On 01/27/2014 08:53 PM, Amos Kong wrote:
> Some legacy options that have arguments weren't added to
> vm_config_groups[], so query-command-line-options returns a
> NULL parameters infolist. This patch try to return help message
> for this kind of legacy options.
>
> Example:
> {
> "helpmsg": "\"-vnc display start a VNC server on display\\n\"",
> "parameters": [
> ],
> "option": "vnc"
> },
>
> Signed-off-by: Amos Kong <akong@xxxxxxxxxx>
> ---
> qapi-schema.json | 5 ++++-
> util/qemu-config.c | 3 +++
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 05ced9d..b3e6f46 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3943,13 +3943,16 @@
> # Details about a command line option, including its list of parameter details
> #
> # @option: option name
> +# @helpmsg: help message for legacy options
Missing "#optional" and "(since 2.0)" designations
> #
> # @parameters: an array of @CommandLineParameterInfo
Might be worth documenting "#optional since 2.0" (we don't yet have good
precedent for documenting when a formerly mandatory field became optional).
Groan. This is an output struct. On input structs, changing a
mandatory field to optional is safe - old callers will always supply the
field. But on output structs, changing a mandatory field to optional is
backwards-incompatible. Old callers may be blindly expecting the field,
and crash when it is not present.
Your approach needs to be modified.
> #
> # Since 1.5
> ##
> { 'type': 'CommandLineOptionInfo',
> - 'data': { 'option': 'str', 'parameters': ['CommandLineParameterInfo'] } }
> + 'data': { 'option': 'str',
> + '*parameters': ['CommandLineParameterInfo'],
> + '*helpmsg': 'str' } }
I suggest:
# @parameters: array of @CommandLineParameterInfo, possibly empty
# @argument: @optional present if the @parameters array is empty. If
# true, then the option takes unspecified arguments, if
# false, then the option is merely a boolean flag (since 2.0)
{ 'type': 'CommandLineOptionInfo',
'data': { 'option': 'str', 'parameters': ['CommandLineParameterInfo'],
'*argument': 'bool' } }
used as:
[
{ "option":"enable-fips", "parameters":[], "argument":false },
{ "option":"smbios", "parameters":[], "argument":true },
{ "option":"iscsi", "paramters":[ ... ] },
...
]
which adequately differentiates between -iscsi taking arguments (but
where we haven't yet hooked it in to introspect those arguments) vs.
-enable-fips being boolean.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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