Re: [Qemu-devel] [PATCH 02/34] qdict: Add qdict_{set, copy}_default()

[Eric Blake]

On 05/08/2015 11:21 AM, Kevin Wolf wrote:
> In the block layer functions that determine options for a child block
> device, it's a common pattern to either copy options from the parent's
> options or to set a default string if the option isn't explicitly set
> yet for the child. Provide convenience functions so that it becomes a
> one-liner for each option.
> 
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  include/qapi/qmp/qdict.h |  3 +++
>  qobject/qdict.c          | 34 ++++++++++++++++++++++++++++++++++
>  2 files changed, 37 insertions(+)
> 

> +/**
> + * qdict_set_default_str(): If no entry mapped by 'key' exists in 'dst' yet,
> + * 'val' is put there, with the QDict taking the reference. Otherwise, the
> + * refcount of 'val' is decreased.
> + */
> +void qdict_set_default_str(QDict *dst, const char *key, const char *val)

Huh? Since when does 'const char *val' have a refcount that needs
decreasing?

> +{
> +    if (qdict_haskey(dst, key)) {
> +        return;
> +    }
> +
> +    qdict_put(dst, key, qstring_from_str(val));
> +}

I'm wondering if you wrote that comment at a point where you were
passing qstrings around, and then changed your mind by using C strings
for the implementation.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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