+static int compare_link(struct cache_entry *ce, unsigned long expected_size)
+{
+ int match = -1;
+ char *target;
+ void *buffer;
+ unsigned long size;
+ char type[10];
+ int len;
+
+ target = xmalloc(expected_size);
+ len = readlink(ce->name, target, expected_size);
+ if (len != expected_size) {
+ free(target);
+ return -1;
+ }
+ buffer = read_sha1_file(ce->sha1, type, &size);
+ if (!buffer) {
+ free(target);
+ return -1;
+ }
+ if (size == expected_size)
+ match = memcmp(buffer, target, size);
+ free(buffer);
+ free(target);
+ return match;
+}
+
+/*
+ * "refresh" does not calculate a new sha1 file or bring the
+ * cache up-to-date for mode/content changes. But what it
+ * _does_ do is to "re-match" the stat information of a file
+ * with the cache, so that you can refresh the cache for a
+ * file that hasn't been changed but where the stat entry is
+ * out of date.
+ *
+ * For example, you'd want to do this after doing a "git-read-tree",
+ * to link up the stat cache details with the proper files.
+ */
+static struct cache_entry *refresh_entry(struct cache_entry *ce)
+{
+ struct stat st;
+ struct cache_entry *updated;
+ int changed, size;
+
+ if (lstat(ce->name, &st) < 0)
+ return ERR_PTR(-errno);
+
+ changed = ce_match_stat(ce, &st);
+ if (!changed)
+ return ce;
+
+ /*
+ * If the mode or type has changed, there's no point in trying
+ * to refresh the entry - it's not going to match
+ */
+ if (changed & (MODE_CHANGED | TYPE_CHANGED))
+ return ERR_PTR(-EINVAL);
+
+ switch (st.st_mode & S_IFMT) {
+ case S_IFREG:
+ if (compare_data(ce, &st))
+ return ERR_PTR(-EINVAL);
+ break;
+ case S_IFLNK:
+ if (compare_link(ce, st.st_size))
+ return ERR_PTR(-EINVAL);
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+
+ size = ce_size(ce);
+ updated = xmalloc(size);
+ memcpy(updated, ce, size);
+ fill_stat_cache_info(updated, &st);
+ return updated;
+}
+
+static int refresh_cache(void)
+{
+ int i;
+ int has_errors = 0;
+
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce, *new;
+ ce = active_cache[i];
+ if (ce_stage(ce)) {
+ printf("%s: needs merge\n", ce->name);
+ has_errors = 1;
+ while ((i < active_nr) &&
+ ! strcmp(active_cache[i]->name, ce->name))
+ i++;
+ i--;
+ continue;
+ }
+
+ new = refresh_entry(ce);
+ if (IS_ERR(new)) {
+ if (not_new && PTR_ERR(new) == -ENOENT)
+ continue;
+ if (quiet)
+ continue;
+ printf("%s: needs update\n", ce->name);
+ has_errors = 1;
+ continue;
+ }
+ active_cache_changed = 1;
+ /* You can NOT just free active_cache[i] here, since it
+ * might not be necessarily malloc()ed but can also come
+ * from mmap(). */
+ active_cache[i] = new;
+ }
+ return has_errors;