From: Michael Haggerty <mhagger@xxxxxxxxxxxx>
Instead of iterating through all of the references, inquire more
pointedly about the references that could conflict with the new name.
This requires checking for a few individual references, plus iterating
through a small subtree of the rest of the references (and usually the
subtree iteration ends without having to recurse). A big benefit is
that populating the whole loose reference cache (which can be very
expensive) can usually be avoided.
Signed-off-by: Michael Haggerty <mhagger@xxxxxxxxxxxx>
---
refs.c | 40 +++++++++++++++++++++++++++++++++-------
1 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/refs.c b/refs.c
index 88ef9dd..6a7f9c3 100644
--- a/refs.c
+++ b/refs.c
@@ -658,7 +658,7 @@ static int name_conflict_fn(const char *existingrefname, const unsigned char *sh
int flags, void *cb_data)
{
struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
- if (data->oldrefname && !strcmp(data->oldrefname, existingrefname))
+ if (!strcmp(data->oldrefname, existingrefname))
return 0;
if (names_conflict(data->refname, existingrefname)) {
data->conflicting_refname = existingrefname;
@@ -669,22 +669,48 @@ static int name_conflict_fn(const char *existingrefname, const unsigned char *sh
/*
* Return true iff a reference named refname could be created without
- * conflicting with the name of an existing reference. If oldrefname
- * is non-NULL, ignore potential conflicts with oldrefname (e.g.,
- * because oldrefname is scheduled for deletion in the same
+ * conflicting with the name of an existing reference in direntry. If
+ * oldrefname is non-NULL, ignore potential conflicts with oldrefname
+ * (e.g., because oldrefname is scheduled for deletion in the same
* operation).
*/
static int is_refname_available(const char *refname, const char *oldrefname,
struct ref_entry *direntry)
{
+ int prefixlen = strlen(refname);
+ char *prefix;
+ char *slash;
struct name_conflict_cb data;
+
+ assert(direntry->flag & REF_DIR);
+
+ if (!oldrefname)
+ oldrefname = ""; /* invalid; cannot match any existing refname */
+
+ /* Check whether a prefix of refname is an existing reference: */
+ prefix = xmalloc(prefixlen + 2);
+ memcpy(prefix, refname, prefixlen + 1);
+ for (slash = strchr(prefix, '/'); slash; slash = strchr(slash + 1, '/')) {
+ *slash = '\0';
+ if (strcmp(oldrefname, prefix)) {
+ struct ref_entry *entry = find_ref(direntry, prefix);
+ if (entry) {
+ error("'%s' exists; cannot create '%s'", prefix, refname);
+ free(prefix);
+ return 0;
+ }
+ }
+ *slash = '/';
+ }
+
+ /* Check whether refname is a proper prefix of an existing reference: */
+ prefix[prefixlen++] = '/';
+ prefix[prefixlen] = '\0';
data.refname = refname;
data.oldrefname = oldrefname;
data.conflicting_refname = NULL;
- assert(direntry->flag & REF_DIR);
-
- if (do_for_each_ref_in_dir(direntry, 0, "", name_conflict_fn,
+ if (do_for_each_ref_in_dir(direntry, 0, prefix, name_conflict_fn,
0, DO_FOR_EACH_INCLUDE_BROKEN,
&data)) {
error("'%s' exists; cannot create '%s'",
--
1.7.7
--
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