Re: [Xen-devel] [PATCH 11/20] libxl: Introduce some convenience macros

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2012-03-16 at 16:26 +0000, Ian Jackson wrote:
> We introduce:
>    <type> *GCNEW(<type> *var);
>    <type> *GCNEW_ARRAY(<type> *var, ssize_t nmemb);
>    <type> *GCREALLOC_ARRAY(<type> *var, size_t nmemb);
>    char *GCSPRINTF(const char *fmt, ...);
>    void LOG(<xtl_level_suffix>, const char *fmt, ...);
>    void LOGE(<xtl_level_suffix>, const char *fmt, ...);
>    void LOGEV(<xtl_level_suffix>, int errnoval, const char *fmt, ...);
> all of which expect, in the calling context,
>    libxl__gc *gc;

All of these get used later in the series?

> Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>

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

> ---
>  tools/libxl/libxl_internal.h |   72 
> ++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 72 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> index 86f25be..465d564 100644
> --- a/tools/libxl/libxl_internal.h
> +++ b/tools/libxl/libxl_internal.h
> @@ -1346,6 +1346,78 @@ _hidden void libxl__ao__destroy(libxl_ctx*, libxl__ao 
> *ao);
>  #define GC_FREE       libxl__free_all(gc)
>  #define CTX           libxl__gc_owner(gc)
>  
> +/* Allocation macros all of which use the gc. */
> +
> +#define ARRAY_SIZE_OK(ptr, nmemb) ((nmemb) < INT_MAX / (sizeof(*(ptr)) * 2))
> +
> +/*
> + * Expression statement  <type> *GCNEW(<type> *var);
> + * Uses                  libxl__gc *gc;
> + *
> + * Allocates a new object of type <type> from the gc and zeroes it
> + * with memset.  Sets var to point to the new object or zero (setting
> + * errno).  Returns the new value of var.
> + */
> +#define GCNEW(var)                                      \
> +    (((var) = libxl__zalloc((gc),sizeof(*(var)))))
> +
> +/*
> + * Expression statement  <type> *GCNEW_ARRAY(<type> *var, ssize_t nmemb);
> + * Uses                  libxl__gc *gc;
> + *
> + * Like GCNEW but allocates an array of nmemb elements, as if from
> + * calloc.  Does check for integer overflow due to large nmemb.  If
> + * nmemb is 0 may succeed by returning 0.
> + */
> +#define GCNEW_ARRAY(var, nmemb)                                 \
> +    ((var) = libxl__calloc((gc), (nmemb), sizeof(*(var))))
> +    
> +/*
> + * Expression statement  <type> *GCREALLOC_ARRAY(<type> *var, size_t nmemb);
> + * Uses                  libxl__gc *gc;
> + *
> + * Reallocates the array var to be of size nmemb elements.  Updates
> + * var and returns the new value of var.  Does check for integer
> + * overflow due to large nmemb.
> + *
> + * Do not pass nmemb==0.  old may be 0 on entry.
> + */
> +#define GCREALLOC_ARRAY(var, nmemb)                                     \
> +    (assert(nmemb > 0),                                                 \
> +     assert(ARRAY_SIZE_OK((var), (nmemb))),                             \
> +     (var) = libxl__realloc((gc), (var), (nmemb)*sizeof(*(var)))))
> +
> +
> +/*
> + * Expression            char *GCSPRINTF(const char *fmt, ...);
> + * Uses                  libxl__gc *gc;
> + *
> + * Trivial convenience wrapper for libxl__sprintf.
> + */
> +#define GCSPRINTF(fmt, ...) (libxl__sprintf((gc), (fmt), __VA_ARGS__))
> +
> +
> +/*
> + * Expression statements
> + *    void LOG(<xtl_level_suffix>, const char *fmt, ...);
> + *    void LOGE(<xtl_level_suffix>, const char *fmt, ...);
> + *    void LOGEV(<xtl_level_suffix>, int errnoval, const char *fmt, ...);
> + * Use
> + *    libxl__gc *gc;
> + *
> + * Trivial convenience wrappers for LIBXL__LOG, LIBXL__LOG_ERRNO and
> + * LIBXL__LOG_ERRNOVAL, respectively (and thus for libxl__log).
> + *
> + * XTL_<xtl_level_suffix> should exist and be an xentoollog.h log level
> + * So <xtl_level_suffix> should be one of
> + *   DEBUG VERBOSE DETAIL PROGRESS INFO NOTICE WARN ERROR ERROR CRITICAL
> + * Of these, most of libxl uses
> + *   DEBUG INFO WARN ERROR
> + */
> +#define LOG(l,f, ...)     LIBXL__LOG(CTX,XTL_##l,(f),##__VA_ARGS__)
> +#define LOGE(l,f, ...)    LIBXL__LOG_ERRNO(CTX,XTL_##l,(f),##__VA_ARGS__)
> +#define LOGEV(l,e,f, ...) 
> LIBXL__LOG_ERRNOVAL(CTX,XTL_##l,(e),(f),##__VA_ARGS__)
> +
>  
>  /* Locking functions.  See comment for "lock" member of libxl__ctx. */
>  



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