Re: [Xen-devel] [PATCH RFC v2 07/13] libxl: internal convenience macros

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2011-10-28 at 19:37 +0100, Ian Jackson wrote:
> Provide some macros which are useful shorthands for use within libxl:
>   * GC_INIT to initialise a gc from a ctx and GC_FREE to free it
>   * CTX(gc) to give you back the ctx
>   * LIBXL_TAILQ_INSERT_SORTED for inserting things into sorted lists
> 
> These will be used by later patches.
> 
> Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> ---
>  tools/libxl/libxl_internal.h |   48 
> ++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 48 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> index 31adbc8..8649788 100644
> --- a/tools/libxl/libxl_internal.h
> +++ b/tools/libxl/libxl_internal.h
> @@ -555,6 +555,54 @@ _hidden void libxl__json_object_free(libxl__gc *gc, 
> libxl__json_object *obj);
>  
>  _hidden libxl__json_object *libxl__json_parse(libxl__gc *gc, const char *s);
>  
> +
> +/*
> + * Convenience macros.
> + */
> +
> +
> +/*
> + * All of these assume (or define)
> + *    libxl__gc *gc;
> + * as a local variable.
> + */
> +
> +#define GC_INIT(ctx)  libxl__gc gc[1] = { LIBXL_INIT_GC(ctx) }

Tricksy, I like it ;-)

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

Is there a massive conversion patch somewhere downseries?

> +#define GC_FREE       libxl__free_all(gc)
> +#define CTX           libxl__gc_owner(gc)
> +
> +
> +/*
> + * Inserts "elm_new" into the sorted list "head".
> + *
> + * "elm_search" must be a loop search variable of the same type as
> + * "elm_new".  "new_after_search_p" must be an expression which is
> + * true iff the element "elm_new" sorts after the element
> + * "elm_search".
> + *
> + * "search_body" can be empty, or some declaration(s) and statement(s)
> + * needed for "new_after_search_p".
> + */
> +#define LIBXL_TAILQ_INSERT_SORTED(head, entry, elm_new, elm_search,     \
> +                                  search_body, new_after_search_p)      \
> +    do {                                                                \
> +        for ((elm_search) = LIBXL_TAILQ_FIRST((head));                  \
> +             (elm_search);                                              \
> +             (elm_search) = LIBXL_TAILQ_NEXT((elm_search), entry)) {    \
> +            search_body;                                                \
> +            if (!(new_after_search_p))                                  \
> +                break;                                                  \
> +        }                                                               \
> +        /* now elm_search is either the element before which we want    \
> +         * to place elm_new, or NULL meaning we want to put elm_new at  \
> +         * the end */                                                   \
> +        if ((elm_search))                                               \
> +            LIBXL_TAILQ_INSERT_BEFORE((elm_search), (elm_new), entry);  \
> +        else                                                            \
> +            LIBXL_TAILQ_INSERT_TAIL((head), (elm_new), entry);          \
> +    } while(0)
> +
> +
>  #endif
>  
>  /*



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