+static void get_local_heads(void)
+{
+ local_tail = &local_refs;
+ for_each_ref(one_local_ref);
+}
+
+static int send_pack(int in, int out, int nr_refspec, char **refspec)
+{
+ struct ref *ref;
+ int new_refs;
+ int ret = 0;
+
+ /* No funny business with the matcher */
+ remote_tail = get_remote_heads(in, &remote_refs, 0, NULL, 1);
+ get_local_heads();
+
+ /* match them up */
+ if (!remote_tail)
+ remote_tail = &remote_refs;
+ if (match_refs(local_refs, remote_refs, &remote_tail,
+ nr_refspec, refspec, send_all))
+ return -1;
+
+ if (!remote_refs) {
+ fprintf(stderr, "No refs in common and none specified; doing nothing.\n");
+ return 0;
+ }
+
+ /*
+ * Finally, tell the other end!
+ */
+ new_refs = 0;
+ for (ref = remote_refs; ref; ref = ref->next) {
+ char old_hex[60], *new_hex;
+ if (!ref->peer_ref)
+ continue;
+ if (!memcmp(ref->old_sha1, ref->peer_ref->new_sha1, 20)) {
+ if (verbose)
+ fprintf(stderr, "'%s': up-to-date\n", ref->name);
+ continue;
+ }
+
+ /* This part determines what can overwrite what.
+ * The rules are:
+ *
+ * (0) you can always use --force or +A:B notation to
+ * selectively force individual ref pairs.
+ *
+ * (1) if the old thing does not exist, it is OK.
+ *
+ * (2) if you do not have the old thing, you are not allowed
+ * to overwrite it; you would not know what you are losing
+ * otherwise.
+ *
+ * (3) if both new and old are commit-ish, and new is a
+ * descendant of old, it is OK.
+ */
+
+ if (!force_update &&
+ !is_zero_sha1(ref->old_sha1) &&
+ !ref->force) {
+ if (!has_sha1_file(ref->old_sha1)) {
+ error("remote '%s' object %s does not "
+ "exist on local",
+ ref->name, sha1_to_hex(ref->old_sha1));
+ ret = -2;
+ continue;
+ }
+
+ /* We assume that local is fsck-clean. Otherwise
+ * you _could_ have an old tag which points at
+ * something you do not have, which may or may not
+ * be a commit.
+ */
+ if (!ref_newer(ref->peer_ref->new_sha1,
+ ref->old_sha1)) {
+ error("remote ref '%s' is not a strict "
+ "subset of local ref '%s'.", ref->name,
+ ref->peer_ref->name);
+ ret = -2;
+ continue;
+ }
+ }
+ memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
+ if (is_zero_sha1(ref->new_sha1)) {
+ error("cannot happen anymore");
+ ret = -3;
+ continue;
+ }
+ new_refs++;
+ strcpy(old_hex, sha1_to_hex(ref->old_sha1));
+ new_hex = sha1_to_hex(ref->new_sha1);
+ packet_write(out, "%s %s %s", old_hex, new_hex, ref->name);
+ fprintf(stderr, "updating '%s'", ref->name);
+ if (strcmp(ref->name, ref->peer_ref->name))
+ fprintf(stderr, " using '%s'", ref->peer_ref->name);
+ fprintf(stderr, "\n from %s\n to %s\n", old_hex, new_hex);
+ }
+
+ packet_flush(out);
+ if (new_refs)
+ pack_objects(out, remote_refs);
+ else if (ret == 0)
+ fprintf(stderr, "Everything up-to-date\n");
+ close(out);
+ return ret;
+}
+
+