On Fri, Apr 25, 2014 at 6:31 PM, Michael Haggerty <mhagger@xxxxxxxxxxxx> wrote:
> On 04/25/2014 06:14 PM, Ronnie Sahlberg wrote:
>> Change ref_transaction_commit to take a pointer to a pointer for the
>> transaction. This allows us to clear the transaction pointer from within
>> ref_transaction_commit so that it becomes NULL in the caller.
>>
>> This makes transaction handling in the callers much nicer since instead of
>> having to write horrible code like :
>> t = ref_transaction_begin();
>> if ((!t ||
>> ref_transaction_update(t, refname, sha1, oldval, flags,
>> !!oldval)) ||
>> (ref_transaction_commit(t, action, &err) && !(t = NULL))) {
>> ref_transaction_rollback(t);
>>
>> we can now just do the much nicer
>> t = ref_transaction_begin();
>> if (!t ||
>> ref_transaction_update(t, refname, sha1, oldval, flags,
>> !!oldval) ||
>> ref_transaction_commit(&t, action, &err)) {
>> ref_transaction_rollback(t);
>
> I understand the motivation for this change, but passing
> pointer-to-pointer is unconventional in a case like this. Unfortunately
> I ran out of steam for the night before I could think about alternatives.
I see.
Yes passing a pointer to pointer is not ideal.
But I still want to be able to use the pattern
t = ref_transaction_begin();
if (!t ||
ref_transaction_update(t, ...) ||
ref_transaction_commit(t, ...)) {
ref_transaction_rollback(t);
Maybe the problem is that ref_transaction_commit() implicitely also
frees the transaction.
What about changing ref_transaction_commit() would NOT free the
transaction and thus a caller would
always have to explicitely free the transaction afterwards?
Something like this :
t = ref_transaction_begin();
if (!t ||
ref_transaction_update(t, ...) ||
ref_transaction_commit(&t, ...)) {
ref_transaction_rollback(t);
}
ref_transaction_free(t);
>
> Regarding patches 01-18, I agree with Jonathan's comments and made a few
> of my own. I definitely don't think that code like "!(t = NULL)" should
> stay in our code base as more than a transitional state. But I'd have
> to play with the alternatives before I can form an opinion on your
> suggestion in this patch.
>
> Thanks for working on this!
>
> Michael
>
>> Signed-off-by: Ronnie Sahlberg <sahlberg@xxxxxxxxxx>
>> ---
>> branch.c | 4 ++--
>> builtin/commit.c | 2 +-
>> builtin/replace.c | 2 +-
>> builtin/tag.c | 2 +-
>> builtin/update-ref.c | 2 +-
>> fast-import.c | 7 +++----
>> refs.c | 18 ++++++++++--------
>> refs.h | 3 ++-
>> sequencer.c | 7 +++----
>> 9 files changed, 24 insertions(+), 23 deletions(-)
>>
>> diff --git a/branch.c b/branch.c
>> index 23cde1e..5d68467 100644
>> --- a/branch.c
>> +++ b/branch.c
>> @@ -303,14 +303,14 @@ void create_branch(const char *head,
>> if (!transaction ||
>> ref_transaction_update(transaction, ref.buf, sha1,
>> NULL, 0, 0) ||
>> - ref_transaction_commit(transaction, msg, &err))
>> + ref_transaction_commit(&transaction, msg, &err))
>> die_errno(_("%s: failed to write ref: %s"),
>> ref.buf, err);
>> } else {
>> if (!transaction ||
>> ref_transaction_create(transaction, ref.buf, sha1,
>> 0) ||
>> - ref_transaction_commit(transaction, msg, &err))
>> + ref_transaction_commit(&transaction, msg, &err))
>> die_errno(_("%s: failed to write ref: %s"),
>> ref.buf, err);
>> }
>> diff --git a/builtin/commit.c b/builtin/commit.c
>> index 7e4c306..3142827 100644
>> --- a/builtin/commit.c
>> +++ b/builtin/commit.c
>> @@ -1682,7 +1682,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
>> current_head ?
>> current_head->object.sha1 : NULL,
>> 0, !!current_head) ||
>> - ref_transaction_commit(transaction, sb.buf, &err)) {
>> + ref_transaction_commit(&transaction, sb.buf, &err)) {
>> rollback_index_files();
>> die(_("HEAD: cannot update ref: %s"), err);
>> }
>> diff --git a/builtin/replace.c b/builtin/replace.c
>> index cf0f56d..51e9ddf 100644
>> --- a/builtin/replace.c
>> +++ b/builtin/replace.c
>> @@ -162,7 +162,7 @@ static int replace_object(const char *object_ref, const char *replace_ref,
>> if (!transaction ||
>> ref_transaction_update(transaction, ref, repl, prev,
>> 0, !is_null_sha1(prev)) ||
>> - ref_transaction_commit(transaction, NULL, &err))
>> + ref_transaction_commit(&transaction, NULL, &err))
>> die(_("%s: failed to replace ref: %s"), ref, err);
>>
>> return 0;
>> diff --git a/builtin/tag.c b/builtin/tag.c
>> index dd53fb4..60b57a1 100644
>> --- a/builtin/tag.c
>> +++ b/builtin/tag.c
>> @@ -646,7 +646,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
>> if (!transaction ||
>> ref_transaction_update(transaction, ref.buf, object, prev,
>> 0, !is_null_sha1(prev)) ||
>> - ref_transaction_commit(transaction, NULL, &err))
>> + ref_transaction_commit(&transaction, NULL, &err))
>> die(_("%s: cannot update the ref: %s"), ref.buf, err);
>> if (force && !is_null_sha1(prev) && hashcmp(prev, object))
>> printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
>> diff --git a/builtin/update-ref.c b/builtin/update-ref.c
>> index a600ab3..4a0901d 100644
>> --- a/builtin/update-ref.c
>> +++ b/builtin/update-ref.c
>> @@ -373,7 +373,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
>> if (end_null)
>> line_termination = '\0';
>> update_refs_stdin();
>> - if (ref_transaction_commit(transaction, msg, &err))
>> + if (ref_transaction_commit(&transaction, msg, &err))
>> die("update_ref failed: %s", err);
>> return 0;
>> }
>> diff --git a/fast-import.c b/fast-import.c
>> index a2b05fa..3ce2f47 100644
>> --- a/fast-import.c
>> +++ b/fast-import.c
>> @@ -1703,11 +1703,10 @@ static int update_branch(struct branch *b)
>> }
>> }
>> transaction = ref_transaction_begin();
>> - if ((!transaction ||
>> + if (!transaction ||
>> ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
>> - 0, 1)) ||
>> - (ref_transaction_commit(transaction, msg, &err) &&
>> - !(transaction = NULL))) {
>> + 0, 1) ||
>> + ref_transaction_commit(&transaction, msg, &err)) {
>> ref_transaction_rollback(transaction);
>> return error("Unable to update branch %s: %s", b->name, err);
>> }
>> diff --git a/refs.c b/refs.c
>> index ffa9c83..0b60250 100644
>> --- a/refs.c
>> +++ b/refs.c
>> @@ -3401,10 +3401,10 @@ int update_ref(const char *action, const char *refname,
>> char *err = NULL;
>>
>> t = ref_transaction_begin();
>> - if ((!t ||
>> + if (!t ||
>> ref_transaction_update(t, refname, sha1, oldval, flags,
>> - !!oldval)) ||
>> - (ref_transaction_commit(t, action, &err) && !(t = NULL))) {
>> + !!oldval) ||
>> + ref_transaction_commit(&t, action, &err)) {
>> const char *str = "update_ref failed for ref '%s': %s";
>>
>> ref_transaction_rollback(t);
>> @@ -3444,16 +3444,17 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
>> return 0;
>> }
>>
>> -int ref_transaction_commit(struct ref_transaction *transaction,
>> +int ref_transaction_commit(struct ref_transaction **transaction,
>> const char *msg, char **err)
>> {
>> int ret = 0, delnum = 0, i;
>> const char **delnames;
>> - int n = transaction->nr;
>> - struct ref_update **updates = transaction->updates;
>> + int n = (*transaction)->nr;
>> + struct ref_update **updates = (*transaction)->updates;
>>
>> if (!n) {
>> - ref_transaction_free(transaction);
>> + ref_transaction_free(*transaction);
>> + *transaction = NULL;
>> return 0;
>> }
>>
>> @@ -3527,7 +3528,8 @@ cleanup:
>> if (updates[i]->lock)
>> unlock_ref(updates[i]->lock);
>> free(delnames);
>> - ref_transaction_free(transaction);
>> + ref_transaction_free(*transaction);
>> + *transaction = NULL;
>> return ret;
>> }
>>
>> diff --git a/refs.h b/refs.h
>> index 8135131..85127f2 100644
>> --- a/refs.h
>> +++ b/refs.h
>> @@ -270,8 +270,9 @@ int ref_transaction_delete(struct ref_transaction *transaction,
>> * problem. The ref_transaction is freed by this function.
>> * If error is non-NULL it will return an error string that describes
>> * why a commit failed. This string must be free()ed by the caller.
>> + * *transaction is reset to NULL in this call.
>> */
>> -int ref_transaction_commit(struct ref_transaction *transaction,
>> +int ref_transaction_commit(struct ref_transaction **transaction,
>> const char *msg, char **err);
>>
>> /** Lock a ref and then write its file */
>> diff --git a/sequencer.c b/sequencer.c
>> index 7d59f58..3f6eced 100644
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -283,11 +283,10 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
>> strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
>>
>> transaction = ref_transaction_begin();
>> - if ((!transaction ||
>> + if (!transaction ||
>> ref_transaction_update(transaction, "HEAD", to, from,
>> - 0, !unborn)) ||
>> - (ref_transaction_commit(transaction, sb.buf, &err) &&
>> - !(transaction = NULL))) {
>> + 0, !unborn) ||
>> + ref_transaction_commit(&transaction, sb.buf, &err)) {
>> ref_transaction_rollback(transaction);
>> strbuf_release(&sb);
>> return error(_("HEAD: Could not fast-forward: %s\n"), err);
>>
>
>
> --
> Michael Haggerty
> mhagger@xxxxxxxxxxxx
> http://softwareswirl.blogspot.com/
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