Re: [PATCH v3 17/19] refs.c: change update_ref to use a transaction

[Michael Haggerty <mhagger@alum.mit.edu>]

On 04/25/2014 06:14 PM, Ronnie Sahlberg wrote:
> Change the update_ref helper function to use a ref transaction internally.
> 
> Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
> ---
>  refs.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/refs.c b/refs.c
> index 1557c3c..95df4a9 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3397,11 +3397,26 @@ int update_ref(const char *action, const char *refname,
>  	       const unsigned char *sha1, const unsigned char *oldval,
>  	       int flags, enum action_on_err onerr)
>  {
> -	struct ref_lock *lock;
> -	lock = update_ref_lock(refname, oldval, flags, NULL, onerr);
> -	if (!lock)
> +	struct ref_transaction *t;
> +	char *err = NULL;
> +
> +	t = ref_transaction_begin();
> +	if ((!t ||
> +	    ref_transaction_update(t, refname, sha1, oldval, flags,
> +				   !!oldval)) ||
> +	    (ref_transaction_commit(t, action, &err) && !(t = NULL))) {

You seem to have extra parentheses around the first || subexpression.

You also don't need the parentheses around the && expression because &&
binds more tightly than ||.

But using "!(t = NULL)" in the middle of a conditional expression is
pretty obscure.  I think you will change this in a later patch, so I
will defer my comments.

> +	     const char *str = "update_ref failed for ref '%s': %s";

Indentation error.

> +
> +		ref_transaction_rollback(t);
> +		switch (onerr) {
> +		case UPDATE_REFS_MSG_ON_ERR: error(str, refname, err); break;
> +		case UPDATE_REFS_DIE_ON_ERR: die(str, refname, err); break;
> +		case UPDATE_REFS_QUIET_ON_ERR: break;
> +		free(err);
> +		}
>  		return 1;
> -	return update_ref_write(action, refname, sha1, lock, NULL, onerr);
> +	}
> +	return 0;
>  }
>  
>  static int ref_update_compare(const void *r1, const void *r2)
> 


-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/