+static int unpack_failed(struct unpack_trees_options *o, const char *message)
+{
+ discard_index(&o->result);
+ if (!o->gently) {
+ if (message)
+ return error("%s", message);
+ return -1;
+ }
+ return -1;
+}
+
+/* NEEDSWORK: give this a better name and share with tree-walk.c */
+static int name_compare(const char *a, int a_len,
+ const char *b, int b_len)
+{
+ int len = (a_len < b_len) ? a_len : b_len;
+ int cmp = memcmp(a, b, len);
+ if (cmp)
+ return cmp;
+ return (a_len - b_len);
+}
+
+/*
+ * The tree traversal is looking at name p. If we have a matching entry,
+ * return it. If name p is a directory in the index, do not return
+ * anything, as we will want to match it when the traversal descends into
+ * the directory.
+ */
+static int find_cache_pos(struct traverse_info *info,
+ const struct name_entry *p)
+{
+ int pos;
+ struct unpack_trees_options *o = info->data;
+ struct index_state *index = o->src_index;
+ int pfxlen = info->pathlen;
+ int p_len = tree_entry_len(p->path, p->sha1);
+
+ for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
+ struct cache_entry *ce = index->cache[pos];
+ const char *ce_name, *ce_slash;
+ int cmp, ce_len;
+
+ if (ce->ce_flags & CE_UNPACKED) {
+ /*
+ * cache_bottom entry is already unpacked, so
+ * we can never match it; don't check it
+ * again.
+ */
+ if (pos == o->cache_bottom)
+ ++o->cache_bottom;
+ continue;
+ }
+ if (!ce_in_traverse_path(ce, info))
+ continue;
+ ce_name = ce->name + pfxlen;
+ ce_slash = strchr(ce_name, '/');
+ if (ce_slash)
+ ce_len = ce_slash - ce_name;
+ else
+ ce_len = ce_namelen(ce) - pfxlen;
+ cmp = name_compare(p->path, p_len, ce_name, ce_len);
+ /*
+ * Exact match; if we have a directory we need to
+ * delay returning it.
+ */
+ if (!cmp)
+ return ce_slash ? -2 - pos : pos;
+ if (0 < cmp)
+ continue; /* keep looking */
+ /*
+ * ce_name sorts after p->path; could it be that we
+ * have files under p->path directory in the index?
+ * E.g. ce_name == "t-i", and p->path == "t"; we may
+ * have "t/a" in the index.
+ */
+ if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
+ ce_name[p_len] < '/')
+ continue; /* keep looking */
+ break;
+ }
+ return -1;
+}
+
+static struct cache_entry *find_cache_entry(struct traverse_info *info,
+ const struct name_entry *p)
+{
+ int pos = find_cache_pos(info, p);
+ struct unpack_trees_options *o = info->data;
+
+ if (0 <= pos)
+ return o->src_index->cache[pos];
+ else
+ return NULL;
+}
+
+static void debug_path(struct traverse_info *info)
+{
+ if (info->prev) {
+ debug_path(info->prev);
+ if (*info->prev->name.path)
+ putchar('/');
+ }
+ printf("%s", info->name.path);
+}
+
+static void debug_name_entry(int i, struct name_entry *n)
+{
+ printf("ent#%d %06o %s\n", i,
+ n->path ? n->mode : 0,
+ n->path ? n->path : "(missing)");
+}
+
+static void debug_unpack_callback(int n,
+ unsigned long mask,
+ unsigned long dirmask,
+ struct name_entry *names,
+ struct traverse_info *info)
+{
+ int i;
+ printf("* unpack mask %lu, dirmask %lu, cnt %d ",
+ mask, dirmask, n);
+ debug_path(info);
+ putchar('\n');
+ for (i = 0; i < n; i++)
+ debug_name_entry(i, names + i);
+}
+