Re: [Qemu-devel] [PATCH v14 10/21] qapi: permit auto-creating nested structs

[Markus Armbruster]

"Daniel P. Berrange" <address@hidden> writes:

> Some of the historical command line opts that had their
> keys in in a completely flat namespace are now represented
> by QAPI schemas that use a nested structs. When converting
> the QemuOpts to QObject, there is no information about
> compound types available, so the QObject will be completely
> flat, even after the qdict_crumple() call. So when starting
> a struct, we may not have a QDict available in the input
> data, so we auto-create a QDict containing all the currently
> unvisited input data keys. Not all historical command line
> opts require this, so the behaviour is opt-in, by specifying
> how many levels of structs are permitted to be auto-created.
>
> Note that this only works if the child struct is the last
> field to the visited in the parent struct. This is always
> the case for currently existing legacy command line options.
>
> The example is the NetLegacy type which has 3 levels of
> structs. The modern way to represent this in QemuOpts would
> be the dot-separated component approach
>
>   -net vlan=1,id=foo,name=bar,opts.type=tap,\
>        opts.data.fd=3,opts.data.script=ifup
>
> The legacy syntax will just be presenting
>
>   -net vlan=1,id=foo,name=bar,type=tap,fd=3,script=ifup
>
> So we need to auto-create 3 levels of struct when visiting.
>
> The implementation here will enable visiting in both the
> modern and legacy syntax, compared to OptsVisitor which
> only allows the legacy syntax.
>
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
>  include/qapi/qobject-input-visitor.h |  22 +++++-
>  qapi/qobject-input-visitor.c         |  59 ++++++++++++++--
>  tests/test-qobject-input-visitor.c   | 130 
> ++++++++++++++++++++++++++++++++---
>  3 files changed, 194 insertions(+), 17 deletions(-)
>
> diff --git a/include/qapi/qobject-input-visitor.h 
> b/include/qapi/qobject-input-visitor.h
> index 1809f48..94051f3 100644
> --- a/include/qapi/qobject-input-visitor.h
> +++ b/include/qapi/qobject-input-visitor.h
> @@ -45,7 +45,7 @@ Visitor *qobject_input_visitor_new(QObject *obj, bool 
> strict);
>   * If @autocreate_list is true, then as an alternative to a normal QList,
>   * list values can be stored as a QString or QDict instead, which will
>   * be interpreted as representing single element lists. This should only
> - * by used if compatibility is required with the OptsVisitor which allowed
> + * be used if compatibility is required with the OptsVisitor which allowed
>   * repeated keys, without list indexes, to represent lists. e.g. set this
>   * to true if you have compatibility requirements for
>   *

Typo introduced in the previous patch, please fix it there.

Skipping the rest of this patch until it's clear we need it.

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