+static int too_many_loose_objects(void)
+{
+ /*
+ * Quickly check if a "gc" is needed, by estimating how
+ * many loose objects there are. Because SHA-1 is evenly
+ * distributed, we can check only one and get a reasonable
+ * estimate.
+ */
+ char path[PATH_MAX];
+ const char *objdir = get_object_directory();
+ DIR *dir;
+ struct dirent *ent;
+ int auto_threshold;
+ int num_loose = 0;
+ int needed = 0;
+
+ if (gc_auto_threshold <= 0)
+ return 0;
+
+ if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
+ warning("insanely long object directory %.*s", 50, objdir);
+ return 0;
+ }
+ dir = opendir(path);
+ if (!dir)
+ return 0;
+
+ auto_threshold = (gc_auto_threshold + 255) / 256;
+ while ((ent = readdir(dir)) != NULL) {
+ if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
+ ent->d_name[38] != '\0')
+ continue;
+ if (++num_loose > auto_threshold) {
+ needed = 1;
+ break;
+ }
+ }
+ closedir(dir);
+ return needed;
+}
+
+static int too_many_packs(void)
+{
+ struct packed_git *p;
+ int cnt;
+
+ if (gc_auto_pack_limit <= 0)
+ return 0;
+
+ prepare_packed_git();
+ for (cnt = 0, p = packed_git; p; p = p->next) {
+ char path[PATH_MAX];
+ size_t len;
+ int keep;
+
+ if (!p->pack_local)
+ continue;
+ len = strlen(p->pack_name);
+ if (PATH_MAX <= len + 1)
+ continue; /* oops, give up */
+ memcpy(path, p->pack_name, len-5);
+ memcpy(path + len - 5, ".keep", 6);
+ keep = access(p->pack_name, F_OK) && (errno == ENOENT);
+ if (keep)
+ continue;
+ /*
+ * Perhaps check the size of the pack and count only
+ * very small ones here?
+ */
+ cnt++;
+ }
+ return gc_auto_pack_limit <= cnt;
+}
+
+static int need_to_gc(void)
+{
+ /*
+ * Setting gc.auto and gc.autopacklimit to 0 or negative can
+ * disable the automatic gc.
+ */
+ if (gc_auto_threshold <= 0 && gc_auto_pack_limit <= 0)
+ return 0;
+
+ /*
+ * If there are too many loose objects, but not too many
+ * packs, we run "repack -d -l". If there are too many packs,
+ * we run "repack -A -d -l". Otherwise we tell the caller
+ * there is no need.
+ */
+ if (too_many_packs())
+ append_option(argv_repack, "-A", MAX_ADD);
+ else if (!too_many_loose_objects())
+ return 0;
+ return 1;
+}
+