Subject: Re: [PATCH 04/15] refs.c: add a new update_type field to ref_update

From: Junio C Hamano <[email-masked]>
Date: Thu, 23 Oct 2014 10:47:53 -0700

Ronnie Sahlberg <[email-masked]> writes:

> commit 1bfd3091a3d95a6268894182117eed823217dd9d upstream.
>
> Add a field that describes what type of update this refers to. For now
> the only type is UPDATE_SHA1 but we will soon add more types.

OK, so the idea is that 03/15 and 07/15 that let callers to say
transaction_update_REF or transaction_update_REFLOG are nicety
wrappers and the underlying machinery will use UPDATE_SHA1 (added
here) and UPDATE_LOG (added in 07/15), which I find is a nice
layering.

Going in a good direction.

> Change-Id: I9bf76454d1c789877a6aeb360cbb309971c9b5c4
> Signed-off-by: Ronnie Sahlberg <[email-masked]>
> Signed-off-by: Jonathan Nieder <[email-masked]>
> ---
>  refs.c | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/refs.c b/refs.c
> index a1bfaa2..8803b95 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3504,6 +3504,10 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
>  	return retval;
>  }
>  
> +enum transaction_update_type {
> +	UPDATE_SHA1 = 0
> +};
> +
>  /**
>   * Information needed for a single ref update.  Set new_sha1 to the
>   * new value or to zero to delete the ref.  To check the old value
> @@ -3511,6 +3515,7 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
>   * value or to zero to ensure the ref does not exist before update.
>   */
>  struct ref_update {
> +	enum transaction_update_type update_type;
>  	unsigned char new_sha1[20];
>  	unsigned char old_sha1[20];
>  	int flags; /* REF_NODEREF? */
> @@ -3571,12 +3576,14 @@ void transaction_free(struct transaction *transaction)
>  }
>  
>  static struct ref_update *add_update(struct transaction *transaction,
> -				     const char *refname)
> +				     const char *refname,
> +				     enum transaction_update_type update_type)
>  {
>  	size_t len = strlen(refname);
>  	struct ref_update *update = xcalloc(1, sizeof(*update) + len + 1);
>  
>  	strcpy((char *)update->refname, refname);
> +	update->update_type = update_type;
>  	ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
>  	transaction->updates[transaction->nr++] = update;
>  	return update;
> @@ -3606,7 +3613,7 @@ int transaction_update_ref(struct transaction *transaction,
>  		return -1;
>  	}
>  
> -	update = add_update(transaction, refname);
> +	update = add_update(transaction, refname, UPDATE_SHA1);
>  	hashcpy(update->new_sha1, new_sha1);
>  	update->flags = flags;
>  	update->have_old = have_old;
> @@ -3684,13 +3691,17 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
>  
>  	assert(err);
>  
> -	for (i = 1; i < n; i++)
> +	for (i = 1; i < n; i++) {
> +		if (updates[i - 1]->update_type != UPDATE_SHA1 ||
> +		    updates[i]->update_type != UPDATE_SHA1)
> +			continue;
>  		if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
>  			strbuf_addf(err,
>  				    "Multiple updates for ref '%s' not allowed.",
>  				    updates[i]->refname);
>  			return 1;
>  		}
> +	}
>  	return 0;
>  }
>  
> @@ -3722,13 +3733,17 @@ int transaction_commit(struct transaction *transaction,
>  		goto cleanup;
>  	}
>  
> -	/* Acquire all locks while verifying old values */
> +	/* Acquire all ref locks while verifying old values */
>  	for (i = 0; i < n; i++) {
>  		struct ref_update *update = updates[i];
>  		int flags = update->flags;
>  
> +		if (update->update_type != UPDATE_SHA1)
> +			continue;
> +
>  		if (is_null_sha1(update->new_sha1))
>  			flags |= REF_DELETING;
> +
>  		update->lock = lock_ref_sha1_basic(update->refname,
>  						   (update->have_old ?
>  						    update->old_sha1 :
> @@ -3750,6 +3765,8 @@ int transaction_commit(struct transaction *transaction,
>  	for (i = 0; i < n; i++) {
>  		struct ref_update *update = updates[i];
>  
> +		if (update->update_type != UPDATE_SHA1)
> +			continue;
>  		if (!is_null_sha1(update->new_sha1)) {
>  			if (write_ref_sha1(update->lock, update->new_sha1,
>  					   update->msg)) {
> @@ -3767,6 +3784,8 @@ int transaction_commit(struct transaction *transaction,
>  	for (i = 0; i < n; i++) {
>  		struct ref_update *update = updates[i];
>  
> +		if (update->update_type != UPDATE_SHA1)
> +			continue;
>  		if (update->lock) {
>  			if (delete_ref_loose(update->lock, update->type, err)) {
>  				ret = TRANSACTION_GENERIC_ERROR;