Re: [PATCH 3/9] libxl: json string object can be NULL

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-07-10 at 19:00 +0100, Wei Liu wrote:
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

It occurs to me that since libxl__strdup can never return NULL due to
allocation failure we could consider make libxl__strdup(gc, NULL) be
well defined as returning NULL.

> ---
>  tools/libxl/libxl_json.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/libxl/libxl_json.c b/tools/libxl/libxl_json.c
> index 346929a..652b3f4 100644
> --- a/tools/libxl/libxl_json.c
> +++ b/tools/libxl/libxl_json.c
> @@ -433,8 +433,13 @@ int libxl__string_parse_json(libxl__gc *gc, const libxl__json_object *o,
>  
>      if (libxl__json_object_is_null(o))
>          *p = NULL;
> -    else
> -        *p = libxl__strdup(NOGC, libxl__json_object_get_string(o));
> +    else {
> +        const char *s = libxl__json_object_get_string(o);
> +        if (!s)
> +            *p = NULL;
> +        else
> +            *p = libxl__strdup(NOGC, s);
> +    }
>  
>      return 0;
>  }