Re: [Qemu-devel] [PATCH v9 08/17] qapi: Plumb in 'boxed' to qapi generator lower levels

[Markus Armbruster]

Eric Blake <address@hidden> writes:

> The next patch will add support for passing a qapi union type
> as the 'data' of a command.  But to do that, the user function
> for implementing the command, as called by the generated
> marshal command, must take the corresponding C struct as a
> single boxed pointer, rather than a breakdown into one
> parameter per member.  Even without a union, being able to use
> a C struct rather than a list of parameters can make it much
> easier to handle coding with QAPI.
>
> This patch adds the internal plumbing of a 'boxed' flag
> associated with each command and event.  In several cases,
> this means adding indentation, with one new dead branch and
> the remaining branch being the original code more deeply
> nested; this was done so that the new implementation in the
> next patch is easier to review without also being mixed with
> indentation changes.
>
> For this patch, no behavior or generated output changes, other
> than the testsuite outputting the value of the new flag
> (always False for now).
>
> Signed-off-by: Eric Blake <address@hidden>
>
> ---
> v9: change title, s/box/boxed/
> v8: improve commit message, defer some implementation, rebase without
> gen_err_check()
> v7: rebase to master
> v6: rebase to earlier changes
[...]
> diff --git a/scripts/qapi-introspect.py b/scripts/qapi-introspect.py
> index e0f926b..60e9877 100644
> --- a/scripts/qapi-introspect.py
> +++ b/scripts/qapi-introspect.py
> @@ -154,14 +154,14 @@ const char %(c_name)s[] = %(c_string)s;
>                                      for m in variants.variants]})
>
>      def visit_command(self, name, info, arg_type, ret_type,
> -                      gen, success_response):
> +                      gen, success_response, box):

You missed a box here.  Can touch up on commit.

>          arg_type = arg_type or self._schema.the_empty_object_type
>          ret_type = ret_type or self._schema.the_empty_object_type
>          self._gen_json(name, 'command',
>                         {'arg-type': self._use_type(arg_type),
>                          'ret-type': self._use_type(ret_type)})
>
> -    def visit_event(self, name, info, arg_type):
> +    def visit_event(self, name, info, arg_type, box):

Likewise.

>          arg_type = arg_type or self._schema.the_empty_object_type
>          self._gen_json(name, 'event', {'arg-type': self._use_type(arg_type)})
>
[...]