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[PATCH 08/12] refs.c: pass a skip list to name_conflict_fn

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jul 16, 2014, 22:23 UTC
Message-ID
<1405549392-27306-9-git-send-email-sahlberg@google.com>
In-Reply-To
<1405549392-27306-1-git-send-email-sahlberg@google.com>

Allow passing a list of refs to skip checking to name_conflict_fn. There are some conditions where we want to allow a temporary conflict and skip checking those refs. For example if we have a transaction that 1, guarantees that m is a packed refs and there is no loose ref for m 2, the transaction will delete m from the packed ref 3, the transaction will create conflicting m/m

For this case we want to be able to lock and create m/m since we know that the conflict is only transient. I.e. the conflict will be automatically resolved by the transaction when it deletes m.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)
diff --git a/refs.c b/refs.c
index d3fedbb..a115478 100644
--- a/refs.c
+++ b/refs.c
@@ -801,15 +801,18 @@ static int names_conflict(const char *refname1, const char *refname2)
 
 struct name_conflict_cb {
 	const char *refname;
-	const char *oldrefname;
 	const char *conflicting_refname;
+	const char **skip;
+	int skipnum;
 };
 
 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
 {
 	struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
-	if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
-		return 0;
+	int i;
+	for (i = 0; i < data->skipnum; i++)
+		if (!strcmp(entry->name, data->skip[i]))
+			return 0;
 	if (names_conflict(data->refname, entry->name)) {
 		data->conflicting_refname = entry->name;
 		return 1;
@@ -822,15 +825,18 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * conflicting with the name of an existing reference in dir.  If
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
- * operation).
+ * operation). skip contains a list of refs we want to skip checking for
+ * conflicts with.
  */
-static int is_refname_available(const char *refname, const char *oldrefname,
-				struct ref_dir *dir)
+static int is_refname_available(const char *refname,
+				struct ref_dir *dir,
+				const char **skip, int skipnum)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
-	data.oldrefname = oldrefname;
 	data.conflicting_refname = NULL;
+	data.skip = skip;
+	data.skipnum = skipnum;
 
 	sort_ref_dir(dir);
 	if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
@@ -2077,7 +2083,8 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 /* This function should make sure errno is meaningful on error */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
-					    int flags, int *type_p)
+					    int flags, int *type_p,
+					    const char **skip, int skipnum)
 {
 	char *ref_file;
 	const char *orig_refname = refname;
@@ -2126,7 +2133,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 * name is a proper prefix of our refname.
 	 */
 	if (missing &&
-	     !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
+	     !is_refname_available(refname, get_packed_refs(&ref_cache),
+				   skip, skipnum)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2184,7 +2192,7 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
+	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p, NULL, 0);
 }
 
 /*
@@ -2654,10 +2662,12 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	if (!symref)
 		return error("refname %s not found", oldrefname);
 
-	if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, get_packed_refs(&ref_cache),
+				  &oldrefname, 1))
 		return 1;
 
-	if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, get_loose_refs(&ref_cache),
+				  &oldrefname, 1))
 		return 1;
 
 	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
@@ -2687,7 +2697,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for update", newrefname);
 		goto rollback;
@@ -2702,7 +2712,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for rollback", oldrefname);
 		goto rollbacklog;
@@ -3580,7 +3590,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						    update->old_sha1 :
 						    NULL),
 						   update->flags,
-						   &update->type);
+						   &update->type,
+						   delnames, delnum);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.0.1.527.gc6b782e
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 18 of 26 in “Use ref transactions part 3”
  1. 00/12 Use ref transactions part 3Ronnie Sahlberg, Jul 16, 2014
  2. 01/12 wrapper.c: simplify warn_if_unremovableRonnie Sahlberg, Jul 16, 2014
  3. Junio C HamanoJul 18, 2014
  4. 02/12 wrapper.c: add a new function unlink_or_msgRonnie Sahlberg, Jul 16, 2014
  5. Junio C HamanoJul 18, 2014
  6. Junio C HamanoJul 18, 2014
  7. Ronnie SahlbergJul 22, 2014
  8. Junio C HamanoJul 22, 2014
  9. 03/12 refs.c: add an err argument to delete_ref_looseRonnie Sahlberg, Jul 16, 2014
  10. 04/12 refs.c: pass the ref log message to _create/delete/update instead of _commitRonnie Sahlberg, Jul 16, 2014
  11. 05/12 refs.c: pass NULL as *flags to read_ref_fullRonnie Sahlberg, Jul 16, 2014
  12. Junio C HamanoJul 18, 2014
  13. Ronnie SahlbergJul 22, 2014
  14. Ronnie SahlbergJul 22, 2014
  15. 06/12 refs.c: move the check for valid refname to lock_ref_sha1_basicRonnie Sahlberg, Jul 16, 2014
  16. Junio C HamanoJul 18, 2014
  17. 07/12 refs.c: call lock_ref_sha1_basic directly from commitRonnie Sahlberg, Jul 16, 2014
  18. 08/12 refs.c: pass a skip list to name_conflict_fnRonnie Sahlberg, Jul 16, 2014
  19. 09/12 refs.c: propagate any errno==ENOTDIR from _commit back to the callersRonnie Sahlberg, Jul 16, 2014
  20. 10/12 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, Jul 16, 2014
  21. 11/12 refs.c: make write_ref_sha1 staticRonnie Sahlberg, Jul 16, 2014
  22. 12/12 refs.c: fix handling of badly named refsRonnie Sahlberg, Jul 16, 2014
  23. Junio C HamanoJul 22, 2014
  24. Ronnie SahlbergJul 22, 2014
  25. Ronnie SahlbergJul 22, 2014
  26. Junio C HamanoJul 22, 2014

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