From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Stefan Beller" <sbeller@google.com>,
"Ronnie Sahlberg" <ronniesahlberg@gmail.com>,
"Jonathan Nieder" <jrnieder@gmail.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Eric Sunshine" <sunshine@sunshineco.com>,
"Jeff King" <peff@peff.net>,
git@vger.kernel.org
Subject: Re: [PATCH v2 4/7] struct ref_lock: delete the force_write member
Date: Tue, 03 Mar 2015 11:50:58 +0100 [thread overview]
Message-ID: <54F59212.5040105@alum.mit.edu> (raw)
In-Reply-To: <xmqqk2yz9ir9.fsf@gitster.dls.corp.google.com>
On 03/02/2015 10:44 PM, Junio C Hamano wrote:
> Michael Haggerty <mhagger@alum.mit.edu> writes:
>
>> Instead, compute the value when it is needed.
>
>> @@ -2318,8 +2317,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
>> lock->ref_name = xstrdup(refname);
>> lock->orig_ref_name = xstrdup(orig_refname);
>> ref_file = git_path("%s", refname);
>> - if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
>> - lock->force_write = 1;
>>
>> retry:
>> switch (safe_create_leading_directories(ref_file)) {
>> @@ -3787,8 +3784,13 @@ int ref_transaction_commit(struct ref_transaction *transaction,
>> struct ref_update *update = updates[i];
>>
>> if (!is_null_sha1(update->new_sha1)) {
>> - if (!update->lock->force_write &&
>> - !hashcmp(update->lock->old_sha1, update->new_sha1)) {
>> + if (!((update->type & REF_ISSYMREF)
>> + && (update->flags & REF_NODEREF))
>> + && !hashcmp(update->lock->old_sha1, update->new_sha1)) {
>> + /*
>> + * The reference already has the desired
>> + * value, so we don't need to write it.
>> + */
>> unlock_ref(update->lock);
>> update->lock = NULL;
>> } else if (write_ref_sha1(update->lock, update->new_sha1,
>
> The code before and after the change are equivalent.
>
> It shouldn't be the case, but somehow I find the original slightly
> easier to understand. [...]
I had the same feeling; thanks for confirming it. How about I introduce
a temporary variable `overwriting_symref` as an aid to the reader? I
think this makes it pretty clear:
> if (!is_null_sha1(update->new_sha1)) {
> - if (!update->lock->force_write &&
> - !hashcmp(update->lock->old_sha1, update->new_sha1)) {
> + int overwriting_symref = ((update->type & REF_ISSYMREF) &&
> + (update->flags & REF_NODEREF));
> +
> + if (!overwriting_symref
> + && !hashcmp(update->lock->old_sha1, update->new_sha1)) {
> + /*
> + * The reference already has the desired
> + * value, so we don't need to write it.
> + */
> unlock_ref(update->lock);
> update->lock = NULL;
> } else if (write_ref_sha1(update->lock, update->new_sha1,
Michael
--
Michael Haggerty
mhagger@alum.mit.edu
next prev parent reply other threads:[~2015-03-03 10:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-02 9:29 [PATCH v2 0/7] Fix some problems with reflog expiration Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 1/7] write_ref_sha1(): remove check for lock == NULL Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 2/7] write_ref_sha1(): Move write elision test to callers Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 3/7] lock_ref_sha1_basic(): do not set force_write for missing references Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 4/7] struct ref_lock: delete the force_write member Michael Haggerty
2015-03-02 21:44 ` Junio C Hamano
2015-03-03 10:50 ` Michael Haggerty [this message]
2015-03-02 9:29 ` [PATCH v2 5/7] reflog: improve and update documentation Michael Haggerty
2015-03-02 22:04 ` Junio C Hamano
2015-03-03 11:35 ` Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 6/7] reflog_expire(): ignore --updateref for symbolic references Michael Haggerty
2015-03-02 9:29 ` [PATCH v2 7/7] reflog_expire(): never update a reference to null_sha1 Michael Haggerty
2015-03-02 22:09 ` [PATCH v2 0/7] Fix some problems with reflog expiration Junio C Hamano
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