When trying to get a list of remote tags to see if we need to fetch
any we were doing a linear search for the matching tag ref for the
tag^{} commit entries. This proves to be incredibly slow for large
numbers of tags. Rewrite the function so that we build up a
string_list of refs to fetch and then process that instead.
As an extreme example, for a repository with 50000 tags (and just a
single commit on a single branch), a fetch that does nothing goes from
~1m50s to ~4.1s.
Signed-off-by: Julian Phillips <julian@xxxxxxxxxxxxxxxxx>
---
Ok, so here it is ...
Sometimes I forget just much we git users value our time and resources.
;)
builtin-fetch.c | 98 ++++++++++++++++++++++++++++++++++++------------------
1 files changed, 65 insertions(+), 33 deletions(-)
diff --git a/builtin-fetch.c b/builtin-fetch.c
index cb48c57..acb08e4 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -504,57 +504,89 @@ static int will_fetch(struct ref **head, const unsigned char *sha1)
return 0;
}
+struct tag_data {
+ struct ref **head;
+ struct ref ***tail;
+};
+
+static int add_to_tail(struct string_list_item *item, void *cb_data)
+{
+ struct tag_data *data = (struct tag_data *)cb_data;
+ struct ref *rm = NULL;
+
+ /* We have already decided to ignore this item */
+ if (!item->util)
+ return 0;
+
+ rm = alloc_ref(item->string);
+ rm->peer_ref = alloc_ref(item->string);
+ hashcpy(rm->old_sha1, item->util);
+
+ **data->tail = rm;
+ *data->tail = &rm->next;
+
+ return 0;
+}
+
static void find_non_local_tags(struct transport *transport,
struct ref **head,
struct ref ***tail)
{
struct string_list existing_refs = { NULL, 0, 0, 0 };
- struct string_list new_refs = { NULL, 0, 0, 1 };
- char *ref_name;
- int ref_name_len;
- const unsigned char *ref_sha1;
- const struct ref *tag_ref;
- struct ref *rm = NULL;
+ struct string_list remote_refs = { NULL, 0, 0, 0 };
+ struct tag_data data = {head, tail};
const struct ref *ref;
+ struct string_list_item *item = NULL;
for_each_ref(add_existing, &existing_refs);
for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
if (prefixcmp(ref->name, "refs/tags"))
continue;
- ref_name = xstrdup(ref->name);
- ref_name_len = strlen(ref_name);
- ref_sha1 = ref->old_sha1;
-
- if (!strcmp(ref_name + ref_name_len - 3, "^{}")) {
- ref_name[ref_name_len - 3] = 0;
- tag_ref = transport_get_remote_refs(transport);
- while (tag_ref) {
- if (!strcmp(tag_ref->name, ref_name)) {
- ref_sha1 = tag_ref->old_sha1;
- break;
- }
- tag_ref = tag_ref->next;
- }
+ /* the peeled ref always follows the matching base ref, so if we
+ * see a peeled ref that we don't want to fetch then we can mark
+ * the ref entry in the list as one to ignore by setting util to
+ * NULL. */
+ if (!strcmp(ref->name + strlen(ref->name) - 3, "^{}")) {
+ if (item && !has_sha1_file(ref->old_sha1) &&
+ !will_fetch(head, ref->old_sha1) &&
+ !has_sha1_file(item->util) &&
+ !will_fetch(head, item->util) )
+ item->util = NULL;
+ item = NULL;
+ continue;
}
- if (!string_list_has_string(&existing_refs, ref_name) &&
- !string_list_has_string(&new_refs, ref_name) &&
- (has_sha1_file(ref->old_sha1) ||
- will_fetch(head, ref->old_sha1))) {
- string_list_insert(ref_name, &new_refs);
+ /* If item is non-NULL here, then we previously saw a ref not
+ * followed by a peeled reference, so we need to check if it is
+ * a lightweight tag that we want to fetch */
+ if (item && !has_sha1_file(item->util) &&
+ !will_fetch(head, item->util) )
+ item->util = NULL;
- rm = alloc_ref(ref_name);
- rm->peer_ref = alloc_ref(ref_name);
- hashcpy(rm->old_sha1, ref_sha1);
+ item = NULL;
- **tail = rm;
- *tail = &rm->next;
- }
- free(ref_name);
+ /* skip duplicates and refs that we already have */
+ if (string_list_has_string(&remote_refs, ref->name) ||
+ string_list_has_string(&existing_refs, ref->name))
+ continue;
+
+ item = string_list_insert(ref->name, &remote_refs);
+ item->util = (void *)ref->old_sha1;
}
string_list_clear(&existing_refs, 0);
- string_list_clear(&new_refs, 0);
+
+ /* We may have a final lightweight tag that needs to be checked to see
+ * if it needs fetching. */
+ if (item && !has_sha1_file(item->util) &&
+ !will_fetch(head, item->util) )
+ item->util = NULL;
+
+ /* For all the tags in the remote_refs string list, call add_to_tail to
+ * add them to the list of refs to be fetched */
+ for_each_string_list(add_to_tail, &remote_refs, &data);
+
+ string_list_clear(&remote_refs, 0);
}
static void check_not_current_branch(struct ref *ref_map)
--
1.6.4.2
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