Re: Making QEMU easier for management tools and applications

[Markus Armbruster <armbru@redhat.com>]

"Dr. David Alan Gilbert" <dgilbert@redhat.com> writes:

> * Markus Armbruster (armbru@redhat.com) wrote:
>> Stefan Hajnoczi <stefanha@gmail.com> writes:
>> > 4. Go and Rust bindings would also be useful.  There is
>> > https://github.com/intel/govmm but I think it makes sense to keep it
>> > in qemu.git and provide an interface similar to our Python modules.
>> 
>> Mapping QAPI/QMP commands and events to function signatures isn't hard
>> (the QAPI code generator does).  Two problems (at least):
>> 
>> 1. Leads to some pretty ridiculous functions.  Here's one:
>> 
>>     void qmp_blockdev_mirror(bool has_job_id, const char *job_id,
>>                              const char *device,
>>                              const char *target,
>>                              bool has_replaces, const char *replaces,
>>                              MirrorSyncMode sync,
>>                              bool has_speed, int64_t speed,
>>                              bool has_granularity, uint32_t granularity,
>>                              bool has_buf_size, int64_t buf_size,
>>                              bool has_on_source_error,
>>                              BlockdevOnError on_source_error,
>>                              bool has_on_target_error, BlockdevOnError on_target_error,
>>                              bool has_filter_node_name, const char *filter_node_name,
>>                              bool has_copy_mode, MirrorCopyMode copy_mode, 
>>                              bool has_auto_finalize, bool auto_finalize,
>>                              bool has_auto_dismiss, bool auto_dismiss,
>>                              Error **errp);
>
> Those might not be as bad when mapped to other languages, all the
> bool/value pairs would become Option<...>  so that removes that doubling.
> The Error ** mechanism should somehow map onto functions returning a
> normal Rust Result<> type.

Fifteen parameters even with the has_FOO and the errp dropped.
Still ridiculous enough for me.