
>>>   keys, and the last one's value is updated to VALUE.
>>> 
>>> * Each key fragment may be up to 127 bytes long.  qemu_opts_parse()
>>>   limits the entire key to 127 bytes.
>>> 
>>> * Overlong key fragments are rejected.  qemu_opts_parse() silently
>>>   truncates them.
>>> 
>>> * Empty key fragments are rejected.  qemu_opts_parse() happily
>>>   accepts empty keys.
>>> 
>>> * It does not store the returned value.  qemu_opts_parse() stores it
>>>   in the QemuOptsList.
>>> 
>>> * It does not treat parameter "id" specially.  qemu_opts_parse()
>>>   ignores all but the first "id", and fails when its value isn't
>>>   id_wellformed(), or duplicate (a QemuOpts with the same ID is
>>>   already stored).  It also screws up when a value contains ",id=".
>>> 
>>> * Implied value is not supported.  qemu_opts_parse() desugars "foo" to
>>>   "foo=on", and "nofoo" to "foo=off".
>>> 
>>> * An implied key's value can't be empty, and can't contain ','.
>>
>> or '=' (but the presence of '=' means no implied key, while the presence
>> of ',' marks end of the implied key's value).  Not sure it's worth
>> tweaking this commit message any further.
>
> Both fail the assertion they're meant to fail (I tested).  I'll fix the
> commit message.

Actually, there is nothing to fix, because there's no difference to
qemu_opts_parse().

Note that the comment in the code documents both ',' and '=', because
it's about keyval_parse(), not its difference to qemu_opts_parse().

>>> I intend to grow this into a saner replacement for QemuOpts.  It'll
>>> take time, though.
>>> 
>>> Note: keyval_parse() provides no way to do lists, and its key syntax
>>> is incompatible with the __RFQDN_ prefix convention for downstream
>>> extensions, because it blindly splits at '.', even in __RFQDN_.  Both
>>> issues will be addressed later in the series.
>>> 
>>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>>> ---
>>
>> Looks like you addressed all the comments.
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> Thanks!