Re: [PATCH] qapi: enable use of g_autoptr with QAPI types

[Eric Blake <eblake@redhat.com>]

On 7/23/20 6:12 AM, Daniel P. Berrangé wrote:
> Currently QAPI generates a type and function for free'ing it:
> 
>    typedef struct QCryptoBlockCreateOptions QCryptoBlockCreateOptions;
>    void qapi_free_QCryptoBlockCreateOptions(QCryptoBlockCreateOptions *obj);
> 

> The above code example now becomes
> 
>    g_autoptr(QCryptoBlockCreateOptions) opts = NULL;
> 
>    opts = g_new0(QCryptoBlockCreateOptions, 1);
> 
>    ....do stuff with opts...
> 
> Note, if the local pointer needs to live beyond the scope holding the
> variable, then g_steal_pointer can be used. This is useful to return the
> pointer to the caller in the success codepath, while letting it be freed
> in all error codepaths.
> 
>    return g_steal_pointer(&opts);
> 

Yep, the idea makes sense!

> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>   include/crypto/block.h | 2 --
>   scripts/qapi/types.py  | 1 +
>   2 files changed, 1 insertion(+), 2 deletions(-)

Missing a counterpart change to docs/devel/qapi-code-gen.txt.  And it 
might be nice to make this a series with at least one followup patch 
using the new capability, or at least so 'make check' coverage.  But 
otherwise on the right track.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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