[libvirt] [PATCH RFC 01/40] util: hash: Add possibility to use simpler data free function in virHash

[Eric Blake]

On 10/18/19 11:10 AM, Peter Krempa wrote:
> Introduce a new type virHashDataFreeSimple which has only a void * as
> argument for cases when knowing the name of the entry when freeing the
> hash entry is not required.
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>   src/conf/domain_addr.c |  4 ++--
>   src/util/vircgroup.c   |  2 +-
>   src/util/virhash.c     | 15 ++++++++++++++-
>   src/util/virhash.h     | 10 ++++++++++
>   4 files changed, 27 insertions(+), 4 deletions(-)
> 

This shows there were not many callers to virHashCreateFull.  (Thankfully)


> @@ -133,6 +134,7 @@ virHashComputeKey(const virHashTable *table, const void *name)
>    */
>   virHashTablePtr virHashCreateFull(ssize_t size,
>                                     virHashDataFree dataFree,
> +                                  virHashDataFreeSimple dataFreeSimple,

Is there any way to create a union argument which takes either a 
dataFree or dataFreeSimple function, rather than having to have two 
separate parameters?  But as there are not many callers, this does not 
hurt too much.

>                                     virHashKeyCode keyCode,
>                                     virHashKeyEqual keyEqual,
>                                     virHashKeyCopy keyCopy,
> @@ -149,7 +151,10 @@ virHashTablePtr virHashCreateFull(ssize_t size,
>       table->seed = virRandomBits(32);
>       table->size = size;
>       table->nbElems = 0;
> -    table->dataFree = dataFree;
> +    if (dataFree)
> +        table->dataFree = dataFree;
> +    else
> +        table->dataFreeSimple = dataFreeSimple;

I guess I'll need to see later in the series why we need this instead of 
being able to use virHashValueFree().  Are there really that many places 
where it is just too much boilerplate to add a simple one-liner 
forwarding function that passes the virHashDataFree signature with two 
parameters and calls the real freeing function with one parameter?

Should this function fail if the user passes non-NULL pointers for both 
dataFree and dataFreeSimple, rather than blindly favoring only dataFree?

But code-wise, the patch is correct.  So if its use later in the series 
proves useful, then consider this as an ACK.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org